GroupDIY

Project Specific Discussions => Dynamic Processors => Topic started by: peter purpose on May 23, 2007, 10:20:07 AM

Title: 525 build thread
Post by: peter purpose on May 23, 2007, 10:20:07 AM
Let's get started with a BOM

http://www.twin-x.com/groupdiy/albums/userpics/525bomupdt3~0.pdf updated again.

and schematic...

(http://www.twin-x.com/groupdiy/albums/userpics/525Cschem21sm.jpg)
Title: 525 build thread
Post by: okgb on May 23, 2007, 11:04:58 AM
Nice Work Peter , thanks for your time on that

 Of course it would be good  to order all the parts and be
ready for when the boards come !
Title: 525 build thread
Post by: Rob Flinn on May 24, 2007, 06:22:12 AM
Peter (me ol' fruit)

Any chance of having this file in excel spreadsheet format ??  Make it a bit easy when trying to work out the cost of parts etc.
Title: 525 build thread
Post by: peter purpose on May 24, 2007, 06:24:55 AM
Give me three or four weeks :green:

http://www.twin-x.com/groupdiy/albums/userpics/525BOM.xls
Title: 525 build thread
Post by: Rob Flinn on May 24, 2007, 07:53:40 AM
Ta Matey !!
Title: 525 build thread
Post by: capnspoony on May 24, 2007, 09:10:10 AM
great!  This should be a breeze  :razz:

--Richie

can't wait for my 8 channels to come
Title: 525 build thread
Post by: hejsan on May 24, 2007, 11:11:11 AM
cool.
what do all the stars mean?
Title: 525 build thread
Post by: peter purpose on May 24, 2007, 03:31:27 PM
Quote from: "hejsan"
cool.
what do all the stars mean?


Not used
Title: 525 build thread
Post by: rafafredd on May 24, 2007, 04:10:59 PM
Hey Peter, are you also using a 2520 for the input opamp? These makes for 4 2520s for each unit. Serious job, if all opamps are DIY.
Title: 525 build thread
Post by: Rob Flinn on May 24, 2007, 07:05:50 PM
Peter

DO you have a source for the edge connector ??
Title: 525 build thread
Post by: Ptownkid on May 24, 2007, 10:45:49 PM
Quote from: "rafafredd"
Hey Peter, are you also using a 2520 for the input opamp? These makes for 4 2520s for each unit. Serious job, if all opamps are DIY.


I think it's 3 per 525...
Title: 525 build thread
Post by: peter purpose on May 25, 2007, 04:24:33 AM
Rafa.. copy of a UREI 5 transistor op amp on the front end. Pcb included in the set.

Rob.. No. You're on your own.
Title: 525 build thread
Post by: gyraf on May 25, 2007, 05:50:46 AM
For A3, the sidechain-transformer driver, it'd probably be enough to use a standard opamp with a couple of BD139/140 power booster transistors.

Question: Why not a simple 10K:10K input transformer instead of additional opamp stuff?

Jakob E.
Title: 525 build thread
Post by: peter purpose on May 25, 2007, 05:57:06 AM
Quote from: "gyraf"

Question: Why not a simple 10K:10K input transformer instead of additional opamp stuff?

Jakob E.


Room on the board Jakob.
(http://www.twin-x.com/groupdiy/albums/userpics/normal_OL.jpg)

Large.. http://www.twin-x.com/groupdiy/albums/userpics/OL.jpg
Title: 525 build thread
Post by: gyraf on May 25, 2007, 09:13:07 AM
:shock:
Title: 525 build thread
Post by: Greg on May 25, 2007, 09:47:41 AM
Been studying this schem getting ready for the build, and I don't understand what Q5 is doing. Can someone explain?

At first I didn't understand the bias of Q1, but I read the datasheet and it cleared that up.
Title: 525 build thread
Post by: rafafredd on May 28, 2007, 03:31:56 PM
Quote
Rafa.. copy of a UREI 5 transistor op amp on the front end. Pcb included in the set.


Nice. I like that simple opamp, it´s almost the same as the Quad8 AM4. Sounds good, and is very simple.
Title: 525 build thread
Post by: mnats on May 28, 2007, 05:42:30 PM
Quote from: "Greg"
Been studying this schem getting ready for the build, and I don't understand what Q5 is doing. Can someone explain?

At first glance it looks like it is adding an AC signal to the gate to reduce distortion.
Title: 525 build thread
Post by: peter purpose on May 29, 2007, 12:54:10 PM
They're in....

(http://www.twin-x.com/groupdiy/albums/userpics/525brds.jpg)
Title: ap2623 transformer
Post by: edanderson on May 31, 2007, 09:19:07 AM
since peter started his project, i've been working on getting some ap2623 type transformers made.  unfortunately, the first supplier i was working with backed out after a few weeks, so now i am a bit behind.

i don't want to discourage anyone from going ahead and buying transformers.  but i should have something good available in a few weeks.  until then, please do not contact me.  as soon as they are available i will post to this thread and post to the black market.

ed
Title: 525 build thread
Post by: gar381 on May 31, 2007, 08:57:57 PM
Peter

What is the size of the transformer cutout on the PCB??

David Geren at Cinemag says maybe the CMOQ-3S might fit
as its smaller than their 2503 replacement (CMOQ-2).

The CMOQ-3S looks like it requires a 32mm X 28mm hole.

These transformers are $25.55 USD each. Much cheaper than the
Sowter 9935 and easer to find than the ap2623.

Ed..... I'm also interested to see what you come up with.  :thumb:

GARY
Title: 525 build thread
Post by: babyhead on June 01, 2007, 01:25:25 AM
I have a question about this schematic...

Why is there no capacitor or load isolator after A2?

It is either that the 2623 is DC capable or the DC output of the 2520 negligible. Or maybe something I'm missing...

Thank you.
Title: 525 build thread
Post by: peter purpose on June 01, 2007, 04:01:44 AM
Quote from: "gar381"
Peter

What is the size of the transformer cutout on the PCB??


