GroupDIY

Project Specific Discussions => Dynamic Processors => Topic started by: rainton on June 11, 2017, 06:46:58 PM

Title: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 11, 2017, 06:46:58 PM
UPDATE:
 
GROUP BUY IS CLOSED NOW

I pasted the info here in this first post, so you don't have to search for it


Here's what will be included in this authentic re-creation of a UA 176 chassis kit:

- main chassis, bent, welded, smoothed and powder coated grey

- first front panel  - also folded edges, welded smoothed and powder coated grey

- custom made hinge manufactured following original specs, powder coated and welded to the first front panel

- second front panel to go on top of the first one: this will be the black panel with white silk-screening

- custom made stainless steel thumb screws designed for original looks

- mounting bracket for input/output jacks on the front

- mounting bracket for optional metering switch inside

- handmade, authentic re-creations of the 2 original pcbs: these will be handmade to original specs with fork turrets just like the original
- handmade PSU turret board

- handmade RATIO turret board

- handmade METERING turret board

- first BOM

- first wiring layout for the entire unit



All of this I will offer as a kit in this LIMITED run for EUR 399.00 + shipping & PP



Actually this is the price if we can reach 50 chassis, but I convinced all suppliers - if we don't hit that margin, but only 40 chassis instead, we'll still get that price :)

And I'm positive that we can reach 40pcs.
And in case we end up with only 38pcs, I will have to buy one for Mom and one for Granny - I'm sure they'd love them  ;D

SO:
I'll get in touch with all of those who posted here and want to have one or two or...

In case you're new to this thread and interested send me an email to [email protected]
If you posted here and don't get an email within the next couple of days, do the same :)


As in the past - I'll collect the funds for the group buy - and after I received your payment you'll be added to the list here.

Lead time for having these gems manufactured will be around 6-8 weeks.

AGAIN: I'll keep this group buy open until March 15th - after that deadline I'll process the orders and have the kits manufactured...

Currently it looks like as if most people want to use API 361 meters (which is the one I used for my prototype) - and forum member moltenwok posted that a friend of his has more than 30 of these available. But they also turn up on eBay fairly often and are actually cheaper than a new SIFAM meter.
But I optionally I can also do a version designed for the SIFAM R32AF meter which is still readily available...

For further discussion and details go to page 8 (and onwards)


(http://www.mediafire.com/convkey/f6e2/ejnui9yz309mqqy5g.jpg)

(http://www.mediafire.com/convkey/0313/f7na9a45acw99505g.jpg)

(http://www.mediafire.com/convkey/a9aa/5ac2ap69ma5cc4k5g.jpg)


GROUP BUY LIST:


kosi   2 [paid]
Shaker-her   1 [paid]
JMarcovis  2 [paid]
TubeMonkey  1 [paid]
damiangiannis  1 [paid]
Phrazemaster  2 [paid]
mro  1 [paid]
moltenwok  4 [paid]
59flame  1  [paid]
ilfungo  1 [paid]
Salomonander  2 [paid]
Craig  1 [paid]
mohausler  1 [paid]
LeRoux  1  [paid]
Adadan  1  [paid]
BramK  1 [paid]
Jeanpierreisyou  1 [paid]
core 13  3  [paid]
Donnie Darko 2 [paid]
Bubbie  2 [paid]
Quayhog  2  [paid]
dbonin 1
wmarden 1 [paid]
Faby  1  [paid]
nickhepfer  1 [paid]
Taoma 1 [paid]
Jefepeters 1 [paid]
Jmcc 1 [paid]
zumwalt 2 [paid]
diylan  [paid]
xarolium 2 [paid]
artur 1 [paid]
potato cakes 2 [paid]
spaceyjb 1 [paid]
Marc O 1
Alex64bit [paid]







+++++++++++++++ original post ++++++++++++++++

Hey guys,

those of you who are familiar with my chassis work know, I always work with great love for detail when approaching a project.

For those who don't know my chassis: https://groupdiy.com/index.php?topic=63423.0


Here in Germany we have a saying that says "Ganz oder gar nicht" which is pretty much the same as "Go big or go home!"
(Maybe that's the basic core of what people commonly call "German engineering"  hehe ;D)

Anyway, I actually wanted to start a UA 176 vari-mu project more than 5 years ago, but as I always found it more challenging to  find out about how original pieces of gear work, how they were built and faithfully recreating them rather than buying a pcb (if available)  and a generic enclosure to make some kind of a clone, the UA 176 was not easiest project to tackle.

But after gathering quite some experience with other chassis projects over the past years, and people keeping on bugging me to do the 175b or 176 I thought ok let's do it - properly! :)

That means faithfully recreating the original chassis work, the original pcbs, the original turret boards etc.

First step: designing & manufacturing the prototype chassis

(https://www.mediafire.com/convkey/4a7b/vgo797gy6l8y47f5g.jpg)


I'll post more pics and updates in the next couple of days and then some more as the project evolves :)

If you want to share your thoughts, you're welcome to do so and if you just want to know how it all turns out,  subscribe to this thread.

If all goes well I plan to do a small run of UA176 kits that include the chassis, pcbs, turret boards and a build manual for recreating on of these gems for yourself ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 12, 2017, 06:45:30 PM
Both -  the 175b and the 176 are based on pcbs as well as some P2P. Since I don't own an original one I have to get all information from pics I found on the web - here's one that shows the inside of a 175b:

(https://www.mediafire.com/convkey/49e0/bwkkrllti1fn1af5g.jpg)

One of the challenges is, that the pcbs and the footprint of the components on it have to match the cutouts on the back of the chassis 100%. And since the back panel is pretty much jam packed there's not much room for mistakes ;) :

(https://www.mediafire.com/convkey/fb52/j470l19y1iihd745g.jpg)

It's funny how some tube-sockets are mounted straight to the back panel while others are soldered to the pcbs and just stick out the back of the unit through circular cutouts - one of them with a cutout large enough to accommodate a tube shield and another one with a cutout just large enough for the tube itself  ???
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on June 12, 2017, 07:59:01 PM
hell yeah - finally!!!! congratulations mate. love your work and dedication! i have all my xformers and meters ready. cant wait :) put me down for a pair please.

oh... and while its not original, id vote for a top enclosure. just to make sure no one fries himself...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 13, 2017, 04:53:22 PM
yes finally ;)

Well the prototype will be as close to the original as possible - also meaning there'll be no lid on this first one.
But if a small run happens I would leave things like that up for discussion.
If the majority wants a lid, then there shall be lid  ;D

There's many more details to discuss later - such as choice of transformers, VU meter etc.

For this first one I'll go with vintage UTC 0-1 on input, UTC-A19 as interstage and - since the original output transformer is unobtainable - Sowter 1285e as output transformer.

Another topic is the attenuators. The vintage units used some Daven (or sometimes Langevin) 600 Ohm T-pad stepped attenuators with 2db steps. They are usually very expensive, but I was lucky to find some for pretty cheap. I was really surprised how huge they are!!  :o

(https://www.mediafire.com/convkey/6e2b/yr18hllbppxg1cc5g.jpg)

From left to right: Alpha stereo pot, vintage Allen & Bradley, NOS Mallory 600 Ohm T-Pad, vintage Daven 600/600 stepped attenuator

The Davens have a great feel to them - they feel more like a very smooth pot with very fine detents than a switch :)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 14, 2017, 11:41:53 AM
Ok let's get serious  8)

Here's the basic prototype chassis - all powder coated with the closest match I could find to the original color:

(https://www.mediafire.com/convkey/7b00/d5g685oeo5vaaz65g.jpg)

Even though it has no lid it is the most complex chassis I've done so far - also due to the top edges of the back chassis as well as the the top and side edges of the front panel are folded inside, the seams in the corners are welded and then smoothed before powder coating - you can see it very well on this pic:

(https://www.mediafire.com/convkey/0dbc/wm2zjmurkwk9ns25g.jpg)

The hinge is welded to the front panel and then powder coated as well:

(https://www.mediafire.com/convkey/e738/qdjt32so0x3g06l5g.jpg)

In these pics you can see even better what I meant by the folded edges. The front panel is actually not just a flat panel - also, you can see that very well on the first pic, the bottom of the front panel has a cutout to exactly fit the hinge  :)

(https://www.mediafire.com/convkey/bb31/65u93lfn3v4w1wz5g.jpg)

Both the 176 as well as the 175b actually feature 2 front panels - the first one is made of solid steel all powder coated with the hinge welded to it, and the second is sitting on top of the first one - a very thin black panel with white silk screening...you'll see that very soon ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 14, 2017, 11:54:14 AM
Since I couldn't find the original panel screws anymore, but still wanted the original looks, I custom designed a screw, visually modeled after the vintage ones and had them manufactured  ;D

(https://www.mediafire.com/convkey/cec1/gk803slbkx6b3uu5g.jpg)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 14, 2017, 07:59:49 PM
One detail  where I deviated from the original:

to fasten the front panel to the rest of the chassis the original units had only some kind of bracket mounted inside the chassis with a clip nut put over it. ???

(https://www.mediafire.com/convkey/2181/roq296j719b73w25g.jpg)

Not a very sleek solution - especially since there's no well-defined stop-piece for the front panel when closing it:

(https://www.mediafire.com/convkey/d140/ksxduoyw0d6ehc45g.jpg)

As you can see in the pic, the front panel is closing against the inner-edge of the rack ear which can make it difficult to feed the screw into the nut (which would explain the screw sitting in there kind of crooked on some pics I found on the web)

Anyway, I came up with the following solution:

(https://www.mediafire.com/convkey/3e24/e494k9u9rq5il375g.jpg)

instead of mounting a bracket inside the chassis with a clip nut on top of it, I designed the bracket as a part of the chassis with a nut punched into it. The depth of the nut also makes it serve as a standoff as well as a stop-piece for the front-panel to close against.

Works great!  ;D
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 15, 2017, 07:25:53 PM
Also visible in the pics of the original unit is the bracket that holds the 1/4" jacks on the left side.
Obviously these connectors allowed for patching the comp into any other piece of gear directly, while the unit also has a barrier strip type terminal on the back for wiring it up a patchbay...

The jacks are mono switching 1/4" inch - so as soon as something plugged in there, the input and/or output on the back is disconnected.
Feeding a piece of gear with a balanced signal through 2 mono jacks seems kind of weird though ;D

BTW: If any of you have access to a real 175b or 176 it would be great to hear your thoughts :)

Here's how this bracket looks in my prototype unloaded:

(https://www.mediafire.com/convkey/170e/j4yjbcyb4xn4ejy5g.jpg)

and loaded with 4x 1/4" jacks:

front:
(https://www.mediafire.com/convkey/cf46/nt2eapcc31nyvxl5g.jpg)

back:

(https://www.mediafire.com/convkey/8475/46le8bmmgctn7fa5g.jpg)


Now the original has a piece of Bakelite mounted in front, I guess that was maybe to support the front panel when closing the unit (?)
I'll probably add it later on, but since the above mentioned stop pieces work very well, it's actually not essential here ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 18, 2017, 05:26:25 PM
I'm proud to announce that with the incredible help of pcb design artist and fellow forum member LIVINGNOTE and my newly aquired turret staking skills, it was possible to recreate the original pcbs of the 176 / 175b to an extend where they're pretty much indistinguishable from the original ones.

Now, after we did a lot of tweaking and comparing, Livingnote finally made the prototypes and I think it's truly a work of art!

Here's some pics of the almost finished pcbs (still some fork turrets missing):

(https://www.mediafire.com/convkey/275b/dje43zyce5aldc75g.jpg)

(https://www.mediafire.com/convkey/b68d/keknm4d74sdv1mb5g.jpg)


and here are the final pcb prototypes with all turrets in place and the prototypes of all 3 additional custom turret-boards (PSU, ratio & metering):

(https://www.mediafire.com/convkey/8f6a/bq6bszd5dt99f875g.jpg)

Up next is stuffing the pcbs & turret boards - and of course mounting all components to the chassis  :)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on June 20, 2017, 11:25:07 AM
amazing work mate!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: gridcurrent on June 20, 2017, 08:35:13 PM
it was possible to recreate the original pcbs of the 176 / 175b to an extend where they're pretty much indistinguishable from the original ones.
did you fix the traces so that C1 and C2 do not have to criss-cross each other?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 21, 2017, 07:33:27 AM
Thanks salomonander :)

Yes it's quite a trip - but we're getting there!


did you fix the traces so that C1 and C2 do not have to criss-cross each other?

Nope - we didn't "fix" that.
If we had done so, we'd have needed to retrace the entire board, and we decided to stay original.
Not a big deal I think - both caps placed next to each other and on one end their (shrink-tubed) wires cross. :)

BTW the first board is stuffed and ready to go into the chassis, but I have to wire up that part of the chassis' back panel first, otherwise the access to the relevant terminals of the transformers will be blocked by the pcb...

(https://www.mediafire.com/convkey/d83d/y82w260opwou6ya5g.jpg)

(https://www.mediafire.com/convkey/129c/nx9x9t2n5c06rp25g.jpg)

I'm now stuffing the 2nd pcb and mounting all components to the back and front of the chassis - stay tuned...

Oh and you're more than welcome to leave a comment or share some thoughts - I just realized this thread has more than 600 views already, but only 2 people involved so far ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: andyfromdenver on June 21, 2017, 12:43:29 PM
Oh and you're more than welcome to leave a comment or share some thoughts - I just realized this thread has more than 600 views already, but only 2 people involved so far ;)

haha! How about, looks f'n amazing and great work so far, to you and Livingnote :-)  You've certainly not "gone home" anytime recently (Cause you have spent so much time "Going Big"  ;D)

Andy
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: moltenwok on June 21, 2017, 03:57:20 PM
Looking amazing mate-2 quick questions-presumably you've allowed for the sowter output transformer for the 176 and do you have a ballpark figure in mind do I can start saving caus I'd hate to miss this!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on June 21, 2017, 04:53:23 PM
im not rainton, but yes its made for the sowter output. the original is unobtainable. i was in contact with magnetica and cinemag. cinemag took over reichenbach - who made the original. but sadly the blueprints were lost. david looked all over but no chance. so sowter it is. they are good xformers...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: moltenwok on June 21, 2017, 05:07:32 PM
Any idea who built the transformer for the retro 176?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on June 22, 2017, 12:06:53 PM
Any idea who built the transformer for the retro 176?

i dont. i thought they were made by cinemag - but david said its not the case.... so i have no clue. cheers
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 23, 2017, 07:17:03 PM
Thanks guys!

great to finally see some movement here :)

Looking amazing mate-2 quick questions-presumably you've allowed for the sowter output transformer for the 176 and do you have a ballpark figure in mind do I can start saving caus I'd hate to miss this!

I'm sorry but at this moment there are still so many things to consider and I'm also still waiting on quotes by suppliers for turret boards etc. that I can't put out any numbers at this time. As soon as I figured it out, I'll let you all know :)


regarding the output transformer & the retro 176.
As far as I've heard from a fellow forum member who owns a retro 176 - that thing sounds absolutely great but in his opinion not vintage at all. Rather clean sounding compared to the original 175b/176.
Unit7 - if you read this it would be great to have you chime in  ;)

Apart from that I can say the OT substitute from Sowter is massive! Bigger than the original - all mumetal covered.
But in terms of specs Sowter said they are very close to the original ones, but with better shielding.
Even the color codes of the wires are pretty much the same as specified in the 176 schematics.

Today I finished the 2nd pcb as well as mounting all components to the chassis. Here's the 2nd pcb - it's not as crowded as the first one, but it has a can cap soldered straight to it:

(https://www.mediafire.com/convkey/cd9a/i5u7w39aw8o353a5g.jpg)

I'm not quite sure how to solve this in the kit version later. The actual can cap used in this spot was a Mallory PFP:

(https://www.mediafire.com/convkey/efd7/c1l7ydk2awydga85g.jpg)

They're pretty much unobtainable nowadays - especially the value needed here. The FP ones with 2x10uf 450V are not unobtainable, but also very hard to get - and I wouldn't recommend using vintage can caps.
In the prototype I used a FP style cap, so the circuit board was prepared with slots to fit the wider terminals .
But frankly it was kind of a drag to mount, and solder it, and we'll have to figure out a way how to do it later in the kits.
I'm thinking about at least adding the footprint of 2 regular modern electrolytics so you guys can choose (?)

Anyway, here's a pic of all components (except for pcbs & tubes) mounted to the back of the chassis:

(https://www.mediafire.com/convkey/4205/rayazmxgz8rmuak5g.jpg)

and another one:

(https://www.mediafire.com/convkey/8721/cc15m1kj3mbodb15g.jpg)

I  already started to wire up the PSU section and the other transformers, so the pcbs can finally go into the chassis very soon...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 27, 2017, 05:25:53 PM
Just finished the PSU section  :)

The pics I found show a small difference here between the UA175b and the UA176.
That's mostly due to R39 being located on the PSU turret board of the 175b, but in the 176 it's located on the ratio turret board mounted to the rotary switch on the front panel, where it's one of the 4 different resistors for different ratio settings (while the 175b is limited to 12:1 ratio only).
I followed the 176 component layout, since that's what I'm building:


(https://www.mediafire.com/convkey/c28c/skd47n6870yrcdt5g.jpg)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: gyraf on June 28, 2017, 05:07:25 AM
...beautiful work...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on June 28, 2017, 06:55:43 AM
We can ask the guys from authenticaps, wether they  roll us some special ones ! I will send a mail
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on June 28, 2017, 07:45:39 AM
sweet. what choke did you use for the build?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 28, 2017, 09:44:21 AM
...beautiful work...

Thanks gyraf - I really appreciate it :)


We can ask the guys from authenticaos, wether they  roll us some special ones ! I will send a mail

Great idea kosi!

sweet. what choke did you use for the build?

I used a Triad C-7X, but you could also use a Hammond 158M I guess.

Finally the pcbs are mounted and I already started to wire them up - now it gets really exciting!
What is coming together in front me now physically resembles what I studied on pics only the last couple of months  :)

(https://www.mediafire.com/convkey/11a6/f1wvw620zhtf72x5g.jpg)

And from the back it also looks exactly as it should - all tube sockets are in the right positions - only the Sowter transformer
makes the difference...

(https://www.mediafire.com/convkey/810f/mrcg5u97zwi8gw95g.jpg)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: KrIVIUM2323 on June 28, 2017, 10:13:38 AM
Hi, reeally nice work.

What reference of switch you used for ratio selection? Where is it availlable?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on June 28, 2017, 12:57:56 PM
Hi, reeally nice work.

What reference of switch you used for ratio selection? Where is it availlable?

Well, the schematics ask for a 3pole 4 pos switch - which are easy to find.
What is a little harder to find is such a switch with all poles and positions located on only one wafer, as used
in the vintage units.
I found one - it's a Centralab PA-2006, but there's enough space behind the switch to use a 2 wafer switch as well.
So no need to worry - plenty of choices. The Centralabs appear on eBay regularly, and they are also available at tedss.com, but they are not cheap there...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jimfowler on July 03, 2017, 09:27:51 PM
Nothing to add other than to say wow...really incredible.  176 clone is on my short.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: weiss on July 04, 2017, 12:49:28 PM
Looking great man!!! :)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: mjrippe on July 11, 2017, 06:12:54 PM
Also visible in the pics of the original unit is the bracket that holds the 1/4" jacks on the left side.
Obviously these connectors allowed for patching the comp into any other piece of gear directly, while the unit also has a barrier strip type terminal on the back for wiring it up a patchbay...

The jacks are mono switching 1/4" inch - so as soon as something plugged in there, the input and/or output on the back is disconnected.
Feeding a piece of gear with a balanced signal through 2 mono jacks seems kind of weird though ;D

Actually these jacks were common in telephone equipment.  They used a single plug body with two prongs and a single cable, see photo below.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on July 12, 2017, 06:06:59 PM
Thanks guys!! And sorry for the lack of updates - the last couple of weeks were extremely busy.
But today I finally made some progress.

Actually these jacks were common in telephone equipment.  They used a single plug body with two prongs and a single cable, see photo below.

Thanks mjrippe - great info! Now it all makes sense  ;D

Now the updates: I finally wired up the pcbs & transformers, as well as the screw-terminal & the 1/4" connectors:

(https://www.mediafire.com/convkey/2e62/o64g6drbeqi0nfe5g.jpg)

As you can see on the pic, I found a piece of Bakelite from an old connector panel in my workshop, so I simply couldn't resist and added a small Bakelite panel to the front of the connector bracket as featured by the original units  ;)

I also started to tie up the wires routed along the upper edge of the pcbs as done in the 60s (it's my first attempt on this technique, so please bear with me)

Beyond that I wired up most of the front panel - except for the ratio switch and the meter. In the next pic you can also see the wires coming from the output transformer for the ratio circuit:

(https://www.mediafire.com/convkey/6480/no5pki4prp5cn015g.jpg)

I'm not quite sure yet how to deal with the ratio circuit - I found very little information on that, and the only pics I found, showed different layouts. The same goes for the meter circuit. In the 175b the turret board for the meter circuit is mounted to the back of the meter switch. But in the 176 the ratio switch takes the position of the meter switch on the front panel - and thus, the ratio turret board is mounted to the back of that switch.

I found pics where the meter switch was mounted to the right vernier pot with the help of a bracket, with the meter turret board mounted to bottom of the chassis. If any of you have more info on that I'd be grateful.
If not I'll find a way to solve it ;)

Apart from that it seems the VU meter is not illuminated ? There's no space for a lamp holder, and all pics of 175bs or 176s I found show now lamp above the meter. The only thing that could fit would be a fuse type lamp. What do you think?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on July 12, 2017, 06:15:05 PM
I bought 2 API 361 VU meters, which have lamp holders.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on July 12, 2017, 06:15:47 PM
different angle.  too big ?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on July 13, 2017, 06:22:18 AM
Well many of the 175bs and even some 176s had the API 361 meter - but without the lamp holder bracket.
For my prototype I also used the API 361 meter and I think it's gorgeous!

But if we can gather enough interest to do a run of chassis, I would most likely go with the SIFAM R-32AF meter, since it's still readily available. Also it can be ordered with a lamp holder that utilizes a fuse type lamp and could indeed fit the chassis. It's slightly larger than the original, but very close to the weston meters that were used in later units...

If some of you want to use the the API 361 meter, I could do some special edition chassis for the group members interested.

What do you think?  ;)

Regarding using a lamp together with the API meter I would indeed try to find a solution with a custom mounted fuse type lamp.
The lamp would need to have some kind of cover from above though, since the chassis has no lid - or it will lighten up the entire rack  ;D
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on July 13, 2017, 09:54:40 AM
I would like to have a special edition chassis for the 361. Oh wait, I take 2 !
In real life, I actually don't need an illuminated meter, but I have a daylight studio.

I thought about the lid situation. Why did they build the units without lid ? Maybe to simply reach the internal pots more easy ? Because they were needed so often ?  Really mysterious. When you have to change settings all the time, it's good to have no lid. When it's about one set and forget, I think, it'S better to have a lid. Case closed ;)

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on July 13, 2017, 10:36:59 AM
I would like to have a special edition chassis for the 361. Oh wait, I take 2 !
In real life, I actually don't need an illuminated meter, but I have a daylight studio.

I thought about the lid situation. Why did they build the units without lid ? Maybe to simply reach the internal pots more easy ? Because they were needed so often ?  Really mysterious. When you have to change settings all the time, it's good to have no lid. When it's about one set and forget, I think, it'S better to have a lid. Case closed ;)

True about the lid. Well I also thought it might have been their ultimate design approach to get as much heat out of this thing as possible. Taking a look at some spots it seems this thing runs rather hot. This would also explain the huge holes all across the bottom of the unit - they're so weirdly placed with no real logic at all. I wondered what they had smoked when designing it...but I designed my unit exactly the same way hahaha!  ;D
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on July 24, 2017, 02:48:17 PM
Please a run for the api meters as i also purchased my pair already. They are not that hard to find. I commit to a pair no problem. Cheers
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 24, 2017, 10:23:09 PM
I third that request - I just got an API 361 meter too and would like the faithful special edition chassis. I would be in for 1.

Also, will you make boards available too?

Thx,

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on July 25, 2017, 08:25:23 AM
Got you guys  ;D

I'm extremely proud  that after a pretty bumpy ride in finalizing my prototype I can finally announce: THE LEGEND IS BACK - ALIVE!!  ;D

Last week, after being pretty much finished with the build I spent a lot of time debugging as it seems there were some errors in the original pcb layout as well as in the schematics + some additional errors on my prototype pcb that gave me a pretty hard time getting this wonderful compressor up & running. But now all errors are corrected and the very first 100% faithful recreation of an original UA176 in more than 50 years is now up and singing!

I only put through some samples yet to make sure everything is working correctly, but the experience when I first heard it doing it's thing - I was absolutely stunned!!  :o
The color and vibe it ads to the signal is unbelievable - and frankly I have never heard a compressor that sounds anything like it.

I have to admit though - I haven't heard a vintage 176 or 175b yet, and in my studio I have "only" LA2As, 1176s, LA3As and SSL comps, but this is an entirely different animal! Absolutely amazing!

I have to play around with it a little more - in the meantime here's the beauty in all its glory:

(https://www.mediafire.com/convkey/0a84/jbav17778d5kd875g.jpg)

(https://www.mediafire.com/convkey/5885/u2bcmsqn6i4c98x5g.jpg)

(https://www.mediafire.com/convkey/0cb6/2cx44ez2nbxtv885g.jpg)

(https://www.mediafire.com/convkey/8e94/zxzx414pj3hrjcj5g.jpg)

(https://www.mediafire.com/convkey/c109/9np05zqej58kejx5g.jpg)

(https://www.mediafire.com/convkey/5b7c/1qka4dqhbpgxbq25g.jpg)

Oh and just for the records - this unit I made for my personal use and the logo is only on there to pay proper respect to the legend going all the way to bring this beauty back to life in every detail when committing to the quest. I hope I'll be forgiven ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: mro on July 25, 2017, 09:58:10 AM
Congratulations!!! Your work is absolutely stunning!!!
Count me in for at least one (depending on the price)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 25, 2017, 03:56:00 PM
Dany is the godfather of german mic clones.

You sir, are the godfather of compressor and eq clones.

STUNNING!!!

I feel the same way about logos. It's not that I'm trying to pass off the gear as an original - it's that the logo lends a feel to the design that makes it feel/look right. Logo-less clones may be more politically correct, and legally correct, but they are missing that something that gives them the right feel. So I shamelessly put logos on my clone gear for those reasons.

By the way, I had read that this compressor uses a tube with a variable-mu feature, and that this tube is unobtainium.

Also that one of the transformers for the ratios is also unobtainium. How do we get around these issues?

Thanks Rainton!! Your work is MASTERFUL!!!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: supersonic on July 25, 2017, 04:11:36 PM
This is so beautiful  :'(
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on July 25, 2017, 07:41:28 PM
Thank you so much for you kind words guys!
I really appreciate it!

To answer some of the questions:


Also, will you make boards available too?


If I can make a run happen for you guys my plan is to offer a kit consisting of a powder coated main-chassis + hinged front panel (also powder coated), 2nd front panel with silk screening (that would be the black panel placed on top of the grey hinged one), mounting bracket for the 1/4" jacks, mounting bracket for the meter switch assembly, custom made panel screws, both pcbs, custom made PSU turret board, ratio turret board & meter switch turret board and some kind of build manual and BOM.

Possibly even a kit with most of the small components such as caps & resistors etc. - not sure yet.


By the way, I had read that this compressor uses a tube with a variable-mu feature, and that this tube is unobtainium.


That's not quite true. This tube is not being manufactured anymore but it's still available NOS at the major tube retailers such as tubesandmore.com or tubedepot.com (just to name a few) or of course also in the bay.

I'll write more about this tube in detail in the build manual ;)



Also that one of the transformers for the ratios is also unobtainium. How do we get around these issues?


Well this is at least true for the original transformer of the 176 as it was custom made. But apart from the different tabs that allowed for switching 4 different ratios, the specs of this transformer were not very special.

Sowter offers a replacement output transformer for the 176 (with all ratio tabs) of which the leads are even color coded according to the original transformer. And as far as I can tell it sounds amazing in this circuit.
The only difference is - physically it's quite a bit larger than the original one, but as you can see in my prototype it works still very well ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 25, 2017, 07:49:37 PM
Thank-you Rainton; your post is most welcome!

Since it will likely be a number of weeks (months?) before this project takes flight, I was wondering if there's any kind BOM showing the tricky/expensive/NOS parts so we can start collecting them? I'd love to start sourcing the Davens, the attenuators/pots etc, but since I don't know enough, and can't tell the brands/best suggestions from the schematic, do you think you might be able to post the specifics of the hard-to-find parts so we can get started? I found some Daven's, but I don't know what size, or if there's a particular model that works well. Things like that. What would you suggest as the ultimate transformers - the ones you used? I have a UTC HA100x that I heard can work really well, but is this the best suggestion?

Thing is, I just don't know where to get this information. I've been Googling, obviously, but it seems tough to find the real deal info on what actual parts were used, as opposed to just the specs of the part.

I'm like you. I like fanatical attention to detail, the result of which is breathtaking.

I know you're busy so I need to let you get back to your prototyping. Thanks for all you contribute here.

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 28, 2017, 11:04:36 PM
There's an eBay seller with some "NOS" brand new looking Daven's for a "reasonable" price.

Here's the listing: http://www.ebay.com/itm/Daven-TQ-255-G-600-Ohm-variable-attenuator-2-dB-with-Taper-off-Cue-NEW-/362020907368?hash=item544a20a968:g:DwMAAOSwwvZZUVl9 (http://www.ebay.com/itm/Daven-TQ-255-G-600-Ohm-variable-attenuator-2-dB-with-Taper-off-Cue-NEW-/362020907368?hash=item544a20a968:g:DwMAAOSwwvZZUVl9)

Would these be suitable for the 176?

Thanks,

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on July 29, 2017, 07:30:57 AM
Well, I think, I will use a Mallory T Pad, which is expensive enough and use the then "free" Vernier spot as meter switch...
So I don't have to mess up the nice original layout.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on July 29, 2017, 11:39:22 AM
Amazing!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on July 29, 2017, 08:11:16 PM
There's an eBay seller with some "NOS" brand new looking Daven's for a "reasonable" price.

Here's the listing: http://www.ebay.com/itm/Daven-TQ-255-G-600-Ohm-variable-attenuator-2-dB-with-Taper-off-Cue-NEW-/362020907368?hash=item544a20a968:g:DwMAAOSwwvZZUVl9 (http://www.ebay.com/itm/Daven-TQ-255-G-600-Ohm-variable-attenuator-2-dB-with-Taper-off-Cue-NEW-/362020907368?hash=item544a20a968:g:DwMAAOSwwvZZUVl9)

Would these be suitable for the 176?

Thanks,

Mike

The original attenuators go from -40db up to 0db in 2db steps.

The one you posted goes from -infinity up to 0db - the first 3 steps are off & taper and from the fourth step on it's also 2db steps.

So given the fact you'll most likely never use the first 3 steps (going from fully CCW) it should still work pretty much the same with the only difference being (with input knob fully CCW) the original would give you the level of the incoming signal minus 40db, while the above mentioned attenuators would kill the signal completely.

Apart from that I think the attenuators in this auction are very expensive! (I paid 25$ ea. for my Daven attenuators on eBay)
And they don't have a thread to mount them to the Frontpanel but these 2 screws instead.
I could add the holes to the frontpanel accordingly but countersunk bolts would be necessary...

Well, I think, I will use a Mallory T Pad, which is expensive enough and use the then "free" Vernier spot as meter switch...
So I don't have to mess up the nice original layout.


That's certainly an option. I own a pair of the same Mallory T-pads as well and will probably experiment with them in the future.
FWIW I would recommend to rather replace the output vernier pot if you had to choose,  since it's not that critical.
So far I found the input vernier to be more important to dial in the right amount of compression...

...as for mods let's talk about that more later.
I already started to do some mods - but just like kosi I didn't want to mess up the original front panel layout.
I'll keep you posted ;)

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 30, 2017, 12:54:37 AM
The original attenuators go from -40db up to 0db in 2db steps.

The one you posted goes from -infinity up to 0db - the first 3 steps are off & taper and from the fourth step on it's also 2db steps.

So given the fact you'll most likely never use the first 3 steps (going from fully CCW) it should still work pretty much the same with the only difference being (with input knob fully CCW) the original would give you the level of the incoming signal minus 40db, while the above mentioned attenuators would kill the signal completely.

Apart from that I think the attenuators in this auction are very expensive! (I paid 25$ ea. for my Daven attenuators on eBay)
And they don't have a thread to mount them to the Frontpanel but these 2 screws instead.
I could add the holes to the frontpanel accordingly but countersunk bolts would be necessary...

That's certainly an option. I own a pair of the same Mallory T-pads as well and will probably experiment with them in the future.
FWIW I would recommend to rather replace the output vernier pot if you had to choose,  since it's not that critical.
So far I found the input vernier to be more important to dial in the right amount of compression...

...as for mods let's talk about that more later.
I already started to do some mods - but just like kosi I didn't want to mess up the original front panel layout.
I'll keep you posted ;)
Rainton THANKS for such detailed info! Such a great help!!

Yes I agree that the Daven's I linked too are terribly expensive; especially compared to the deal you got! I've been buying some of the background parts and they all seem expensive to me.

But yeah, if I can get some for on the cheap that will be fabulous! I'm keeping my feelers on the lookout!

Having that info is surely a great help in the quest.

Thanks man, and keep up the great work!!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 30, 2017, 12:58:23 AM
Apart from that I think the attenuators in this auction are very expensive! (I paid 25$ ea. for my Daven attenuators on eBay)
And they don't have a thread to mount them to the Frontpanel but these 2 screws instead.
I could add the holes to the frontpanel accordingly but countersunk bolts would be necessary...
I'd rather find the right parts than have extra screw holes on the front panel, personally. I'll keep looking; things always pop up!

That's certainly an option. I own a pair of the same Mallory T-pads as well and will probably experiment with them in the future.
FWIW I would recommend to rather replace the output vernier pot if you had to choose,  since it's not that critical.
So far I found the input vernier to be more important to dial in the right amount of compression...
I'm not clear what you mean about "replacing" the vernier pot - with what? And are you saying you would use the Mallorys in place of the Davens?

Thanks Martin!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on July 30, 2017, 03:50:47 AM
http://www.uaudio.com/webzine/2004/february/text/content4.html

"The Input and Output controls are both stepped at 2dB increments, and “Vernier” controls are provided for both Input and Output allowing fine-tune adjustment of the gain structure between the 2dB increments."

https://en.wikipedia.org/wiki/Vernier_scale

Mallorys or the likes are continous potentiomenters, so, there is no need to use an extra Vernier poti. So you can replace one of the Verniers with a 3 way switch to change the VU meter display (In/GR/Out). 
Or do something else. Have a look on the Retro 176, especially the left front side
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 30, 2017, 04:14:31 AM
http://www.uaudio.com/webzine/2004/february/text/content4.html

"The Input and Output controls are both stepped at 2dB increments, and “Vernier” controls are provided for both Input and Output allowing fine-tune adjustment of the gain structure between the 2dB increments."

https://en.wikipedia.org/wiki/Vernier_scale

Mallorys or the likes are continous potentiomenters, so, there is no need to use an extra Vernier poti. So you can replace one of the Verniers with a 3 way switch to change the VU meter display (In/GR/Out). 
Or do something else. Have a look on the Retro 176, especially the left front side
Very helpful kosi! Thanks!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on July 30, 2017, 04:15:22 AM
I thought for the purists out there it might be nice to see some more photos of a (similar) unit - a 175b.

https://reverb.com/item/4625116-universal-audio-175b-1964-black-grey (https://reverb.com/item/4625116-universal-audio-175b-1964-black-grey)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: hugo on July 30, 2017, 11:35:52 AM
If some of you want to use the the API 361 meter, I could do some special edition chassis for the group members interested.
I'm in for 2 chassis with 361 meter :-)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on July 31, 2017, 10:09:49 PM
do these attenuator can replace the daven?
other values are available

http://www.ebay.com/itm/EIZZ-100K-24-Step-HIFI-Audio-Gold-Plated-Stepped-Serial-Attenuator-Potentiometer-/252662364443?hash=item3ad3d9b91b:g:L~gAAOSwXeJYHDUz

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on August 01, 2017, 06:47:18 PM
do these attenuator can replace the daven?
other values are available

http://www.ebay.com/itm/EIZZ-100K-24-Step-HIFI-Audio-Gold-Plated-Stepped-Serial-Attenuator-Potentiometer-/252662364443?hash=item3ad3d9b91b:g:L~gAAOSwXeJYHDUz

Well - correct me if I'm wrong but this auction is for a serial stepped attenuator. That means the output impedance would change when turning the attenuator. (plus with every step of attenuation another resistor would be in the signal chain - meaning up to another 23 resistors would be in the signal chain for each attenuator)

The schematics call for a T-pad or Ladder attenuator for the input and output impedance to remain consistent at 600 Ohms no matter the degree of attenuation.
That is important because the input signal hits the attenuator first and from there it goes straight to the (600 Ohm) input transformer. The same goes for the output: from the output transformer the signal goes to the output attenuator and from there to the output of the unit.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on August 01, 2017, 07:54:40 PM
Thank you Martin

I need to read about T pad and how they maintain the same impedance.

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: craig on August 01, 2017, 08:49:10 PM
I feel the Attenuators  may stop many of us attempting to realise an historically authentic build,  I'm sure alternative options will be discussed. Perhaps this project may spawn a sister thread on the creation of  DIY 600 stepped Attenuators ?
Can someone shed more light on the Verniers used in the originals. Are these indicated as R1 and R30  300 ohm on the 176 schematic?   and,  are they a Vernier reduction dial attached to a standard pot or something else entirely.

Thank you Rainton for another brilliant project.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 02, 2017, 03:11:34 AM
Hi Martin, I wonder will a "ladder" attenuator work instead of a "T" - does it matter? I'm not clear if this will compromise the operation of the unit. Also, does the taper need to be "audio" or can it be linear? I'm not sure what was used on the original.

Thanks for thoughts,

Mike

Edit: well in doing my own digging it seems the ladder attenuators do not hold impedance the same on input/output as well as the T-pads. Can anyone confirm this? So therefore ladders would not be desirable here on input/output controls? I ask because an awful lot of the daven/langevins I find are ladder types. Thank-you.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on August 02, 2017, 05:11:43 AM
I feel the Attenuators  may stop many of us attempting to realise an historically authentic build,  I'm sure alternative options will be discussed. Perhaps this project may spawn a sister thread on the creation of  DIY 600 stepped Attenuators ?
Can someone shed more light on the Verniers used in the originals. Are these indicated as R1 and R30  300 ohm on the 176 schematic?   and,  are they a Vernier reduction dial attached to a standard pot or something else entirely.

Thank you Rainton for another brilliant project.

Great idea - maybe we could check the forum - someone else might have done DIY 600/600 attenuators before.
Alternatively - as mentioned before one could use something like Mallory 600 Ohm T-pads which are not stepped and actually pots, but would work in this project for sure.

R1 & R30 are just plain 300 Ohm linear pots place between the input attenuator and input transformer and between output transformer & output attenuator respectively to fine adjust the levels, since the stepped attenuators were only adjustable in 2db steps. I'm not sure wether they used 300 Ohm pots indeed or just any other linear pot with resistor in parallel. (e.g. a 500Ohm pot with a 750Ohm resistor in parallel - or a 10K pot with a 310 Ohm resistor in parallel)


That pretty much answers the following question:

Also, does the taper need to be "audio" or can it be linear? I'm not sure what was used on the original.


The attenuators can control the signal from 0db down to -40db in 2db steps -> linear.

Actually all pots found across the 175b & 176 circuit are linear pots.

Hi Martin, I wonder will a "ladder" attenuator work instead of a "T" - does it matter? I'm not clear if this will compromise the operation of the unit.

Yes a ladder attenuator does hold the impedance.

As far as I found out - by default the 175 & 176 were equipped with 600/600 Daven LA-353-G attenuators:

(https://www.mediafire.com/convkey/20dd/y61x1012n1esd1g4g.jpg)

According to the spec sheet these were unbalanced LADDER attenuators with 600/600 in/out impedance:

(https://www.mediafire.com/convkey/4809/w1jw5tc1j7ddev94g.jpg)

As you can see there were other attenuator models that went from 0db to -infinite, which means - as stated before, with the knob full CCW the one model would attenuate the signal by 40db while the other one would turn off the signal completely.
I tried to explain that in more detail in an earlier post.

Anyway - the default config for these units was the LADDER attenuator. BUT as a "built-to-order" configuration both the 176 as well as the 175 were available with T-pad attenuators on either input, output or both - which would add either one "T" at the end of the model number ( for a T-pad on either input or output) or "TT" (for a T-pad on both).
So it would have been a "UA 176-TT" for example.

Each T-pad would increase the level by 6db compared to using the regular LADDER attenuator.

I've seen a 176 that had a regular Daven LADDER attenuator on input and a Langevin T-PAD attenuator on output.

Since I now have a working unit at hand I can say that this configuration can make sense indeed:

I have Daven on input & output at the moment and I while on input I feel it gives me a perfect range to control the gain reduction (which as you most likely all know is the same principle as in an 1176, driving the input signal against a predefined threshold) where I think the 6db increase of a T-pad in this position would make the unit compress much earlier on the scale and thus make it a little more difficult to control. (Also I really love how the "VERNIER" pot let's me fine tune the compression here)

On the output on the other hand I mostly have to turn up the attenuator to somewhere around the 3 o' clock position to make up for the gain reduction. Which is not a huge problem, since astonishingly the 176 I've built here has an extremely low noise floor - I haven't exactly measured it yet, but even with the attenuator fully CW I can't hear any noise in a real world situation.
But still - I think here the 6db increase of a T-PAD would come in handy. So I might just try to use a Mallory T-PAD in this spot...

...anyway this should give all of you many more options ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on August 02, 2017, 09:06:11 AM
Thank you very much for the detailled answer martin

does ladder attenuator are what we call L pad?

If yes I found these differences on wikipedia

A speaker L pad is a special configuration of rheostats used to control volume while maintaining a constant load impedance on the output of the audio amplifier.[1] It consists of a parallel and a series rheostat connected in an "L" configuration. As one increases in resistance, the other decreases, thus maintaining a constant impedance, at least in one direction. To maintain constant impedance in both directions, a "T" pad must be used. In loudspeaker systems having a crossover network, it is necessary to maintain impedance to the crossover; this avoids shifting the crossover point.

https://en.wikipedia.org/wiki/L_pad


also does 500 ohm instead of 600 make a difference?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 02, 2017, 01:39:01 PM
Magnificent Martin! Many thanks! I’m so excited to get this project going!

By the way I will be in for 2 Classic API meter versions!

Thx!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: ilfungo on August 02, 2017, 02:38:29 PM
Hi
I'm In for one with Api361 VU!!!
Great Project!!!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 02, 2017, 03:29:40 PM
Hi Martin, if you were to drill holes to fit the Davens, would they be hidden behind the knobs? I can't tell from pictures. If so, it might be nice to have the holes for Davens pre-drilled and countersunk, if they won't be visible no matter what the user chooses.

I got myself a pair of Mallory t-pads for a good price on the bay, so I'm stocking up parts!

Great, great work man!

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: ilfungo on August 02, 2017, 03:35:48 PM
Hi Phrazemaster
the Mallory t-pads you have hare 600 ohm?
Thanks!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 02, 2017, 04:04:15 PM
Hi Phrazemaster
the Mallory t-pads you have hare 600 ohm?
Thanks!
Yes! You can find them on eBay NOS very easily right now!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on August 02, 2017, 05:00:51 PM
Thank you very much for the detailled answer martin

does ladder attenuator are what we call L pad?


Nope.
Here's the schematic of a stepped ladder attenuator:

(https://www.mediafire.com/convkey/c722/xi1q2avkbxx557d4g.jpg)

in every position only 2 resistors are in the signal chain - one between input and output and one between output and ground.



also does 500 ohm instead of 600 make a difference?

I honestly don't know how much of a difference that makes in this particular circuit. We'd have to measure the frequency response of an actual unit equipped with 500/500 attenuators to find out.

FWIW many builders of my Pultec EQP-1A chassis project used a UTC-A20 on input for their builds (which is 500/500) instead of the Triad HS56V (600/600) with great results.

Hi Martin, if you were to drill holes to fit the Davens, would they be hidden behind the knobs? I can't tell from pictures. If so, it might be nice to have the holes for Davens pre-drilled and countersunk, if they won't be visible no matter what the user chooses.


Just to clarify: there are Daven attenuators with regular threaded bushing as well as Daven attenuators without bushing but with 2 mounting screws instead.

Now in this particular project we have actually 2 front panels: one has a hinge welded to it, is made of steel and powder coated  the same color as the rest of the chassis.
The second panel is a very thin anodized black aluminum panel with white silkscreening.

IF I added the 2 mounting holes for the use of above mentioned attenuators, these holes would be in the grey hinged front panel ONLY - covered by the black front panel on top of it.

BUT that means:

1. the screw heads would need to be countersunk completely or the upper front panel won't fit. And all attenuators I found so far don't come with countersunk screws - so that could make it complicated to design the chassis accordingly - you know what I mean?
2. that also means you would have to mount the attenuators before everything else on the front panel - even before mounting the second front panel - which can make it a PITA if you want to change the attenuators...
3. the second front panel is held in place by all pots, switches and screws - I don't know if that would be a problem but right now it's also held in place by the mounting nuts of the attenuators...

Just some thoughts ;)

On a different note:
Today I swapped my Daven output attenuator for a Mallory T-PAD and even though I don't like the feel as much as the Daven's, it indeed increases the output by 6db and I think I'll leave it like this for now.


I also started to add some mods without altering the original looks of my unit - I'll talk more about that later ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 02, 2017, 05:29:27 PM
Martin, you’ve got a laser-sharp mind. Thanks so much for the extremely clear response.

I think it would be good to give builders the option to have the screw holes if possible; those that don’t need it, won’t use it. I found a lot of Davens without the bushing mount, but with only screw holes.

Also, do you or anyone know if the Davens can be rebuilt? If I find a 20-step version with 1.5DB steps, can I open the unit and change resistors to get 2DB steps?

Thanks,

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: hugo on August 02, 2017, 06:41:51 PM
If it works well, mallory have long shaft, so it would be easy to put a metal plate between the inside panel and the attenuator.. Like a mini third panel on each side. This panel can be fixed by using the holes for Daven . I am not sure it is clear, but it is just like the pots in a chandler limiter unit, or a Neve module. But in this case, only a small plate covering the place needed. All pots can be used with that method if shaft is long enough for all panels
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: EmRR on August 02, 2017, 06:58:18 PM
Also, do you or anyone know if the Davens can be rebuilt? If I find a 20-step version with 1.5DB steps, can I open the unit and change resistors to get 2DB steps?

They can be rebuilt, but in that case it'd be very dumb because the 1.5dB/step versions are worth significantly more, and really offer you better control. 

As to the earlier questions about T versus ladder, the ladder does not need to be loaded in a bridging environment, while an output T does need a 680R resistive load on the output side.   A proper T presents a load to ground around 5K at the first step down, and full gain is actually open, with no loading at all.   Most limiters/comps of old use ladders, as did most mixers. 
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 02, 2017, 07:00:05 PM
They can be rebuilt, but in that case it'd be very dumb because the 1.5dB/step versions are worth significantly more, and really offer you better control. 

As to the earlier questions about T versus ladder, the ladder does not need to be loaded in a bridging environment, while an output T does need a 680R resistive load on the output side.   A proper T presents a load to ground around 5K at the first step down, and full gain is actually open, with no loading at all.   Most limiters/comps of old use ladders, as did most mixers.
Thank-you Doug; extremely informative.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: craig on August 02, 2017, 09:12:23 PM
This is great info and clears things up for me regarding the attenuators. I think i will at first use the Mallory T Pads i already have as well  and hopefully get lucky on some  Daven's or Shalco attenuators or something suitable at some point. With Raintons unit up and running and already experimenting with alternatives and modifications i can only wait for what he can disseminate to us.  I already sourced most of my critical parts, have to start thinking about those can caps now. I realise some of these are multi section but which  one is which? Is it too early to ask which cap positions relate to the schematic designations/values. Just to get my head around it. Personally i would use all new caps but i guess this will be thrown to a consensus at some point as to what is available,  as Rainton has done in his other project threads.
Looking good
Universal Audio 176 from scratch - a 100% faithful recreation of a legend! even 80% would be great!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jpharaoh on August 05, 2017, 12:08:13 PM
This looks awesome I am definitely in for 1 possibly 2, I don't know which version yet.

Thanks,
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: moltenwok on August 05, 2017, 10:20:05 PM
cough-sidechainHPF-cough mod  cough
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on August 07, 2017, 03:40:14 PM
  I already sourced most of my critical parts, have to start thinking about those can caps now. I realise some of these are multi section but which  one is which? Is it too early to ask which cap positions relate to the schematic designations/values. Just to get my head around it. Personally i would use all new caps but i guess this will be thrown to a consensus at some point as to what is available,  as Rainton has done in his other project threads.


Yes we have 3 multi-section can caps in this circuit - two of them being located in the PSU. C11 & C8 to be precise.
C11 is a four section cap with 4x 20uf/450V of which 3x 20uf are connected in parallel to give 60uf + 1x 20uf, and C8 is a 2x 20uf/450V.
Both of them are still available and I'll point out where to get them in the BOM later.
The 3rd can cap is C9 which is 2x10uf and a little harder to come by - especially since the original one was a PFP cap.
Here's a pic so you know what that means:

On the left is an FP chassis mount cap - those kind of can caps are still available new. On the right is a pcb mount PFP can cap which are not being made anymore:

(http://www.mediafire.com/convkey/efd7/c1l7ydk2awydga84g.jpg)

Well this particular cap (C9) is soldered directly to the pcb (you can see it in some pics that show the back of my unit - it's the can cap on the right sticking out through the rectangular cut-out in the chassis)

For the prototype Livingnote and I agreed to keep the original footprint on the pcb, but instead of just putting holes in the pcb to mount a PFP type can cap, Livingnote cut in slots to hold the FP type terminals.
But to be frank mounting that cap was a drag, and we're still figuring out a way to make it easier. Especially it's a lot of extra work to cut these custom slots in every single pcb...
I'll let you know when we did ;)

Anyway we'll include the option to mount 2 regular electrolytics in this spot, so you could always go that route.
I would highly recommend NOT to look for vintage PFP type can caps to use for this project as that's asking for trouble.

On a different note - I'm getting lots of mails and messages of what parts to source etc. You can make it easier for yourself if you wait until I finished a first revision of BOM - then we can discuss further.  :)
One thing many people ask in particular I will try to explain here briefly:

"What are these things here and where can I source them":

(https://www.mediafire.com/convkey/2c6e/tuwbyrkkr36sa854g.jpg)

These are oil filled 0.5uf 600V caps (C6 & C7) and extremely hard to find.
Here's a pic of a very early state of my build that shows the terminals of these caps from inside the chassis:

(https://www.mediafire.com/convkey/b0e4/pht7bp2io9oep024g.jpg)

Anyway - there were also many models of original 175b and 176 that had film caps in this spot - mounted inside the chassis with the help of a small turret board and some spacers:

(https://www.mediafire.com/convkey/3396/w340at4rny4b5az5g.jpg)

Thus, the chassis doesn't feature the 4 cutouts for the terminals of the oil caps as you can see in this pic:

(https://www.mediafire.com/convkey/e284/4ycvp5rdamsp6op5g.jpg)

Since these oil filled can caps with the exact physical dimensions needed are pretty much unobtainable and there were original units with film caps instead,  I will design the chassis for the use of film caps here and most likely add a turret board to let you mount (whatever) film caps (you like).
So I hope all of you who laid awake at night wondering what these things were and where to get them can now finally sleep again  ;D
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on August 07, 2017, 03:43:37 PM
cough-sidechainHPF-cough mod  cough

*cough* how to implement *cough*

I read something about placing a switchable 10k log pot between C6 & C7 but then again I read somewhere else that it wouldn't work.

Retro added a variable HPF to their 176 - and as far as I know they used a pot, but does anybody know how they did it?

I figured it could also be implemented by changing the values of C6 & C7 but that wouldn't work with a pot then right...

any idea anybody?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 07, 2017, 04:56:52 PM
Hey Martin, what about these:

http://www.ebay.com/itm/2-X-GE-GENERAL-ELECTRIC-0-5uF-600V-OIL-FILLED-CAPACITOR-WITH-MOUNTING-HARDWARES-/300937643660?hash=item461148068c:m:ma06Fle7xoY5HG6xFxkPaWg (http://www.ebay.com/itm/2-X-GE-GENERAL-ELECTRIC-0-5uF-600V-OIL-FILLED-CAPACITOR-WITH-MOUNTING-HARDWARES-/300937643660?hash=item461148068c:m:ma06Fle7xoY5HG6xFxkPaWg)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: craig on August 07, 2017, 07:09:50 PM
Or something like this.

http://www.ebay.com.au/itm/2x-MBGCH-0-5uF-500V-Russian-PiO-Paper-in-Oil-Audio-Capacitors-0-5uF-0-5kV-/302188911606?hash=item465bdcdbf6:m:mZPFkLMEc0SlmBheHgUybwA (http://www.ebay.com.au/itm/2x-MBGCH-0-5uF-500V-Russian-PiO-Paper-in-Oil-Audio-Capacitors-0-5uF-0-5kV-/302188911606?hash=item465bdcdbf6:m:mZPFkLMEc0SlmBheHgUybwA)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on August 08, 2017, 07:25:35 AM
The problem is guys, that they all have different dimensions and that makes it close to impossible to design the chassis for them (fora production run)

The one Phrazemaster posted is smaller than mine and the terminals are closer together.
And the one craig posted won't work at all - unfortunately - since it has the terminals on one side and the mounting brackets on the other side - and apart from that the size appears to be different, too.

The ones I used look pretty much like this:

(https://www.mediafire.com/convkey/5356/wmua9yv4d93kf684g.jpg)

But like I said - since the original units also were available with film caps I wouldn't bother.
I could design the cutouts into the chassis but the possibility that the caps you'll find - if you find any - won't fit is like 90%

And I think having holes you don't need in the chassis doesn't make the end result look any better.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 13, 2017, 09:04:54 PM
I just bought some A19's in an eBay auction and will have extras. See the black market if interested.

Mike

EDIT: these may be gone. Still post interest in case sales don't go through, but I got responses in just minutes...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: EmRR on August 14, 2017, 12:52:09 PM
UTC A-18 was apparently the primary part here, though either 18 or 19 should work fine.

https://groupdiy.com/index.php?topic=17733.msg207048#msg207048

I too, have one piece for sale in the black market.  Looks like Phrazemaster's A-19's are all gone, so hopefully not stepping on his toes. 
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 14, 2017, 07:56:36 PM
UTC A-18 was apparently the primary part here, though either 18 or 19 should work fine.

https://groupdiy.com/index.php?topic=17733.msg207048#msg207048

I too, have one piece for sale in the black market.  Looks like Phrazemaster's A-19's are all gone, so hopefully not stepping on his toes.
Not a bit. I'm a little disappointed though because in my research I had found the A-19 to be the original. Can't tell from the schematics - at least I can't. My copy is fairly blurry and haven't found a clear copy yet. I found another reference that stated that either one was used.

So what would be the difference between them?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: EmRR on August 14, 2017, 08:26:31 PM
A-19 is meant to handle DC current directly to a tube plate, at reduced low frequency response.   Not applicable here, low response should be better than spec with no DC as here.  Maybe not as good as A-18, maybe just as good, either way they used some of both. 
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 14, 2017, 08:30:46 PM
A-19 is meant to handle DC current directly to a tube plate, at reduced low frequency response.   Not applicable here, low response should be better than spec with no DC as here.  Maybe not as good as A-18, maybe just as good, either way they used some of both.
I appreciate that Doug. Sometimes EE talk sounds like Greek to me, but I'm slowly learning. So I gather from what you shared, both the A18 and the A19 were used in these units? With the A18 the preferred one, although it may or may not make a difference sonically?

Thanks - I see your posts over at GS sometimes and other places and I appreciate your wisdom.

In fact - all of you guys are amazing! Thanks to Martin (Rainton) for making this PTP possible, along with the rest of you geniuses and wannabes like me ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: moltenwok on August 15, 2017, 04:34:40 AM
Well that's all good-I found a nos pair of A18s  on eBay for $100 ea a while ago. So that leaves two of phrazemasters A19 up for grabs now that Doug has cleared that up. Thanks for your wise input..
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 15, 2017, 02:03:38 PM
A-19 is meant to handle DC current directly to a tube plate, at reduced low frequency response.   Not applicable here, low response should be better than spec with no DC as here.  Maybe not as good as A-18, maybe just as good, either way they used some of both.
By the way would the increased DCR of the A19 vs the A18 cause any issues?

Also to clarify, you said both the A18 and A19 were used in the 176, correct? References online said it was the A19, and one said both were used.

Thanks Doug!

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 15, 2017, 02:04:37 PM
Well that's all good-I found a nos pair of A18s  on eBay for $100 ea a while ago. So that leaves two of phrazemasters A19 up for grabs now that Doug has cleared that up. Thanks for your wise input..
Lucky! Jealous! Way to go!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on September 01, 2017, 07:00:17 AM
Great info emrr!!
Thanks for sharing!

And sorry for the silence guys - I had so much work at the studio right now and the holiday season makes it very slow to finally get all quotes and infos I need to launch a possible run of 176 chassis kits.
But we're getting closer.

I'm on vacation now with my family until Sept. 14th and hope I'll have all info I need when I return.

In the meantime we could discuss some details. Many of you who are interested in the project want to use the API meter.
I actually planned to do the production run with a cutout for the SIFAM R32 meter - it's slightly larger than the API, but looks awesome, is very HQ and readily available.
HOWEVER I can do a special version for you guys with API cutout. But that would be ONLY for those who preorder a chassis kit, since I don't want to offer a kit later where people are struggling to find a certain vintage meter, you know what I mean?

Oh - and one more thing: I heard from a fellow forum member, that there might be a way to arrange a group buy for some vintage components such as UTC trannys, API meters, attenuators etc. for this build...we should here more about that soon ;)

I'm still loving my prototype 176 and I'm afraid I need to build a 2nd one - damn it  ;D
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: EmRR on September 03, 2017, 04:29:49 PM
The context of my ancient quote is that there was a point that no one wanted a UA compressor, and they sold for little/less than the various units with higher quality transformers, then once the UA company restarted they went up 10x in value on name recognition alone.   The minute before that they could be bought for $500-700 every day, then they were suddenly $7000 almost overnight.    Right before, you'd have had to trade (4) UA's for a BA-6, then they are suddenly worth more, for no sensible reason at all. 

If you are recreating something, you haven't done it unless you get the sound signature, which should mostly be the reason you would go to such trouble.  Which means as close to original transformers as you can get.  If it's the actual operating action of the device, you are then free to redesign with whatever you want, change large portions of the circuit, and call it whatever other than a UA 175/176 you want.  As well, it's not 'frequency response' exactly, as that may appear no different, but harmonic content among other minor things. 
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Quayhog on September 03, 2017, 06:36:25 PM
What power transformer and choke set are the USA builders considering?   I can't find anything at Edcor and the Hammond site is hard to search.
The minimum requirements that I get from looking at the schematics are an X mount type.   200ct @ 100 ma, 6.3v @ 2a and 5v @ 2a..   A 225ct could be manageable.
The plate current requirements for the tubes, less GZ34 is 63 ma,  and the heaters consume 1.6 amps.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: beatnik on September 05, 2017, 10:16:27 AM
Hammond 372X should be a good candidate and it has configurable primaries
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Quayhog on September 05, 2017, 12:32:44 PM
I think that's the one I found that would  work.  When I bought the Sowter output transformer they recommended a 225ct at 100 ma.   I couldn't see where in the circuit that would require that much current. Almost double what I figure.   

We need to locate a source for the switched 25KL attack pot.   DP1T.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: beatnik on September 05, 2017, 05:46:27 PM
urei schematics shows a 650V C.T. transformer and 295V on the output tube plates. the sowter transformer could probably work with some tweaking of the power supply resistors, but as you said this circuit doesn't need that much current

the attack pot is the same as the 1176 . you can get it from mouser
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on September 05, 2017, 05:51:43 PM
expensive version:
https://goo.gl/VXj8uf
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on September 05, 2017, 06:36:04 PM
What beatnik wrote regarding the attack pot.
Also available at Banzaimusic.com:

https://www.banzaimusic.com/Alpha-24-SPDT-25k-lin.html

The schematic calls for a DPST switch (which is exactly the one kosi posted the link to) - but the way it's wired you can also use an SPDT and the Alpha has a nice feel and does the job well!

Regarding the power transformer - I welcome the discussion :)

Following several 175b or 176 projects, they all used the Hammond 370BX - which is the same one as suggested for the Pultecs.
Drip Electronics recommends it for their 175b pcb version and another builder here successfully used it for his 176 build a couple of years ago.
I tried that transformer for my prototype and it works.
I have to admit though - I had the primaries wired up for 240V use first (even though we have mostly more like 220-230V here) and ended up being rather on the low side voltage wise. I rewired the primaries for 220V and am now still a little low but within 6% of specs - so that's not too bad ;)

Even though I can say the transformer gets rather hot after a couple of hours of use. I'd say like 50°-55° celsius.

The problem is, space is at a premium at the back of the unit. On the right side (viewed from the back) we're completely depending on the pcbs, since many components that stick out the back are soldered straight to the pcbs. So the layout is predefined.
And to the left of the output transformer the space is extremely tight. I could try to get maybe 8-10mm more to mount a larger transformer but I'm not sure yet if it's possible.
The size of the 370BX make it fit perfectly.

Choke can either be Hammond 158M or Triad C-7X.

In terms of the "low budget" UTC iron: I think emrr's posts say it pretty well.

When I'm committing to the quest in recreating the iconic vintage gear I want to go for it's original signature sound. I want to find out what exactly it is why people love the sound of a particular unit.
That certain sound character was,  what I experienced many times in the past when I finished an authentic replication, instantly sounded familiar in some way - most likely due to having it heard on countless records?

What I can say in regards of the 176 - I used UTC-01 and UTC-A19 together with a Sowter output transformer - and my 176 indeed sounds very special compared to other pieces of gear I own - but in a very very pleasant way!! I love it :)
I'd love to do a shoot out with a vintage unit one day...

And YES - I will offer adapter plates ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on September 06, 2017, 08:10:22 AM
Thank you Rainton for the precision

for USA poeple the pot can be found here

http://www.hairballaudio.com/catalog/parts-store/potentiometers/fet-compressor-attack-control

concerning the power tx, if it get hot and voltage are low  it's because it reach his limits curent wise and it isn't very good.
it can fail some day

does sowter power tx can do the job?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: beatnik on September 06, 2017, 12:43:30 PM

I have to admit though - I had the primaries wired up for 240V use first (even though we have mostly more like 220-230V here) and ended up being rather on the low side voltage wise. I rewired the primaries for 220V and am now still a little low but within 6% of specs - so that's not too bad ;)


in this case make sure filament voltages are still within correct ranges, if they too hot that might shorten tubes life.
with just 20V difference on the primary it should be fine, but it's better to double check this. in any case would be easy to drop the voltage with some resistors in series with the heaters

imho it would be better tweaking the power supply resistor R44 / 1,5K , since all the circuit gets powered off that node, it would be easy to adjust the resistor value to drop less voltage thus getting the optimal voltages at the plates.

i suggested the 372X because the ht voltage is a bit closer to what it's on the diagram. the currents for the ht and the 6.3 filament have also more margin, the 370BX is a bit closer to the limit

i know the 372X fits a 2U chassis mounted horizontally, because I used it in the past, but you will have to check with your chassis
 imho I would go for a less authentic look on the back panel (which anyway nobody ever looks at) but having a power transformer that runs cool, even after more than two hours operation
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: beatnik on September 06, 2017, 12:44:14 PM
expensive version:
https://goo.gl/VXj8uf

that's not expensive, it's ridiculous
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on September 06, 2017, 01:12:29 PM
Quote
i suggested the 372X because the ht voltage is a bit closer to what it's on the diagram. the currents for the ht and the 6.3 filament have also more margin, the 370BX is a bit closer to the limit

i know the 372X fits a 2U chassis mounted horizontally, because I used it in the past, but you will have to check with your chassis
 imho I would go for a less authentic look on the back panel (which anyway nobody ever looks at) but having a power transformer that runs cool, even after more than two hours operation

aggree with that
the 370bx is sized X7 and the 372X is sized X8 so it's bigger
if we are sure it can fit I will go with this model also
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on September 06, 2017, 03:11:22 PM
I agree as well but the X8 size is 10mm wider - im not sure if that's possible.
And it's not just about authentic looks it's simply about space.

This thing is packed on the back.
We have two the GZ34 + the OB2 Tube + fuse holder to the left of the power tranny (even the cutout for the power cable is on the side of the unit because of that)

And to the right of the power tranny there's 2 can caps before the first pcb mounted Tube

I also found the 372x to be a better choice electronically but the one thing is I don't know if I can make it fit and the other thing is that - as mentioned by beatnik another option would be to change the values of the power supply resistor R44 (which I haven't done yet)

Anyway - in regards of the correct voltages - all measured voltages - even filaments are within 6% of specs ;)

I'll see what can be done to make the 372X fit but can't promise yet.

Maybe we could talk to Gregory with Drip electronics - he suggests the 370BX for his 175b as well

I know a couple of people who built a Drip 175b but none of them had a power tranny failure yet...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: beatnik on September 07, 2017, 10:38:05 AM
imho it would be better to sacrifice the obsolete capacitors in favour of a beefier power transformer, with a bit of headroom in terms of current supply, so it doesn't run hot. this is just my personal opinion and i am not an engineer, i don't know how long it takes to burn out a power transformer, so if you are sure the smaller transformer it's gonna be fine anyway, then ignore my comments
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: kosi on September 07, 2017, 11:10:02 AM
Difference between Hammond Sizes X7 / X8 is only 6,35 mm in length, width and height is the same

Hammond 372x is 82,55 mm
Hammond 370BX is 76,2 mm
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on September 18, 2017, 02:52:02 AM
Difference between Hammond Sizes X7 / X8 is only 6,35 mm in length, width and height is the same

Hammond 372x is 82,55 mm
Hammond 370BX is 76,2 mm

Well if that's the case - I'm sure I can make it fit.
Anyway I can make mounting slots instead of just holes for the power transformer, so one could use both - X7 or X8 size ;)

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on September 18, 2017, 02:54:01 AM
Because I get asked this quite frequently - the correct output transformer for the build is the Sowter 1285e (for a 176)

But fear not - I'm working on a BOM - and since preparing everything for a production run takes longer than expected you should all have enough time to order your stuff once we get this thin going ;)

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on September 20, 2017, 10:32:58 PM
Is it possible to do a kind of altec 436C mod?

bypassing the interstage tx with a switch and sending the signal from the 6BC8 with caps and resistor to mimic the sound of ALTEC 436C
here the schematic
http://img.photobucket.com/albums/v295/rafoote/Altec%20436C/Altec436C.gif

The Idea came from here
https://www.gearslutz.com/board/high-end/109707-universal-audio-175b.html#post1136249
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on September 21, 2017, 09:09:11 PM
Is it possible to do a kind of altec 436C mod?

bypassing the interstage tx with a switch and sending the signal from the 6BC8 with caps and resistor to mimic the sound of ALTEC 436C
here the schematic
http://img.photobucket.com/albums/v295/rafoote/Altec%20436C/Altec436C.gif

The Idea came from here
https://www.gearslutz.com/board/high-end/109707-universal-audio-175b.html#post1136249
That might be cool. I think rainton (Martin) is after creating an exact clone - see title of thread "100% faithful recreation."