GARY


Tis 1.1" x 0.9"
Title: 525 build thread
Post by: peter purpose on June 01, 2007, 04:05:13 AM
Quote from: "babyhead"

It is either that the 2623 is DC capable or the DC output of the 2520 negligible.


The latter.
Title: 525 build thread
Post by: peter purpose on June 01, 2007, 04:48:47 AM
Mr. Ed Anderson of Brooklyn, come on down.

Good stuff Ed. Nice to have options.

peter
Title: 525 build thread
Post by: gar381 on June 01, 2007, 10:48:40 AM
Thanks for the info Peter :thumb:

sounds like the Cinemag CMOQ-3S  is to big :?


Quote from: "peter purpose"
Mr. Ed Anderson of Brooklyn, come on down.

Good stuff Ed. Nice to have options.

peter


Thanks for working on this Ed :thumb:  :guinness:  :sam:

GARY
Title: 525 build thread
Post by: mata_haze on June 04, 2007, 08:38:55 PM
Sorry guys for the silly question but:

what is the POT called RATT (10K) going to do?
on the original schemo it's underlined and therefore it should appear on the front panel,but it's not.
on the other hand it's on the new boards designed by Peter.

can anyone spread some light on this please?

many thanks.
Title: ratt
Post by: shabtek on June 05, 2007, 07:04:10 AM
resistance attack
Title: 525 build thread
Post by: mata_haze on June 05, 2007, 06:40:33 PM
Quote from: "shabtek"
resistance attack


 :roll:  sorry,what would that do? I mean what sort of control would that be? I cannot see it on the original unit,
 does any of you know why?

Best,
Mattia.
Title: 525 build thread
Post by: peter purpose on June 06, 2007, 06:11:27 AM
It varies the attack time.
Title: 525 build thread
Post by: mata_haze on June 06, 2007, 02:11:42 PM
Quote from: "peter purpose"
It varies the attack time.


thanks!
Title: 525 build thread
Post by: peter purpose on June 08, 2007, 06:30:56 AM
For the boys who bought kits only.....

I just started to put one together and the small switch pcbs are going to need the mounting holes elongating by about 3mm.
This will allow the pcbs to sit between the face and main pcb.
Tis dem pesky little brackets again..!!
Either that or make some little brackets up yourselves.

Well, I couldn't make it too bloody easy for you.

pedro

(http://www.twin-x.com/groupdiy/albums/userpics/swbrds.jpg)
Title: 525 build thread
Post by: Kid Squid on June 08, 2007, 06:35:49 AM
Oi Oi big daddy P,

got the boards, and they look WICKED  :grin:

 :thumb:
Title: 525 build thread
Post by: peter purpose on June 08, 2007, 06:38:53 AM
:thumb:
Title: 525 build thread
Post by: louder on June 09, 2007, 07:25:01 PM
Hi Peter
just starting this project,let me ask you this:
in your bom,in the cap section,you have(what i used).
why?
because it was a improvement to the circuit,or because was what you had at hand?.
another:
rl1/rl2 led dependent.what`s this?.i`m ashamed to ask.
best regards
pedro
Title: 525 build thread
Post by: peter purpose on June 10, 2007, 06:05:50 AM
<<because it was a improvement to the circuit,or because was what you had at hand?. >>

Bit of both really.  

<<rl1/rl2 led dependent.what`s this?.i`m ashamed to ask. >>

Don't be.  
The in/bypass switch has provision for a tricolour led. Use whatever floats your boat to get the desired brightness.

peter
Title: 525 build thread
Post by: Reptil on June 11, 2007, 10:55:55 AM
:grin: parts hunting time...
any preference towards specific capacitors? (brand, type)
Panasonics too clean? (hope to turn this 525 into a personality)
Title: 525 build thread
Post by: peter purpose on June 12, 2007, 07:36:36 AM
Not being a cap snob and lacking the lug holes to tell the difference, I shove whatever I have in there.

peter
Title: 525 build thread
Post by: BladeSG on June 12, 2007, 08:14:31 AM
Quote from: "peter purpose"
<<because it was a improvement to the circuit,or because was what you had at hand?. >>

Bit of both really.  

peter


Are those 50V caps necessary @ C15 + C16?

Will 25V caps work there or is the extra voltage handling part of an improvement in addition to going from 10uF to 220uF?

Truth is I have sh*tloads of FC 220/25v caps I can use here :wink:
Title: 525 build thread
Post by: peter purpose on June 12, 2007, 08:34:53 AM
25 volters will work fine in there, but check pin spacing.
Title: 525 build thread
Post by: Reptil on June 12, 2007, 12:17:42 PM
localised some ROE caps. Are these too old? I find them all over my old german stuff.

then, is this still on?
Quote from: "rascalseven"
Ahhhh..... got it, T, makes sense.  I missed that.

That'd be cool too.

BTW, is anyone familiar with this manufacturer?  http://www.handlesunlimited.com/knobs.html  (check out the bottom three styles....  Look familiar???)

 :shock:  :shock:  :shock:  :shock:

They are apparently available in black anodized as well as natural aluminum.  How cool would black anodized be for a DIY 525 (or 553, 312, etc...)???

Can you spell G-R-O-U-P B-U-Y ???  

 :thumb:

JC
Title: 525 build thread
Post by: SSLtech on June 12, 2007, 12:20:44 PM
Quote from: "peter purpose"
Not being a cap snob and lacking the lug holes to tell the difference, I shove whatever I have in there.

Nominated for best post of 2007.

Gawd bless ya Pete.

Keef
Title: 525 build thread
Post by: peter purpose on June 12, 2007, 03:43:50 PM
Quote from: "SSLtech"
Gawd bless ya Pete.

Keef


Gawd bless you n yorn.
Title: 525 build thread
Post by: peter purpose on June 12, 2007, 03:51:59 PM
OOPS....

Due to my being a stupid bastard, I sent the wrong file to fab.

The upright op amp needs a teeny weeny mod.

(http://www.twin-x.com/groupdiy/albums/userpics/mod.jpg)

Leave a leg long on C1 and take it to the base of Q4.