I'm sure some mods can be done. Maybe a separate thread would be good for that?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on September 22, 2017, 01:45:36 AM
That might be cool. I think rainton (Martin) is after creating an exact clone - see title of thread "100% faithful recreation."

I'm sure some mods can be done. Maybe a separate thread would be good for that?

Thanks Phrazemaster - and yes I am after building an exact clone, which I did, but I already started to mod my unit  ;D

I tried to do the mods in a way so I don't need to change the original looks - e.g. by using push-pull pots with switches.
I'll talk about that in a bit.

But I think it would be cool to collect everything 176 related here - also the mods :)

So we'll have everything in one spot
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on September 22, 2017, 02:49:06 AM
Thanks Phrazemaster - and yes I am after building an exact clone, which I did, but I already started to mod my unit  ;D

I tried to do the mods in a way so I don't need to change the original looks - e.g. by using push-pull pots with switches.
I'll talk about that in a bit.

But I think it would be cool to collect everything 176 related here - also the mods :)

So we'll have everything in one spot
No worries man - it's your thread!

- However -

Having done many projects here that have a gazillion pages to read through, it might be nice to have a dedicated thread for mods vs the original. Your call - I'd rather it be separated so it's clear who's modding and who's just building. It's a real drag to have to read through tons of material that's not related to what you're trying to do.

That's my $.02.

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on September 23, 2017, 08:55:57 AM
I though about a non invasive and easily removable mod,
like using inside switch or something like that
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on October 03, 2017, 11:35:32 AM
it can be interesting to add also a hpf on the sidechain.

maybe a 4 position switch instead of a vernier pot.
1 original
2 original hpf
3 Altec
4 Altec hpf
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on October 07, 2017, 10:11:21 PM
Just to set the record straight - did the originals use A18's or A19's for the interstage transformer? I've tried a lot of googling but can't seem to find the answer.

Thanks!

Mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: dbonin on October 08, 2017, 12:48:55 PM
I'm down for one case and kit and all...  depending on cost, of course.  Such great work - inspiring!
Thanks!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: core13 on October 11, 2017, 07:07:05 PM
I found to add the sidechain we just need to change value of C6 and C7 with a switch

also what is the Asymmetry mod on the retro 176?

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: ilfungo on October 30, 2017, 08:58:29 AM
 News???  :)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: JCN1218 on November 10, 2017, 08:20:31 PM
This project is just too good to resist. I'm definitely in for a case/kit when the time comes(API meter version). Absolutely beautiful work!

By the way, to anyone interested, as of writing this reply (Nov. 10th, 2017) there's an ebay listing for a bunch of vintage API 361 meters for about $40 each, which seems like a pretty good deal based on modern meter prices.https://www.ebay.com/itm/API-VU-Meter-Model-361-Scully-MCI-Magnetic-MTG/162734912816?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649 (https://www.ebay.com/itm/API-VU-Meter-Model-361-Scully-MCI-Magnetic-MTG/162734912816?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2055119.m1438.l2649)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: wmarden on December 30, 2017, 02:08:00 AM
rainton, you my friend are a master! That is a beautiful re-creation! I am definitely down for one when they become available.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jslstudio on December 30, 2017, 02:45:06 PM
Thanks Phrazemaster - and yes I am after building an exact clone, which I did, but I already started to mod my unit  ;D

I tried to do the mods in a way so I don't need to change the original looks - e.g. by using push-pull pots with switches.
I'll talk about that in a bit.

But I think it would be cool to collect everything 176 related here - also the mods :)

So we'll have everything in one spot


Are you doing a run of these soon..? Date..? Prepay ready...Thanks!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jslstudio on December 30, 2017, 04:01:52 PM
News???  :)

No go on this??? No updates in a long while.?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on January 05, 2018, 04:53:07 PM
No go on this??? No updates in a long while.?

Sorry for the long silence guys!
I just returned from my xmas vacation and realized quite some people have posted here.
The 176 will definitely happen, but it takes much longer than expected.

That's mostly due to working on an idea that I feel is bigger than the 176 project. It's kind of a knowledge base - or more like a platform that gathers all information on my projects in one place. And that in a way it's very intuitive to find what you need from basic information through BOMs with sources to step-by-step guides in form of e-papers and videos.

There'll also be a blog/vlog with tips & mods not just from myself but also from other builders around the world.

To make this happen I want to build up a community where project related knowledge can be exchanged.

Why not using Group DIY?
Well, I love Group DIY and I learned a lot here! But the "problem" is there are 1000s of threads with some of them being more than 400 pages long. So it can be very hard to find what you're looking for - especially as a newbie.
Partly due to this, I've been getting tons of mails and messages from people asking build related questions and I found myself answering the same questions again and again - many of which were already answered here at some point.

So I figured it would be best to create one place were all these answers are gathered - limited to my projects and all info prepared in a way it's easy to understand...
long story short, I'm working on it and in order to build up a community I launched a first little "mini-website" and if you think this could be a cool idea I welcome you to check it out:

www.analogvibes.com

The 176 will definitely be a project there too and if you follow me along you'll know when it's ready.
I'm planning to do a small run of 176s in Q1 2018 for all of those who have been waiting for so long.

In the meantime I tested some mods on my 176 and I also took it to Berlin with me to have other engineers do some testing in their studios - one of them was fellow forum member kosi  :)

If you're interested and kosi is ok with it we can talk more about it. We also compared it to kosi's STA-Level and the results were remarkable. The 176 is an amazing piece of gear!


Anyway , I'd really appreciate your feedback regarding my idea - either here, or in the comment section on my page
and thank you so much for your patience guys!!

Martin

Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: moltenwok on January 05, 2018, 05:04:53 PM
Happy new year to you Martin ~been collecting parts to build four 176 when released ~an early bom would be awesome so we can be ready to build when you release the chassis & boards ~thanks very much ~love your work.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jslstudio on January 05, 2018, 06:03:29 PM
Sorry for the long silence guys!
I just returned from my xmas vacation and realized quite some people have posted here.
The 176 will definitely happen, but it takes much longer than expected.

That's mostly due to working on an idea that I feel is bigger than the 176 project. It's kind of a knowledge base - or more like a platform that gathers all information on my projects in one place. And that in a way it's very intuitive to find what you need from basic information through BOMs with sources to step-by-step guides in form of e-papers and videos.

There'll also be a blog/vlog with tips & mods not just from myself but also from other builders around the world.

To make this happen I want to build up a community where project related knowledge can be exchanged.

Why not using Group DIY?
Well, I love Group DIY and I learned a lot here! But the "problem" is there are 1000s of threads with some of them being more than 400 pages long. So it can be very hard to find what you're looking for - especially as a newbie.
Partly due to this, I've been getting tons of mails and messages from people asking build related questions and I found myself answering the same questions again and again - many of which were already answered here at some point.

So I figured it would be best to create one place were all these answers are gathered - limited to my projects and all info prepared in a way it's easy to understand...
long story short, I'm working on it and in order to build up a community I launched a first little "mini-website" and if you think this could be a cool idea I welcome you to check it out:

www.analogvibes.com

The 176 will definitely be a project there too and if you follow me along you'll know when it's ready.
I'm planning to do a small run of 176s in Q1 2018 for all of those who have been waiting for so long.

In the meantime I tested some mods on my 176 and I also took it to Berlin with me to have other engineers do some testing in their studios - one of them was fellow forum member kosi  :)

If you're interested and kosi is ok with it we can talk more about it. We also compared it to kosi's STA-Level and the results were remarkable. The 176 is an amazing piece of gear!


Anyway , I'd really appreciate your feedback regarding my idea - either here, or in the comment section on my page
and thank you so much for your patience guys!!

Martin

Not all beginners here! I say please put out the chassis first with pcb. First run keep it simple! No mods either...faithful
clones. Then maybe second half of year talk about mods etc........
My two cents..Why wait If we can get a chassis and pcb,s and start rolling....just make the first run of kits and disclaimer
not for first timers so you are not bombarded by questions that most people know!
Thanks for doing these!
John
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: efinque on January 06, 2018, 10:08:15 AM
I just read the whole thread..

Instant envy.  :o
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: TubeMonkey on January 09, 2018, 01:51:03 AM
Hey Rainton,

You can put me down for two! In addition we have 2 UA175s,  a UA176, and a  UA177 at our studio here in Nashville. If you need any hands on info I'd be happy to oblige

EB
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: wmarden on January 09, 2018, 01:55:27 AM
Hey Rainton,

You can put me down for two! In addition we have 2 UA175s,  a UA176, and a  UA177 at our studio here in Nashville. If you need any hands on info I'd be happy to oblige

EB

It's helping hands like you that make this such a great community!  I can't wait for this build!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on January 10, 2018, 04:45:09 PM
Hey Rainton,

You can put me down for two! In addition we have 2 UA175s,  a UA176, and a  UA177 at our studio here in Nashville. If you need any hands on info I'd be happy to oblige

EB

What wmarden said! Thank you so much for your offer that's so awesome.
I'll definitely get back to you.

During the entire ride building my 176 I had only pics I gathered from all across the web (which were mostly 175b and only a few 176), the original service manual and the schematics. So that was not an easy task!

I'd love to get some more pics from the inside of the original 176.
If you have the chance to take some pics of your unit, please send it to [email protected]

Thanks!!
Martin
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: damiangiannis on January 13, 2018, 02:46:57 PM
I can't miss that train ! Please count me in for an Api fit Case ! Don't have to say that these are great moments you're creating !!! Gongrats !!!!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on January 15, 2018, 06:46:18 PM
Hey guys,

I'm getting lots of mails concerning the 176 project. I can't make any definite statement on pricing yet, but due to the many requests, I really try to have all information ready to finally open preorders for a very limited run in February!

If you wanna make sure you don't miss it, please post here if you're interested.

I'll go through the list once I'm ready :)

Thanks for your patience guys - you're the best!
Martin
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on January 15, 2018, 06:51:51 PM
Hey guys,

I'm getting lots of mails concerning the 176 project. I can't make any definite statement on pricing yet, but due to the many requests, I really try to have all information ready to finally open preorders for a very limited run in February!

If you wanna make sure you don't miss it, please post here if you're interested.

I'll go through the list once I'm ready :)

Thanks for your patience guys - you're the best!
Martin
Thanks Martin. Do you anticipate doing many runs, or is this the only one planned? I definitely will be in for 2 sets, but I'm not in position right at this moment to pay for them.

Loving what you're doing bud!

mike
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: mro on January 15, 2018, 07:22:14 PM
Hello Martin,

I'm definitely in for one set. I've been following this thread from the very beginning. I already gathered most parts for the build  :) Wouldn't want to miss this run.

Best,
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: moltenwok on January 15, 2018, 09:07:12 PM
Woo hoo, great news Martin ~hoarded enough bits for 4 here please. Also have a friend with about 16  O~17 shields and he has 30~40 a pi  361 meters that he could print up ua logos for, let me know team
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: TubeMonkey on January 16, 2018, 11:26:31 PM
Woo hoo, great news Martin ~hoarded enough bits for 4 here please. Also have a friend with about 16  O~17 shields and he has 30~40 a pi  361 meters that he could print up ua logos for, let me know team

I would be in for a pair of these!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: 59flame on January 17, 2018, 03:45:55 AM
I'd be down for a pair  of these with the api  361 meters Martin!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: ilfungo on January 17, 2018, 04:50:19 AM
One for me with API 361 meter...
Thanks!!!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: salomonander on January 17, 2018, 02:21:35 PM
hey Martin,
great to hear! its jakob (gave you the a19) - please put me down for a pair with api meters and hopefully logo (im only doing repairs - promise :) best
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: craig on January 17, 2018, 04:53:18 PM
One for me
Thanks
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: mohausler on January 17, 2018, 07:15:27 PM
I would like one, too  :)
Merci
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Le Roux on January 18, 2018, 09:24:04 AM
Put me down for one

Thanks
Neil
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: TubeMonkey on January 19, 2018, 04:15:37 PM
Alright guys I have some archival photo documentation of our four units. I'm uploading currently, but here is a sneak preview.

I call this one the "Putnam Glory Shot"
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: wmarden on January 19, 2018, 04:47:42 PM
SaWeet Tubemonkey!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Adadan on January 19, 2018, 10:07:29 PM
Put me down for one (using API 361 meter), these look too amazing to pass up.  I'm already trying to do too many projects, but I have most of the hard to source parts for this already!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: BramK on February 14, 2018, 12:25:11 PM
I'm also in for a kit with the API 361 meter if I have not already missed the boat. Thanks!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jeanpierreisyou on February 17, 2018, 11:05:32 PM
Totally interested in one!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: JMarcovis on February 23, 2018, 02:55:29 AM
I've been waiting for something like this!!!! Count me in for a pair! Not picky on the meter, either is fine for me.
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: mro on February 23, 2018, 08:36:44 AM
Maybe a run for API meters would be better since most of us already bought them?   :)
Any updates about the project rainton?

Best,
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: rainton on February 26, 2018, 11:59:10 AM
Alright guys - let's do this!!

Sorry it took me so long but as some of you probably noticed I've been working a lot on my own analogvibes.com platform.

Anyway, besides working on analogvibes I got in touch with all suppliers needed to do a limited run of 176 chassis kits - FINALLY!

This will be the most sophisticated and complete kit I've done so far, so it was a lot to organize.

A couple of things though:

VU meter:
Of course I can do this run for the API 361 meter only as it turns up fairly often and relatively cheap on eBay - much cheaper than a new sifam for example. And besides - as moltenwok posted here, he has a friend who has 30-40 of them for sale...

But I could also do a part of the run for  the SIFAM R32AF on order as it's still readily available.

Logo: there won't be a UA logo on these kits - but a) they look equally as amazing without it and b) if you still want there's plenty of options by now you can get it on there

On the back there are 4 cutouts to mount the two 0.5 oil caps, but some vintage units didn't use these oil caps but regular film caps mounted on a little turret board inside with standoffs.
Should I leave these cutouts in, and whoever wants can use the oil cans if they can be sourced or decide to use regular film caps instead (in the case of the latter these cutout would remain empty)?
I mean it's 4 little holes with a diameter of probably 1cm (0.39in)

The mounting holes for the oil caps can also be used to mount the turret board inside in case of using film caps...


Anyway - we'll find a solution here, right ;)


Here's what will be included in this authentic re-creation of a UA 176 chassis kit:

- main chassis, bent, welded, smoothed and powder coated grey

- first front panel  - also folded edges, welded smoothed and powder coated grey

- custom made hinge manufactured following original specs, powder coated and welded to the first front panel

- second front panel to go on top of the first one: this will be the black panel with white silk-screening

- custom made stainless steel thumb screws designed for original looks

- mounting bracket for input/output jacks on the front

- mounting bracket for optional metering switch inside

- handmade, authentic re-creations of the 2 original pcbs: these will be handmade to original specs with fork turrets just like the original
- handmade PSU turret board

- handmade RATIO turret board

- handmade METERING turret board

- first BOM

- first wiring layout for the entire unit



All of this I will offer as kit in this LIMITED run for EUR 399.00

Actually this is the price if we can reach 50 chassis, but I convinced all suppliers - if we don't hit that margin, but only 40 chassis instead, we'll still get that price :)

And I'm positive that we can reach 40pcs.
And in case we end up with only 38pcs, I will have to buy one for Mom and one for Granny - I'm sure they'd love them  ;D

SO:
I'll get in touch with all of those who posted here and want to have one or two or...

In case you're new to this thread and interested send me an email to [email protected]
If you posted here and don't get an email within the next couple of days, do the same :)

Lead time for having these gems manufactured will be around 6-8 weeks.

ONE MORE THING: I'll keep this group buy open until March 15th - after that deadline I'll process the orders and have the kits manufactured...

I'll add some more pics in a bit...

Thanks A LOT for your patience guys!! I really really appreciate it!
Martin

Some pics (I'll share more later)

(http://www.mediafire.com/convkey/f6e2/ejnui9yz309mqqy5g.jpg)

(http://www.mediafire.com/convkey/0313/f7na9a45acw99505g.jpg)

(http://www.mediafire.com/convkey/a9aa/5ac2ap69ma5cc4k5g.jpg)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: nickhepfer on February 27, 2018, 12:43:19 PM
hell yeah, you know i'm in for such a beauty!  ;D
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: wmarden on February 27, 2018, 02:51:18 PM
Great work Rainton!!! I'm definitely in for one, if not two! But it's all about where I am with the $. I'm shooting for two  ;D
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: rainton on February 27, 2018, 03:27:03 PM
Great to see you on board guys!

I changed the title of the thread, so people know we're taking off now!!  8)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: mro on February 27, 2018, 07:48:51 PM
Anyone for a group buy of Sowter 1285e/ or any other trafos from them to combine the order/lower the cost?  If so  a slightest idea how to organise it?  :)  is it worth the effort?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: jefepeters on February 27, 2018, 08:11:18 PM
Are there any parts required for this build that can be hard to find?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: rainton on February 28, 2018, 06:50:19 AM
Are there any parts required for this build that can be hard to find?

Well it depends - some of the original parts can be difficult to source such as the transformers or the attenuators.
BUT there good alternatives.
Also the can caps turned out to be a problem. When I built my prototype the 2x20uf  1" can cap was still available and also the 2x10uf cap could be sourced. Now both are out of production...

...BUT our fellow forum member and friend Jonathan (aka Quayhog) found a possible supplier, who will - as it looks - be able to custom make these caps to our specs!!  ;D
Jonathan you are THE MAN!!

And the best part of it - if we order like 50 sets as a group the caps will turn out much cheaper than the actual available can caps by CE manufacturing or the like.
So I think we're safe here as well  ;)

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: ilfungo on February 28, 2018, 06:51:31 AM
Hi

long ago I wrote that I would like one with API meter.
How can I confirm to be sure?
Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: rainton on February 28, 2018, 06:56:53 AM
Hi

long ago I wrote that I would like one with API meter.
How can I confirm to be sure?
Thanks!

Just write me an email to [email protected] - including your shipping address, VAT number if you're in the EU and have one and how many kits you want...  ;)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: Adadan on February 28, 2018, 05:05:39 PM
I'm definitely in for one set designed to use the API meter, and can pay whenever you're ready for us!

I would also be interested in a groupbuy for the custom can filter caps, and for the Sowter output transformer, but I already have the API meter and many of the other parts.

On the back there are 4 cutouts to mount the two 0.5 oil caps, but some vintage units didn't use these oil caps but regular film caps mounted on a little turret board inside with standoffs.
Should I leave these cutouts in, and whoever wants can use the oil cans if they can be sourced or decide to use regular film caps instead (in the case of the latter these cutout would remain empty)?
I mean it's 4 little holes with a diameter of probably 1cm (0.39in)

The mounting holes for the oil caps can also be used to mount the turret board inside in case of using film caps...

Anyway - we'll find a solution here, right ;)
In reference to these holes for the rectangular oil caps, I'd definitely vote for them to be included.  (That's partly selfish, because I have a large stash of those oil caps of different values and sizes, but it also doesn't seem like that option would really be a drawback people who are putting film caps on a separate board inside.)   That's just my "two cents."

Thanks so much for your work on this, it's just unbelievable.  Truly above & beyond for DIY!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: rainton on March 05, 2018, 12:01:37 PM
Hey guys,

I updated the first post with THE LIST  8)

Please check if you're in there - and if not please let me know ASAP!

Including the ones from our FB group we have more than 40 kits together!!

So  for those who still want to join, you should do so now BECAUSE THIS IS GOING TO HAPPEN!!!

hooray!!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: gevermil on March 07, 2018, 11:49:35 AM
So. Just curious
The optimal transformers - ( well
Original transformers ) are the Utc
0-1  the Utc a-18 and the sowter repro output , correct ?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: Jmcc on March 07, 2018, 03:28:40 PM
So. Just curious
The optimal transformers - ( well
Original transformers ) are the Utc
0-1  the Utc a-18 and the sowter repro output , correct ?

Correct!  I think UTC O-2 (input) or UTC A-19 (interstage ) will work too.

Jasper
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: rainton on March 11, 2018, 06:41:30 PM
Just a quick heads-up guys

Including the ones from the FB group we have more thant 50 kits now!!

as the group buy will close later this week - if you still want to join: NOW IS THE TIME!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: Potato Cakes on March 13, 2018, 02:13:46 AM
Is there an estimated total cost for the entire build?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: DonnieDarko on March 13, 2018, 11:12:09 AM
Hey guys, long time absence here, but back for good.

Ordered two Kits with Rainton.

He mentioned someone round here could sell some meters and/or caps?

I´m from Berlin/Germany, maybe someone is nearby.

Cheers!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: rainton on March 13, 2018, 08:19:21 PM
Is there an estimated total cost for the entire build?

Thanks!

Paul

Depending on the parts you use - how vintage you wanna go and depending on where you're located, since most parts can be found in th US.
Also depending on how lucky you are on your hunt for parts :)

I think somewhere between $700 and $1000 for all the parts + chassis & pcb kit.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: wmarden on March 14, 2018, 02:50:40 PM
Paid! Thanks again Martin!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: salomonander on March 14, 2018, 04:32:20 PM
paid. best jakob
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: JMarcovis on March 15, 2018, 05:37:50 PM
paid for 2, thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: BramK on March 16, 2018, 12:44:38 AM
Paid and ready for the adventure!
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Spaceyjb on March 16, 2018, 03:16:28 PM
Hi Martin

I guess I've missed it... :( or is there still any chance?
I found about you too late through analogvibes - great Job btw.

Greets from Stuttgart

Jan

Alright guys - let's do this!!

Sorry it took me so long but as some of you probably noticed I've been working a lot on my own analogvibes.com platform.

Anyway, besides working on analogvibes I got in touch with all suppliers needed to do a limited run of 176 chassis kits - FINALLY!

This will be the most sophisticated and complete kit I've done so far, so it was a lot to organize.

A couple of things though:

VU meter:
Of course I can do this run for the API 361 meter only as it turns up fairly often and relatively cheap on eBay - much cheaper than a new sifam for example. And besides - as moltenwok posted here, he has a friend who has 30-40 of them for sale...

But I could also do a part of the run for  the SIFAM R32AF on order as it's still readily available.

Logo: there won't be a UA logo on these kits - but a) they look equally as amazing without it and b) if you still want there's plenty of options by now you can get it on there

On the back there are 4 cutouts to mount the two 0.5 oil caps, but some vintage units didn't use these oil caps but regular film caps mounted on a little turret board inside with standoffs.
Should I leave these cutouts in, and whoever wants can use the oil cans if they can be sourced or decide to use regular film caps instead (in the case of the latter these cutout would remain empty)?
I mean it's 4 little holes with a diameter of probably 1cm (0.39in)

The mounting holes for the oil caps can also be used to mount the turret board inside in case of using film caps...


Anyway - we'll find a solution here, right ;)


Here's what will be included in this authentic re-creation of a UA 176 chassis kit:

- main chassis, bent, welded, smoothed and powder coated grey

- first front panel  - also folded edges, welded smoothed and powder coated grey

- custom made hinge manufactured following original specs, powder coated and welded to the first front panel

- second front panel to go on top of the first one: this will be the black panel with white silk-screening

- custom made stainless steel thumb screws designed for original looks

- mounting bracket for input/output jacks on the front

- mounting bracket for optional metering switch inside

- handmade, authentic re-creations of the 2 original pcbs: these will be handmade to original specs with fork turrets just like the original
- handmade PSU turret board

- handmade RATIO turret board

- handmade METERING turret board

- first BOM

- first wiring layout for the entire unit



All of this I will offer as kit in this LIMITED run for EUR 399.00

Actually this is the price if we can reach 50 chassis, but I convinced all suppliers - if we don't hit that margin, but only 40 chassis instead, we'll still get that price :)

And I'm positive that we can reach 40pcs.
And in case we end up with only 38pcs, I will have to buy one for Mom and one for Granny - I'm sure they'd love them  ;D

SO:
I'll get in touch with all of those who posted here and want to have one or two or...

In case you're new to this thread and interested send me an email to [email protected]
If you posted here and don't get an email within the next couple of days, do the same :)

Lead time for having these gems manufactured will be around 6-8 weeks.

ONE MORE THING: I'll keep this group buy open until March 15th - after that deadline I'll process the orders and have the kits manufactured...

I'll add some more pics in a bit...

Thanks A LOT for your patience guys!! I really really appreciate it!
Martin

Some pics (I'll share more later)

(http://www.mediafire.com/convkey/f6e2/ejnui9yz309mqqy5g.jpg)

(http://www.mediafire.com/convkey/0313/f7na9a45acw99505g.jpg)

(http://www.mediafire.com/convkey/a9aa/5ac2ap69ma5cc4k5g.jpg)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: JMarcovis on March 16, 2018, 05:31:18 PM
Woo hoo, great news Martin ~hoarded enough bits for 4 here please. Also have a friend with about 16  O~17 shields and he has 30~40 a pi  361 meters that he could print up ua logos for, let me know team

Hey moltenwok, I am looking for a pair of 0-17 shields and 1 API 361 meter. Can you connect me with your friend?
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: mro on March 16, 2018, 05:50:18 PM
Hey moltenwok, I am looking for a pair of 0-17 shields and 1 API 361 meter. Can you connect me with your friend?
I second that  question.  I'd be interested in the 0-17
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: moltenwok on March 16, 2018, 05:56:07 PM
Hi team, yahoo we're all go... If you pm or email me I'll just do a group deal with him, I've also got spares of the jacks from an old patch panel here!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! OPEN!!
Post by: BramK on March 16, 2018, 07:54:30 PM
There are a few NOS UTC O-1 transformers up for sale on the Bay:

https://www.ebay.com/itm/Vintage-New-Old-Stock-UTC-0-1-Transformer/132536874891?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/Vintage-New-Old-Stock-UTC-0-1-Transformer/132536874891?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on March 17, 2018, 05:34:07 AM
Wow, I didn't expect that much interest in this project!!  :o

Great to have all of you on board guys!!

GROUP BUY IS NOW CLOSED!

I'll place the order with the manufacturers on Monday...

I'll keep you posted  :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mro on March 17, 2018, 06:26:46 AM
If anyone's interested I have quite a few switchcraft longframe jack sockets.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on March 19, 2018, 12:13:00 PM
How risky is it buying used vintage transformers (instead of NOS) such as the UTCs? Do these go bad over time from use?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mjrippe on March 19, 2018, 01:24:34 PM
How risky is it buying used vintage transformers (instead of NOS) such as the UTCs? Do these go bad over time from use?

They will generally not go bad from use, only from abuse.  If the seller can at least verify DC resistance with an ohmmeter or multimeter, the transformer should be ok.

I actually came here to say I have two UTC O-2 with O-17 shields available.  They are the same as O-1 but with a center tapped secondary.  Used, desoldered, tested, $100 each.  PM if interested.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on March 19, 2018, 10:49:15 PM
Thanks for the info mjrippe - I just slept past the auction end for an A-18 and missed it. Whoops.  ::)

If anyone has any extra UTC A-18's for sale, please let me know!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: xarolium on March 22, 2018, 12:26:06 PM
Hi diyer
As I bought a  pair of 176 I need two Api 361 meter. Let me if you have some to sell.

Best regards,
Vincent
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 26, 2018, 10:23:10 AM
How risky is it buying used vintage transformers (instead of NOS) such as the UTCs? Do these go bad over time from use?

Are these the mono? With the angled up ground connection?  That is what is in the originals. Though a lot of people switched to two STEREO jacks.
J
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jslstudio on March 26, 2018, 12:01:54 PM
By the way would the increased DCR of the A19 vs the A18 cause any issues?

Also to clarify, you said both the A18 and A19 were used in the 176, correct? References online said it was the A19, and one said both were used.

Thanks Doug!

Mike

For what it is worth.....My original UA 175b  has a UTC- A 19  . With the UTC A 33 shield over it....
Original never changed.
J
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on March 26, 2018, 05:14:44 PM
Hey guys,

as some may have probably found out the 20uf/20uf can caps with 1" diameter are not longer available.
When I built my prototype back then they still were offered by CE manufacturing.

Now thanks to Jonathan aka Quayhog we may have a solution for the problem! :)

He found a little company that can custom make can caps for us!! And the good thing is, if we order more than 50 caps from them, they will be even cheaper than the CE manufacturing ones!

They can also make the long out of production 10uf/10uf can caps that are soldered directly to the pcb...here's a pic - they have a chrome finish  8):

(https://www.mediafire.com/convkey/0499/th5k3k6rr3iih285g.jpg)

Now we only have to find out if they can make the 10uf/10uf caps with pcb pins instead of regular twist lock terminals - which would be great!
If not we'll also find a was to make them compatible ;)

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on March 26, 2018, 07:39:23 PM
Count me in for 2 units worth!

Hey guys,

as some may have probably found out the 20uf/20uf can caps with 1" diameter are not longer available.
When I built my prototype back then they still were offered by CE manufacturing.

Now thanks to Jonathan aka Quayhog we may have a solution for the problem! :)

He found a little company that can custom make can caps for us!! And the good thing is, if we order more than 50 caps from them, they will be even cheaper than the CE manufacturing ones!

They can also make the long out of production 10uf/10uf can caps that are soldered directly to the pcb...here's a pic - they have a chrome finish  8):

(https://www.mediafire.com/convkey/0499/th5k3k6rr3iih285g.jpg)

Now we only have to find out if they can make the 10uf/10uf caps with pcb pins instead of regular twist lock terminals - which would be great!
If not we'll also find a was to make them compatible ;)
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jslstudio on March 26, 2018, 07:52:19 PM
I would like to have a special edition chassis for the 361. Oh wait, I take 2 !
In real life, I actually don't need an illuminated meter, but I have a daylight studio.

I thought about the lid situation. Why did they build the units without lid ? Maybe to simply reach the internal pots more easy ? Because they were needed so often ?  Really mysterious. When you have to change settings all the time, it's good to have no lid. When it's about one set and forget, I think, it'S better to have a lid. Case closed ;)

SiFam AL 22 is closer to the original Weston. RF 32 is to big...
API meters where used on the Very early 175 not the 175b.   Basically 175b / 176 are the Weston 3" Same as the later Urei/La3a/1176 blue etc.......

I would say do not cut out meter rectangle.....Leaves options for the original meters...
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on March 27, 2018, 07:25:32 AM
API meters where used on the Very early 175 not the 175b. 

That's not true John - I've seen several 175b with API meter - here's one of them:

(https://www.mediafire.com/convkey/5409/a1brq1ke1ua5nis5g.jpg)

SiFam AL 22 is closer to the original Weston. RF 32 is to big...

I would say do not cut out meter rectangle.....Leaves options for the original meters...

The AL22 is not being made anymore so it makes no sense as an option as it's extremely rare.
Besides - pretty much everyone in this thread wants the API meter anyway ;)

BUT my friend Aaron with Don Audio has a good connection to SIFAM - and he's actually the only retailer that still has the R32AF. But these are discontinued and he has the last batch made by SIFAM
.
He's now asking if SIFAM could make a limited run of customized AL29 meters - with a scale closer to the Weston in terms of looks - and maybe even with a custom bezel and pointer. But that's not confirmed yet!


If not, I would leave the R32AF option as planned (besides the API option of course) since it looks absolutely great and the build quality of the old R series is far superior to the newer AL series. (metal bezel and full VU specs)

The Retro 176 also uses the R32AF meter by the way...

Anyway, I can do yours without VU cutout John, but I think not cutting out the VU rectangle in general is not really an option.
The main front panel (the one with the hinge welded to it) is made of 1.5mm steel - so you might have a hard time cutting out the rectangle by hand...
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 27, 2018, 10:09:28 AM
AL 29 would be great!!!!

Because that is what is on 176 and most 175b.... For that one pic you posted I can post 40 that do not have that meter If you want..?:-).

175 had the big meter and maybe a few as they transition to the smaller Weston..If we are being authentic here...Please lets
get the smaller meter! :-) I really want it to match my  original 175b.
So keep me posted on the AL 29 option....
Thanks!!!!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on March 28, 2018, 02:20:49 AM
Hey guys,

as some may have probably found out the 20uf/20uf can caps with 1" diameter are not longer available.
When I built my prototype back then they still were offered by CE manufacturing.

Now thanks to Jonathan aka Quayhog we may have a solution for the problem! :)

He found a little company that can custom make can caps for us!! And the good thing is, if we order more than 50 caps from them, they will be even cheaper than the CE manufacturing ones!

They can also make the long out of production 10uf/10uf can caps that are soldered directly to the pcb...here's a pic - they have a chrome finish  8):

Now we only have to find out if they can make the 10uf/10uf caps with pcb pins instead of regular twist lock terminals - which would be great!
If not we'll also find a was to make them compatible ;)

Sign me up!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on March 28, 2018, 10:39:44 AM
I'm in for the caps as well. I am building two units.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mro on March 28, 2018, 02:25:54 PM
Same here, but just for one unit,

Best,
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on March 28, 2018, 03:51:41 PM
I'm in for a caps for One unit!
Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on March 28, 2018, 03:57:11 PM
I'm in for caps on 1 unit!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: peskado on March 28, 2018, 04:19:58 PM
Couple for me!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on March 28, 2018, 06:54:47 PM
Hey guys,

at this point I'm not sure if I find the time to handle a group buy for the caps as well.
I did something like that in the past with the EQP-1A when I started a group buy for the S-217D trannys while doing the chassis kits at the same time and it was tough to do all of it at once - given the fact that I'm doing chassis kits for a 2nd group buy (the tube opto comp) over on analogvibes.com

Maybe Jonathan can chime in, but I think if we can find a way to guarantee the manufacturer we're taking at least 50 caps and then organize ourselves so the caps going to the US are maybe sent straight to the buyers and the rest is sent here to Germany and sent off in one box with the chassis kits that would help all of you guys, right?

As far as I know the caps usually would be like $29.50 ea. which is quite a bit cheaper than CE manufacturing. But given we take like 50 caps they would give us a discount of around 15%-17% - somewhere around $ 25.00 ea.

Any suggestions how we could proceed is welcome. I think posting here to create a list would help. Maybe you could add wether your in the US or elsewhere in the world to your posts.


Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on March 28, 2018, 07:02:29 PM
BTW I got some more GOOD NEWS - especially for you John  ;)
And those who go the SIFAM route

My friend Aaron with Don-Audio who is the German distributor for SIFAM talked to them about our project here and they offered to make a custom version of their AL29WF meter for us to resemble the look of the Weston meter used in the later versions of the 175b an 176 as mentioned by John before - or at least get close to it - here's a mockup of what it will look like:

(https://www.mediafire.com/convkey/bc8c/flf5ln6b6o8t9v95g.jpg)

Again since the most group buy members use the same API meter I used in my prototype, it's only relevant to a few, but given the fact that the API meter is not being made anymore, I needed to find a solution for the future if we want to keep this project alive.

However the API version will be limited to this run - so 1time only  8)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on March 29, 2018, 04:58:05 PM
I def don't mind them getting sent to you in Germany and then being sent out with the Chassis kits. I'm in Pennsylvania, USA.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2018, 06:11:18 PM
I agree!
Awesome Martin!!!! Also are these close to 3" wide?

This is great news!!!! And I think the RIGHT way to go since you have spent so much time making everything else right!!!!
Tell Don Audio Thanks!!!!!
John :-)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on March 29, 2018, 06:44:34 PM
Well..... for those of us in the first round with the api 361, can source them for 50US each and the O~17 shields for 20US..cheers team
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2018, 07:00:36 PM
Where can you find the shields?  0-17 

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on March 29, 2018, 07:06:59 PM
My buddy has about 20 nos units
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2018, 07:17:10 PM
I will take one...are they the early ones? Or the TRW ones..?
Thanks!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on March 29, 2018, 07:53:00 PM
They're the jrw units
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on March 29, 2018, 08:07:26 PM
Jrw O~17
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2018, 08:29:33 PM
Excellent...Perfect....Where can I buy..? I am in Seattle..
Thanks!
John
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: jslstudio on March 31, 2018, 12:08:57 PM
By the way would the increased DCR of the A19 vs the A18 cause any issues?

Also to clarify, you said both the A18 and A19 were used in the 176, correct? References online said it was the A19, and one said both were used.

Thanks Doug!

Mike

That is just not true! I have an original UA 175b and the interstage is a UTC A-19 with a UTC A-33 shield....
Hope this helps!
J
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on March 31, 2018, 08:59:44 PM
Just posted a spare A18 for sale in the Black Market if anyone if looking for one.

https://groupdiy.com/index.php?topic=68675.0
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 14, 2018, 05:12:59 PM
Hi, Martin,

I'd like to start looking at buying transformers for the pair of cases I have built. Looking to do modern equivalents instead of trying to search for used originals. Can you provide the model numbers for the Sowter units that you used on your build?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mro on April 14, 2018, 06:27:00 PM
I'm no Martin  :) but those should be 1285e, 1449 and 1133. The info's on their website. I don't know about now but betore the build rush it was fairly easy to get UTC 0-1 or 0-2 for cheap on ebay.  If you consider using A18 for interstage I know a guy who has quite a few for a fair price. Cheaper than the Sowter equivalent for sure
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 14, 2018, 07:02:40 PM
Any word about the custom capacitors for this project?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on April 14, 2018, 10:34:26 PM
Hi team, just sent out invoices for meters and shields, the only person I can't seem to reply to is [email protected], if you could please get in touch via PM or another email address I can reply to..... Cheers johnny
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on April 15, 2018, 01:51:19 AM
Ok guys, whats the  best way to collect monies to pay for this, I'm not a business and just trying to help everyone out so I don't want to incur any PayPal fees personally, do let me know, cheers johnny
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 15, 2018, 07:55:32 PM
Hi, Martin,

I'd like to start looking at buying transformers for the pair of cases I have built. Looking to do modern equivalents instead of trying to search for used originals. Can you provide the model numbers for the Sowter units that you used on your build?

Thanks!

Paul

For people in the US...Matt Can do the Power Transformers. But Not until June 1st.  He can do the correct 650V CT.
I measured to my original UA 175b..And the height is just 1/4" shorter. All other dimensions are spot on size wise.

Musical power supply PT325.2
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on April 16, 2018, 11:13:09 AM
Ok guys, whats the  best way to collect monies to pay for this, I'm not a business and just trying to help everyone out so I don't want to incur any PayPal fees personally, do let me know, cheers johnny

Having people send payment through 'Friends & Family' would be the way to do it without fees - buyers don't get any protection from eBay if anyone goes wrong in the process though.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on April 18, 2018, 01:37:54 PM
Question about the Sowter 1285...

Earlier in the thread it was mentioned to use a 1285e, I don't see the 'e' version on the website. There's also 3 styles: Open Frame, Fully Shrouded, & Mumetal Can w/ threaded grommet - which one do we want for this build?

Are there any other sowter parts to put in with this order? I'm already using a UTC A-18 and 0-1.

Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 18, 2018, 02:02:36 PM
I answered your mail yesterday Bram.

But in case anybody else is wondering - the „e“ version is the one with mumetal can and threaded grommet.

If you’re already using the UTC input and interstage, no other parts needed from Sowter.

I almost finished a first BOM and will upload it soon so we can discuss it :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on April 18, 2018, 02:14:03 PM
Ah, yep - looks like your email made its way into Spam.

Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 24, 2018, 06:52:43 PM
Just a quick heads up guys:

- The black front panels are going to the silk screener's tomorrow.
- Pcbs are already being made
- Turret boards production is being prepared.
- The custom SIFAM meters are already ordered and will be ready in 6 weeks
- first BOM will be shared later this week for all of you to discuss :)

Regarding the can caps: Jonathan's (Quayhog's) initiative was to find a way to have access to the can caps we need to complete this build - since CE manufacturing ceased the production of their 2x20uf and 2x10uf can caps.

AS far as I understand there won't be a group buy for the caps. At least not yet. And as far as I'm concerned I think I can't take care of that as well for now.

If I understood correctly the price is already slightly lower compared to the CEs even if ordered individually.
But if we could organize a group buy the discount would be around 17% off which would be cool too.

Anybody volunteering to organize a group buy?  ;D
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 24, 2018, 06:55:51 PM
BTW:
anybody here has access to a RETRO 176?
I'd really like to know how they implemented the Sidechain HP filter...from the pics on the web I can tell it's an Alpha pot with SPST switch, but I can't see the value, nor can I tell where exactly it's going on the pcb...

some insight would be great :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on April 25, 2018, 06:47:02 PM
Hey Rainton,

We have a Retro here as well..... I'll check the cap value as soon as I'm back in the studio

EB
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 25, 2018, 07:11:05 PM
Hey Rainton,

We have a Retro here as well..... I'll check the cap value as soon as I'm back in the studio

EB

Awesome!!

here's the only pic I have from that HPF side chain pot:

(https://www.mediafire.com/convkey/3e67/3ic2hl3bjczhzpr5g.jpg)

The color code points towards a 20K resistor.
The question is what value is the pot?
Where do the wires go on the pcb? What are the next connections from where it's connected to the pcb/what are the surrounding components?

It's a shielded wire and it seems both leads are only connected through the pot with the resistor in parallel when the switch is set to ON - meaning the knob on the front is pulled...

If we can find out how it works it should be easy to add this as a mod to our 176 project :)

Thanks!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on May 02, 2018, 05:08:49 AM
Hi guys, our meters have all been tested for ballistics and correct operation and all our order is on its way here ready to despatch to you all! Cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 02, 2018, 04:32:40 PM
Fantastic news! Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on May 02, 2018, 07:03:07 PM
Hey guys,

here's my first version of the 176 BOM.

I posted it here to discuss - open for your input :)
That's why I labeled it V 0.1

 
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on May 02, 2018, 09:37:26 PM
Thanks Rainton, taking a look now... What resistor wattage are we looking for for the ones which are not currently marked?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on May 02, 2018, 10:23:33 PM
Hi guys, our meters have all been tested for ballistics and correct operation and all our order is on its way here ready to despatch to you all! Cheers

Great news, moltenwok - thank you for spearheading that for us.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on May 03, 2018, 04:20:50 AM
Thanks Rainton, taking a look now... What resistor wattage are we looking for for the ones which are not currently marked?

All resistors are specified 1/2W as per the schematics - but there actually are some 1W resistors used in the vintage units.
I'll check which ones and add it to the BOM.
But in terms of what's necessary 1/2W is fine.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on May 03, 2018, 06:47:26 AM
One thing guys,

I'm just finalizing the blueprint for the PSU turret boards for the production.
So far I offered two options for the power transformer - the Hammond 370BX and the Hammond 372X.

The 372X is slightly wider and I solved the issue regarding the mounting holes on the chassis by adding slots instead of holes to the chassis in this position. So you guys can choose.

Now it came to me that the PSU turret board is mounted to the same mounting screws - which means I would have to add slots to the PSU board as well (so you can still choose your power xfmr)
OR we all agree on one model - preferably the larger one (372X) since it has more headroom in terms of specs...

What do you think?

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on May 04, 2018, 03:40:03 PM
I'm cool with the 372X, but I'd understand if others wanted a choice
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Taoma on May 04, 2018, 04:04:45 PM
Also happy with the 372x
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on May 04, 2018, 04:12:56 PM
Happy with 372x for my 4 units
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on May 04, 2018, 04:58:17 PM
I already have a 370BX...
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 04, 2018, 06:49:06 PM
372x sounds good to me.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on May 04, 2018, 07:11:22 PM
372X is good here.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: 59flame on May 04, 2018, 10:07:27 PM
372x good here as well
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on May 04, 2018, 11:03:26 PM
I fine with either
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on May 05, 2018, 02:51:14 AM
Alright guys :)

Both transformers will fit the chassis anyway, since I designed slots in there and the case are in production so no changes can be made.  The main thing why I asked is because in the chassis these slots won't be visible  later when everything is mounted, but if I add theses slots to the PSU turret board, they will be visible (at least as long the unit isn't racked up  ;D)

Now since  pretty much everyone either prefers the 372X has no preference, I would do design the PSU board with mounting holes fitting the 372X and add tiny markings or holes that show the mounting hole position for the 370BX.
And in case anyone wants to use the 370BX the mounting holes could be drilled easily?

I already have a 370BX...

The Hammond 370BX also fits the Pultec EQP-1A and the MEQ-5, in case you want to build one of those in the future ;)


Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on May 09, 2018, 08:55:46 AM

I don't know why I the solution regarding the power xfmr came to me earlier!!

Of course both power transformers have mounting slots which are 0.375" wide (95mm)

And since the difference between the 370BX and the 372X in terms of mounting slot distance is only 50mm there's no problem at all! :)

Because that means we can make the distance for the PSU board mounting holes somewhere in the middle and it will fit both  ;D

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on May 09, 2018, 10:46:58 AM
Great!!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on May 21, 2018, 09:13:02 PM
Hi guys, our meters have all been tested for ballistics and correct operation and all our order is on its way here ready to despatch to you all! Cheers

Moltenwok,
Any update for those who ordered meters and 0-17 shields? When will you be shipping them? Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on May 22, 2018, 03:57:53 AM
Hi guys, finally got them here after customs clearance which took over a week and more money. Will be posting out on Thursday, cheers johnny
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on May 22, 2018, 11:20:31 PM
Thanks Johnny!

Also heads up to all y'all. I have an extra UTC A18 available. The auction I purchased from sold as a pair and I only need one. PM or email if interested.

-B
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on June 05, 2018, 05:29:44 AM
Hi Raiton!
News?
When do you think could be ready to shipment?
Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 05, 2018, 09:26:31 AM
Yeah,
Everything Is ok.......No problems on delay....
Thanks!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 05, 2018, 10:19:46 AM
Sorry guys - posted everything over in our FB group and didn't  post it here.

I'll copy and paste it - hang on...

"A quick heads-up
Unfortunately we have a delay for the 176

1. the 2nd front panels were supposed to be silk screened last week already but they painted the panels black in order to print the white scales etc. afterwards.
The quality was not what I expected and besides, when placing the order we actually agreed they would silk-screen the panels black - and then add another (white) layer on top...why tried to do it differently I have no clue...
2. the manufacturer of the main chassis and front panels
was ordered to do like 60 (or so) kits with API cutout and around 20 pieces with SIFAM cutout...well they did it the other way round :(
The only good thing is that they let me know before powder coating them, and since the API cutout is larger than the SIFAM, now 40 panels have to be modified with a CNC.
But they can't do it there in the factory because the panels are already bent and welded, so I had to have them shipped somewhere else etc...
...you see it sounds like a lot of fun...NOT.
Anyway all of that means the kits need at least 2 weeks extra until they are finished - what a drag.
I'm really sorry you have to wait so long guys - I'm working on it..."

As for not getting back - sorry John I get like over a dozen of mails every - and that's only the ones concerning my projects.
To most of them I get back very quickly - if I don't get back to you within 3 days, your mail is most likely lost in the abyss created by new mails coming in...

From my experience it happens that some problems occur in the supply chain - problems that are causing delays.
That's especially the case when doing new projects - but even with projects I did almost half a dozen times such as the LA2A it can happen.
Like this time when the powder coating just wasn't good enough and I had the company that does it redo all 50 LA2A front panels.
It causes delays, but in the end it's about getting a great product.

It's totally my bad though that I posted the update to the FB group only and didn't post it here.
As a matter of fact I found a Safari tab where I began to post a reply here, but never finished it...guess I was being distracted at some point...

Again sorry  guys - I fixed the wrong cutouts by now and all 176 panels were forwarded to getting powder coated with the rest of the chassis.

Martin
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on June 05, 2018, 02:04:57 PM
Thanks Martin
for all info!!!
And thanks for your great work!!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on June 05, 2018, 03:41:53 PM
No worries Martin, thanks for the heads up.  Can someone post a link to the FB group? I'd like to join. Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on June 05, 2018, 04:20:37 PM
All good Martin,  like a good cheese these things take time to mature, thank you so much for your  massive efforts to the DIY community
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 07, 2018, 04:21:09 PM
No worries Martin, thanks for the heads up.  Can someone post a link to the FB group? I'd like to join. Thanks!

Here's the link to the FB group:
https://www.facebook.com/groups/1615927638648181/

:)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on June 12, 2018, 11:21:52 PM
Hi guys, meters and shields were posted out on 31 May. Please let me know when they arrive so I can stop worrying about the post. So far its cost me over 300 to help you all out, so I hope they all arrive. Cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on June 16, 2018, 04:46:51 PM
Hi guys, meters and shields were posted out on 31 May. Please let me know when they arrive so I can stop worrying about the post. So far its cost me over 300 to help you all out, so I hope they all arrive. Cheers

Mine arrived, yes. Thank you so much for helping us out on this one molten. Sorry to hear that the process ended up costing you more than anticipated. Super appreciated!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 17, 2018, 12:37:11 AM
Has anybody made any inquiry regarding the caps? I'm not sure on what specs are needed to ask myself.

Anxiously awaiting to start on this project.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 17, 2018, 12:21:23 PM
I have a real 175b....
I was able to find the 40,40,40,40 uf by CE Manufacturing...But As stated before they stopped making the 20/20uf 450V..
And I have been looking and looking with no luck...
Im thinking all the CE Manufacturing where just relabeled  NOS sprague caps. No reason they would stop making them If they
where being sold.
Hopefully a company will make these along with the hard to find 10/10uf 450V circuit board mount can cap. Of course you can use
two single electrolytic caps....
But would be nice to have exact proper caps. I was able to score a couple NOS 10/10uf on eBay..... For recapping my original and
doing one kit.
Anybody have links to can caps that we need? Please post! :-)
Thank,s
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 17, 2018, 03:31:18 PM
Good news everyone!!

The chassis are powder coated and on the way here.
Also the front panels are silk screened and and should be here Monday or Tuesday!

I haven't seen neither yet, but I was told they all came out pretty nicely! I can tell you more once I have them here.

Livingnote is about to finish the handmade pcbs and he told me I should have them in the mail later this week.
The turret boards are CNC'd and they should arrive later this week as well.

The only thing left to do now for me is adding the fork turrets to all pcbs & turret boards...
This will take me a couple of days once I have the boards, since it's roughly 50 turrets per kit!!

But we're getting closer now :) 

Martin
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 17, 2018, 06:49:38 PM



Good news everyone!!

The chassis are powder coated and on the way here.
Also the front panels are silk screened and and should be here Monday or Tuesday!

I haven't seen neither yet, but I was told they all came out pretty nicely! I can tell you more once I have them here.

Livingnote is about to finish the handmade pcbs and he told me I should have them in the mail later this week.
The turret boards are CNC'd and they should arrive later this week as well.

The only thing left to do now for me is adding the fork turrets to all pcbs & turret boards...
This will take me a couple of days once I have the boards, since it's roughly 50 turrets per kit!!

But we're getting closer now :) 

Martin

Excellent! :-) Now you see why originals are so much! :-))) ALOT of work as you know! To make this type of compressor with NO short cuts! Great work Martin! Did you see the one on eBay right now for $11,000 !!!!!!
:-))))))

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 17, 2018, 10:48:32 PM
I did find some CE Manufacturing capacitors that were 20/20/10/10uF and was wondering if this could be used for C8a/b and C9a/b or if they needed to be separate components.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 17, 2018, 10:57:50 PM
Another silly question:

I'm looking at the Daven 600/600 attenuators that are listed on the BOM, but the ones I've found do not have threaded shafts to mount to the chassis as shown on the first page of this thread. They have screws that attach to the body of the attenuator. Does the chassis have mounting holes for this or do I just need to find ones with threaded shafts?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 17, 2018, 11:13:37 PM
I think Martin said he would have hidden counter sunk?
Under the faceplate......But most real ones have threaded shafts.........
J
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 18, 2018, 01:37:53 AM
All the Langevin ones seem to have the threaded shaft, but the Daven 600/600 ones I've found so far do not seem to be. I'm also bad at the Internet.

Another question I have regarding the Daven stepped attenuators is that I have found some with different dB ratings but are still 600 ohm. What is the gain range for the input and output needed for the UA 176?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 18, 2018, 01:45:04 AM
No hidden countersunk holes - sorry.

But it shouldn’t be a problem to drill two little holes into the chassis front-panel to be hidden underneath the black faceplate.

The only thing though:
The faceplate is held in place by all the nuts used to mount the pots & switches on the front.

In the above mentioned case two rather important nuts would be missing.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 18, 2018, 01:45:40 AM
I think Martin said he would have hidden counter sunk?
Under the faceplate......But most real ones have threaded shafts.........
J

It looks like they have a plate that goes with them that has a threaded part that goes over the shaft.

https://www.ebay.com/itm/173254186435?rmvSB=true

The ones I initially found are missing this part, hence the confusion.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 18, 2018, 01:47:23 AM
No hidden countersunk holes - sorry.

But it shouldn’t be a problem to drill two little holes into the chassis front-panel to be hidden underneath the black faceplate.

The only thing though:
The faceplate is held in place by all the nuts used to mount the pots & switches on the front.

In the above mentioned case two rather important nuts would be missing.

No worries. I can figure something out. I was just trying to make mine as sweet as yours but may have to just go with the Bourns option.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 18, 2018, 01:54:14 AM
All the Langevin ones seem to have the threaded shaft, but the Daven 600/600 ones I've found so far do not seem to be. I'm also bad at the Internet.

Another question I have regarding the Daven stepped attenuators is that I have found some with different dB ratings but are still 600 ohm. What is the gain range for the input and output needed for the UA 176?

Thanks!

Paul


The original ones are 40db with 2db steps - 20steps

The ones you posted have 5db steps - a little bit difficult to adjust the comp with 5db steps ;)

The original was 2db steps with additional “vernier” pots on input and output for fine tuning
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 18, 2018, 02:15:09 AM
Copy 40dB.

What I think I have decided to do is to make my own stepped attenuator so that the resistor values with more closely matched than vintage ones, especially since I'm building a pair. I'm going to start working on a layout and if I works I'll post it here.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 18, 2018, 11:00:25 PM

The original ones are 40db with 2db steps - 20steps

The ones you posted have 5db steps - a little bit difficult to adjust the comp with 5db steps ;)

The original was 2db steps with additional “vernier” pots on input and output for fine tuning
I went a bit OCD trying to find the exact attenuators for this - Martin you really scored to get the originals for such an amazing price.

Here are some interesting parts, some of which might work. See EDIT note below for exact vintage part numbers for the exact parts.

Daven:
   • LA-353-G: Part Rainton used - 600/600 Ladder, 20 steps, detents, 40DB reduction, threaded bushing mount
   • T-257-G: 20 steps, 2DB/Step, 600/600, "T", no taper, 40DB total, Detents
   • T-320-G: 20 steps, 2DB/Step, 600/600, "T", no taper, 40DB, Detents, last step infinity
   • T-520-G: 20 steps, 2DB/Step, 600/600, "T" - 1% precision
   • P-350: 2DB/Step, Infinite, Linear
   • P-354: 2DB/Step, Infinite, Tapered
Langevin:
   • RMX-601: "T" 20 step 2DB/Step, 1-gang, infinity cutoff
   • RMX-601-2: "T" 20 step 2DB/Step, 2-gang, infinity cutoff
   • RMX-601-3: "T" 20 step 2DB/Step, 3-gang, infinity cutoff
   • RAT-631: 20 steps, 40DB, 2DB/Step, linear, no infinity, detented positions, Unbalanced Ladder
   • RAT-633: same as above, Balanced Ladder
   • RAT-601: same as above, Bridged "T"

After many, many months of hunting the snipe - the elusive LA-353-G, Daven 600R 2db stepped 40db total attenuator complete with bushing threads, or a corresponding Langevin, I gave up and contacted Shallco directly and had them custom made. I'm not going to tell you how much that cost.

Looking forward to (eventually) doing this project. Great job Rainton!!!

Mike

EDIT: in post https://groupdiy.com/index.php?topic=66175.msg882754#msg882754 (https://groupdiy.com/index.php?topic=66175.msg882754#msg882754)John shares the exact part numbers from a vintage unit.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 18, 2018, 11:42:50 PM
I am going to be using 2x24 position Elma switches to build ladder and t-pads. I think I will be better served with newer components in this position. And I wanted to learn how to do it. I found some formulas and plugged them into Excel to come up with the resistor values.

I also contacted Hayseed Hamfest and they are willing to produce the same multi section caps that they provided Martin, so I'm just going to order from them and keep it simple. They said that the tabs on their capacitors will need some minor trimming to fit these boards but shouldn't be a problem for anyone experienced enough to take on this project. Pricing is reasonable, especially for a low quantity custom order.

Can't wait to get started on this!

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 18, 2018, 11:44:08 PM
I went a bit OCD trying to find the exact attenuators for this - Martin you really scored to get the originals for such an amazing price.

As far as "original" specs this is what I dug up, along with related similar parts:

Daven:
   • LA-353-G: Actual Part used as per rainton in previous thread here - 600/600 Ladder, 20 steps, detents, 40DB reduction, threaded bushing mount
   • T-257-G: 20 steps, 2DB/Step, 600/600, "T", no taper, 40DB total, Detents
   • T-320-G: 20 steps, 2DB/Step, 600/600, "T", no taper, 40DB, Detents, last step infinity
   • T-520-G: 20 steps, 2DB/Step, 600/600, "T" - 1% precision
   • P-350: 2DB/Step, Infinite, Linear
   • P-354: 2DB/Step, Infinite, Tapered
Langevin:
   • RMX-601: "T" 20 step 2DB/Step, 1-gang, infinity cutoff
   • RMX-601-2: "T" 20 step 2DB/Step, 2-gang, infinity cutoff
   • RMX-601-3: "T" 20 step 2DB/Step, 3-gang, infinity cutoff
   • RAT-631: 20 steps, 40DB, 2DB/Step, linear, no infinity, detented positions, Unbalanced Ladder
   • RAT-633: same as above, Balanced Ladder
   • RAT-601: same as above, Bridged "T"

After many, many months of hunting the snipe - the elusive LA-353-G, Daven 600R 2db stepped 40db total attenuator complete with bushing threads, or a corresponding Langevin, I gave up and contacted Shallco directly and had them custom made. I'm not going to tell you how much that cost.

Looking forward to (eventually) doing this project. Great job Rainton!!!

Mike

Hi Mike,
Not trying to rain on your parade!...But the most Common ACTUAL used where the smaller Langevin and Smaller Daven attenuators!
I have an original and the most common Langevin was the small Model 1923 non balanced and mine also has a very rare output being the Cinema engineering 7250 on the output. These are original with untouched solder joints.......
The Cinema is one of the coolest looking done in Blue anodized with a yellow sticker.........
Anyway there are a few units that you will see with the larger stepped attenuators. But the many I have seen in person and in pictures tend to have the small Davens and the smaller Langevin Attenuators.
This is what was happening in the mid 1960,s. The larger Attenuators are left over from the 1950,s.
Of course most 600/600 2 db step 40db will work in these units.....

Very cool you where able to get Shallco to make these.....Maybe we should have had a group buy.????
:-)
Best,
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 20, 2018, 03:15:31 AM
Hi Mike,
Not trying to rain on your parade!...But the most Common ACTUAL used where the smaller Langevin and Smaller Daven attenuators!
I have an original and the most common Langevin was the small Model 1923 non balanced and mine also has a very rare output being the Cinema engineering 7250 on the output. These are original with untouched solder joints.......
The Cinema is one of the coolest looking done in Blue anodized with a yellow sticker.........
Anyway there are a few units that you will see with the larger stepped attenuators. But the many I have seen in person and in pictures tend to have the small Davens and the smaller Langevin Attenuators.
This is what was happening in the mid 1960,s. The larger Attenuators are left over from the 1950,s.
Of course most 600/600 2 db step 40db will work in these units.....

Very cool you where able to get Shallco to make these.....Maybe we should have had a group buy.????
:-)
Best,
John
Hey John - no worries man! It's kind of hard to get the info on these kinds of things, so I welcome your input! Yeah the Shallco's are pretty big though! I would much preferred to have found vintage units but could not seem to find any after many, many months of diligent searching.

I tried to find a Langevin "model 1923" you shared but could not. Is that the exact part number? If not, can you share the exact numbers/model number etc.  from the attenuators, if that isn't too big a deal?

Any more data on what the exact parts were for other units is most welcome.

Thanks!

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 20, 2018, 10:29:00 AM
Hey John - no worries man! It's kind of hard to get the info on these kinds of things, so I welcome your input! Yeah the Shallco's are pretty big though! I would much preferred to have found vintage units but could not seem to find any after many, many months of diligent searching.

I tried to find a Langevin "model 1923" you shared but could not. Is that the exact part number? If not, can you share the exact numbers/model number etc.  from the attenuators, if that isn't too big a deal?

Any more data on what the exact parts were for other units is most welcome.

Thanks!

Mike
Yeah,
I hear you! I search very day just about ! OCD...:-) I will take some pics and dig up some specs....But If I recall when you pull
up the Langevin model #,s They will actually show the spec. If It is just one #. As in Langevin  TYPE 1923 .
Will get back to you!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 20, 2018, 04:16:57 PM
Yeah,
I hear you! I search very day just about ! OCD...:-) I will take some pics and dig up some specs....But If I recall when you pull
up the Langevin model #,s They will actually show the spec. If It is just one #. As in Langevin  TYPE 1923 .
Will get back to you!
John
Thanks John. Lady Google doesn't find that part number, but I'm sure someone could find it in some old catalog...

Thanks!

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mro on June 21, 2018, 10:10:33 AM
Hi guys, meters and shields were posted out on 31 May. Please let me know when they arrive so I can stop worrying about the post. So far its cost me over 300 to help you all out, so I hope they all arrive. Cheers

0-17 shield made it's way to Warsaw, Poland. Thank you Johnny!

As for the Daven attenuators I'v spotted at least five of them (600/600, 40dB att 2 dB pre steb, sometimes with the knob) for under 70$ on ebay since Rainton started the project . I didn't go for it since I want to use just T-pads in those spots and in place of verniers put a meter switch and (possibly) a SCF. But if you want Daven or Schalco for a fair price it's doable, just be patient  ;)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 21, 2018, 03:48:06 PM
0-17 shield made it's way to Warsaw, Poland. Thank you Johnny!

As for the Daven attenuators I'v spotted at least five of them (600/600, 40dB att 2 dB pre steb, sometimes with the knob) for under 70$ on ebay since Rainton started the project . I didn't go for it since I want to use just T-pads in those spots and in place of verniers put a meter switch and (possibly) a SCF. But if you want Daven or Schalco for a fair price it's doable, just be patient  ;)
Ah but the devil is in the details. I too have been watching those, and most have an "off" on the last step. I actually watched these for months and months and months. You probably don't want one with an "off."

Also, the other even bigger issue is the mounting. Most of the Davens I saw do not have the threaded bushing mount that will fit the original part; they have 2 screws which would require some drilling/jery rigging.

In any case, good luck!

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 21, 2018, 03:56:28 PM
I ordered some 2x24 Elma switches and I'm going to work out how to do ladder and T-pads out of them. I've worked out the numbers for the ladder but haven't settled on a good way to do the T-pad. I'll let you guys know when I get this sorted. Hopefully it will be a good alternative to trying to source old switches.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 21, 2018, 06:11:08 PM
I ordered some 2x24 Elma switches and I'm going to work out how to do ladder and T-pads out of them. I've worked out the numbers for the ladder but haven't settled on a good way to do the T-pad. I'll let you guys know when I get this sorted. Hopefully it will be a good alternative to trying to source old switches.

Thanks!

Paul
In the long run it will probably be easier!

Although, "old switches" may be an accurate term, believe me those Daven's are ANYTHING but ratty! They have incredible build quality and feel and were made to last a 100 years, literally. Silver contacts, built like tanks. There's a reason they go for so much money. ;)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 21, 2018, 06:34:26 PM
In the long run it will probably be easier!

Although, "old switches" may be an accurate term, believe me those Daven's are ANYTHING but ratty! They have incredible build quality and feel and were made to last a 100 years, literally. Silver contacts, built like tanks. There's a reason they go for so much money. ;)
[/quote

This is actual FACT! Not Just the Davens..But also these small sealed Langevins in my original 175b...Still feel great and NO scratchy noise!
The build quality of most early Pro Audio is nothing like it.......
I have Vintage Altec A322C with Big  Davens original..from early to mid 50,s.........Still work great!!!! Pop the back off and clean the contacts....Good as new. This stuff is working ART as far as I am concerned....
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on June 22, 2018, 08:24:53 PM
Hey guys,

I've posted this to the FB group already, so I'll also post it here:

I have good news and not so good news:

The good news first: The 176 chassis arrived and as far as I could check they all look absolutely great!

The not so good news:
The 176 faceplates arrived as well and unfortunately the quality of the print is far below my expectations to say the least. It's actually intolerable.

The faceplates (to be mounted on top of the chassis front panel) are made of thin aluminum which is then silkscreened black and finally aa white silkscreening on top. The white print actually looks good, but that's about it.

I really don't get it - it's the same printing house that does all my panels - and looking at the tube opto - they all look very good. (I have to add though that all the tube opto comp and Pultec style front panels get powder coated elsewhere and only the scales etc. are silkscreened.)

Anyway, the black printing seems to have all kind of dust & dirt underneath, some have scratches across the panels and some panels are even bent or have dents.

Even the ones that look better still not meet my expectations of a high quality product which is what I want to deliver.
I even talked to their boss last week and he said they are all ok except one - he actually said they came out pretty nicely...and when I opened the package I was like WTF?! What were they thinking?

Folks, I know you all have been waiting for a long time now, and I'm really sorry about that, but I just can't send out kits with faceplates like that. It's one of the most important parts of the entire kit and it has to be perfect!

What I'm gonna do now: I will get in touch with the printing house on Monday letting them know that what they delivered in terms of the 176 panels is not acceptable.
I want them to refund the expenses for the laser cut aluminum face plates I provided as they messed up my entire batch.

Furthermore I already talked to the company who does the metalwork and they will do another run of faceplates for me "super-express" - meaning within a couple of days.

Then I won't send them to the printing house to have them printed black, but will have all panels anodized black instead.
That's more expensive, but judging on the anodized tube opto compressor parts it should look amazing. The draw back is that this step can take up to two weeks until we can forward the panels to have the scales etc. printed on them.

If I can come to an agreement with the printing house regarding the messed-up panels I will also tie them down to print the new panels as soon as they reach their doorsteps.(usually lead time is 2-3 weeks)
Again I'm very sorry guys, but it especially since we all have been waiting so long, I owe it to you to deliver nothing but a great product - and that's what I'm gonna do...
I attached some pics, so you know what I'm talking about.

(https://www.mediafire.com/convkey/ba4d/0v4nv5pcb2uwd305g.jpg)

(https://www.mediafire.com/convkey/0e31/yqqa5s10peukw2n5g.jpg)

(https://www.mediafire.com/convkey/c550/26az3uinqx1rgp05g.jpg)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 22, 2018, 08:34:24 PM
No Worries Martin,
Huge undertaking...But yeah those look like sh*t.....:-)...........I want them like the one you posted! At beginning of thread!
Appreciate the perfection because that is what I want!
Thank,s
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on June 22, 2018, 09:21:46 PM
Also for me no problem
and thanks for your great work!!!
Thanks!!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 22, 2018, 11:41:02 PM
All good, brother.

Do what you need to do and just know that there is no pressure or malicious thoughts directly your way from the rest of your DIY compatriots. This is totally out of your control.

The upside is this gives us more time to gather parts.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 23, 2018, 01:29:35 AM
Martin I've been nothing but impressed with what you do, so if you feel it needs to be redone, then it does. I know everyone supports you here in that regard.

Best,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 23, 2018, 01:32:18 AM
By the way, does anyone know if the main knobs are 1.5" diameter? I found both 1.5" and 2". Damn bakelite is expensive if you want the real deal.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 23, 2018, 10:37:51 AM
I bought the real deal......1.5" on the real unit. I bought two for $30 good deal! They should say Viz on the back in a small circle.
Hope that helps.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on June 23, 2018, 04:44:53 PM
I bought the real deal......1.5" on the real unit. I bought two for $30 good deal! They should say Viz on the back in a small circle.
Hope that helps.
John
Good on ya!

Yes that really helps thx John! Envy you got a real unit! Good for you!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 24, 2018, 02:01:57 PM
For anybody looking for proper voltage Power Transformer and size.