Sorry about that chaps.

peter
Title: 525 build thread
Post by: peter purpose on June 14, 2007, 06:43:20 PM
Possible mod?
Would it make sense to put a 75R resistor at each of these points to stop the output of A1 shorting to ground when pots are at FCCW?

(http://www.twin-x.com/groupdiy/albums/userpics/pots.jpg)

(http://www.twin-x.com/groupdiy/albums/userpics/525Cschem21sm.jpg)
Title: 525 build thread
Post by: SSLtech on June 14, 2007, 10:15:25 PM
No. The output only sees 1kΩ to ground, not a short.

Keith
Title: 525 build thread
Post by: Reptil on June 14, 2007, 10:16:20 PM
Quote from: "SSLtech"
Quote from: "peter purpose"
Not being a cap snob and lacking the lug holes to tell the difference, I shove whatever I have in there.

Nominated for best post of 2007.

Gawd bless ya Pete.

Keef


fair enough LOL

btw.. RS Components carries the edge connectors.
(the only one afaik over here)

also found some flat, white leds (through the x0xb0x kit).
maybe I can persuade them to fit. that would be neat.
Title: 525 build thread
Post by: Jim50hertz on June 15, 2007, 04:42:51 AM
Quote from: "Reptil"

btw.. RS Components carries the edge connectors.
(the only one afaik over here)


Any chance of posting the part no.?

Cheers

Jim
Title: 525 build thread
Post by: Reptil on June 15, 2007, 06:34:10 AM
have to dive into the pile of papers in the corner of the room  :shock:
give me a moment please... couldn't find the email...too. mmmm
and the laserprinter crapped out, and came back on... not one of my best day
hold on please..
 :green:
Title: 525 build thread
Post by: Reptil on June 15, 2007, 06:36:29 AM
on the connector itself... cinch  252 15 30 240
and 50 15B-10 and small print 09 75
is that sufficient?
Title: 525 build thread
Post by: Walrus on June 15, 2007, 07:44:30 AM
Unfortunately RS only seem to do stock number 483-865 now, which is an 18 way connector. It is the correct pitch but will have to be cut down.
Title: 525 build thread
Post by: Reptil on June 15, 2007, 08:07:40 AM
yeah, better contact them.
I did, and they could get me the right connectors, probably they had them sent over from a US stock. I had to be persistent.  :wink:
Title: 525 build thread
Post by: peter purpose on June 15, 2007, 08:34:40 AM
Quote from: "SSLtech"
No. The output only sees 1kΩ to ground, not a short.

Keith


Cheers Keef.

Must engage brain before opening mouth.
Title: 525 build thread
Post by: peter purpose on June 15, 2007, 10:02:38 AM
I've just scanned the original schematic for a better view.
Things have changed, but I'm not going to go through all that again.

http://www.twin-x.com/groupdiy/albums/userpics/525.jpg

peter
Title: 525 build thread
Post by: gar381 on June 15, 2007, 10:31:23 AM
the Edge connecter I use on all my api/melcor cards are:

EDAC 306-015-500-102

This connecter seems to fit Peter's PCB as well.

Digikey # EDC306150-ND


Mouser # 587-306-50-015

GARY
Title: 525 build thread
Post by: peter purpose on June 15, 2007, 10:38:17 AM
Quote from: "gar381"
This connecter seems to fit Peter's PCB as well.

GARY


Would you Adam & Eve it..!!
Title: 525 build thread
Post by: capnspoony on June 15, 2007, 11:03:23 AM
Im chompin at the bit for these kits.  I was wondering if anyone else was planning on using Ptowns 990 kits for the DOA's.   I checked the 990 threads but it seemed that a lot of people were having a lot of problems getting their DOA's up and running.  Now that I have 24 kits-- I'm a little concerned that my skills may not be up to par.  

--Richie
Title: 525 build thread
Post by: Rob Flinn on June 15, 2007, 11:56:40 AM
Quote from: "Walrus"
Unfortunately RS only seem to do stock number 483-865 now, which is an 18 way connector. It is the correct pitch but will have to be cut down.


Why not just stuff a bit of old pcb in it to blank off the unused pins.
Title: 525 build thread
Post by: peter purpose on June 15, 2007, 12:11:31 PM
Jayzus... someone in the USA sort it out for these poor brethren.
Title: 525 build thread
Post by: Reptil on June 15, 2007, 08:16:05 PM
I found it through www.mercateo.com. RS Components is their reseller in Holland. So, since Mercateo didn't want to ship, I asked RS Components.
Article number is: 108EL-2508740065
Hope this helps.
Title: 525 build thread
Post by: peter purpose on June 16, 2007, 06:44:45 AM
Good stuff Mr. Reptil.. :thumb:

Now don't let me be the first to the finish line,

(http://www.twin-x.com/groupdiy/albums/userpics/525a.jpg)
Title: 525 build thread
Post by: capnspoony on June 16, 2007, 01:56:20 PM
I'll catch up to you as soon as I get em'  :green:

--Richie
Title: 525 build thread
Post by: Denyle Guitars on June 16, 2007, 04:11:04 PM
Quote from: "capnspoony"
Im chompin at the bit for these kits.  I was wondering if anyone else was planning on using Ptowns 990 kits for the DOA's.   I checked the 990 threads but it seemed that a lot of people were having a lot of problems getting their DOA's up and running.  Now that I have 24 kits-- I'm a little concerned that my skills may not be up to par.  

--Richie


That was mine plan as well. My 990 kits and 525 kits are all still in their boxes. I don't who'll be 1st to complete theirs but I do know who'll be last. I'm not feeling rushed as I have no space in my lunchbox.
Title: 525 build thread
Post by: gar381 on June 16, 2007, 04:28:14 PM
Peter

R7 in the BOM is 47k and R7 on the Schemo is 4.7k.

Should I asume 4.7k is correct??

Thanks  GARY
Title: 525 build thread
Post by: edanderson on June 16, 2007, 04:50:35 PM
Quote from: "kubi"
Looks good, Peter.
What transformers do you use? I just tried some Profiles 4804 I had around, they are too big for the cut outs  :sad:  As somebody posted before, Cinemags seem to be too big, too. Not many alternatives left  :?


sowter makes some transformers that would work, but are somewhat costly.  i am planning to offer something that will work, and shouldn't break the bank.  more details when they are ready; please don't contact me about this, i'm going as fast as i can.

ed
Title: 525 build thread
Post by: peter purpose on June 16, 2007, 05:32:27 PM
Quote from: "gar381"

Should I asume 4.7k is correct??