650V CT  6.3V and 5.0V      USA Made.

He has another batch coming........

https://www.ebay.com/itm/PT325-2-USA-POWER-TRANSFORMER-TUBE-AUDIO-650Vac-325-0-55-325-x90mA/163082066284?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on June 29, 2018, 04:27:40 PM
Hey guys, was just wondering if there was a preferred tube manufacturer for all the tubes. Would NOS RCA's work well? Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on June 29, 2018, 04:29:06 PM
For anybody looking for proper voltage Power Transformer and size.

650V CT  6.3V and 5.0V      USA Made.

He has another batch coming........

https://www.ebay.com/itm/PT325-2-USA-POWER-TRANSFORMER-TUBE-AUDIO-650Vac-325-0-55-325-x90mA/163082066284?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

Do you know the original Power Transformer specs? And is this one closer compared to the Hammond?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on June 29, 2018, 06:26:56 PM

Original is 117V 60 cycle 650V CT  6.3V and 5.0V .  I have been searching all over for the original. And Chicago transformers
are one of the ones I see the most with the 117V .

I found a Stancore model that had exact specs but was physically smaller.....I am sure that the original can be had. And I am still
searching.

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 29, 2018, 11:48:04 PM
What is the lead spacing needed for C3 and C4 to match the PCBs?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on June 30, 2018, 10:10:27 PM
Also, does anyone have any modern recommendations for C6 & C7? There seem to be an abundance of old Soviet old caps, but I'm not too keen on using old oil caps for the obvious reasons. Would I just find an axial film equivalent and install it inside the case? I'd like to make use of the cutouts on the case for aesthetics, but ultimately I'm more concerned about how it sounds.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 01, 2018, 11:53:58 AM
Nothing wrong with Oil can capacitors! They last forever If they do not lose their oil. I have them in a lot of my vintage gear....
I had only one that has physically leaked.
Older gear was made with better raw materials in my opinion.  But many poly caps can be used as some have had those also.

Also here is a link for the EXACT proper mono long frame mono Switchcraft jacks. ...I put witchcraft......:-)
Universal audio used these with  the angled ground lug. So It would be out of the way. If you are going for original HI/LO
on separate jacks these are what you want for authentic build.

https://www.ebay.com/itm/253698681243?ul_noapp=true

Many people would run stereo tip/ring/sleeve witchcraft on original units and plug the two holes. Thats how my original was.
But I put it back stock.

John

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 01, 2018, 07:25:59 PM
Then if I do use oil caps I would need to know the dimensions so it would fit the cut out. Does anyone have this info?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 01, 2018, 08:05:43 PM
Yes,
Martin went with the wider ones that where on some of the later UA 176.  Double check with Martin!
But I am pretty sure these are the wide spacing ones he went with.....

https://www.ebay.com/itm/222628240213

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 01, 2018, 08:12:36 PM
Sounds great. Standing by.

The last couple of bits I still haven't sorted out are the trimmer values for plate, cathode, and meter zero, and how many decks are needed for each rotary switch. I did not see this info posted earlier in this thread so forgive me if they have.

Also, does anyone have a link for the correct terminal board and screws for this project?

I believe that is all I am missing to finish this project.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 01, 2018, 08:19:07 PM
All linear potentiometers -  Cathode  100 ohms and Plate  1K, GR zero  1K  . Modified post to show link above for oil can caps!
I believe switch ( 3 ) is a 3 pole 3 position and it is single deck.

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 01, 2018, 08:52:39 PM
Thanks for the info and the link.

The BOM calls for 0.5uF and the one in the link are 1uF. Does this difference in values matter for what these capacitors are doing in this circuit?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 01, 2018, 09:18:28 PM
Usually
You can always go a little higher in rating without ever hurting anything.  My original UA 175b has 1.0uf 600v oil cans.
Hope that helps!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 05, 2018, 06:23:09 PM
Thanks for all the replies!

One last one (for now), where can I find the correct mounts for O-1 to attach it to the chassis. From the pictures it looks like it is some sort of tube mount.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 05, 2018, 06:48:41 PM
Ebay.....
$20 bucks....Studio electronics....But you can probably find for cheaper If you want to save. I think its pretty much a capacitor clamp
for chassis mount.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on July 08, 2018, 02:51:16 PM
Hey guys! just wondering a couple things:

What rotary switches did the original UA 176 use? I was looking at elma switches and was wondering if those are ok?

Also, what is the correct jewel lamp cover for this unit? I didn't see anything about that on the BOM.

Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on July 08, 2018, 03:02:16 PM
Sorry, forgot to ask, what is the diameter of the smaller front panel knobs (ratio, veneer, etc)? Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mutterd on July 23, 2018, 12:24:16 AM
Hey Everyone,

I know this has been closed for a while, and for sure this is a long shot - but Rainton - if you happened to make a spare one of these  kits thats not yet claimed, or if anyone has an extra one of these kits kicking around, or if someone got multiples and has since changed their minds - please let me know.

I'll take it off your hands - I would love to get in on this!

Thanks!
Timothy



Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on July 23, 2018, 06:59:26 PM
Sorry, forgot to ask, what is the diameter of the smaller front panel knobs (ratio, veneer, etc)? Thanks!
I believe it's 3/4" - can anyone verify this?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 23, 2018, 11:46:14 PM
YES...3/4" originals very hard to find now...reissues on eBay...Studio electronics.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on July 25, 2018, 06:12:59 AM
Hey guys,
I have news concerning the 176 panels.
We had another badge of them made - this time anodized black and they are already at the printing house.

Now the owner called me and said they were about to print the panels but taking a closer look, in his opinion the quality of the anodic layer is not up to par with our demands...

...and if they should still go on printing the panels it would completely up to my responsibility.

Well, I couldn't judge from the pic he sent me, so we decided he would send all panels to me, so I can judge for myself.

If I think they are good enough, I will send them back to the printing house for printing - BUT they're closed next week and the week after for holidays...

If they are not living up to my expectations we'll have to have them re-done anyway...

I don't know what it is that makes this project so complicated...duh!

Besides - I received the CNC'd turret boards last week hoping they would be ready to stake the turrets.
But the holes for the turrets were too small!! Checked my dxf files and the hole diameter was correct there.

Right diameter should be 1.52mm and the holes in the boards were merely 1.2mm.
Turned out the CNC get's pretty unprecise when moulding into fiberglass boards for values below 2mm - especially when the holes have to be that deep.
All boards went back to the manufacturer straight away and the holes will now be drilled instead of moulded..

Anyway I'll hang in there until we have some proper kits!
I'll keep you posted on the progress.

Sorry for that epic delay guys!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 25, 2018, 09:11:30 AM
Just curious?
How come you cant just have the people who did the one of your proto type? Do them?
That one looks great from the pictures?
Thank,s
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on July 25, 2018, 11:26:57 AM
I don't know what it is that makes this project so complicated...duh!

----

Anyway I'll hang in there until we have some proper kits!
I'll keep you posted on the progress.

Sorry for that epic delay guys!

It's your epic dedication to quality and detail, and it's totally worth the wait. Thank you!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: xarolium on August 01, 2018, 10:26:58 PM
Hi guys, meters and shields were posted out on 31 May. Please let me know when they arrive so I can stop worrying about the post. So far its cost me over 300 to help you all out, so I hope they all arrive. Cheers

I contacted moltenwok a month ago to tell him that i still not get my package with API 361 meters,
He told me to wait, but today still nothing so i asked him to be refund and he told me that he doesn't want.
So i paid 100$ for nothing and i still missing the API 361 meters to complete my 176 build.

If someone have a pair of spare API 361 i'm in to buy it ;)
Let me know

thank you
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on August 01, 2018, 11:37:23 PM
Well obviously you'll get your money back as you've lodged a PayPal claim, it's unfortunate that you haven't received the meters. So this exercise of helping people obtain parts will now have cost me over 400 dollars, where I simply could have just got my own.... Cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: xarolium on August 06, 2018, 12:23:07 AM
Well obviously you'll get your money back as you've lodged a PayPal claim, it's unfortunate that you haven't received the meters. So this exercise of helping people obtain parts will now have cost me over 400 dollars, where I simply could have just got my own.... Cheers
although I made a request on paypal, as the transaction is more than 4 months old. Paypal can not do anything for me.
So I will ask you to send me the amount of 100USD to the following address: xarolium(at)hotmail(dot)com

Thank you
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jefepeters on August 10, 2018, 10:38:35 AM
Apologies if this was already posted, but I just noticed Hayseed Hamfest has listed a capacitor kit for this project: https://hayseedhamfest.com/products/ua-176 (https://hayseedhamfest.com/products/ua-176)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Spaceyjb on September 07, 2018, 03:54:56 PM
Apologies if this was already posted, but I just noticed Hayseed Hamfest has listed a capacitor kit for this project: https://hayseedhamfest.com/products/ua-176 (https://hayseedhamfest.com/products/ua-176)

I hope I do not steal the Topic, but I think it is good idea to try Group buy for capacitor set:

If there is enough of us from Germany ( mybe even rest of the EU). We can even save some shippment money, if we order alltogether. I run a small a company with all the necisties for importing out of the U.S. and VAT registration, which should make all the process even cheaper for us. So PM me if you would 100% go for groupbuy so I can ask about special pricing.

cheers Jan
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on September 30, 2018, 10:56:48 PM
This is starting to be a loooong time....?

Any updates? Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on October 11, 2018, 06:16:44 AM
Sorry for the delay again folks,

In the meantime, after having the faceplates manufactured for the 2nd time I went through every single panel - and still more than 20 were not living up to my expectations.
So I had them re-done - for the third time(!)

The manufacturer told me that they were delivering German industry standard (which is actually rather high), but if that wasn’t enough for me, I should look for another supplier in the future...

Anyway, I received word yesterday that the 3rd run of faceplates was finished and the quality is supposedly very good.

They are on the way here now.
If they are all ok, the entire bunch is going to the printing house again and hopefully ready for shipping end of next week.

We’ll see. After all I went through with this project, I still try to stay optimistic.
So far it was the most obstacles I experienced with any of the projects I did so far.

The good thing is, that the chassis came out absolutely perfect - powder coating is flawless & the overall quality is outstanding!
To shorten the wait some pics of the actual production chassis with mounting brackets for the 1/4" jacks and the meter switch - I'll take some pics of the turret boards and pcbs when I'm at the studio tomorrow :)

(https://www.mediafire.com/convkey/cdd9/o6p40584wjn8ti05g.jpg)

(https://www.mediafire.com/convkey/1999/igew7zlgjqzpno85g.jpg)

(https://www.mediafire.com/convkey/0d00/ql849ypsadio5725g.jpg)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on October 11, 2018, 10:56:44 AM
Looks Great!!!!
Nice work!!!!
Thanks,
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on October 11, 2018, 04:07:22 PM
Great WORK!!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on October 14, 2018, 07:32:42 PM
Fantastic news mate, thanks for your efforts
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jeanpierreisyou on October 30, 2018, 04:07:33 PM
Looks awesome! Can't wait to build it!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on October 30, 2018, 04:12:38 PM
Why not just mail Chassis out now..? That way we can get started...Faceplate is the last thing that can go on anyway!
Thanks!
Let us know.....
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on November 01, 2018, 04:10:32 PM
Why not just mail Chassis out now..? That way we can get started...Faceplate is the last thing that can go on anyway!
Thanks!
Let us know.....
Well you can see why not - shipping cost twice as much! Plus twice the hassle...
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JessJackson on November 01, 2018, 07:51:16 PM
LET ME IN ON THIS!!! :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on November 08, 2018, 10:17:55 AM
Well you can see why not - shipping cost twice as much! Plus twice the hassle...

Exactly ;)

I know it must be kinda hard to wait for so long, but believe me I'm on it :)

I just received word that the new faceplates are on the way here, so if nothing else goes wrong the first kits will finally ship next week. In the meantime I'm finishing up the turret boards and pcbs - I attached some pics.
Gentlemen - these are all handmade pcbs. Credits go out to fellow forum member livingnote who did an amazing job! I'm adding the fork turrets as we speak.

(https://www.mediafire.com/convkey/dcc7/8g1w127en8l5ilu5g.jpg)

(https://www.mediafire.com/convkey/1543/cg4j83r74d6rwq85g.jpg)

(https://www.mediafire.com/convkey/df5d/86w3q6ucxegcql95g.jpg)

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on November 08, 2018, 11:47:01 AM
Beautiful work!...Stoked..this will be fun!!!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on November 10, 2018, 12:01:38 AM
Hi team, got 4 sets of hayseed can caps today~really hoping that c9a, b is gonna fit that pcb, looks like a tag has got to go... and maybe slim down the 2 copper tags.... Cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on November 27, 2018, 10:16:48 AM
Hi team, got 4 sets of hayseed can caps today~really hoping that c9a, b is gonna fit that pcb, looks like a tag has got to go... and maybe slim down the 2 copper tags.... Cheers

Any confirmation on the hayseed caps fit @rainton?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on December 01, 2018, 03:22:10 PM
Hi All,

As we get closer to delivery wanted to share a dropbox folder containing detail images of our 4 units.

https://www.dropbox.com/sh/3ha3or8vgm096bu/AADmkFUu_M3ugOGQ_Bjp1ztha?dl=0

Also I know there was already some discussion about the attenuators earlier in this thread but wanted to clarify as I've been down that road a few years ago and there are a few confusing elements.

These are 21  POSITION stepped attenuators with 2db difference between steps.  They should feel like a 21 position switch.  I saw mentioned earlier how they felt "smooth."   The ones that feel smooth are indeed still stepped attenuators, but the control doesn't have any "positions." 

This can be very confusing as many ebay listings correctly state "stepped" attenuator, but this does not necessarily mean they are the "locking position" type.

We are looking for a 21 position, 600 or 500 ohm attenuator, "taper" (audio) scale with Off position.

If you don't mind an extra dead position at the bottom you can buy one with the "cue" position, but the originals do not have this.

These are very hard to find and I have purchased around 12 different shallco and daven attenuators only to come up with two of the correct ones.

The best bet is to stick to finding a pair of LA-350-G's "Taper and off"

LA-353-G or F or LA-352-G or F will work but they will be linear scale.

LA-351 G or F may work but the scale is 1.5db per step so won't be true to the original.

It might be more worth your time to build a 21 position switch with the correct resistors.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on December 01, 2018, 03:25:00 PM
Also worth mentioning the originals mostly used LANGEVIN rat601's  which are electrically identical to what I mentioned, however I've been searching for the better part of 4 years for them and have never seen them in the wild. They may have been a custom job for UA at the time.

Actually just found them in the Langevin catalog..... still haven't seen them around though.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on December 01, 2018, 04:56:36 PM
Yes you are correct....I was very lucky to Find original Langevin 600/600  NON position attenuators........
Will know when Installed If they work correct....But are just like the ones on my original....Same connections on back etc.....
Just smooth no positions.....
Will see..:-)
Thank,s For info!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on December 01, 2018, 05:07:13 PM
Nice John!

you may be able to convert them if you can find a pair of the locking position langevin attenuators of the same time but wrong value for our project.

The same can be said of the shallco's and the davens.  If you can find a cheap  locking position attenuator of a weird spec you sould be able to just pop the top and transfer the spring & roller mechanism to the desired attenuator.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on December 01, 2018, 05:14:31 PM
Cool!!! Good to know!!!!
Thanks! For info!!!!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on December 02, 2018, 02:06:43 AM
thanks Tubemonkey !!!
 highly inspiring


Hi All,

As we get closer to delivery wanted to share a dropbox folder containing detail images of our 4 units.

https://www.dropbox.com/sh/3ha3or8vgm096bu/AADmkFUu_M3ugOGQ_Bjp1ztha?dl=0


Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on December 05, 2018, 02:27:05 PM
Is the 600ohm T-Pad from Hairball a viable option for the output attenuator?

https://www.hairballaudio.com/catalog/parts-store/attenuators/bi-600-t-pad-attenuator (https://www.hairballaudio.com/catalog/parts-store/attenuators/bi-600-t-pad-attenuator)

Quote
Bournes 51 Series 1/2" Modular Potentiometer
Module 1: Conductive Plastic Linear Element 500Ω +/-10%
Module 2: Conductive Plastic Logarithmic Element 1KΩ +/-10%
Module 3: Conductive Plastic Linear Element 500Ω +/-10%
Shaft/Bushing: 1/4" shaft with 3/8" bushing
Shaft Length: 3/4" FMS
Shaft End: Slotted
Bushing Length: 3/8" length
Terminals - PC Pin on .1” centers
Mounting Hardware: Mounting Nut & Lockwasher
PCB Included
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on December 05, 2018, 03:27:43 PM
Exactly ;)

I know it must be kinda hard to wait for so long, but believe me I'm on it :)

Face Plate update..????  :-)   ETA ?.....Thanks! John

I just received word that the new faceplates are on the way here, so if nothing else goes wrong the first kits will finally ship next week. In the meantime I'm finishing up the turret boards and pcbs - I attached some pics.
Gentlemen - these are all handmade pcbs. Credits go out to fellow forum member livingnote who did an amazing job! I'm adding the fork turrets as we speak.

(https://www.mediafire.com/convkey/dcc7/8g1w127en8l5ilu5g.jpg)

(https://www.mediafire.com/convkey/1543/cg4j83r74d6rwq85g.jpg)

(https://www.mediafire.com/convkey/df5d/86w3q6ucxegcql95g.jpg)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on December 06, 2018, 01:34:08 PM
Is the 600ohm T-Pad from Hairball a viable option for the output attenuator?

https://www.hairballaudio.com/catalog/parts-store/attenuators/bi-600-t-pad-attenuator (https://www.hairballaudio.com/catalog/parts-store/attenuators/bi-600-t-pad-attenuator)

Yes, but it won't be "true to orginal".  If you want it to feel like an original you will have to fill out a dual deck 21 position switch.   Electrically it will work great, if you are okay with a "continuos" feel instead of a stepped feel.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on December 06, 2018, 03:40:37 PM
Thanks Tubemonkey!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on December 21, 2018, 10:26:03 AM
Hey folks,

sorry for the long silence again!
I just wanted to let you now, that 65 of the 80 kits ordered are now shipping!!!
I just forwarded the last of the first 65 orders to Don-Audio who takes care of shipping & handling for me
and he told me that due to the many orders it will take him a couple of days until he has processed all of them.
But the last one of the first 65 should be on its way by end of next week at the lastest!

The remaining 15 kits will be shipped after the xmas holidays.
But if by now you haven't received a notification from me letting you know that your kit will be among the last 15 on the list, you are obviously among the first 65  ;D 8

Happy Holidays and Merry Christmas everyone!!!

Martin
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on December 21, 2018, 02:28:39 PM
Martin,

This is amazing! Will there be a general guide available on your site or will it be posted here?

I can't wait to get started. I have most all of the parts I need to build both of mine.

Oh, and Merry Christmas to you as well!

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on December 26, 2018, 07:42:05 PM
Hi All,

As we get closer to delivery wanted to share a dropbox folder containing detail images of our 4 units.

https://www.dropbox.com/sh/3ha3or8vgm096bu/AADmkFUu_M3ugOGQ_Bjp1ztha?dl=0

Also I know there was already some discussion about the attenuators earlier in this thread but wanted to clarify as I've been down that road a few years ago and there are a few confusing elements.

These are 21  POSITION stepped attenuators with 2db difference between steps.  They should feel like a 21 position switch.  I saw mentioned earlier how they felt "smooth."   The ones that feel smooth are indeed still stepped attenuators, but the control doesn't have any "positions." 

This can be very confusing as many ebay listings correctly state "stepped" attenuator, but this does not necessarily mean they are the "locking position" type.

We are looking for a 21 position, 600 or 500 ohm attenuator, "taper" (audio) scale with Off position.

If you don't mind an extra dead position at the bottom you can buy one with the "cue" position, but the originals do not have this.

These are very hard to find and I have purchased around 12 different shallco and daven attenuators only to come up with two of the correct ones.

The best bet is to stick to finding a pair of LA-350-G's "Taper and off"

LA-353-G or F or LA-352-G or F will work but they will be linear scale.

LA-351 G or F may work but the scale is 1.5db per step so won't be true to the original.

It might be more worth your time to build a 21 position switch with the correct resistors.
My understanding was we do not want the off position. I did a lot of research on these.

My understanding is we want a 600R, 20 pos switch with no off. 2db/step, 40 dB attenuation. People are talking about “locking” but the term is “with detents.”

Any confirmation? I did internet research only, including this and other threads. I do not have an original unit.

Thx
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on December 26, 2018, 07:50:50 PM
I have an original unit..And there is NO off position!  20 position and you could use 1.5 or 2 db. steps.
Obviously 1.5 Is going to be more fine tuned...Or NO steps at all even more fine adjustments. 40DB.

But I am sure variations either way spec wise would still work. Because there is a General area that most music material
will live on the input/output settings.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on December 26, 2018, 08:34:00 PM
Many thanks John!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on December 31, 2018, 10:39:14 AM
Has anyone received shipping notification from Don Audio?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on December 31, 2018, 11:32:42 AM
nope....
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mro on December 31, 2018, 11:35:22 AM
Yeah, I did. It was on the 28th
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: ilfungo on December 31, 2018, 11:48:44 AM
Me too 28th!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on January 02, 2019, 06:02:06 PM
I received shipping confirmation on the 28th as well.  When I track it via DHL's website it doesn't look like it's actually shipped yet though.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 02, 2019, 06:40:21 PM
Yeah,
I have notice now.....So should be on its way by next week.
Will post a link I found for the proper 300 ohm wire wound potentiometers for the VERNEIR fine
adjustments. I can confirm owning a original that test are wire wound precision.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on January 03, 2019, 12:24:49 AM
Received my shipping notification today (USA).  :)


Rainton, will a build guide be released?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: salomonander on January 06, 2019, 09:19:08 AM
received my package on saturday - didn't open it up yet.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on January 08, 2019, 01:35:12 AM
Yeah,
I have notice now.....So should be on its way by next week.
Will post a link I found for the proper 300 ohm wire wound potentiometers for the VERNEIR fine
adjustments. I can confirm owning a original that test are wire wound precision.
John

Any chance we could see that link?  :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 08, 2019, 11:38:29 AM
Yes,
Sorry for delay! This place looks great!  They have min orders..so maybe a group buy for the 300 ohm precision....
They also have the MR series for maybe main input/output.....They look very high quality like the old original series.....
Lots to look through.....

State Electronics in Ney Jersey  :http://www.potentiometers.com/WW24.cfm
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: core13 on January 09, 2019, 10:37:57 PM
5w wirewound is needed here?
do you think 500r with 750R in serie with classic 2W AB pot is not enough?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 09, 2019, 11:39:06 PM
The wire wounds give a nice precision feel. Instead of a slipping all over the place.
Not  critical but If you want like the original that is what they are.

You should be fine.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on January 11, 2019, 12:01:14 AM
Thanks jslstudio - re: 300ohm wire wound pots. At this point, I'm leaning more towards just doing the 500r+750 for the sake of ease.  - I"ll keep an eye out  if a group buy comes together though.

---------------------

In the process of finalizing my Mouser cart - I just realized the version of the BOM I have doesn't have the pots for 'PLATE BAL' 'CATHODE BAL' and 'GR ZERO' listed.  Difficult to make out on the schematic that's floating around online.  Anyone have the values for these?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: core13 on January 11, 2019, 08:07:52 AM

In the process of finalizing my Mouser cart - I just realized the version of the BOM I have doesn't have the pots for 'PLATE BAL' 'CATHODE BAL' and 'GR ZERO' listed.  Difficult to make out on the schematic that's floating around online.  Anyone have the values for these?

plate bal is 1K
cathode bal is 100R
gr zero is 1K
they are all linear.

interested in 4X wirewound jslstudio you convinced me.
will go with 500R and replace later with these one, since all the parts I used are original.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on January 11, 2019, 02:08:10 PM
Just saw that jsls had answered that earlier in the thread. Thanks for info core13!

edit:

The pots that rainton used in one of the first pages of this thread are:

Cathode Bal: RV4LAYSA101A  (POT 100 OHM 2W CARBON LINEAR)
Plate Bal, GR Zero: RV4NAYSD102A (POT 1K OHM 2W CARBON LINEAR)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on January 12, 2019, 01:18:13 PM
FYI regarding use of the vernier pot.... on our vintage units I try to keep the vernier wide open... It seems dialing the vernier back gives a bit of a roll-off on the high end. Nothing drastic, but it is noticeable. Maybe due to mismatching the impedance?  Anyway just a note on practicality.    ....or you may want to use that roll off to your advantage.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 12, 2019, 01:37:27 PM
Hmmm...Mine doesn't seem to do that at all......But I just roll the output one back a bit...Input I usually leave full on.

Also note! If you adjust the RELEASE pot at the VU meter moves at all along with it. You have a going bad or BAD
6BC8 tube!!!
The Vu meter should not move when adjusting the release!
As David Kulka from studio electronics has said:
This the is very important for function and stability of unit! So It needs to be 90% or better functioning tube!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on January 19, 2019, 05:20:17 PM
The UA176 chassis arrived today - beautiful work, the front panel is crisp! Thank you @rainton

Can you provide us with an ETA on the wiring layout / build guide?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 19, 2019, 05:37:59 PM
How long did it take to arrive.?
Been two weeks when I received a notice coming from warehouse..?
Thank,s
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on January 19, 2019, 05:41:04 PM
DHL notification email on Jan 2nd . I’m in the US.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on January 19, 2019, 09:52:54 PM
Still waiting to receive a shipment notification. I do not believe I was in the group that was delayed.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on January 21, 2019, 04:31:15 PM
received mine in Nashville on January 15th. Incredible work! Thanks rainton!

EB
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TubeMonkey on January 21, 2019, 04:53:48 PM
Anybody have a spare API 361 meter and a spare UTC O-1 with shield? looking to buy :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on January 21, 2019, 08:11:40 PM
Anybody have a spare API 361 meter and a spare UTC O-1 with shield? looking to buy :)

I may have an extra O-1 but not any shields I don't think.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 21, 2019, 09:12:01 PM
I may have a extra shield..The real UTC marked one.....I think I bought two...
Let me check.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on January 27, 2019, 09:03:30 PM
Received my kit. Looks great came out great.But, The one thing that I think needs to be addressed is the PSU Turret board.
It barely fits the original 10ohm and 30 ohm Koolohm resistors.
And In my opinion to thin.
These Boards get very hot!!! I ave a original....It twice the thickness almost then the kit one.  And the turrets should be large
on the PSU board.

The good thing is this board is easy to make. But It is to small and thin. Just a Heads up...It will work.
But should be thicker and more spaced out for the original Koolohms.

Git looks great though!!! Nice work......
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on January 28, 2019, 12:53:03 PM
Just got the pre-shipment notification from Don Audio. Looking forward to starting on these. I guess I should start building those ladder attenuators I mentioned earlier. I have a some two deck Elmas that I'm going to use to make them, and I made some notes for the resistors needed, but those notes got lost in shuffling and cleaning during some renovations over the last couple of months. So unless someone here has already made some and would like to share that information, I may have to go back to the drawing board...

I still lack output transformers and some potentiometers for internal calibrating.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: salomonander on January 29, 2019, 07:11:24 PM
Received my kit. Looks great came out great.But, The one thing that I think needs to be addressed is the PSU Turret board.
It barely fits the original 10ohm and 30 ohm Koolohm resistors.
And In my opinion to thin.
These Boards get very hot!!! I ave a original....It twice the thickness almost then the kit one.  And the turrets should be large
on the PSU board.

The good thing is this board is easy to make. But It is to small and thin. Just a Heads up...It will work.
But should be thicker and more spaced out for the original Koolohms.

Git looks great though!!! Nice work......
John

argh that doesn't sound too promising.  it would be a bummer to build this and have bend boards down the line.... maybe martin can comment? id rather pay for some new boards i think
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mikebalboa on January 29, 2019, 07:19:55 PM
My understanding is that since that board gets very hot, there are cases where the actual board starts to become conducive due to becoming burnt and turning into carbon.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: salomonander on January 30, 2019, 04:04:12 PM
Received my kit. Looks great came out great.But, The one thing that I think needs to be addressed is the PSU Turret board.
It barely fits the original 10ohm and 30 ohm Koolohm resistors.
And In my opinion to thin.
These Boards get very hot!!! I ave a original....It twice the thickness almost then the kit one.  And the turrets should be large
on the PSU board.

The good thing is this board is easy to make. But It is to small and thin. Just a Heads up...It will work.
But should be thicker and more spaced out for the original Koolohms.

Git looks great though!!! Nice work......
John

ps: is this the case for the psu board only? that wouldn't be too bad. devil sits in the detail :)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: DonnieDarko on February 04, 2019, 07:37:53 AM
Hey guys,

has someone a more recent BOM than the rev 0.2 that Martin sent me a while ago?

Maybe with some mouser/digikey/farnell/banzai/audiomaintenance/surplussales/hairball links?

Would be appreciated!

Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on February 13, 2019, 07:04:36 PM
I received both of my kits yesterday and I am looking forward to getting stared on these. I have all the parts except for output transformers, a couple of the caps, and ladder attenuators. I bought some Elma switches to build some, but I can't seem to find my notes where I had it all mapped out. Has anyone made their own as opposed to using the old Daven attenuators?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: diylan on February 14, 2019, 03:51:29 PM
Hey Martin,

I received my kit a couple days ago. The build quality looks great, but there's an issue with the faceplate... it looks like the lettering/design was silk screened on the wrong side!

I have attached a picture to show the issue. Please let me know what you think would be the best way to handle this.

For anyone that received a package and put it away for the future, I would encourage you to double check as well.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TillM on February 14, 2019, 03:59:23 PM
Hey Martin,

I received my kit a couple days ago. The build quality looks great, but there's an issue with the faceplate... it looks like the lettering/design was silk screened on the wrong side!

I have attached a picture to show the issue. Please let me know what you think would be the best way to handle this.

For anyone that received a package and put it away for the future, I would encourage you to double check as well.

What do you mean ?
I don't see any issue. It looks like the original UA176.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: diylan on February 14, 2019, 05:04:34 PM
If you look at the alignment of the holes in my previous post, that's not poor positioning on my part. Most of holes are off on their alignment by at least a few mm. The holes for the front facing screws are also on the bottom, when they should be on top.

Here's a picture with the faceplate flipped (all holes properly aligned).
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on February 14, 2019, 05:57:25 PM
Hey Martin,

I received my kit a couple days ago. The build quality looks great, but there's an issue with the faceplate... it looks like the lettering/design was silk screened on the wrong side!

I have attached a picture to show the issue. Please let me know what you think would be the best way to handle this.

For anyone that received a package and put it away for the future, I would encourage you to double check as well.

That was definitely screened with the panel upside down. Hopefully Martin can get a replacement out to you.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: TillM on February 14, 2019, 05:58:38 PM
Now I see what you mean ;)
yes, that looks definitely not right
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on February 18, 2019, 04:58:51 AM
Sorry guys,

somehow the notifications don’t work anymore - after Dylan wrote me a PM I came back here to find pages of new posts on the kit...

First of all - Dylan: they printed your faceplate upside down - unbelievable :(

Even stranger that Don Audio didn’t see it when preparing the kits for shipping.

I’ll make sure you’ll get a proper replacement ASAP!

Thanks for the heads up on the PSU turret boards. Since I didn’t have an original unit here I had to judge from pics. Could you measure the thickness and turret size John?

For what it’s worth my prototype has exactly the same turret board as you all have an it’s been working fine for over a year now. It didn’t bend or get burned or whatever.
I think leaving some space between the large resistors and the board is crucial.

Those of you who are also in the analogvibes FB might have seen the progress I made on the wiring layouts.
At the moment I’m sick and in bed but when I’m up and running (and at the studio) again I’ll upload some pics here too.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on February 21, 2019, 05:57:00 AM
diylan's new faceplate is on its way I heard :)

I also attached the first screenshots of the illustrations I made for the wiring layout - here's the upper pcb front & back:

(https://www.mediafire.com/convkey/3fad/8ucthkz5tqewxm65g.jpg)

and the lower pcb:

(https://www.mediafire.com/convkey/c7c6/bbpmsbjr1e6cuco5g.jpg)

It's all gonna be part of the wiring layout that shows all components - but I'm still working on it - here's another screenshot:

(https://www.mediafire.com/convkey/65ec/s4kb89m493wgckp5g.jpg)

It's a ton of work though.

I'll put together a folder with all the build pics I made while building my prototype and share the link directly with all members of the group buy...

For now here's the corrected schematic (as mentioned before there were quite some errors in there):
http://www.mediafire.com/file/w1wa7eti78ytc3s/Universal_Audio_176_Schematic_CORRECTED.pdf/file

And for those who haven't received it yet the V0.2 version of the BOM.  There's no BOM with Mouser links etc. yet, but you're welcome to contribute ;)

http://www.mediafire.com/file/zr69mu542424vfy/analogvibes_176_Parts_List_rev.0_2.pdf/file

Many builders are also over in our analogvibes Facebook group - might be worth checking out for help:

https://www.facebook.com/groups/analogvibes

hope that helps for now

Martin
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on February 23, 2019, 06:45:19 PM
Hello everyone,

I spent the day working values for a stepped 600 ohm T-pad. I've attached my calculations. See here (https://groupdiy.com/index.php?topic=71582.0)  for further explanation and wiring.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mutterd on February 23, 2019, 09:38:31 PM
Hey everyone  - I’ve looked thru the thread - so I apologize if this has been covered - but can someone confirm the size of the big and small knobs on the original?

I’m guessing it’s 2 1/8” for the big ones and 7/8” for the small?

Is that correct?

Thanks.
Timothy

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on February 24, 2019, 02:06:37 AM
Hey everyone  - I’ve looked thru the thread - so I apologize if this has been covered - but can someone confirm the size of the big and small knobs on the original?



I’m guessing it’s 2 1/8” for the big ones and 7/8” for the small?

Is that correct?