Thanks  GARY


Yep, sorry about that.

Updated bom...
http://www.twin-x.com/groupdiy/albums/userpics/525bomupdt2.pdf

Also added Ed's transformers and changed value of C4.

peter
Title: 525 build thread
Post by: peter purpose on June 16, 2007, 05:37:50 PM
Quote from: "capnspoony"
I'll catch up to you as soon as I get em'  :green:

--Richie


Good luck with that Richie..!!
Title: 525 build thread
Post by: capnspoony on June 16, 2007, 11:57:26 PM
(http://i135.photobucket.com/albums/q157/capnspoony/Photo61.jpg)

gimmie somewhere to put these nuggets of love.

Sheesh they take a while to make.... thanks ptown!

 :green:

--Richie
Title: 525 build thread
Post by: peter purpose on June 17, 2007, 07:17:58 AM
3 down... 21 to go. I envy you not. :shock:
Title: 525 build thread
Post by: capnspoony on June 17, 2007, 11:34:05 AM
Quote
i am planning to offer something that will work, and shouldn't break the bank. more details when they are ready; please don't contact me about this, i'm going as fast as i can.


I'd be interested in this... mostly because the sowter option will cost me 1200 when all said and done.

Quote
3 down... 21 to go. I envy you not. Shocked


I already got it down to a half hour per DOA -- tested and workin'

--Richie
Title: 525 build thread
Post by: on June 17, 2007, 02:15:14 PM
How come capnspoony and greg are never seen in the same place?
I have discovered
greg sans glasses = capn spoon
Title: 525 build thread
Post by: capnspoony on June 17, 2007, 02:57:44 PM
It would be too much of a good thing in one thread  :wink:

--Richie
Title: 525 build thread
Post by: capnspoony on June 17, 2007, 11:46:57 PM
(http://i135.photobucket.com/albums/q157/capnspoony/Photo64.jpg)

I raise you to 18 Peter  :wink:
Title: ,
Post by: shabtek on June 18, 2007, 01:29:06 AM
to carspoony:

have you considered an edcor WSM series for the sidechain? it will fit the board but DC could be a problem...I think 150 to 600 will be our guy and that is what I plan to use there

anybody think this won't work?
Title: 525 build thread
Post by: peter purpose on June 18, 2007, 07:09:06 AM
Quote from: "capnspoony"

I raise you to 18 Peter  :wink:


Top job Richie.. :thumb:
Title: 525 build thread
Post by: capnspoony on June 18, 2007, 07:14:12 AM
Quote
have you considered an edcor WSM series for the sidechain? it will fit the board but DC could be a problem...I think 150 to 600 will be our guy and that is what I plan to use there

anybody think this won't work?


I'll wait for others to chime in on this one.   If the footprint is the same size -- we should be ok right?   I'm also curious to see what Edanderson comes up with.

--Richie
Title: 525 build thread
Post by: peter purpose on June 18, 2007, 07:17:04 AM
That transformer needs a dual winding secondary with centre tap.
Title: Re: ,
Post by: edanderson on June 18, 2007, 10:26:27 PM
Quote from: "shabtek"
to carspoony:

have you considered an edcor WSM series for the sidechain? it will fit the board but DC could be a problem...I think 150 to 600 will be our guy and that is what I plan to use there

anybody think this won't work?


the wsm series is the right size, if you take off the channel frame mount.  probably easier to order it without, since 150:600 ohms isn't a regular order item.  while you're at it, ask for leads instead of the quick connect terminals, which might stick up a bit high otherwise.

or...
Title: 525 build thread
Post by: edanderson on June 18, 2007, 10:30:21 PM
(http://edanders.home.comcast.net/diy/525trafo.jpg)

some samples came in today, along with my PCBs from peter.  so far so good... i've sent a pair off for pp approval, though they test well enough on the bench i don't think it'll be a problem.  pretty darn close to the originals.

lead wire and tape wrapper colors subject to change.

price and estimated availability when i have them.

ed
Title: 525 build thread
Post by: capnspoony on June 18, 2007, 11:10:54 PM
count me in for 16  :wink:

--Richie
Title: 525 build thread
Post by: gar381 on June 18, 2007, 11:18:22 PM
Ed

Very nice....I need 2 of 'em!! :thumb:


GARY
Title: 525 build thread
Post by: Sammas on June 19, 2007, 01:58:58 AM
Quote from: "gar381"
Ed

Very nice....I need 2 of 'em!! :thumb:


GARY



put me down for 4  :green:
Title: 525 build thread
Post by: peter purpose on June 19, 2007, 08:58:25 AM
Great stuff Ed.. :thumb:
Title: 525 build thread
Post by: Rob Flinn on June 19, 2007, 10:23:02 AM
At the risk of being thought of as a heathen for life,  I'm wondering whether anyone is planning to use a regular OP amp in the side chain rather than a DOA ?    Would something like a 5534 have the drive capability for the transformer it is feeding  ??

I am thinking that a really expensive DOA might be wasted in this position of the circuit?

Anyway I am already wearing my flack jacket, while waiting for replies !
Title: 525 build thread
Post by: edanderson on June 19, 2007, 10:25:53 AM
Quote from: "capnspoony"
count me in for 16


Quote from: "gar381"
Very nice....I need 2 of 'em!!


Quote from: "sammas"
put me down for 4


no need to tell me how many each of you want.  i'm getting enough so that everyone who bought a PCB from peter can buy two transformers per PCB.  i may not get them all at once, but there should be enough to go around eventually.

ed
Title: 525 build thread
Post by: peter purpose on June 19, 2007, 10:32:34 AM
Quote from: "Rob Flinn"
At the risk of being thought of as a heathen for life,  I'm wondering whether anyone is planning to use a regular OP amp in the side chain rather than a DOA ?    Would something like a 5534 have the drive capability for the transformer it is feeding  ??