Thanks.
Timothy

No Timothy, it’s 1,5” for the big ones and 3/4” for the small ones

Martin
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: salomonander on February 24, 2019, 07:16:02 AM
do we have any source for the funky capacitors sitting on the back of the unit (the can caps and the two rectangular ones)? cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on February 24, 2019, 07:42:10 AM
https://hayseedhamfest.com/products/ua-176

rectangular ones were 0.5uF Gudeman paper in oil, pretty rare these days
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on February 24, 2019, 12:27:50 PM
The hayseed 10uf/10uf cap that attaches directly to the pcb will need a tag removed and the others modified to fit the pcb.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: DonnieDarko on February 25, 2019, 09:07:30 AM
Wow, that are some nice Illustrations @rainton ! Can´t wait to see the completed build instructions!

 I accidentally bought 2x C11 from tubesandmore.com - those are the 4x20uF/450V caps. If anyone needs those, I can sell them for what I paid for them.

Located in Germany, already paid tax and  customs for them.

Cheers!

diylan's new faceplate is on its way I heard :)

I also attached the first screenshots of the illustrations I made for the wiring layout - here's the upper pcb front & back:

(https://www.mediafire.com/convkey/3fad/8ucthkz5tqewxm65g.jpg)

and the lower pcb:

(https://www.mediafire.com/convkey/c7c6/bbpmsbjr1e6cuco5g.jpg)

It's all gonna be part of the wiring layout that shows all components - but I'm still working on it - here's another screenshot:

(https://www.mediafire.com/convkey/65ec/s4kb89m493wgckp5g.jpg)

It's a ton of work though.

I'll put together a folder with all the build pics I made while building my prototype and share the link directly with all members of the group buy...

For now here's the corrected schematic (as mentioned before there were quite some errors in there):
http://www.mediafire.com/file/w1wa7eti78ytc3s/Universal_Audio_176_Schematic_CORRECTED.pdf/file

And for those who haven't received it yet the V0.2 version of the BOM.  There's no BOM with Mouser links etc. yet, but you're welcome to contribute ;)

http://www.mediafire.com/file/zr69mu542424vfy/analogvibes_176_Parts_List_rev.0_2.pdf/file

Many builders are also over in our analogvibes Facebook group - might be worth checking out for help:

https://www.facebook.com/groups/analogvibes

hope that helps for now

Martin
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on March 12, 2019, 01:45:48 AM
I'm almost done acquiring all the parts, mostly just down to the output transformers and deciding on what to do about C6 and 7 (rectangle oil capacitors or electrolytics). But I would like if anyone has a link or part numbers for mounts that work with C8, C11, and the UTC-01 transformer.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 18, 2019, 11:41:11 PM
ps: is this the case for the psu board only? that wouldn't be too bad. devil sits in the detail :)
Other pcb boards are good. And mil is good. Just PSU.

But his boards are wider then the original (from left to right )  PSU is small and thinner then original....
Going by eye Martin  did an amazing job. But If he does another run. I would like to send him all*** original measurements*** exact!
The 20uf x 4 Hole should also be cut out larger. about the size of the rectifier hole. 
The terminal strip used the 4 screws that mount it. Tapped direct in to the chassis. with #4-40 screws.

This kit really could be nailed 100%.....
I will post pics when I get a chance....
Lots of other stuff I am still gathering..Im going for 95% original parts..I also have original UA176 logo meter.
Im also painting my chassis and transformer housing the original  GM 1964 light blue metallic.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: DonnieDarko on March 23, 2019, 03:43:24 AM
Hey guys,

I´m in the process of mounting the bigger components on the back of the unit -see attached picture.

I encountered a problem with the mounting clamp of C8 - it´s protruding into the spaced need for V4.

@rainton: Could you post a link to the mounting clamps you used on the build?

Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on March 23, 2019, 08:41:28 AM
you need a mounting plate inside
https://www.tubesandmore.com/products/mounting-plate-metal-1-can-capacitor

you can also use one for the other cap with 4 "slits"
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 23, 2019, 10:09:57 AM
you need a mounting plate inside
https://www.tubesandmore.com/products/mounting-plate-metal-1-can-capacitor

you can also use one for the other cap with 4 "slits"

I have an original...These holes are to close together.....On Raintons kit.
The 20uf x 4 Hole also should be bigger diameter closer to the open size of the GZ34 tube opening.
If you want it like the original you should also be using a flat mounting plate.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 23, 2019, 12:44:13 PM
Exact mounting hardware for PCB boards is:

Slotted metal #4-40 screw 1-1/8"  long exact   (mounting through back of chassis )
With a inner round locking washer inside unit.

Then:  3/4" long #4-40  non threaded aluminum spacer / flat round #4-40 round washer

Face of of PCB is:   #4-40 round inner tooth locking washer and a #4-40  nut with small 3/16"
drive size.

John

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: DonnieDarko on March 24, 2019, 04:12:58 AM
you need a mounting plate inside
https://www.tubesandmore.com/products/mounting-plate-metal-1-can-capacitor

you can also use one for the other cap with 4 "slits"

Thank you Kosi, I ordered those.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: DonnieDarko on March 25, 2019, 04:34:05 PM
Hey guys,

I´m having problems sourcing some of the parts needed for the build.

Maybe some of you have some suggestions where I can get these:

C3 + C4 -> BOM calls for Radial Caps (film I guess) 0.047 @630V  - I found many WIMAs and similar, but in the pics they look more like electrolytic caps. What kind of type and brand did you guys use?

C5 & C10 -> They are rated the same but seem to be different sized. What did you guys use on those?

C6+C7 -> I researched the usual shops and eBay, but didn´t find these Gudemans that are specced. Might go with Mundorf Oil Caps @450V - what you guys think?

R1+R30 -> I have some 500r PECs on the shelf, so might use these with the 750r resistor in parallel. But just out of curiousness - where could I get 300r Pots?

Lamp Holder (8mm Cut Out) -> Did you guys find a lamp holder with the proper look? I even checked the curiosity cabinet of nebraskasurplussales with their large variety of rare miniature lamp holders but couldn´t find similar looking parts.

Thanks my friends!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 25, 2019, 05:20:44 PM
I will go in to more detail when I can..I have an original 175b so I can match 100%
what is on this compressor. The exact BUSS fuse holder and cap is on eBay right now.
I just bought two. This is exactly what is on the UA.
Here is proper fuse holder......So cool most of these parts still available! :-)
https://www.ebay.com/itm/Vintage-NOS-Buss-Panel-Mount-Fuse-Holder-250V-15A-For-3AG-1-4-x-1-1-4/153399009757?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649

The Lamps are on eBay two right now DRAKE jewel lamps. The Universal audio I have seen including mine have been round smooth. But the jewel shape I have seen on a few.
You have to make sure the small with twist socket.

You should be able to find all of the original parts.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on March 27, 2019, 01:11:17 PM
Did I read correctly that Cinemag was contacted about making the output transformer? Is there been any further news to this? Are there any other transformer companies that could properly wind this strange animal?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on March 27, 2019, 05:01:34 PM
Have you checked with Sowter? Any reason you don't want to use their recreation?

Did I read correctly that Cinemag was contacted about making the output transformer? Is there been any further news to this? Are there any other transformer companies that could properly wind this strange animal?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on March 27, 2019, 05:26:55 PM
Have you checked with Sowter? Any reason you don't want to use their recreation?

Lead time and cost. Also it is my understanding that the winding isn't the same as the original. Not saying that it won't sound good, but if I've taken the time to acquire the other transformers used in the original 176 then I'd like to see if I could get an output transformer that more closely matches the early revision units. It's just a preference and not a requirement.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 27, 2019, 08:03:43 PM
I was very fortunate to get an original Reichenbach 176 output Transformer.
When he was still alive. He did a batch off of a broken 176 original output........
I contacted cinemag and gave him the number off my transformer ..But sadly could not find the documentation.
I did send him the output of the schematic with the percentage of windings etc.......
Anyway If I hear anything will let you know.....
Its definitely smaller then that sowter...:-)
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on March 27, 2019, 08:16:56 PM
I was very fortunate to get an original Reichenbach 176 output Transformer.
When he was still alive. He did a batch off of a broken 176 original output........
I contacted cinemag and gave him the number off my transformer ..But sadly could not find the documentation.
I did send him the output of the schematic with the percentage of windings etc.......
Anyway If I hear anything will let you know.....
Its definitely smaller then that sowter...:-)
John

Sounds good. I'm going pretty slow building my pair so I'm not in a rush. If they do respond please let us know.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 27, 2019, 08:24:14 PM
Cool,
Yeah I am going slow also....getting as much original as possible!
Original tube sockets are Cinch brown. And GZ 34 socket is amphenol black vintage with double loop
holes.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on March 27, 2019, 08:45:56 PM
From what I gathered the sowter is supposed to be a clone of the original, where are you finding that it isn't? What is different about the winding?

Lead time and cost. Also it is my understanding that the winding isn't the same as the original. Not saying that it won't sound good, but if I've taken the time to acquire the other transformers used in the original 176 then I'd like to see if I could get an output transformer that more closely matches the early revision units. It's just a preference and not a requirement.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 27, 2019, 08:55:09 PM
Nothing is ever going to be exact..Unless they cloned an original.
Core material? Gauge of wire? Scattered or perfect winding? It all affects the sound....
The original outputs are very small. Compared to the very large sowter. I would be curious
as to what the size of the sowter inside the mu metal case is.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on March 27, 2019, 09:01:09 PM
From what I gathered the sowter is supposed to be a clone of the original, where are you finding that it isn't? What is different about the winding?

Here:

https://groupdiy.com/index.php?topic=71002.msg904966#msg904966
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: JMarcovis on March 27, 2019, 09:24:01 PM
Was it verified that the original had a 7:1 ratio and not a 9:1? I read through that thread and didn't see a conclusion. Can't beat that price though, would have gone that route had I not already bought the Sowters.

Here:

https://groupdiy.com/index.php?topic=71002.msg904966#msg904966
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2019, 02:27:00 PM
Here is the original 1964 silver blue metallic paint.
Really gives the unit the right vintage vibe! Very cool color. It looks gray in pics. But In light you see the
blue!
Pics against my real unit. Then outside light picture in next post.

All screws are #4-40 pan head small drive nuts. #6-32 with small drive nuts. Haven't measured the Transformer bolts yet. Next size up and the largest.
All screws are single slotted pan heads.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2019, 02:27:48 PM
Here is the real color in the light. Gray primer then silver blue metallic.
After I ream the large 20uf x 4 Hole. Then knock out side studs and door studs for #4-40
screw and nuts. Then paint the chassis.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2019, 04:13:27 PM
Here is a picture of the 20uf x 4 450V - Cut out proper size to the original. It should clear all ground lugs.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2019, 06:27:39 PM
Cut four large studs off. Drilled and installed proper  ( 6 ) #4-40 screws with small drive nuts.
Will bondo non used holes to simulate original.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 29, 2019, 06:28:42 PM
Back side. #4-40 slotted pan heads like the original.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 30, 2019, 02:38:26 PM
Filled holes. Gray primer ,1964 Silver Blue metallic....I guess nobody cares and is ok with 75% recreation...LOL..:-)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 30, 2019, 02:39:32 PM
First coat. Will let this dry a couple days. Then fine sand and do a final coat.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 31, 2019, 06:01:04 PM
Just about done. As cool as Martins brackets are I am going to cut them off. And add the L shape brackets with U clip nuts. And the slotted thumb screws with point. I am going for all original look.

This pic shows how the color changes with light and angle. The rack ear on left looks gray. But its just
as silver blue as the rest.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on March 31, 2019, 06:02:54 PM
Another shot.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mikebalboa on April 01, 2019, 01:29:45 AM
Wow! John, great work. I want my 176’s  to be as accurate as yours. Thanks for all your informative posts.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 02, 2019, 11:06:00 AM
Thank You Mike!
Here is the original 8/32" U clips for door hinge. These actually work better for alignment and adjustment
of front door holes. My kit did not line up that great.
The original holes drilled in the sides are also oval shaped so you can adjust up or down. Metal U clips are still used today for car door panels etc......
The 8/32" pointed thumb screws actually enable you to hit the hole quickly and turn in.
And it looks original.:-)
Thank,s
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: salomonander on April 05, 2019, 07:34:46 AM
sorry if this has been asked before, but do we have a replacement/source for the rectangular capcitors on the back?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 05, 2019, 08:50:37 AM
They are on eBay all of the time.
And they are very good capacitors. Very low leakage on my peak capacitor tester!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: salomonander on April 05, 2019, 08:57:45 AM
They are on eBay all of the time.
And they are very good capacitors. Very low leakage on my peak capacitor tester!
John

thanks. could you le me know what to search for specifically on ebay. i tried searching once and found nothing. guess im using the wrong key words..... cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 05, 2019, 09:11:24 AM
Even though we've been in touch through email I can only repeat great work John!

If I only had an original unit at hands when I was starting all this. All I had were some pics from the web and schematics  ;D

Regarding the color - if John can provide a physical sample of the color I can try to find out if there's anything closer to that available as a solution for the powder coating service I use.
On the other hand - even though I still haven't had the chance to hold a vintage unit in my hands yet, the feedback I got in the meantime from several people who own one or more 175b/176 was they all vary in terms of color. Some are more like blueish grey metallic, some grey metallic and some are even just plain grey with no metallic effect at all.
Given the fact that the 175 and 176 was the first commercially available compressor by Bill Putnam back in the days, I guess they simply used what was available - so each batch is slightly different.

I experienced the same when I was doing the research for my Pultec EQP-1A project back then. I asked in a studio that has several units what color they were and they laughed at me saying "They are all different" Some blueish grey, some plain grey and some more like a greenish gray...

Anyway I'm extremely grateful for all the feedback you are mailing me on the details such as pcb dimensions etc. John - that's incredibly valuable in the mutual quest to get it right! And having a physical sample of the color of original units would be great to see how close we can get.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 05, 2019, 10:50:46 AM
Yes,
Very true....On the color! BUT! You won't see much of the blue If they are not in direct sunlight! :-) In a dark studio
they look completely gray. My 175B has a metallic blue chassis. But the transformer is plain gray. The 176 I am referencing has
the transformer painted the same metallic as chassis. But yes many variations.
And original units depending on how much sunlight exposure.  Have faded over the past 40 years. As metallics do.
The one I am copying is very blue. 
As is my 175b. And If  UA was having them sprayed in a auto shop ( more then likely ) And paints where being hand mixed.
Its a good explanation of the varying colors also.....
That is what I love about the old stuff.:-)
Kits are great Martin! A lot of hard work getting these to people!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 06, 2019, 01:32:26 PM
Here is how the GZ 34 is wired up on my original.
Pins 5/7 (unused )on the GZ 34 are used for the second set of 6.3v
heaters (green leads ).
No twisting of leads. The old school wire is left/right angles. Still waiting for my small pattern #6/32
nuts. So larger on for now.
The V4 tube is then hooked up via long thin 22 gauge wires to pins 5/7. This way you don't have large
mains leads going to the small tube (V4)
Thought this might be helpful to some..... Also on the original ALL of the mains leads come out of the left chassis hole. But I am using both. As that is how the leads come off my USA power supply.
John
*** I would also note that I have seen these units without the 2nd set of 6.3V heaters going to pins 5/7
on the GZ34 ***  But I am copying my own unit. And my bulb is also connected to these pins.
Original untouched mains I will add.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: mohausler on April 08, 2019, 05:18:50 AM
Thank you for all this info everyone! Tube monkey's pics were really helpful. Little request. Does anyone have more info on which type of components were used for the less obvious parts and would care to share? C1,2,3,4,5,10 for example. I assume the units in the pictures have been recapped at some point and caps aren't original?
Martin (amazing work btw!), I noticed you used two (three?) different colours for resistors. I assume brown means carbon composite. What types were the red ones?
Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 08, 2019, 10:50:01 AM
The red/brown resistors most common that where used in these units where IRC and Aerovox.
1/2 watt 1% precision resistors. I have seen a coupe others but these where the most common!
 Cinch made the Tube sockets,Terminal strips etc..... 
I am still searching for the red 180K half watt. If anybody bought a packed can spare two? Also the 1.1M.
I have also seen 1.21 M in these units.
Most hardware nuts are:
#4-40 slotted pan head screws with small pattern nuts except the two big caps use standard size #4-40 nuts.
Mounting bolts for mains transformer is #8/32 with small patter nuts.
GZ 34 uses #6/32 slotted pan heads with small pattern nuts.

Also after looking at my unit I was trying to find what they used for the center ground lug. Its actually one of the Cinch terminals
taken from a block and mounted upside down!

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 08, 2019, 03:54:14 PM
Here is the other way they hooked up the second set of (green ) 6.3V heaters. 
Actually four turrets on right side of pcb. The upper two are the green. Then attach the
heaters going to V4 to the rear of these turrets. Input power is below the 6.3V.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 08, 2019, 06:07:12 PM
Thanks John! Also thanks for you mails ;)

I was always wondering how they hooked up the heaters when I built my prototype.
Some 175b or 176 have 2 turrets on the right hand side of the PSU turret board while others have 4 - as shown in your pics.

My unit is modeled after the ones that only use 2 turrets, and in my wiring layout you can see what I came up with. But  hooking up the heaters via the unused pins of the GZ34 makes totally sense!

The only thing I find a little strange is that they used thin 24AWG wire for the further heater wiring as there's quite some current flow here.
Even though I use 24AWG in audio circuits, I mostly  go with AWG22 throughout the pretty much the entire circuit of a tube build I was taught to always use at least AWG 20 or 18 for the heaters as those thin wires otherwise might get pretty darn hot.

But obviously most unit made it through the last 60 years anyway  ;)

Anyway - great info John - keep it coming!

Martin

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 08, 2019, 06:37:07 PM
Yes Railton,
***UPDATE ***Compared to my original small 26 gauge wire is correct for 90% of the wiring. ( even smaller 28 in some places ) Except heaters 22 gauge (brown/white ) Could also be 24 gauge on heaters. I bought a bunch of gauges to compare.
Most is very small gauge!
The only big gauge wire on these units  are mains transformer and the 18 gauge for bulb and on/off switch.
 The turrets should have protruding back side pins. These are a bit hard to find off the shelf!

John        PS going for the original parts and details are very very painstaking.......:-)))
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 12, 2019, 06:19:41 PM
Who has mounted the small 9 pin tube sockets to pcb yet?
New Old stock foot print is to big.....will have to try and bend legs in.....Martin what sockets did you use? Spec on these
pcb,s?  The holes for the original sockets are inward to small...
Thank,s
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on April 13, 2019, 05:14:07 PM
I used Belton Micalex sockets for the 9-pin sockets on the pcb.
I simply bent the legs in a bit - worked like a charm.
I attached a pic of one of the pcbs, but it's kinda hard to see:

(https://www.mediafire.com/convkey/46d6/f5flr4ycratafeh5g.jpg)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 13, 2019, 05:43:32 PM
Ok,
Yeah I will bend the legs in..But the holes should still be a little more OUT diameter...:-) *** Bending worked on the Cinch sockets! ***

Looks great though.....:-)
Here is my original UA 175b can I repaired and stuffed the original spec Reichenbach 176 output in.....I was going to build
my own can. Now I know how the original was done so I can build my own in the future.
Next fill the hole. For sowter spec..... I would have done this in the beginning but wasn't sure how I was going to approach
the mounting. Until I found original can....:-)

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Le Roux on April 14, 2019, 05:31:49 PM
Mallory T-pad input and output pots

I plan on using these for the build.

Question is; do i wire them like you would for the 1176 rev d? see pic for reference

Thanks!

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on April 14, 2019, 10:42:55 PM
I have an original unit..And there is NO off position!  20 position and you could use 1.5 or 2 db. steps.
Obviously 1.5 Is going to be more fine tuned...Or NO steps at all even more fine adjustments. 40DB.

But I am sure variations either way spec wise would still work. Because there is a General area that most music material
will live on the input/output settings.
John
By the way John - I meant to ask you exactly which attenuators your original unit has. I’m assuming they are langevin - but which exact model info? I still dream of sourcing originals...

Thx kindly,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 14, 2019, 11:39:38 PM
Sent you message! Phraze.....

Here is the link again If People still looking for the American Mains transformer...American made and exact specs....

https://www.ebay.com/itm/PT325-2-USA-POWER-TRANSFORMER-TUBE-AUDIO-650Vac-325-0-55-325-x90mA/163566013348?hash=item26154b4ba4:g:sCgAAOSwmVBbFerS:sc:USPSPriorityMailPaddedFlatRateEnvelope!98102!US!-1
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 12:37:12 AM
I started getting my first one assembled today and I ran into some things that inspired some questions. The first was double checking the schematic. All the capacitors are shown as non polarized, but on the can capacitors there are + and - connections. Is there a different schematic available that shows the polarization? I still have to order C3 and C4 (0.047uF), and I am wondering if these are to be electrolytic as well.

The barrier strips from the BOM do not have a place that I can see to connect the wires from the back. Am I missing something? This should be a no brainer but it seems that I do not have all the correct parts. The BOM has the 7x Y terminals, but those look like they are for making the connections on the screw terminal side with the XLR cables.

I've attached a picture of how I had to make the connection for C9 A and B. This is the Hayseed capacitor. I seems to be too big to fit next to C1 and 2 like on the layout illustration. It should work but I would have preferred something cleaner looking. On that note, is there a reason to have to use the can capacitor? For this one, is there a reason I couldn't use two separate electrolytics?

I haven't decided about which type of capacitor to use for C6 and C7. The oil cans would be cool for creating the look, but once it's in the rack the only thing that matters is that it works sounds like a 176, and I generally don't put too much stock in making things like the original, whatever that means in terms of serial numbers. I'll check around for some oil capacitors but I think I'm going to end up using a quality film capacitor.

Does anyone have a part number for a strain relief that will fit in the opening in the side of the case where the AC cable goes?

On a side note, I reached out to David at Cinemag about making an output transformer and he says they never made one nor knows how to get his hands on the info for the windings. So unless there is another adventurous person who can make these I think only option is the Sowter.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 24, 2019, 10:04:37 AM
Yes they are Polarized. And you need to know this by looking at the schematic. The sides opposite of your
ground is your positive! And the case/ground lugs are your negatives!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 05:39:00 PM
Yes they are Polarized. And you need to know this by looking at the schematic. The sides opposite of your
ground is your positive! And the case/ground lugs are your negatives!
John

If that is the case for C3&4, I will need some help finding them or knowing if there is a lesser voltage rating that can be used. 0.047uF is mostly for film capacitors and the only current offerings for this value rated for 630VAC are screw in caps that are way too big to fit on the PCB and are about $40 a piece. So I don't know where to find the ones that work like what Rainton used.

Also any additional guidance for the internal connections on the barrier strip would be welcomed.

Outside of those two things, I should be good finish this up myself once I order the remaining parts. I'm debating building the stepped attenuators or just using the ones from CAPI/Hairball.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 24, 2019, 05:55:21 PM
C3 and 4 are not polarized.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 06:36:34 PM
Thanks. I figured it out but I will gladly take confirmation regarding this project. I would like to not make this one blow up when I power it up for the first time.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 24, 2019, 07:09:42 PM
I started getting my first one assembled today and I ran into some things that inspired some questions. The first was double checking the schematic. All the capacitors are shown as non polarized, but on the can capacitors there are + and - connections. Is there a different schematic available that shows the polarization? I still have to order C3 and C4 (0.047uF), and I am wondering if these are to be electrolytic as well.

The barrier strips from the BOM do not have a place that I can see to connect the wires from the back. Am I missing something? This should be a no brainer but it seems that I do not have all the correct parts. The BOM has the 7x Y terminals, but those look like they are for making the connections on the screw terminal side with the XLR cables.

I've attached a picture of how I had to make the connection for C9 A and B. This is the Hayseed capacitor. I seems to be too big to fit next to C1 and 2 like on the layout illustration. It should work but I would have preferred something cleaner looking. On that note, is there a reason to have to use the can capacitor? For this one, is there a reason I couldn't use two separate electrolytics?

I haven't decided about which type of capacitor to use for C6 and C7. The oil cans would be cool for creating the look, but once it's in the rack the only thing that matters is that it works sounds like a 176, and I generally don't put too much stock in making things like the original, whatever that means in terms of serial numbers. I'll check around for some oil capacitors but I think I'm going to end up using a quality film capacitor.

Does anyone have a part number for a strain relief that will fit in the opening in the side of the case where the AC cable goes?

On a side note, I reached out to David at Cinemag about making an output transformer and he says they never made one nor knows how to get his hands on the info for the windings. So unless there is another adventurous person who can make these I think only option is the Sowter.

Thanks!

Paul
False! I have the Reichenbach.....I also have the numbers. They where made! But before David took over!...I also have the emails when I talked with David..he said he could not find the numbers and the paper work was lost.....
More then likely he makes the output for Retro 176......
And since they sell more then a handful..He is probably sole provider to them......
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 07:38:48 PM
I don't disagree with you, but it wouldn't do me much good to inform him he's mistaken as I would just be a third party with second hand information. Maybe someone else can ask him. For now I'm going to be looking at the Sowter option as it seems t be the only one that is known to be available.

Still struggling with the terminal blocks. I can't seem to find in the Cinch catalog anything that would facilitate making connections behind the barrier strip inside the chassis. I may have to make something custom but it shouldn't be necessary unless all barrier strip manufacturers no longer make a rear mounted terminal option.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 07:55:50 PM
Mallory T-pad input and output pots

I plan on using these for the build.

Question is; do i wire them like you would for the 1176 rev d? see pic for reference

Thanks!

Look at the schematic and wiring layout then apply it your T-Pad. You can see both - connection points are joined together, so use them for the C connection on the layout. The rest should be self explanatory.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 24, 2019, 08:09:56 PM
I don't disagree with you, but it wouldn't do me much good to inform him he's mistaken as I would just be a third party with second hand information. Maybe someone else can ask him. For now I'm going to be looking at the Sowter option as it seems t be the only one that is known to be available.

Still struggling with the terminal blocks. I can't seem to find in the Cinch catalog anything that would facilitate making connections behind the barrier strip inside the chassis. I may have to make something custom but it shouldn't be necessary unless all barrier strip manufacturers no longer make a rear mounted terminal option.

Thanks!

Paul
You need the terminal block? You need the terminals! If you just have the double row screws..you have NO terminals! Here is a pic of a 5 pin.
Terminals coming out the back. This is what you solder to...The main star ground lug uses this same terminal also........
Im afraid to see some of the frankenstein 176...:-) The whole point of these chassis is to make original.....
Otherwise just throw in a bud box.....:-)))
John
Let me know....
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 08:46:55 PM
John,

That is exactly what I have been struggling to find! Do you have link for the terminals? I could not find them on the Cinch accessory data sheet. I knew I was missing something and it has been quite infuriating that can't find the thing I know has to exist.

Yes, I am trying to make an original looking one to a point, but I figured I could at least get the barrier strip as it should be without what I was contemplating doing.

Thanks!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 24, 2019, 09:25:51 PM
Here you go!
I would just buy the block..Because each size has bigger terminal lugs.....And you might buy the wrong size.
This is the 8 block...with terminals. You can also cut these blocks down. But first drill out the two lugs.
If that is the way to go. But If you have the 7-140 block. Pull these terminals off!

https://www.ebay.com/itm/4x-8-140-Y-Cinch-8-Position-Double-Row-Terminal-Barrier-Block-Board-Strip-8pos/131805186039?_trkparms=aid%3D111001%26algo%3DREC.SEED%26ao%3D1%26asc%3D56922%26meid%3D63b1f69e6b294b4cb2cbae49ed6c04ed%26pid%3D100675%26rk%3D1%26rkt%3D15%26sd%3D131805186039%26itm%3D131805186039&_trksid=p2481888.c100675.m4236&_trkparms=pageci%3Ad6945354-66fb-11e9-9951-74dbd1800b8c%7Cparentrq%3A522b7edc16a0a8832de7184bfff3fe76%7Ciid%3A1
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 24, 2019, 10:11:44 PM
Awesome. Thanks! This is what I thought I was buying but it was the version for mounting inside an service box for low voltage applications, so I was very confused and I imagined that others were also confused at my confusion. Thanks for this link. Getting closer to being able to finish up this first one.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 27, 2019, 06:39:01 PM
Working on my UA 176......:-) Many new old stock parts.....
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 29, 2019, 03:54:45 PM
Is there a modern equivalent lamp holder that will fit the power indicator drill hole in the face plate? I have some that are the standard Fender sized version but they are too big and I would like to avoid doing any alterations to the faceplate.

Also, what are people using strain relieve the power cable? I bought some that I thought would fit but they are sill a little too big. I didn't know if there was something small enough for the AC cable opening or if I had to use a grommet. There' s always drilling out the hole, I suppose.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 29, 2019, 04:02:18 PM
The early Originals where a gourmet. The extra hole you see below the choke is for a small C wire loom clamp.
That is also where the power cable was strain relieved from pulling out.
The power bulb is 5/16" Jewel lamp. A couple on eBay now. You need the #47 bulb holder.
The Drake Lamp assembly that will work is the 5-B .
Don't put a big fender power jewel......Unless you are doing the first version 175..;-))) They used that giant Fender amp size....
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 29, 2019, 04:08:20 PM
One more question for now:

Where is the meter board and switch supposed mount? I can't seem to see these things on the photos of the originals or Martin's build.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 29, 2019, 04:10:40 PM
And here is how the original power 18 gauge wires are twisted around.....I am doing my unit exact 100% original.....
Wire bends,color, wire gauge and all...They use a lot of 26 gauge and even 28 gauge. Besides the 24 gauge.
The reason being is to keep the wiring clean and the wire looms from being to big! They only used the bigger wire gauge where needed.
I have learned a lot on how these units where built...They are very detailed they way they did things.
Also I put a arrow where I will be installing the metal single line clamp they are called. This keeps the wires firm when door opens and shuts.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on April 29, 2019, 04:19:47 PM
Also suppose to be a extra turret board that the output goes to first. On 175b you will see the mounting holes on floor of chassis,s.
I have to make this. Arrows show meter board and output turret board. Keeps it all nice and clean wiring wise....
Front facelate wires go through 1/4"gray and clear  pcv tubing.......
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 29, 2019, 05:39:02 PM
The early Originals where a gourmet. The extra hole you see below the choke is for a small C wire loom clamp.
That is also where the power cable was strain relieved from pulling out.
The power bulb is 5/16" Jewel lamp. A couple on eBay now. You need the #47 bulb holder.
The Drake Lamp assembly that will work is the 5-B .
Don't put a big fender power jewel......Unless you are doing the first version 175..;-))) They used that giant Fender amp size....
John

I didn't think about using clamps. The clamps will make that part a little easier.

I found the ones on eBay and I think I'll wind up getting those. It's unfortunate because I was going to use these:

https://reverb.com/item/4481370-invisible-sound-guitar-amplifier-jewel-lamp-indicator-amp-jewel-model-370-for-pilot-light

I ordered a pair and I'll use them for something else, but was hoping to do something unique for the jewel light.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on April 29, 2019, 05:55:02 PM
Also suppose to be a extra turret board that the output goes to first. On 175b you will see the mounting holes on floor of chassis,s.
I have to make this. Arrows show meter board and output turret board. Keeps it all nice and clean wiring wise....
Front facelate wires go through 1/4"gray and clear  pcv tubing.......
John

Thanks for the additional photos.

I think I'm going to do mine without the meter selection as for me there is no need for one as I don't plan on opening this up once it's done. And it will simplify things for me a little. I just need to verify which resistor gets connected.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 01, 2019, 11:45:02 PM
I'm using the newer switches which don't have the screws in the back to mount the ratio board, so I used some JB Weld to fasten some #4-40 threaded L-brackets to the side of the switch.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 01, 2019, 11:47:59 PM
Doing one on each side makes the contact points too wide for the holes already drilled in the ratio board, so I had to add two more that were on the opposite ends length wise (perpendicular to the original holes). Seems to work great and it will still fit inside the chassis.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 02, 2019, 05:22:17 PM
Finally wrapped the power section on the first one. I drilled a hole below the opening for the AC cable and made that my star ground connection, making it as close as possible the power coming into the unit.

The hold up now is the output transformers. I don't want to mount and wire the PCBs then have to move them and to attach and connect the transformer windings. Good news is Don Audio has them in stock. Bad news is I'm still waiting on payment for some things.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 02, 2019, 05:33:23 PM
For the barrier strips, I should let everyone know that the solder terminals needed are on the BOM. I was thrown into disarray because when I checked the data sheet for the part, I only seemed to see terminals for joining adjacent connections. In the middle there is a tiny drawing that is the part which is listed in the BOM. The drawings also didn't have part numbers next to them, so I had to look at the measurements to decipher which part number was which drawing. Add that to the fact that I kept skipping over the really small one which was the one I needed seemed to put me in a state of uncontrollable fits of crying, anger, depression, and bowel irritation... things that normally take place when I build gear.

I added some shrink tubing on the terminals to protect from unintended contact with the chassis as it passes to the inside.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 02, 2019, 05:44:12 PM
Since I decided to not use the meter select function (GR only), I was wondering if the external meter connections could be repurposed for some like a side chain link to my other 176 I'm building or external SC in. Or something else?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 02, 2019, 07:20:53 PM
I'm using the USA power transformers that are found on eBay. They have a lead that is 55VAC referenced to the center tap and is labeled bias. I don't see this connection on the 176 schematic, so I wanted to confirm this is not being used. If it is I might need some help pointing out where it goes.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 02, 2019, 08:26:03 PM
I asked owner..He said clip it. Shrink it and push back in the case!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 02, 2019, 09:07:39 PM
I asked owner..He said clip it. Shrink it and push back in the case!
John
Copy that.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 03, 2019, 01:33:54 AM
This is as far as I'm wanting to go until I get my hands on the output transformers. I'm tempted to start assembling the second one but I want to make sure this one works correctly first so as to not build both in correctly and double the troubleshooting fun.

The 1/4" connectors I have on the front are for balanced connections, so I think they are a little longer and the originals. I had to use some shorter stand offs so the PCBs will fit behind them and not create any shorts.

I think I might just use the Bourns 600 ohm T-Pad for the time being. I bought nice rotary switches to build stepped attenuators, but I don't know it will be worth the effort. Maybe this will be something I do after the fact, but chances are once it's in my rack and being put to use I won't think about it any more.

Thanks!