I am thinking that a really expensive DOA might be wasted in this position of the circuit?

Anyway I am already wearing my flack jacket, while waiting for replies !



see Jakob's post back a bit.

"For A3, the sidechain-transformer driver, it'd probably be enough to use a standard opamp with a couple of BD139/140 power booster transistors. "

It'll have to be something hybrid to drive this particular transformer.

(http://www.twin-x.com/groupdiy/albums/userpics/normal_hybrid.jpg)
Title: 525 build thread
Post by: tommypiper on June 19, 2007, 03:44:24 PM
Can't we use CMOQ-2S off-board?
Title: 525 build thread
Post by: Reptil on June 19, 2007, 04:36:29 PM
Quote from: "edanderson"
....
no need to tell me how many each of you want.  i'm getting enough so that everyone who bought a PCB from peter can buy two transformers per PCB.  i may not get them all at once, but there should be enough to go around eventually.

ed


terribly nice!
please don't hurry, because some projects I'm doing were delayed, I'll have funds mid august again. :?   Count me in though!

minor edit :) (cut some mud)
Title: 525 build thread
Post by: peter purpose on June 19, 2007, 05:08:55 PM
Quote from: "tommypiper"
Can't we use CMOQ-2S off-board?


Don't see why not, but the right transformers are a far more elegant solution.
Title: 525 build thread
Post by: tommypiper on June 20, 2007, 08:59:35 PM
Right.  Thanks.  But isn't bigger better?  :grin:  Besides, I already got em on hand.
Title: 525 build thread
Post by: edanderson on June 20, 2007, 10:07:54 PM
the CMOQ-2S should work, though obviously it wont fit the board and it may sound a bit different.  just wire two windings in parallel for the primary, and the other two windings in series for the secondary with center tap.

ed
Title: 525 build thread
Post by: tommypiper on June 21, 2007, 12:27:22 PM
Thanks, Ed!  I'll probly get a coupla yours and then make a comparison test with the CMOQ-2S.
Title: 525 build thread
Post by: kazper on June 21, 2007, 05:04:02 PM
Anyone have a idea on the dimensions for the front panel and the thickness of the metal plate of a 500 series API unit... IE 525 compressor.

I'm trying to do up a Front pannel Express plate for this project but don't have any API stuff myself.

I think it's close to 1.5"x5.25" anyone able to verifiy this? and measure the thickness of the material?

Kevin
Title: 525 build thread
Post by: edanderson on June 21, 2007, 05:34:01 PM
the front panel should be 1/8" thick.

ed
Title: 525 build thread
Post by: kazper on June 22, 2007, 09:05:26 AM
How critical is the MBB 12 pole switches? Ive been looking for a suitable part for my BOM list for this.  The only thing I have found in the big 2 US dealer's is a BBM 1x12 with 2 decks.

thanks...

Kevin
Title: 525 build thread
Post by: peter purpose on June 22, 2007, 10:52:18 AM
Quote from: "kazper"
How critical is the MBB 12 pole switches?


Not entirely sure if critical, but MBB is what was used on the original and you may well experience pops if using anything else.

peter
Title: 525 build thread
Post by: SSLtech on June 22, 2007, 01:44:22 PM
Quote from: "peter purpose"
you may well experience pops if using anything else.

I dunno bout your family, but my pops wasn't a very pleasant experience...

Keef
Title: 525 build thread
Post by: kazper on June 22, 2007, 02:25:22 PM
I found some MBB that are not instock but avalble with decent enough lead time (45 days) for me. Specialy since I'm sure this is a next year'er for me. Now only if Mr. Posty delivers the good's to figure out the rest of the parts that I don't have already.

I almost have a FPE front done.. any ideas on what screw size these use?

Kevin
Title: 525 build thread
Post by: peter purpose on June 23, 2007, 07:46:09 AM
Kevin,
Panel size is 1.5" x 5.25" and is secured with 4-40 screws.

(http://www.twin-x.com/groupdiy/albums/userpics/cutout.jpg)
Title: 525 build thread
Post by: kazper on June 23, 2007, 09:42:37 AM
Thank's Peter...

Hopefully my million not so important but important to me question's are worth it to all...

After my board's show up I'll check out the layout against my FPE document and then upload it somewhere for those that didn't get your full kit. The front's should be under $50 for a one and two but around $38 for a 10 pack. Minus the fact that there pricing is outdated...hmmm

I would have done the full monty, but DIY funds were low at the 11th hour.
That and our money is pretty worthless when going to pounds...
Title: 525 build thread
Post by: tommypiper on June 24, 2007, 12:12:54 AM
Kazper.  Why are you going to all the bother trying to make an API face plate when you don't have an API lunch rack for it?  Why not put it in a regular rack case.  More roomy and options...
Title: 525 build thread
Post by: Siegfried Meier on June 24, 2007, 12:17:46 AM
I'm thinking of doing just this - make a single rack space, Front Panel Express file, get EDAC connectors, or whatever, and just rack the 2 units.  Only thing is the P/S.  Anyone know what I need?  Or maybe just buy the JLM powerstation, and that will most likely work for what I need.

Thanks,
Sig
Title: 525 build thread
Post by: Siegfried Meier on June 24, 2007, 06:29:09 PM
Will these even fit into a single space chassis, with the size of the transformers??

Thanks,
Sig
Title: 525 build thread
Post by: edanderson on June 24, 2007, 10:31:06 PM
Quote from: "Siegfried Meier"
Will these even fit into a single space chassis, with the size of the transformers??

Thanks,
Sig


sure.  remember that there are single rack space racks for 500 modules:

http://www.apiaudio.de/500-h.pdf
(seems to have disappeared from the API usa site)

http://www.avedisaudio.com/R52.html

ed
Title: 525 build thread
Post by: kazper on June 25, 2007, 12:49:29 AM
I'm planning on buying a lunch box for them.. and the edison mic pre's I want to do..

I'm wishing that I bought the full kit now.... after seeing the small part's needed.