Paul

Hopefully next week I'll be able to resume this guy. I'm not too far from having it completed
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 03, 2019, 01:51:14 AM
Also, and last one for the night, I thought I saw information on calibrating this guy within this thread, but I think I was mistaken. Where can I find this information?

Edit: I there is a UA175 manual on the Sowter website, and it requires going back and forth between GR and output metering. Since I'm planning on not using the meter select function, I wonder if I can just connect a VU Meter to the output connection and proceed that way.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on May 03, 2019, 01:59:02 AM
Hopefully next week I'll be able to resume this guy. I'm not too far from having it completed
Looks like you’re doing a beautiful job Paul!

Thanks for sharing your journey with us in all your posts.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Le Roux on May 03, 2019, 10:37:43 AM
I may be wrong but, would this not calibrate the same way as a rev d?
Mnats & Hairball have great info for calibration on their sites.
I’ll update once I’m there. 3/4 finished my unit
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 03, 2019, 11:31:27 AM
If it's similar to the 175 procedure then it is quite a bit different as you are balancing the tubes and not solid state components. For the 1176 you're setting the inductance for the FETs and adjusting things like distortion (which is sometimes optional).

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 07, 2019, 06:07:48 PM
Wire lace and a few more parts And I will have this thing done! sh*t load of work copying the original...But well worth it......
Original wire color codes ,wire bends route etc.....
Wire lacing next. Rock!!! :-)))
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 08, 2019, 04:26:15 AM
That is looking pretty nice.

I finally bit the bullet and ordered a pair of Sowter output transformers from Don Audio who happens to have them in stock. I was holding out to see if CJ was going to be able to make some but he's usually really busy and I think work has his full attention at the moment. So when those arrive I'll be able to get at least one up and running.

John, if you beat me to it, can to share how you went about calibrating/balancing your 176 build?

Also, I'm still halfway looking for the appropriate sized 0.5uF oil can caps that are working correctly. Right now I'm proceeding with the film caps I have soldered on the PSU board unless I do find some of the other type that are of the correct mounting position and terminal spacing dimensions.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 18, 2019, 01:30:33 PM
Hi everyone, i also started mine and it all comes together pretty nice.
But I run into a few small problems.
First: How do I get the cables from the Sowter to the front of the lower PCB ? In the pics of the originals, there's a pretty big hole, where the cables come thru, but in Martins pcb there's only one small hole.
Are we supposed to drill this up ? Or do I miss something  ?
I thought, I ask, before I bring out the 7mm drill
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 18, 2019, 01:38:13 PM
Second:
When I rechecked my solder joints on the pcbs, I found a few contacts, which weren't connected !
But I thought, my solder points were good. I found, that the little vias sometimes make no contact to the trace and you have to make sure, that the solder flows to the trace underneath. This took me by surprise and I resoldered both pcbs completely.
attached are pics of 2 points, where I thought, I'm good, but I wasn't.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 18, 2019, 02:34:33 PM
Original has bigger hole drilled in middle of pcb. Then contacts to another small pcb.
Martin did not include in kit. I made mine.
And yes. The solder joints are crucial on both sides of pcb. The metal material on traces is not like
gold traces. And takes a good amount of heat to solder the contacts.......
This kit is not for the faint hearted......A reason of detail was a lot of SMALL wire 24 and 28 gauge wire.
As measured in my original.  These original units where made with a very high quality of detail and lace wiring
to keep everything neat a tidy........
Also the plate/cathode pots and meter. Are suppose to be wire wound pots.
Along with the vernier pots.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 18, 2019, 05:41:58 PM
In the manual it mentions that since the turrets are pressed on, you should solder them to the board to ensure contact to the traces. The same would apply to the rivets as well making sure solder goes fully around the outside of them.

Have you worked out the output transformer mounting? I have the same transformers on the way and am curious if I need to make any alterations.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 19, 2019, 01:17:55 PM
Sowter fits perfect
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 19, 2019, 01:20:28 PM
backside
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on May 21, 2019, 01:15:37 AM
Surely you mean trace from R15 to pin 2 of 12ax7?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on May 21, 2019, 02:52:57 AM
On my pcbs pin 7 has a complete track to r17, as does pin 2 go via to r15, sorry if I've missed something. Happy to hear you've built one~congratulations
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 21, 2019, 12:10:40 PM
Few Points,
I have mine up and running sounds great and just like my original.....

The trace to pin 7 on the 12AX7 is missing from from R15. It can be jumpered or use a small pice of resistor lead
and solder to the above hole on pin 7 of the 12AX7...On the original this is left open and has a direct trace.
I think even in the original schematics this trace is not shown...Probably how it was missed....

Also being these boards are longer then the original and thinner gauge. They flex. They should not. On the original they are 1/8"
thick and also shorter and do not flex.

Flex is not good because when you change tubes it stresses the traces on the tube sockets. I actually had a trace lift when I was changing a 12ax7....Be careful and hold the pub when changing tubes.
Thought I would post this to save people some trouble....And make sure all contacts tested after soldering of course....

Other then that its pretty great..But would like to see thicker  pcb boards 1/8" thick like the originals....
John

Sounds like your original ! That's what I wanted to hear :) Congratulations !
Also thanks for the tip with the flexable pcbs !   
I checked mine and I have a perfect connection from R15 to pin 2 and from R17 to pin 7, like moltenwok mentioned. Maybe you just need to resolder the via ?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 21, 2019, 01:56:27 PM
Surely you mean trace from R15 to pin 2 of 12ax7?

Let me double check..The pin 2  that has the open trace to the top is not used..Only for test points I believe.
Yeah maybe my socket came lose from trace...But I will look at the pcb again.
There is a trace but it goes above the socket....on backside..I could be mistaken...will re check....
Im pretty detailed but will check......If you have connection via the 20K ohm to pin 2/7
 then you are good.
( not pin 7 ) Removed previous post. Do not want to confuse people.....:-)
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 22, 2019, 06:09:13 PM
Other notes:
OB2 tube is suppose to have pin 2  to to ground per schematics.
Also the Poles to the compression ratio switch are suppose to be to C 8 "A" goes to the compression RATIO board.
He has this going to the wrong spot on diagram.

C6 and C7 go to the left and right side ratio taps.  Per the schematic.

John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on May 23, 2019, 07:05:09 PM
Hi, John,

Do you have any notes for the calibration process for this build?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on May 23, 2019, 07:56:10 PM
Wow you guys you've been busy over here!
Sorry for not chiming in earlier!

First of all - I'm putting together all infos on the calibration procedure  as per the service manual as we speak and will share it with all group buy members on the weekend.

John's indeed right regarding the grounding of the OB2 - I missed to add that ground wire in my wiring layout. Will correct that asap.
As for C8A, as well as C6 & C7 I don't quite get the point - the schematic shows all 3 are connected to one of the 3 poles of the ratio switch each as per the schematic.
And if I'm not mistaken that's how I drew it on the wiring layout...

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 23, 2019, 08:18:03 PM
Yes you have going to poles! But C 8  ( A )  goes to the Ratio board!
On the Diagram..not schematic you don't have the pole of meter ratio board going to the
Cap C 8 A......... On the diagram. You have C 8 going to one side of the taps.
Unless I am reading your pole designation wrong......:-))
I have mine working anyway......Just trying to help with any frustration.....:-)

Thanks!
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 31, 2019, 05:35:33 PM
I'm using the newer switches which don't have the screws in the back to mount the ratio board, so I used some JB Weld to fasten some #4-40 threaded L-brackets to the side of the switch.
What switch do you use here ?  I found out today, that I somehow forgot to order the ratio switch ...
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on May 31, 2019, 06:06:11 PM
The BOM is wrong, for the ratio switch we need a 3P4T switch and the BOM says 4P3T ...
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on May 31, 2019, 09:14:53 PM
Second:
When I rechecked my solder joints on the pcbs, I found a few contacts, which weren't connected !
But I thought, my solder points were good. I found, that the little vias sometimes make no contact to the trace and you have to make sure, that the solder flows to the trace underneath. This took me by surprise and I resoldered both pcbs completely.
attached are pics of 2 points, where I thought, I'm good, but I wasn't.

Yes,
This is a major deal...The traces are not high quality silver traces.....They do not solder that great. I have soldered ALOT in my life.
And the metals/traces on these boards need to be tested at every solder joint! Every one!
The metals are very strange the way they resist solder.... I know exactly what you mean.....
I think the older lead solder may work better on these.....
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: kosi on June 01, 2019, 07:02:59 AM
That's my status, about one day work from finish, but I have to wait for the new ratio switch. Also ordered a new jewel lamp, my first one was too big...
I'm using the API meter and kind of improvised the mounting, if anybody has a proper idea, let me know !
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 04, 2019, 09:20:22 PM
Just got mine wired up with no smoke on first power up. However I don't have the correct fuses for the size fuse holder I am using (6.3x32mm) so it doesn't stay powered on too long before the 250mA fuses I do have blow. But it's encouraging that there was no violent reaction to me throwing the power switch.

I had started this with the original wiring diagram and I believe my OB2 is missing the ground connection per the new layout. I also need to go back over the correct wiring diagram and make sure I'm good.

For my build, I am only using the GR function for the meter so I am omitting the metering controls as once I have this racked up and am using it, I won't be flipping the front panel down to change the meter setting. Per the schematic, the GR function has the + side of the meter connected to the wiper of the GR Zero potentiometer and the - side to ground. Am I missing anything? I noticed the meter did not make any movement towards the 0 position but I'm certain that has to do with the fact that OB2 is missing the ground and the unit won't stay powered up long enough for the other tube's voltages to come up to nominal operation. If I am mistaken someone please let me know. I did go back over all the stakes and rivets with solder to ensure connection to the traces.

Also, could someone like jslstudio or anyone else that has theirs up and running share how they set the cathode and plate adjustments? And does any peoples know a place in town that consistently has 32mm fuses? I think Ace Hardware does but they are 2A. I'll try them in the morning as I would like to know that this unit works so I can proceed with the second one I have to build.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 04, 2019, 10:23:54 PM
All righty!

I took the spring out of the other fuse holder so I could make a 5x20mm fuse with the correct value work and I'm able to start testing. Also added the missing ground connection on OB2 tube. Voltages seem  good on the PSU and I am passing signal and am able to get what seems to be appropriate gain reduction when switching through ratios, although I am not getting any change at 2:1. This may be due to the current plate and cathode settings. Or, which is more likely, a bad solder connection.

However I am not getting voltage to the meter. I have confirmed that it does work when applying signal directly to the meter. So I've got some more digging as to why this is. But the unit does seem to be working as far as the compression circuit which I'm pretty happy about.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 05, 2019, 01:31:00 AM
I found I was missing a jumper for the GR Zero pot and now the meter goes to 0 when I power up. However, when I was going over and fixing this and a couple of other connections revealed I there are other issues going on. I'm getting very low output and the attack knob in the OFF position does not disengage the limiting that I am seeing with a volt meter on the output. The meter itself stays at 0 even with gain reduction taking place. My fear is the issue is on the rear of the bottom board which is very inconvenient to access with everything wired in place. The contacts from the input to phone jack to input attenuator seem fine and the same is true on the output. I did notice on the schematic there is a Hi/Lo Gain connection but I don't know if it's relevant to this build or if it was something they incorporated to connect to various pieces of gear at the time like the old Collins modules. I know it's a mistake somewhere, but I don't think I can stare at this schematic anymore tonight. Suggestions on where to look are definitely welcome.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 05, 2019, 01:46:59 AM
What switch do you use here ?  I found out today, that I somehow forgot to order the ratio switch ...

I just saw this. Did you find the correct switches?

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 06, 2019, 12:43:25 AM
It works!

It turns out the biggest culprit was that Test 1, 2, and operate functions are backwards for me. I am using a 2x6 switch since Pole 3 on the wiring diagram for S3 is not being used. I checked my wiring twice and confirmed that I didn't have a stop pin incorrectly installed and it still behaves this way. Maybe the wiring is meant to be shown on the other side of the PCB. All I know is when switched to Test 2 I get the full functionality of the unit.

I also had a number of errors on my part that I found when troubleshooting:

- Missing ground connection for C10
- Wires for Pb and Pc on the ratio switch were backwards. This gives you an incorrect voltage for V4 on Pins 1 and 5 according to the schematic. This also made me realize that I wasn't getting compression before but just attenuation from the output transformer as the different windings were being selected.
- Solder bridge on between bottom solder pads R19 R20 and the trace below it. I may have done this after initially thought I was finished when I was trying to reflow solder to make sure the rivets were properly connected. What was annoying was that I couldn't resolve this with some wick. I had to take a razor and cut away material between the trace and the solder pad to ensure they weren't shorting together.

There are some other things I found to be incorrect with the wiring diagram which I noticed during initial signal tests.

First was the wiring of the output attenuator. I am using the Bourns T-Pads from Jeff at CAPI and when wiring the In/Out according to the diagram, turning clockwise decreased output signal, swapping those connection fixed that. See below

On the output Venier, CW and the wiper are shorted together which mirrors the input Venier control. This decreases the signal when turning CW. Swapping those connections to match the input Venier fixes this.

For S4 as related to the switched potentiometer that I have, the wiring is also backwards. With the attack turned to the off position, the center solder lug for S4 should be shorting to ground. Again, this maybe because I have a different switch from what was modeled in the drawing, so one needs to check which solder lug is shorting to the center lug when in the off position and make that the ground connection.

I still need to verify the attack and release controls function properly with the current wiring.

One thing to be aware of is when applying solder to the rivets to ensure a proper connection is you may have turn up your iron a little hotter than normal. I usually have my iron around 750F and at this temperature what I found was as I applied solder it wasn't heating up the rivet quickly enough to create a bond, pushing solder to the other side forming large blobs which I had to remove. This was what caused the solder bridge mentioned above. When it turned the iron up to 800F it seemed to resolve this.

My last tip is before you install the boards, double check that all the of rivets are properly soldered to the traces and verify connections and that you do not have any shorts between points that are close but are not supposed to touch. Pulling these boards out after they've been wired into place is no fun.

Now I just need some knobs and this goes in the rack. I had high hopes for neatness of the wiring, but during the course of troubleshooting it starting to get a bit messy.

On to the second one!

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 06, 2019, 12:51:06 AM
One more.

I forgot to mention for the plate and cathode balance, I adjusted their respective pots till I got equal voltages on CW and CCW referenced to ground. Don't know if this is correct and I await the release of calibration documents for this project for the correct settings.

I must say again a huge thank you to Martin for this project. Getting this made from a couple of photos off the Internet and a schematic must have been quite the endeavor. I thank you very much for letting me be apart of this project. I hope I am able to answer any questions and help others complete successful builds.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on July 06, 2019, 04:06:52 AM
I haven’t started my builds yet - and won’t for quite awhile.

But I want to thank you Paul for your hard work, openness, and sharing your experiences with us. It’s going to make it that much easier. You and JLStudios are blazing the trail that Martin laid out.

Thanks to all of you!

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 06, 2019, 10:24:37 AM
Does anyone know of a source for the correct style knobs stateside? I know Don Audio has them but it would be faster to get them on this side of the pond.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on July 06, 2019, 10:29:53 AM
Does anyone know of a source for the correct style knobs stateside? I know Don Audio has them but it would be faster to get them on this side of the pond.

Thanks!

Paul


You can get the original knobs at www.studioelectronics.biz

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 06, 2019, 10:39:52 AM
Got it. Thanks for the link.

I found some NOS versions for like $37 a piece. I don't need mine to be that vintage looking.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 06, 2019, 10:58:52 AM
Congrats on the build! Paul.
I will try and post calibration.In next day. Busy..But Its fairly simple.......
Attack and Release mid point.
Attenuators full clock wise.
Test position 1
Plate balance trim pot for min deflection ( In either direction )
Cathode balance trim pot min deflection ( In either direction )

Those are the basis steps......Will post the doc in a bit.

I would like to see the pcb,s thicker 1/8" thick so they do not flex.
Being longer then the original and thinner they bend to much!
The traces should be of higher quality silver so they take the solder better.
I have a feeling old lead solder might be better to use.....

Other then that Its a great kit! But It can be even better.
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 06, 2019, 11:09:48 AM
Sounds good. Looking forward to seeing the info you have. I'll wait till I complete the other one and do them together (hopefully this weekend).

Years ago I bought a bunch of Sn/Pb lead that I still use. The lead free stuff seems to create more problems than I normally cause for myself.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 09, 2019, 12:43:54 PM
This is probably a silly question, but is the area around the PSU board supposed to generate a noticeably high amount of heat? I've never used one the original units but the fact the PSU resistors have such a high wattage rating I am guessing this is normal for this circuit.

Thanks!

Paul

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 09, 2019, 12:56:50 PM
Yes Yes and Yes...:-) This design  gets VERY Hot on the Power resistors!
The original Sprague Koolohm are some of the best!!! As in the originals..Look at the originals and see ALL
of the Burned/Brown circuit boards! Thats how hot they get.
As long as your voltages measure correct......Its right........
John
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 09, 2019, 02:00:43 PM
Yes Yes and Yes...:-) This design  gets VERY Hot on the Power resistors!
The original Sprague Koolohm are some of the best!!! As in the originals..Look at the originals and see ALL
of the Burned/Brown circuit boards! Thats how hot they get.
As long as your voltages measure correct......Its right........
John

That's what I figured. The voltages are measuring well with the tolerance of the components being used.

I've yet to do any actual listening tests yet. I'm waiting on the T-Pads to come in for the second unit (tomorrow I hope) and then test them both.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 10, 2019, 08:50:27 PM
I got the second one up and running. I manage to swap the same two of pole connections on the ratio switch as before, even while trying to avoid making that mistake again! I also had a rivet not making a connection to it's related trace, but fortunately it was on the side facing inward and was easy to spot.

Now I have one issue that is seemingly minor but mind boggling that I would like to try to sort out before putting in the rack. It seems the input Venier control has no affect on the signal. I can measure the same resistance changes between the input terminal and OUT connection on the attenuator on both units. The input controls work the same as well. What is confusing is if the potentiometer is reading correctly and wired the same as the working example (as per the wiring guide), then they should behave the same as they are an inline with the input transformer and everything else is functioning properly. I certainly don't see how I could be getting the same measurements but one is a faulty part. I'll poke around some more when I am about to get back to this.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 17, 2019, 12:30:10 AM
I went to do some more testing and listening on these units today and found some more errors. I first thought there was an issue with the wiring diagram in regards to the output pot. For some reason during my initial tests I thought it should be backwards, but it is indeed correct on the wiring layout. The Output Venier does need to have the strap swapped so that the wiper and CCW are shorted together. The input Venier on the second one still baffles me.

On the first one that was built, it seems to work great. I do get a buzz when the output control is turned past halfway, but keeping it at 11 O'clock is more than loud enough. The buzz does not change with adjusting the input control. I am wondering what is an acceptable level of noise on these units. The attack, release, and ratio controls all seem to respond correctly. I feel the noise could be less, but I wasn't plugged into the balanced power I use for my studio, so maybe that will help. I do have issues with EMI from somewhere as when tracking guitars, the player has to sit on a stool and rotate to find the spot where it cancels out, but I don't know if this is the same thing.

On the second one, there is a masssive increase in gain and the buzz is at a very high level. Somewhere at the input past the attenuator where signal is feeding into V4 is where I am suspecting as the gain reduction is much more sensitive than the other one and the throughput gain is wildly different. Like the other one, the input control does not change the noise level. I do seem to be getting correct voltages, but that may require double checking as well. The only thing that my mind keeps going to the Hi/Lo settings as shown after the input transformer, but followed the wiring diagram the same for each build, so I am wondering where a short or open connection to cause the gain to be wildly different. The ratio settings seem to be correct as I do hear and see on the meter the behavior I would expect at the various ratios.

I don't think I can look at it any more tonight. I'll circle back to this tomorrow and see if any bright ideas come to mind.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: jslstudio on July 17, 2019, 03:03:47 PM
I will say this again......
Mine works perfect!!!!
If you use anything other then what was used in the original...Asking for problems. IMHO.
The 300 ohm Verniers must be wire wound.....
Centralab WN or WW 300 are the PROPER ones. 
Langevin where used in 90% of the 176,s  600/600 ohm. ( Some Daven) I have seen in person and on 100,s of pictures of actual
176,s......
I copied mine down to the exact! Screws etc.......
My only gripe with this kit is the PCB,s are to THIN! And to long......They need to be shorter and thicker.
And better quality silver traces.
Check every solder joint!!!
My Attenuation works perfect on my unit.....Just like my 175b.......At 12:1 ratio sounds JUST like my 175b........
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on July 17, 2019, 04:54:27 PM


I'm pretty sure it's minor issues Paul. Great to hear that for the most part your units are up and running!

Back then when I built my prototype I spent days to trace the signal through the circuit even though that included finding errors in the original pcb layout and schematics - at least they were present in the original service manual.

I have to admit it's always worth to double check the solder joints at turrets of the pcbs while tracing the signal. I have been talking to Livingnote about the pcbs and they will be thicker next time and we'll also try to find ways to improve them otherwise.

Back then, after realizing how crucial it was, I made sure I added some solder to every single fork turret and rivet from both sides.

My unit has been working perfectly ever since - even though I used 500ohm pots with a resistor in parallel for the verniers, so your choice of pots there is not as crucial as long as you use good quality pots.
I eventually replaced my "regular" vernier pots with switchable ones as I modded my unit along the way and it still works great.
I used push-pull switched pots for both verniers - the input one switches the unit to hi-gain when pulled (optional as per the original pcb) and the output vernier switches the meter from GR to OUTPUT when pulled...

There are some more mods - even ones that were offered by UA directly back then. Such as the 600 Ohm T-Pad option for input and output attenuators which - according to the service manual gives you an additional 6db ea.

The optional t-pad attenuators were Langevin AT-601 and the actual model number of the 176 would vary depending on wether input, output or both were equipped with the t-pad option.

The models were: standard 176, 176T or 176TT depending on what was in there - and BTW the list price for the base model was $480 back then, while the 176TT was $520.50

Yes 500 bucks for a 176  hahahaha :D
Last time I checked now was 12K... :o

Whatever model the unit actually was, the front panel obviously always just said "176"

The standard model mostly used DAVEN LA-353G attenuators as per the original schematics (attached below)

In my unit I had  DAVEN LA-353G for both - input and output, but I eventually swapped the output attenuators for a 600 Ohm T-pad - so my unit is actually a 176T.

Anyway - back to topic. The unit shouldn't be too noisy actually - at least with my unit I was surprised how quiet it was in terms of noise or hum. If the hum is noticeable double check your ground wires and routing. In this circuit pretty much every ground wire is routed to that one star ground left of the PSU board.
But if your unit was not plugged into the balanced power and you have problems with interferences or hum in your studio anyway that might very well be the culprit for hum being introduced.

The gain being wildly different on the second unit IMHO is pointing towards a cold solder joint.

Also check your 6BC8 tubes - the first one I tried in my unit was gassy - even though it tested well on the tube tester, and also could be balanced during calibration, the signal distorted pretty easily and the meter would drift wildly in GR setting when turning the release pot...

...another 6BC8 fixed all of that.


Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 17, 2019, 04:56:45 PM
Did you have to use shielded cable anywhere?

For the Venier controls, the 500R carbon track ones with a 750R  resistor parallel is working fine except for one of them where it doesn't seem to doing anything. I may have a bad pot and not know it. The Bourns T-pads are also working well and have a very nice tactile feel to them. I'm not sure what advantage electrically the Daven stepped T-pad has unless there is a shielding component which I am not aware. The same for the wire wound 300R pots.

I did start out on this build trying to acquire all original parts, but I could not seem to find any of the Daven/Langevin T-pads with the correct values nor the 0.5uF oil can caps that had the proper dimensions. So I had to decide if I wanted to keep spending time scouring the internet for parts that are hard to find and command a high premium or if I just wanted to get the units built with equivalents that are of high quality. I did use original UTC input and interstage transformers as well as much quality NOS tubes that I could find. The 12AX7 and GZ34 are modern Mallory tubes. For 0.5uF I used nice 0.47uF film caps.

So circling back to my post above, the noise I get when the output gain on the "properly" working unit is above halfway is more of a buzz and not a hum that one might experience from AC heaters. The noise is the same type on both builds. The input gain issue I know I'll find and sort out as it shouldn't be hard to track down, it's my laziness which is the biggest obstacle. Is there anywhere in the build where shielded cable is necessary? When you crank open the output on either of your units do you experience any type of noise other than the natural noise floor of this circuit? I will check solder joints again but I did test continuity with all the solder points and their respective traces on the both boards before I installed them. Not saying that I didn't miss anyone of them, but it is less likely than some other error of mine.

I will say that with the properly gained unit of mine, it does sound very nice just testing is with program material. I'm down to finding a way to get them quieter.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 17, 2019, 05:12:31 PM
Hi, Martin,

I'm pretty sure it's something easy/silly regarding the gain issue. Most of my build issues usually are.

I'll double check with the balanced power source. Other builds I can initially test with regular wall power and be just fine, but they usually have a well regulated PSU.

$500 for a UA176 is also as crazy to think about as dumpster diving for Fairchild 670's in the 80's.

I did have my star ground moved closer to where the power comes into the unit as that is what seems to recommended in modern electronics and I have used this on every other build of mine with no noise issues. I'm not sure if this would matter in this instance as well.

I don't seem to have any sort of issue with the 6BC8 tubes as I'm not getting any distortion or strange meter behavior but it is good to know that having those issues could be a bad tube.

I'll report back when I sort out the gain issue then I'll move on to the noise issue.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 20, 2019, 03:48:51 AM
Got back at it tonight.

The gain difference was due to having missed a rivet that connects R3 and R4, which was where I was suspecting to be the vicinity of the problem. All the venier controls are working properly now. Also, both units seem to behave the same with matching control settings.

I connected the first unit to properly balanced power and +4 gear and the noise floor is significantly lower. I do still hear the buzz when I crank on the headphone volume and the output attenuator, but I get so much level at that point that it nearly clips the converters. At the halfway mark it is much quieter and I still get a very usable level. The second unit still has a noise problem even though the gain issue is resolved. Through a happy accident whilst doing other tests, I found that I am getting 2.4VAC between ground and either hot or cold connections on the XLR immediately on power up with no signal present. The sound is the same buzz as before at a higher level than the other unit with what sounds like a 60Hz hum. There is no voltage between hot and cold themselves. On the other unit I am getting 0.06VAC between audio pins and ground. This is also taking place with both the GZ34 and OB2 pulled. So I thought maybe the power transformer might have an issue with the center tap so I pulled that and the voltage dropped to 1.8VAC, which means that maybe somehow the one yellow lead on the power transformer that ties to pin 8 of the GZ34 is somehow leaking voltage across C11D to ground. For fun, I pulled all the tubes and I get 1.1VAC immediately on power up (with no tubes I quickly turned it off to prevent the H+ from going too high from having no load). So I'm not exactly sure how this much voltage is getting leaked to the ground. I'm afraid I'm going to have to pull it all apart and ruin my fairly decent wiring job.

So this brings me to some more questions:

What is an acceptable noise level for this circuit? Is there a knowable S/N ratio I can use to compare to my quieter unit (1kHz tone at 0dBu with input and output controls set to halfway and compressor turned off)? I also noticed that there are two ground connections on each of the PCBs. Is it necessary to use separate connections or can they be tied together and then sent to the star point? I will admit I did combine grounds on each PCB on both builds. This means I can rule out the combined grounds for mystery voltage on the one unit, but I am wondering if separating them would make the other unit quieter.

On a side note, I did manage to find an error in the wiring guide. In the layout, Pb of the ratio switch, which connects all of the color/white leads from the output transformer, is connected to C8A and Pa, which connects to the ratio resistors, is connected to C7. On the schematic it is reverse of this and this is how I have mine wired which gives me compression. The other way does not compress.

I probably still have a bad solder joint on the noisy unit that I haven't found or even missed a connection. I just don't want to unnecessarily undo a bunch of work if it's not needed.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 20, 2019, 04:35:25 PM
I pulled it apart and added the extra ground wires to both PCBs. I found one spot on the bottom board that seemed to have a standoff shorting to an adjacent trace. I also found that the outer rim of the PCB has a copper trace that I believe was left over from the etching process which was shoring to an actual trace which was very close by. I cut between them and verified there was no longer a short. I checked to make sure the connections were being made from each solder point the reassembled it. I still have the the stupid buzz and 2.3VAC on power up. With the unit powered off but still plugged in I am getting 0.43VAC between pin 3 and ground. Also, when listening to the unit, if I flex the bottom PCB enough the buzz lessens considerably but never goes away. I also managed to lay the soldering iron on my middle knuckle and experience my first tube voltage shock as my frustration and anger became more visible. I'm quite bummed out at the moment as I am having hard time understanding where this voltage to ground it coming from and the fact that unless I spot the issue or get a better idea of what could be happening I will then have to start pulling it apart again. The only thing that comes to mind is a bad power transformer or one of the can caps has an issue. Or the PCB in question has more problems with it.

In the interim, I'm going to redo the grounding on the one that is much quieter and see if I can get rid the buzz all together.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 21, 2019, 01:09:31 AM
All righty, one is finally done and in the rack. I took the less noisy of the two and rewired the grounding scheme. I ran individual wires to both of the can caps mounted on the chassis. the meter -, ratio resistor ground, and attack switch ground were all tied together and ran to the star ground as one unit. On the bottom PCB, the bottom ground connection was already connecting to the chassis somehow, and I had no desire to rip apart this one that was already working well, I just left it and connected the top ground connection. I think it made a little bit of a difference, but I didn't take a before measurement as I was so focused on getting at least one and I was pretty angry at that point about some additional setbacks I had in ground rewiring process. But I did take some afterwards and I am measuring about a 95dB S/N ratio at 1kHz with the following settings:

Input: 20
Output: 18
Compressor: off
Both Venier controls all the way down
1kHz tone at -20dBFS (this measures 0.775VAC on the output of my converter)

The buzz is still there if I really crank on the output control, but it's in a region that would be unusable for me regarding gain structure. In initial listening tests with the controls set to how I would use this guy for various artistic decisions, I cannot hear any noise. Even when stopping the playback, I have to strain to hear what I think might be the buzzing sound I was describing in the previous post. I'd be curious to know what adding a 6.3VDC PSU to use for tube heaters would do in terms of noise. At any rate, what I am getting is well within the acceptable range of modern tube gear expectations.

Here is a list of modern substitutes that I used in place of parts that may be very hard to near impossible to find and within a reasonable price:

- Input/Output attenuators - Bourns T-pads from CAPI
- C6/C7 - Axial Film 0.47uF 630V - I can't remember the brand. They are yellow and possibly Vishay. If you really had your heart set on some oil can caps but couldn't find the right size, you can always spend the extra money for the high end paper oil ones and still feel fancy
- PRP resistors through out except for the 1M2 resistors. Those are carbon comp. Don't ask. That's just what happened.
- Output transformer - Sowter 1290e. I think this is currently the only readily available option. Don Audio stocks them (or did) so you don't have wait for the 3 week lead time directly from Sowter
- Test switch - Lorlin 2x6 - The layout has a 3x4 switch but the third pole isn't used, so I went with a Lorlin 2x6 that I had.
- Venier controls - 500R pot with 750R parallel. This seems to work just fine.
- Power transformer - In the US, a company called Musical Power Supplies makes a power transformer to the UA176 specs as jslstudio pointed out. These work great and are less cost prohibitive than the Hammond option.

I also left out the internal meter switching as I won't have any need or desire to open the unit up just so I can look at the output level. To do this, run a wire from the GR Zero wiper pot on the top PCB to the Meter + connection. Meter - goes to ground.

For calibration, I had to make something up based on some poorly educated guessing, but the results seems to work well. I set the compression to 12:1, injected a 1kHz tone and adjusted the input till I got about 10dB of reduction on the meter. I then measured VDC on CW and CCW for both plate and cathode balance referenced to ground and made adjustment so that both sides of each pot had the same voltage. I'm not sure if I would have achieved the same results with no signal present but I didn't bother to check. If there is a better way do this with just the GR function on the meter then I'm willing to try it. Currently I'm very pleased with how this build performs with my faux calibration.

I would have liked to have built one with all original parts, but the end result still sounds really great and I would be curious to do a comparison with a "real" one if I could find one in Nashville to rent or have someone bring by. The parts used are per schematic values and have much tighter component tolerances than when these were made 50 years ago, so I have no doubt this will perform as well as a good working sample of originals. If you do lose patience with trying to make these 100% historic, you should know that using modern alternatives will still give you the sonic and compression characteristics that made you want to build one of these in the first place.

I've attached a pic of the measurement taken with 1kHz tone.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 21, 2019, 01:11:44 AM
And here is the baseline with no signal present and the same control settings. Converter used was a Lynx Aurora(n) set to 24/192.

For whatever reason I get a weird reading in the low end with no signal present using this plug in. I definitely don't hear that low end bump in noise.

Now to figure out what is going on with the other one...


Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on July 21, 2019, 03:58:27 AM
Manual for 176

https://www.sowter.co.uk/schematics/UA17567Litcomp.pdf (https://www.sowter.co.uk/schematics/UA17567Litcomp.pdf)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 21, 2019, 03:31:04 PM
I believe I have a copy of this downloaded. The procedure described therein requires the metering selection to monitor output. My takeaway from reading it is balancing the plate and cathode is balanced voltages, which is what I am doing (I think) while the components are under signal load and compressing. I think I'm just going to go with this for now as I said it is performing like one would expect and I don't hear any undue distortion or frequency loss. I'll do further measurements later to confirm this.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on July 21, 2019, 04:55:07 PM

My unit has been working perfectly ever since - even though I used 500ohm pots with a resistor in parallel for the verniers, so your choice of pots there is not as crucial as long as you use good quality pots.
I eventually replaced my "regular" vernier pots with switchable ones as I modded my unit along the way and it still works great.
I used push-pull switched pots for both verniers - the input one switches the unit to hi-gain when pulled (optional as per the original pcb) and the output vernier switches the meter from GR to OUTPUT when pulled...
Hey Martin, just wondering which switched pots you used? Those mods sound ace!