Don't know where yet to look for the 0.1" spaced switches

Honestly This is a back burner project for me.
Title: 525 build thread
Post by: gar381 on June 25, 2007, 11:17:49 AM
Peter

I'm I safe to asume that CD5 and CD6 are both 33p and
the 2 unmarked caps next to A4 are 100n ??

These parts are not on the BOM. :?

Thanks

GARY
Title: 525 build thread
Post by: peter purpose on June 25, 2007, 12:57:14 PM
Yeah, sorry again Gary. Your assumptions are correct.
Title: 200 uA meter
Post by: mata_haze on June 25, 2007, 05:47:43 PM
Hi everybody.
I am trying to understand if I could use a 100uA amperometer on the 525 instead of the 200uA.
I thought I might just add a resistor in series to make the 100 uA work like a 200uA.
is this assumption correct? if so could someone suggest me a value for the resistor?
Title: 525 build thread
Post by: capnspoony on June 25, 2007, 11:12:17 PM
In the BOM I'm a bit confused by the capacitor section where it says

C1  250UF/ 6 V   (470UF/16V)

does that mean we can use either or?

--Richie
Title: .>>
Post by: shabtek on June 25, 2007, 11:13:58 PM
ohms law

to halve the current, double the resistance

this works for a more sensitive movement: but for one with more mA for FSD the driving bit might poop out
Title: 525 build thread
Post by: capnspoony on June 26, 2007, 11:15:29 PM
So I ordered most of my parts from Digikey and Mouser tonight.  I had some questions regarding the rest.  

Where could I find.

1)  VCR2N transistor and socket

2)  all the caps that are in the pf range minus the 150pf ... mouser and digikey seem to not go that small.

3)  and I don't understand what "LM391X meter driver IC if using the LED meter or 200uA FSD meter" means.

thanks

--Richie
Title: 525 build thread
Post by: dissonantstring on June 26, 2007, 11:40:49 PM
hi richie,
i haven't had time to really take a good look at this project yet, but here's my understanding of the following:

1) VCR2N transistor and socket
this is the vertical opamp i believe.  One of the smaller boards square-ish boards with the 5 transistors on it.  you do not necessarily need sockets for this board but it might be a good idea if you want to remove it later.
you could just add some buss wire and solder to the pads on the DOA board and then solder to the pads on the mother board for connection.  look on the third page of the BOM it shows what parts go into this DOA marked "upright opamp".

2) all the caps that are in the pf range minus the 150pf ... mouser and digikey seem to not go that small.
haven't had a chance to check on these yet.  :?  edit: i just checked the BOM and the only pF value caps are 47pF and 150pF which are readily available in ceramic versions from both mouser and digikey.  

3) and I don't understand what "LM391X meter driver IC if using the LED meter or 200uA FSD meter" means.

you'll need an LM391x series IC to do the meter driver duties.  there is a meter driver board that Peter supplies with the set of PCBs (the one with the row of LED markings on the overlay).  the LM391x IC goes on this board.
hope this helps.
-grant
Title: 525 build thread
Post by: capnspoony on June 26, 2007, 11:54:44 PM
Thank you soo much Grant

I wasn't aware we could use ceramic in this situation- Past projects have said when to use them so I wasn't sure.  

there is an optional 10pf cap to put in also there is a 5pf cap that goes on the opamp board

I understand the rest, Great!  :thumb:

--Richie
Title: Cinemag Iron for this build
Post by: Tubemooley on June 27, 2007, 04:41:20 AM
yo - check it......
i've been e-mailing with David at Cinemag. i measured the 525 circuit board and sent him a crude but effective drawing showing dimensions allowed for the transformers. he had to go do a little measuring but he is positively recommending his CMOQ-3 for our 525 compressor kits. he does not have any drawings or datasheets for this model on his website yet. but he made up a one page .pdf of the mechanical dimensions and sent it to me. it shows overall dimensions of the CMOQ-3 to be 41.5mm x 33.27mm. the center-to-center distance between the mounting holes is not shown. i measured the space on the board to be 43mm x 37mm so it definitely looks like this trannie will fit on the board. it is unclear whether the board will have to be trimmed or modified (for the bobbin or the mounting screws) but i'd be fairly certain that this can be done with a minimum of effort and not much risk in terms of damaging the board.

i've already asked David if he minds if i post that drawing on this here forum. i doubt he will but it's best to check first. if he says OK, then i will post the drawing. but the july 4th holiday is coming up and i'm taking a few days off so getting this done for you guys may take up to a week.

i'm sure that Ed's edcor trannies will work fine and they are probably very cost effective. however, i will probably get the Cinemag's for my 525's. i did not check on pricing for these bad boys yet. the CMOQ-3 comes in two versions: the -3H and the -3L. i believe that the -3H is the high nickel version and the -3L is the "regular" nickel version but we'll find out from David. go to www.cinemag.dot.biz

thought you guys would want to know. DW.
Title: 525 build thread
Post by: peter purpose on June 27, 2007, 08:46:47 AM
Grant... tsk tsk.

The vcr2n and it's little house.....

(http://www.twin-x.com/groupdiy/albums/userpics/vcr2nsocket.jpg)

It is not mandatory to use the socket, but makes testing and swapping a breeze.
Title: 525 build thread
Post by: peter purpose on June 27, 2007, 08:57:54 AM
VCR2N available at...
http://www.goldmine-elec.com/

Punch in VCR2N to the search. 2 for a buck, 100 for 40.
Title: 525 build thread
Post by: peter purpose on June 27, 2007, 09:39:00 AM
Quote from: "capnspoony"
In the BOM I'm a bit confused by the capacitor section where it says

C1  250UF/ 6 V   (470UF/16V)

does that mean we can use either or?

--Richie


The stuff in brackets is what I had to hand and used.
Some were used for improvement.
Title: 525 build thread
Post by: peter purpose on June 27, 2007, 10:01:19 AM
Bom updated again...

http://www.twin-x.com/groupdiy/albums/userpics/525bomupdt3.pdf

Added CD5 & CD6
Title: 525 build thread
Post by: peter purpose on June 27, 2007, 10:05:58 AM
And again....

http://www.twin-x.com/groupdiy/albums/userpics/525bomupdt3~0.pdf

added unmarked caps.
Title: Re: Cinemag Iron for this build
Post by: peter purpose on June 27, 2007, 10:34:39 AM
Quote from: "Tubemooley"
thought you guys would want to know. DW.


Good stuff DW.. :thumb:
Title: re: output transformers for the 525
Post by: edanderson on June 27, 2007, 10:35:14 AM
cinemag makes great transformers.  i'm sure they can make something that will fit in the hole and work with minimal mechanical modification to the PCB.  and i'd imagine that whatever they come up with could work, but will likely sound different.  for those that want something different from the original, it wont bother me at all if you decide to buy from cinemag.

my order of transformers is coming along.  they are quite close to the original transformers.  i gave the winder an original 2623 to check against.  i've gone through some samples to get it just right.  and i think the pricing should be agreeable for most:

qty 1 - $25ea
qty 2 - $20ea = $40 total
qty 4 - $18.75ea = $75 total
qty 8 - $17.50ea = $140 total
qty 16 - $15ea = $240 total

these are not being made by edcor, btw.  when peter first made his announcement, i went to edcor asking them to make these for me.  after a few weeks of consideration, they decided not to do it.  so i got a bit of a late start on making these with a different winder.  i should have them in a few weeks.

ed
Title: 525 build thread
Post by: peter purpose on June 27, 2007, 10:37:38 AM
Cracking news Ed. Still untested my end, but expect a substantial order from this side of the pond.

peter
Title: 525 build thread
Post by: dissonantstring on June 27, 2007, 03:30:53 PM
Quote from: "peter purpose"
Grant... tsk tsk.
The vcr2n and it's little house.....
It is not mandatory to use the socket, but makes testing and swapping a breeze.


oooooops!!  :oops:
i should really start a project before supposedly answering questions about it -damn me and my big mouth!  :razz:
sorry about the wrong info richie and thanks for cattle prodding me back in line with that image peter!  :grin: zaaapppp!!
thanks again for clearing that up peter and thanks for lead on their availability at goldmine (newark is $6.95 per - too expensive)! :thumb:
-grant

ed great news and the pricing is outstanding!  thanks as always for putting in the time and effort for the group!  this is exciting!
Title: 525 build thread
Post by: capnspoony on June 27, 2007, 06:20:27 PM
Hey ed where are you in brooklyn ?

Im right below prospect park... I'd be happy to give you a hand / learn how you do this sort of stuff... and of course I'm totally in for 16  :thumb:

--Richie
Title: 525 build thread
Post by: mata_haze on June 27, 2007, 07:55:09 PM
if you guys can meet the specs with this round of trafos, PLEASE count us in for 8!!!!

Mattia
Nico.
Title: 525 build thread
Post by: edanderson on June 27, 2007, 09:03:11 PM
Quote from: "capnspoony"
.. and of course I'm totally in for 16 Heck Yeah!
--Richie


Quote from: "mata_haze"
if you guys can meet the specs with this round of trafos, PLEASE count us in for 8!!!!


thanks for the encouragement.  PLEASE, everyone else, there's no point to saying how many you want.  my order has already been placed.  when they go on sale it will be first come first served.  there should be enough for everyone.

ed
Title: 525 build thread
Post by: ask on June 28, 2007, 10:44:00 AM
Does anyone know whether Lundahl makes a good sustitute? As far as I can see, the LL1555 is the only line XF small enough for the 525 boards. It's max +27dBu wheras the 2623 is +30dBm (haven't quite figured what the 525 load, hence output would be) and the primary is 120 Ohm instead of 75.

 :roll:
Title: 525 build thread
Post by: CJ on June 28, 2007, 03:44:46 PM
An interesting experiment would be to use a non API type xfmr on the output.
Something that quits at 40K instead of 40 MHz.
Title: 525 build thread
Post by: jensenmann on June 28, 2007, 03:59:28 PM
CJ, did you ever get my pm´s or emails? never got a reply :roll:

 :guinness: ,anyway :grin:
Title: 525 build thread
Post by: edanderson on June 28, 2007, 04:53:58 PM
Quote from: "jensenmann"
CJ, did you ever get my pm´s or emails? never got a reply


yeah me too CJ... i wanna send some things to be publicly hacked on the forum, but not if CJ already has them.

ed
Title: Cinemag CMOQ-3
Post by: Tubemooley on June 29, 2007, 05:13:39 AM
I have received an updated mechanical drawing of the Cinemag CMOQ-3 from David at Cinemag. He sent me a .pdf and a .jpg. Each file is only 40kB. But I don't know how to post files on the forum here. Either someone can splain this to me or I can just e-mail them to one of you guys and you can post them or host them. I don't have any hosting capabilities. Sorry I'm such an idiot here. Anyone who can help, please post or PM me. DW.
Title: 525 build thread
Post by: Tubemooley on June 29, 2007, 05:19:10 AM
Coupla things.....

Ed's trannies sound like they will be the bomb. And his prices are fantastic. I will probably get in on his buy if he doesn't mind even though I've been pursuing the Cinemags.

Also - I too have looked for a suitable Lundahl trannie for this build. I am a huge fan of the Lundahl's. They rock. I've used at least 10 different models of his. Unfortunately, his datasheets are different from Cinemag and Jensen. He doesn't list impedances even though I can usually figure those out from the DC resistances. I'll go look at the LL1555 mentioned above and see what I think. Unfortunately the Lundahl's are rather pricey also. But if you can swing the cash for them, you won't be disappointed with their performance and sound. They kick butt.

Rock on gentlemen. DW.
Title: 525 build thread
Post by: ask on June 29, 2007, 05:27:57 AM
Good point about resistance/impedance!
I'm a Lundahl fan as well, but it looks like Ed's custom wound XF's would be just right, especially since it's for at module, not just a rack unit with lotsa space. We'll see :)
Title: 525 build thread
Post by: ask on June 29, 2007, 03:19:19 PM
What are the dimentions of the L-bracket the pcbs mount to? I was going to ask whether Purusha could do the metalwork.