Thx,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 22, 2019, 12:08:39 AM
I pulled the second one apart and copied the grounding as before. I scoured both main PCBs and checked again for shorts and that connecting traces in fact had continuity. I found that I was missing a connection between C10 and R38 on the PSU and that a lead was causing an unintended connection on one of the front jacks, but neither of those proved to be the culprits. I have been working on this nonstop for 9 hours today and what is causing the buzz is escapes me still. It sounds like a grounding problem, which at this point is almost impossible unless I have a bad component.

I did go through tubes. With only the 12BH7 pulled the noise goes away. I swapped this and both power tubes with the other unit with but it did not solve the issue. With all the other audio tubes pulled and just the 12BH7 installed the noise is still present. Hopefully I'm on to something and not chasing the wrong thing because I misinterpreted the schematic.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 22, 2019, 04:41:39 AM
Alrighty, some helpful clues have emerged.

Without the 12BH7  it is not completely quiet. It is however this way in the working unit. In the noisy unit, when the 12BH7's are pulled, I get about the same noise level that I should be getting to match the other 176. I decided to listen to it again to verify they at least sounded the same with equivalent settings and there was a drastic difference in the compression characteristics. At 12:1, the working 176 still sounds smooth even at high attack settings, while the noisy one has significantly more gain reduction and the attack, even at a slower setting, is much more aggressive. Also, the output is not only less on the noisy unit but seems slightly band passed as the working one has better high and low frequency response. This is possibly an artifact of the more exaggerated compression characteristics. I swapped the 6AL5 tubes but fix the problem. I am getting 38VDC for pins 1 and 5, which are 7V less than what is listed on the schematic, but this is the same value (I think) that I got on the other unit. I'll have to double check that. The values and connections that I have on this build are lining up with the schematic when doing continuity tests, so even though I think I've narrowed it down I still can't seem to find what ever is ailing this guy. I did the same plate and cathode balance procedure as on the working unit, which were initially off and had even more aggressive compression characteristics. The heater voltage is 6.6VAC at the tube.

Any thoughts? I know it's something stupid as it usually is, but I think my problem is that I've stared at the same schematic and layout for so long and rewired this thing so many times my eyes are starting to glaze over and it's getting hard to come up with fresh new approaches.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 22, 2019, 11:51:14 PM
At it again tonight. I pulled it apart again. I found that where the R23 and R24 connect their solder legs poked through and seemingly melted through the covering of C1 on the other side. This would seem to make sense about I was experiencing. It did not seem to go deep enough to damage it, so I put some electrical tape on it temporarily and swapped position with C2, but this turned out to be a bust as well. I angrily started probing around to see if could make the noise go away and still pass audio and managed to get shocked a second time trying to fix this stupid noise. It took every bit of self control not to get my 4lb hammer and beat this into a folded piece of scrap metal. The problem is my OCD won't let me walk away from this. It's a buzz and the compression is much more aggressive and erratic than the working unit, and as much pulling apart I've done and redoing everything I should have found the problem.

I've attached a pic of the noise I am experiencing with approximately the same level settings as the working unit in case someone may have seen this before during their troubleshooting process.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: core13 on July 25, 2019, 08:57:18 AM
what are you using for the 0,047 C3 & C4 radial caps?

it's hard to find radial polypro caps exept orange drop
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 25, 2019, 09:53:03 AM
I'm actually using axial caps installed like resistors when building a 2520 style op amp. The lead that is exposed I cover with shrink tubing for safety.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: core13 on July 25, 2019, 12:06:44 PM
thanks

it's I wanted to do, but curious if someone know the original model of C3 C4 caps?
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 27, 2019, 04:04:22 AM
The second one is now done!

After rebuilding it for the 5th time and still getting the same noise, I installed a DC tube heater that I built from one of the boards currently being sold on eBay which are really well designed. I installed it for the input, output and compression tubes. I left the GZ34 and OB2 connected to other 6.3VAC winding. I fired it up and it is even quieter than the other unit. There is no hum or buzz, even when I crank the output of the 176 all the way up and then turn up the monitoring section. With every thing wide open and I hear some faint fizzling/crackling which I can see on the same analyzer plugin as before, but in normal operation it is dead quiet. I believe this from one of the tubes.

I also discovered that the super aggressive compression was from the 6BC8. Before I installed the heater, I was still trying to figure out where the noise was coming from as, like I mentioned the before, the other unit was built with AC heaters per the layout/schematic and is quiet. I swapped all of the tubes from one unit to the other and compression characteristics moved with it, but not the noise, making me realize that one had nothing to do with the other and that I had been using this line of thinking for troubleshooting in error. Started swapping them back and when I did the 6BC8 the compression characteristics swapped back over. The spare one that I ordered turned out to be dead, and I also managed to break a 6AL5 when swapping everything back and forth several times.

What are some recommendations for either of these tubes that function well and are fairly consistent between batches?

Thanks!

Paul



Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 27, 2019, 04:35:30 AM
For ensuring rivets are indeed making contact with the traces, I found a good thing to do before you install components is to apply some solder on the trace connecting to the rivet at a very short distance away and work to the rivet till you see solder flow around it but not in the hole. Then when you solder in components they are making direct connections to the traces and thus the other parts which they need to make an electrical connection. It seems like a bit of a pain, but it will save you time metering between all the solder points trying to find a missing connection, which may not be visually obvious.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: rainton on July 27, 2019, 05:36:26 AM
The second one is now done!

After rebuilding it for the 5th time and still getting the same noise, I installed a DC tube heater that I built from one of the boards currently being sold on eBay which are really well designed. I installed it for the input, output and compression tubes. I left the GZ34 and OB2 connected to other 6.3VAC winding. I fired it up and it is even quieter than the other unit. There is no hum or buzz, even when I crank the output of the 176 all the way up and then turn up the monitoring section. With every thing wide open and I hear some faint fizzling/crackling which I can see on the same analyzer plugin as before, but in normal operation it is dead quiet. I believe this from one of the tubes.

I also discovered that the super aggressive compression was from the 6BC8. Before I installed the heater, I was still trying to figure out where the noise was coming from as, like I mentioned the before, the other unit was built with AC heaters per the layout/schematic and is quiet. I swapped all of the tubes from one unit to the other and compression characteristics moved with it, but not the noise, making me realize that one had nothing to do with the other and that I had been using this line of thinking for troubleshooting in error. Started swapping them back and when I did the 6BC8 the compression characteristics swapped back over. The spare one that I ordered turned out to be dead, and I also managed to break a 6AL5 when swapping everything back and forth several times.

What are some recommendations for either of these tubes that function well and are fairly consistent between batches?

Thanks!

Paul

glad you made it Paul!

I was on the road the entire week, but when I read about the weird compression behavior I was about to say that it's the 6BC8 since that tube is responsible for compression in the 176.
That's the "variety-mu" tube. I had a bad one too when I first fired up my prototype. The good thing is that they're not expensive, so I just bought a bunch of them - mostly RCA.

In terms of noise coming from the AC heaters routing and twisting the wires tightly is crucial. But I'm sure you know all of that.
I just remember when restoring an old Ampeg B15 I also had a buzz going on and in the end it were several minor things I changed in terms of routing  that solved the problem.
You did triple check all ground wires do have a proper connection I assume? Not only that you multimeter shows connection but also the resistance it's measuring when checking for continuity...e.g. in one build I removed the star ground screw from the chassis and removed a little bit more of the chassis' powder coating around that spot and it helped tremendously.

Anyway - glad you made it!!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 27, 2019, 01:29:56 PM
I believe I had the heater wires from the transformer twisted well enough. Again, after the first build was successful, I copied that one while trying to make the wiring neater, so when it didn't have the same low noise as before the madness ensued. I don't know how many more times I could have checked ground connections. And I did take apart the star ground connection and remove more paint from the area and tighten it back up to the extreme. I do know what you are talking about with testing continuity and getting 1-5 ohms of resistance as I had that happen when checking between the points on the board. I have a Fluke 112 that I've been using for years, and the only time I've had issues is when the test leads start to go bad. So the only thing I didn't redo was the twisting of the heater winding from the transformer, and that very well may have been it. But I'm not going to go back and verify as I have to move on to other projects. It may not be completely historic, but it is not uncommon for studios to have modified their old tube gear to deal with noise issues, so maybe it could be considered historic in that sense.

Thanks again (again) for making this project available. Much was learned about this circuit and I now have two amazing sounding compressors to use on an upcoming project.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on July 27, 2019, 10:25:47 PM
One more follow up. I installed a DC heater circuit in the unit that was already quiet. I did notice that I had a tighter twist on those heater lines than I did on the noisy unit, which may have been the culprit all along. With the heaters running on DC, all remnants of buzz and hum are completely removed. With the monitoring and output of the 176 cranked all the way up, I only hear a slight amount of hiss, which is what I would expect at those extremes. It's about the same as a good solid state circuit. In normal use, I don't hear anything noise wise. It's almost as if the monitoring is muted. I highly recommend adding this to one's 176 build, especially if they're in an area where the local power has a tendency to cause noise.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on August 03, 2019, 12:07:48 AM
I've enjoyed following the builds here. Glad that things are finally coming together Potato Cakes.

I'm getting ready to start my build. I ordered most of the components way back when. I quickly perused my stock this evening and had a few questions come up.

1. 372X mounting holes don't fit the chassis cutout vertically. Two holes will line up, but not all 4. Are folks just mounting the top two screws?

2. C6 & C7 - Looks like I ordered some old PIO Gudeman caps, they're axial ones, not the square cans. Mine are rated 400V - will that be sufficient or is 600V needed here?

3. Resistors - I'm not concerned with visual originality here, but I want to do good on the character sound. I went almost entirely metal film with my resistor purchases last year. Which spots in this design would benefit sonically from the Carbon Comp distortion?


4. What is a recommended order to approach this build? Mount chassis back panel transformers/sockets/hardware first? Populate PCBs? Wiring?

Thanks!

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on August 03, 2019, 12:45:56 AM
Hi team, building up all 4 at once here, with the 372x mounting I just milled out the mounting holes in the transformer feet and put big pan head screws in. That way didn't have to drill chassis or change pcb mounts. Cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 03, 2019, 10:04:16 AM
I've enjoyed following the builds here. Glad that things are finally coming together Potato Cakes.

I'm getting ready to start my build. I ordered most of the components way back when. I quickly perused my stock this evening and had a few questions come up.

1. 372X mounting holes don't fit the chassis cutout vertically. Two holes will line up, but not all 4. Are folks just mounting the top two screws?

2. C6 & C7 - Looks like I ordered some old PIO Gudeman caps, they're axial ones, not the square cans. Mine are rated 400V - will that be sufficient or is 600V needed here?

3. Resistors - I'm not concerned with visual originality here, but I want to do good on the character sound. I went almost entirely metal film with my resistor purchases last year. Which spots in this design would benefit sonically from the Carbon Comp distortion?


4. What is a recommended order to approach this build? Mount chassis back panel transformers/sockets/hardware first? Populate PCBs? Wiring?

Thanks!

Some suggested answers to your inquiries:

1 - see moltenwork's answer

2 - On the schematic, it shows a test voltage of 310V that goes from R44 on the PSU through both primary windings and connects to C6 and 7. Using modern components this might not be an issue, but whether you are using NOS or new parts it would be safe to use 630V rated ones.

3 - If you read page one of the 175b manual posted by Martin from Sowter's website, it says in the first paragraph that the unit was designed for low distortion to be used in high quality audio systems and in the second paragraph that it was designed with overrated components and precision 1% resistors. It seems that the whole series of these limiters (175x, 176) were designed for fidelity and not tone (distortion). I wouldn't get too hung up on where to install carbon comp for character. When you use this unit with fast attack and release settings you naturally start to get distortion/artifacts/character/tone or similar quality. Also, can you even buy 1% carbon comp resistors? I've never seen anything below 5%.

4 - As a general rule, I would start on the PSU side and work the left as you look at the chassis from the front. Here's my recommended order of operations:

1. Build PCBs (this can be done at any point up to actually installing them). I would strongly recommend before you install any components that you solder any and all rivets where they connect to their respective traces. Apply solder directly to the trace and then work it to the rivet. When your iron it touching the side of the rivet, leave it and work your solder on the side of the rivet till you see it flow around it and adhere to it's trace. Obviously you don't want it to go inside of the rivet. Do this for every one, even if there will be no component placed there as some of the rivets are vias to make connections on the other side of the board.

2. Install Power transformer. Get a hand drill to do the twisted pairs per the build guide. Grip the leads being twisted at the transformer so you don't rip out the windings. Use the slowest setting, naturally.

3. Install the inlet AC cable, GZ34 socket, OB2 socket. Wire the 325V leads to the GZ34 socket. Any connections on the OB2 and GZ34 should be made with appropriate wire lengths to their destination per the wiring guide. You want this whole section prewired as you won't be able to get to them when the choke and PSU board is installed.

4. PSU board - I would recommend making your connections between components on the PSU board on the back using the appropriate turrets.

5. Install 6AL5 socket and C6,7 if you are using the designated mounting holes.

6. Install Input, Interstage, and output transformers. If any of these are original you need to prewire these as well.

7. Barrier strip. I put shrink tubing over each terminal where it went through to chassis to ensure no contact was being made there.

8. Input/Output jack assembly. Prewire this as well and double check to make sure the terminals for passing signal do indeed have continuity. Same for the ground

9. Install front panel. You could do this before the jacks if you wanted. One of the nuts is under the jack assembly which you may find difficult to tighten with the jacks in place. For me it didn't matter, so 8 and 9 are which ever you prefer.

10. Install PCBs. I would recommend using standoffs that are slightly varying in length to allow the appropriate leads from the output transformer to make connections to the ratio switch buy passing between the top and bottom PCBs. Otherwise you will have to extend them to reach with the front panel fully open.

11. Install front panel components.

12. Install tubes.

13. Calibrate/Test. Be sure to have several 6BC8 tubes as I've had 2 out of 7 test/perform poorly. A good gauge is to set the ratio to 12:1 and attack/release to 12 o'clock and run some known program material that hasn't been smashed to pieces to be earbud optimized. Bad tubes will compress (if they even pass sound) in a dramatic fashion on the transients with extreme swings in gain reduction, almost as if there is an intermittent audio connection. I'm sure someone here with a tube tester can give you objective measurements for what range to expect in a quality functioning 6C8B tube.

These are my recommendations and in no way any sort of official guide. Use at your discretion/risk. Let us know how you get on.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on August 03, 2019, 11:10:28 AM
Very helpful! Thanks for the general walkthrough Paul, and the PSU mounting tip, Molten. I'll post progress pics and any questions that come up along the way, aiming to get started next week.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: core13 on August 03, 2019, 12:33:31 PM
I would like to know if the 2 psu resistor value must be changed when using the 370bx because it deliver less voltage.

also if someone know what are the original radiall film capacitor C3 and C4?

thank you
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 07, 2019, 10:53:10 PM
Are these capacitors OK for the build?

I'm not sure the quality of Sprague paper in oil - I read somewhere the paper breaks down and that can degrade/damage the capacitor...

Thx all

PS having trouble finding the right lamp holder...does anyone have a part number or know what exactly was used? Thx!
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 08, 2019, 04:20:31 AM
Are these capacitors OK for the build?

I'm not sure the quality of Sprague paper in oil - I read somewhere the paper breaks down and that can degrade/damage the capacitor...

Thx all

PS having trouble finding the right lamp holder...does anyone have a part number or know what exactly was used? Thx!

If the can is sealed, it measures correctly, and fits the chassis you should be fine. I believe what you are referring to is when the paper is exposed, like I have on some old Colins modules. When the paper is exposed the material can form holes/become porous, and then the oil dries out.

The correct lamp holder is posted earlier in this thread.

Nice find, by the way. I had searched for quite a bit before I gave up and went with some nice film capacitors.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 08, 2019, 10:58:09 AM
Thank you Paul. I think if you keep looking those caps pop up from time to time.

As far as the lamp holder - yes I saw that link (I read this whole thread) - but that link doesn’t work.

I tried taking just the text from the link and doing a search for that, but no go.

If anyone has extras I’m looking for two lamp holders and jewels.

Thanks everyone!

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on August 08, 2019, 06:32:18 PM
Alright, first setback going through my parts inventory. Looks like I had ordered the wrong Sowter 1285e and I'll need to drill some holes in the chassis to fit this one.

Does anyone foresee any hum/noise issues with either of these orientations? If so perhaps I should see if it's possible to replace it with the numetal can.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 08, 2019, 07:34:32 PM
Hey Bram,

There is only one Sowter 1285e.

The one you bight looks like the “k” version.

I bet you could contact them and exchange it. There’s a price difference maybe $50-60.

Good luck,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on August 08, 2019, 09:15:12 PM

Hey Paul, I've been trying to decipher from your build photos how you mounted your Hayseed can caps to the chassis, but it's unclear. Any insights there?

How are folks mounting the API Meter?

And thanks Phraze... Looking back through my emails from last year, it looks like I ordered and paid for the numetal version but was sent the open frame by mistake. I've contacted Sowter to see if they'll exchange it.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 08, 2019, 10:22:47 PM
And thanks Phraze... Looking back through my emails from last year, it looks like I ordered and paid for the numetal version but was sent the open frame by mistake. I've contacted Sowter to see if they'll exchange it.
WOOT!  ;D
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 08, 2019, 10:29:27 PM
Hey Paul, I've been trying to decipher from your build photos how you mounted your Hayseed can caps to the chassis, but it's unclear. Any insights there?
Kosi posted a link to a mounting plate awhile back; not sure if it's for the right capacitor (sorry), but may this helps...

you need a mounting plate inside
https://www.tubesandmore.com/products/mounting-plate-metal-1-can-capacitor

you can also use one for the other cap with 4 "slits"
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 09, 2019, 05:37:42 AM

Hey Paul, I've been trying to decipher from your build photos how you mounted your Hayseed can caps to the chassis, but it's unclear. Any insights there?

How are folks mounting the API Meter?

And thanks Phraze... Looking back through my emails from last year, it looks like I ordered and paid for the numetal version but was sent the open frame by mistake. I've contacted Sowter to see if they'll exchange it.

The mounting plate are indeed how those caps are mounted. Be sure to get the appropriate sized ones as each cap needs a different one.

There is mounting hardware included with the API meter. It fastens to the front panel similar to how the Hairball meter is installed on their FET rack builds. I think you can see how it's done on some of the photos posted on this thread.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 09, 2019, 06:00:02 AM
I would like to know if the 2 psu resistor value must be changed when using the 370bx because it deliver less voltage.

also if someone know what are the original radiall film capacitor C3 and C4?

thank you

The wiring guide prescribes either the 372 or 370x with no correction to the PSU, so I would imagine you would probably be fine. However, if you are looking to modify the PSU resistor values to accommodate the power transformer, you can simply do some good ol' Ohm's law as you know the target voltage drop per resistor based off of the UA176 schematic to calculate amperage then use that and plug in the voltage based on the 370x (370x voltage from the GZ34 minus the target voltage).

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on August 09, 2019, 06:06:31 AM
Here's a side shot of the mounting
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on August 10, 2019, 12:31:49 PM
Here's a side shot of the mounting

Ahah! That's what that random baggie of hardware I had floating around was for.  ;D Thanks for the capacitor mounting plate reference, I had missed Kosi's response.

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: core13 on August 12, 2019, 05:15:47 PM
The wiring guide prescribes either the 372 or 370x with no correction to the PSU, so I would imagine you would probably be fine. However, if you are looking to modify the PSU resistor values to accommodate the power transformer, you can simply do some good ol' Ohm's law as you know the target voltage drop per resistor based off of the UA176 schematic to calculate amperage then use that and plug in the voltage based on the 370x (370x voltage from the GZ34 minus the target voltage).

Thanks!

Paul

Thank you paul
I think I will use the 370bx
I will do my math and see :)

edit.

the 370bx deliver 2x275v instead of 2X325v
on the schematic going from ac to dc with GZ34+Choke 10HY add 40v
maybe with the 370bx it will add also 40v or maybe less like 35v
so 275+35v=310v

310V is the voltage needed after the first dropping 1,5k resistor (R44).
too much resistance is going to reduce  the voltage on the 12BH7 plate.

so do I need to remove completely the first resistor?
put only 300ohm or something and lower the second resistor (R43)?







Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 12, 2019, 09:52:36 PM
Some little things.

Question about the large resistors, 1.5K and 10K:

I found an Ohmite wire wound for the 1.5K 20W; it is not "non-inductive." I'm a little concerned if this matters? I know when current stops in an inductor, there's a large spike/kickback...usually this is handled with diodes. Maybe I'm being paranoid but somehow I doubt the originals were non-inductive.

Anyway this is what I found. Are these all right?

1.5K:

https://www.alliedelec.com/product/ohmite/b20j1k5e/70022623/?gclid=CjwKCAjwnMTqBRAzEiwAEF3ndnh7BY-Z6EbyxBlVzrzvmh5S1WDv3yUOskEy7S2d0_JFY998KYlM-xoCriQQAvD_BwE (https://www.alliedelec.com/product/ohmite/b20j1k5e/70022623/?gclid=CjwKCAjwnMTqBRAzEiwAEF3ndnh7BY-Z6EbyxBlVzrzvmh5S1WDv3yUOskEy7S2d0_JFY998KYlM-xoCriQQAvD_BwE)

10K:
https://www.alliedelec.com/product/ohmite/b12j10ke/70022596/ (https://www.alliedelec.com/product/ohmite/b12j10ke/70022596/)

Also, being somewhat of a purist, I'd love to use NOS parts where possible. Martin's build guide so far is marvelous - an outstanding achievement! I'd love to also know what actual parts were used. I've gleaned some tips from John (jlstudios) in some threads (thanks mate!) - but I'd love to know more precisely which exact parts were used where.

For example, the resistors R36, R37, R38 all look like carbon comp to me. Is that true? What was used - AB? This is the kind of info I'd love to have. I'm not that great at just looking at a picture and instantly knowing what the part is.

Thanks for any insights into any of these questions.

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 19, 2019, 12:44:00 AM
Another Question about the CE cap (C11). There's 2 listed at tubesandmore.com

https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic-25-height (https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic-25-height)

https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic (https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic)

They both have same electrical specs, but one is shorter and fatter and the other longer and skinnier. Or so the pictures seem. But they both claim to have bottom diameter of 1.375".

Anyone has bought this cap (C11) and knows which is the right one?

Thanks,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 19, 2019, 01:07:31 AM
Another Question about the CE cap (C11). There's 2 listed at tubesandmore.com

https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic-25-height (https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic-25-height)

https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic (https://www.tubesandmore.com/products/capacitor-ce-mfg-475v-20202020-f-electrolytic)

They both have same electrical specs, but one is shorter and fatter and the other longer and skinnier. Or so the pictures seem. But they both claim to have bottom diameter of 1.375".

Anyone has bought this cap (C11) and knows which is the right one?

Thanks,

Mike

Regarding the externally mounted capacitors, you have plenty of room in relation to adjacent components that it wouldn't matter if you go with the fatter ones. For the one that mounts to the PCB, you will probably want to get the skinnier version to ensure it fits through the opening in the back of the chassis.

If you're really uncertain then go here:

https://hayseedhamfest.com/products/ua-176

This is what I used and it works great. I believe this is where Martin got his caps for his prototype.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 19, 2019, 01:20:39 AM
Thank you paul
I think I will use the 370bx
I will do my math and see :)

edit.

the 370bx deliver 2x275v instead of 2X325v
on the schematic going from ac to dc with GZ34+Choke 10HY add 40v
maybe with the 370bx it will add also 40v or maybe less like 35v
so 275+35v=310v

310V is the voltage needed after the first dropping 1,5k resistor (R44).
too much resistance is going to reduce  the voltage on the 12BH7 plate.

so do I need to remove completely the first resistor?
put only 300ohm or something and lower the second resistor (R43)?

On the spec sheet for Electro Harmonix branded 12BH7 it shows maximum plate voltage for class A circuits listed at 300V and for typical applications 250V. With all things being equal and you do end up with with 310V after AC to DC conversion with the 370bx transformer and you also get the 50V drop across R44 as shown on the schematic, that will still put you at 260V, which is above the typical plate voltage from the 12BH7 spec sheet. If the voltage does indeed prove to be too low, you can try using something like 1k for R44 and see if that satisfies the power requirements.

I would not recommend or condone leaving off any resistors from this PSU for safety purposes.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 19, 2019, 01:23:10 AM
Regarding the externally mounted capacitors, you have plenty of room in relation to adjacent components that it wouldn't matter if you go with the fatter ones. For the one that mounts to the PCB, you will probably want to get the skinnier version to ensure it fits through the opening in the back of the chassis.

If you're really uncertain then go here:

https://hayseedhamfest.com/products/ua-176

This is what I used and it works great. I believe this is where Martin got his caps for his prototype.

Thanks!

Paul
Thank-you Paul. It's strange they have two nearly identical - and also fail to put the dimensional differences on their site...

Edit: my real concern is I don’t know the quality of the hamfest caps. I trust in the CE Mallory name more than off-label generics...although the CE’s are only rated to 65C and the hamfest to 105C...
Title: Re: Universal Audio 176 from scratch - a 100% faithful recreation of a legend!
Post by: Phrazemaster on August 19, 2019, 03:09:29 AM

Regarding using a lamp together with the API meter I would indeed try to find a solution with a custom mounted fuse type lamp.
The lamp would need to have some kind of cover from above though, since the chassis has no lid - or it will lighten up the entire rack  ;D
Hey Martin - did you ever solve this?

Thx

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Potato Cakes on August 19, 2019, 10:44:38 AM
Thank-you Paul. It's strange they have two nearly identical - and also fail to put the dimensional differences on their site...

Edit: my real concern is I don’t know the quality of the hamfest caps. I trust in the CE Mallory name more than off-label generics...although the CE’s are only rated to 65C and the hamfest to 105C...

During the quite literally painful troubleshooting process, those particular caps got abused by my soldering iron during the multiple times of de- and re-soldering. If they were of poor quality I'm certain I would have had failures. Go with what you know and are comfortable with, but as for the Hayseed capacitors I think they make a fine product.

Thanks!

Paul
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 19, 2019, 11:54:58 AM
During the quite literally painful troubleshooting process, those particular caps got abused by my soldering iron during the multiple times of de- and re-soldering. If they were of poor quality I'm certain I would have had failures. Go with what you know and are comfortable with, but as for the Hayseed capacitors I think they make a fine product.

Thanks!

Paul
Thanks for your thoughts Paul.

I’ve never rated a component’s quality by how well it stood up to a soldering iron. But I appreciate it.

I’m still collecting the big money bits, like I just ordered the Sowter.

Thx!

Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 26, 2019, 12:21:48 PM
Just FYI anyone looking for the big knobs - great deal on ebay right now (I'm not the seller or affiliated).

https://www.ebay.com/itm/Lot-of-5-RCA-Daven-1-1-2-Vintage-Audio-Knobs-Collins-Western-Electric/153541681905?_trkparms=aid%3D777001%26algo%3DDISCO.FEED%26ao%3D1%26asc%3D20180911133149%26meid%3D4b6190c297494705a59000fcd6cee5bd%26pid%3D101002%26rk%3D1%26rkt%3D1%26itm%3D153541681905%26pmt%3D0%26noa%3D1%26pg%3D2481888&_trksid=p2481888.c101002.m4497&_trkparms=pageci%3Aaef5ed1f-c81d-11e9-8a04-74dbd18006f7%7Cparentrq%3Acebc4c7316c0a4b7b6bd5c90ffe4e5fe%7Ciid%3A1 (https://www.ebay.com/itm/Lot-of-5-RCA-Daven-1-1-2-Vintage-Audio-Knobs-Collins-Western-Electric/153541681905?_trkparms=aid%3D777001%26algo%3DDISCO.FEED%26ao%3D1%26asc%3D20180911133149%26meid%3D4b6190c297494705a59000fcd6cee5bd%26pid%3D101002%26rk%3D1%26rkt%3D1%26itm%3D153541681905%26pmt%3D0%26noa%3D1%26pg%3D2481888&_trksid=p2481888.c101002.m4497&_trkparms=pageci%3Aaef5ed1f-c81d-11e9-8a04-74dbd18006f7%7Cparentrq%3Acebc4c7316c0a4b7b6bd5c90ffe4e5fe%7Ciid%3A1)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 26, 2019, 03:37:22 PM
I just scored a wonderful Russian switch for the meter switch - as an alternative to that oak industries switch. I've bought these before - really nice action and built like a tank.

I'm not entirely sure the shaft is long enough so I have to double check that when I get home (oops). But anyways.

There's still a few left if you think it would work.

https://www.ebay.com/itm/Ceramic-Rotary-Switch-3-pole-3-positions-Make-Before-Break-NOS-Lot-of-1/263435091599?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649 (https://www.ebay.com/itm/Ceramic-Rotary-Switch-3-pole-3-positions-Make-Before-Break-NOS-Lot-of-1/263435091599?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2057872.m2749.l2649)
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on August 30, 2019, 06:27:44 PM
After weeks and weeks of searching I found an acceptable jewel for the front panel, plus lamp holder.

There's one left on the bay right now:

https://www.ebay.com/itm/151126076598 (https://www.ebay.com/itm/151126076598)

Good luck!

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: BramK on September 03, 2019, 05:32:30 PM
After weeks and weeks of searching I found an acceptable jewel for the front panel, plus lamp holder.

There's one left on the bay right now:

https://www.ebay.com/itm/151126076598 (https://www.ebay.com/itm/151126076598)

Good luck!

Mike

Thanks Mike, do you know which is the proper bulb specs/dimensions for this lamp holder?

In other news, Sowter replaced the transformer for the numetal can quickly and with no questions asked. Great customer service.

In other other news, if anyone is still sourcing parts, I have an extra UTC A18 available.

cheers
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on September 03, 2019, 09:16:57 PM
Thanks Mike, do you know which is the proper bulb specs/dimensions for this lamp holder?
Hey Bram,

Bulb is #51 according to schematic; Martin used a #47 I believe, which is lower power.

I don’t know lamp holder dimensions but the jewel is 5/16” as opposed to  the standard .5” guitar amp jewels.

I have an extra jewel and lamp holder coming so PM me if you need one.

Glad Sowter sorted you out!

Best,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on September 06, 2019, 01:45:03 PM
I really want to break the meter switch out of the box and put it on the front panel where the output vernier is. I know Martin used a push/pull pot, but this doesn't add full functionality of the meter switch, which is 3P3T shorting.

I spoke with Elma switches this morning. They can make a custom hollow shaft, 4-pole, 3 position shorting switch with mounting hardware for a pot behind. It's not a cheap switch; right now ballpark is $40 - $50/switch. it will probably take 6-8 weeks for them to produce as well.

I was thinking to use an 1/8" shaft through the switch, which Elma also sells as an add-on, and then adding a retaining clip behind it and making the end of the shaft like a screwdriver slot to interface with a pot that is 1/4" diameter shaft. Kind of like what the Grayhill Add a Pot series does. Can't use the gray hills though because they are stupid expensive - over $250/pop, have to be dual deck to get enough poles, plus they are too big for this project. The Elma's are smaller diameter, have just one wafer, and would fit.

Also, the front panel hole would need to be widened from 8.2mm to 10.2 mm. Not a big change, but thought I would mention it.

I have to specify the length of the shaft, so I thought 0.5" would be a good size.

I have to order min of 20 pieces, and I am seriously thinking of doing it.

So I wanted to know if any of you have any interest in getting one of these as a group buy?

I myself would take 4 of them.

Please let me know - PM is fine. I'll post back here about it when I have more definite info. I hope it's ok to post here; this is a mod of the original project after all, and I didn't think it was appropriate to put in the black market yet. This is just a feeler.

Attached is a representative pic of the 01-switch, although this one shown is not customized.

Thx,

Mike

Note: Don Audio has a switch similar to this, but it's 2 pole 6 position. The one I'm going to order is 4 pole 3 position. The Don Audio switch wouldn't work sadly.

Edit: for clarity.
Edit 2: changed out picture to be more representative - will look like this.
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on September 06, 2019, 07:40:17 PM
Also, if this all works out as planned, I'm going to use the fender concentric knob set attached in the pic here. But I'll use the correct UA 176 knob for the top of the pair.

What is unknown is how large the bottom half is - I've ordered a couple. So if the bottom piece is too large then I'll have to use something else or (gasp!) actually DIY something.  ;D

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on September 22, 2019, 10:41:31 PM
I've attached a picture of how I had to make the connection for C9 A and B. This is the Hayseed capacitor. I seems to be too big to fit next to C1 and 2 like on the layout illustration. It should work but I would have preferred something cleaner looking. On that note, is there a reason to have to use the can capacitor? For this one, is there a reason I couldn't use two separate electrolytics?

Paul
Hi everyone, I have the same question Paul posed here - how are we to mount C9a-b? It isn't clear to me what the right way to go is. Kudos to Paul for being innovative...but is this how to do it?

On some photos of original units it looks like one has the large can cap like the Hayseed, and other units seem to use a pair of electrolytics. I have the large Hayseed cap.

Thanks,

Mike

Thanks,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on September 23, 2019, 01:11:31 AM
This thread is starting to sound like an echo chamber...isn't anyone else building or gathering parts?

I was also wondering what folks are using for C3 and C4. In Martin's pix it looks like he used tall electrolytic-looking caps, but there is no side shot so I can't tell. The only film caps I can find that might be appropriate are some orange drops (which I've seen used on originals). But they don't match what Martin used.

So what did you guys who already built use for C3 and C4?

Thanks,

Mike
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: moltenwok on September 23, 2019, 02:01:33 AM
Hi mate, I ended up folding 2 tags over, and putting wire 'hooks' thru the other rivets and into the holes in the cap legs to add strength
Title: Re: GROUP BUY: Universal Audio 176 - a 100% faithful recreation of a legend! CLOSED!
Post by: Phrazemaster on September 23, 2019, 03:32:27 AM
Hi mate, I ended up folding 2 tags over, and putting wire 'hooks' thru the other rivets and into the holes in the cap legs to add strength
Many thanks Moltenwok. I appreciate it. Great to see photos of your build!

Best,

Mike