 :wink:
Title: 525 build thread
Post by: Purusha on June 29, 2007, 03:34:08 PM
Yap, this could give me something to do in August  :thumb:
Title: 525 build thread
Post by: ask on June 30, 2007, 04:05:14 AM
Alternative housing:

http://www.atlasproaudio.com/atlasrecordinggear.html
Title: 525 build thread
Post by: Purusha on June 30, 2007, 07:31:26 AM
I don't think there is a case which I could not put together  :wink:
Title: 525 build thread
Post by: ask on June 30, 2007, 07:37:54 AM
I belive you, Purusha. However, I just posted it for general info, but worth a thought for sure.

 :wink:
Title: 525 build thread
Post by: Purusha on June 30, 2007, 07:51:43 AM
Sure, but c'mon 450$ for a piece of steel called "revolver" :green:  this guys are really just about the money  :cool:
Title: 525 build thread
Post by: ask on June 30, 2007, 08:01:15 AM
I believe there is a PSU included, so I guess it's comparable to the API two-slot rack unit, in price.

But I find it a bit expensive too, espec. since you have to get a case/psu for every two 500 modules.
Title: 525 build thread
Post by: Denyle Guitars on June 30, 2007, 05:51:01 PM
A-Designs apparently has a 1u dual module powered rack on the way for $300. Looks like it would be great for these 525's.
Title: 525 build thread
Post by: Purusha on July 01, 2007, 02:44:04 AM
300$ IMHO is still a lot for such product...  I could probably offer them for less than 100€ and considering
the DIY PSU parts all together can't go over 150€ per one dual rack... probably even much less than that.
Title: 525 build thread
Post by: Denyle Guitars on July 01, 2007, 01:53:34 PM
Well sure, they can be made for less. If someone wants to offer a chassis kit/psu pcb combo, the price would come down significantly and I'd be all over that. OTOH, the cost and effort to build a one-off from a blank enclosure (if you don't have a metal shop) makes the A-Designs rack look pretty good.
Title: 525 build thread
Post by: babyhead on July 01, 2007, 05:24:58 PM
I'm just going to put them in a 1 space rack just because I dont  have the API chassis and have no plans on getting one. Then I can disguise it!

-BH
Title: 525 build thread
Post by: peter purpose on July 02, 2007, 08:53:20 AM
Lunch boxes and their larger brethren are a little more complex than a box.
2-11 connectors have to be accommodated. Either by a pcb or inter panel.
Not saying it's rocket science, but a simple box it aint.

peter
Title: 525 build thread
Post by: gar381 on July 02, 2007, 10:03:45 AM
Quote from: "Purusha"
 I could probably offer them for less than 100€ and considering


I would be VERY interested tat. :thumb:

GARY
Title: 525 build thread
Post by: Purusha on July 02, 2007, 10:17:58 AM
Sure, I just need someone to help me with all the measures  :thumb:
Title: 525 build thread
Post by: okgb on July 02, 2007, 10:19:15 AM
Now that is a case i'd be interested in !
but what drives the cost up ?

 It's part of what makes my projects expensive to the point ,
of just buying comercial things already

 Might as well start a separate thread , to leave this one for
circuit build questions .

regards Greg
Title: 525 build thread
Post by: Purusha on July 02, 2007, 11:13:19 AM
Quote
Might as well start a separate thread , to leave this one for
circuit build questions .


Good idea. I just started a new thread HERE (http://www.groupdiy.com/forum/posting.php?mode=editpost&p=276880)
Title: 525 build thread
Post by: Brizco on July 03, 2007, 02:40:49 PM
started building:
now i have some questions:

what is cr6? have i overseen something?

what is "mode" under the lm319 ?


of course there are coming more questions :)

thanks!
Title: 525 build thread
Post by: peter purpose on July 03, 2007, 03:03:56 PM
CR6 is a diode. 1N4004, as are they all.
Check the schematic.

Mode can change from lighting a single led to lighting them all.
Use a jumper or a switch.

peter
Title: 525 build thread
Post by: Brizco on July 04, 2007, 02:20:30 AM
thanks! ive overseen that!

more questions :)

i can substitute the 2n5087 with bc560c, right?

it doesnt matter if i use bc184c or bc184b, right?
184b has a lower minimal value for the small signal current gain than the 184c, 184c has higher maximal value than the 184b)

can i substitute the vcr2n with a vcr4n ?
(vcr2n has a max. drain-source resistance of 60ohm, the vcr4n of 600ohm)


thanks a lot!
bye
martin
Title: 525 build thread
Post by: peter purpose on July 04, 2007, 06:10:56 AM
<<i can substitute the 2n5087 with bc560c, right? >>

Yes, but watch orientation. Collector is marked.

<<it doesnt matter if i use bc184c or bc184b, right? >>

Probably. Any of the usual suspect hfe matched NPN input pair will get the job done.

<<can i substitute the vcr2n with a vcr4n ? >>

I'd say no.

peter
Title: 525 build thread
Post by: capnspoony on July 05, 2007, 11:41:17 PM
Been doin' this for quite some time and I might be blind.... where in the world is R64 -- 3k9?

When I blow up the schematic I can't read it.  Is there anyway to get a larger one hosted on the this thread?

EDIT:  

Also, are we allowed to only put the .39uf cap in for the (150nf+220nf)  ?

so far so good!

best

Richie
Title: 525 build thread
Post by: Walrus on July 06, 2007, 06:47:12 AM
R64 is on the bottom of S5 B.
Title: 525 build thread
Post by: peter purpose on July 06, 2007, 07:52:21 AM
Pay attention at the back of class.....
http://www.twin-x.com/groupdiy/albums/userpics/525.jpg

<<where in the world is R64 >>

As Mr. Walrus says .. tis on the rotary switch.

<<are we allowed to only put the .39uf cap in>>

I'll allow it just this once..!!
I used 2 caps to make up the value-ish. I couldn't find .39uF anywhere.
If you've got em, use em.
peter
Title: 525 build thread
Post by: capnspoony on July 06, 2007, 08:07:47 AM
Thank you Peter... I can see it now!

I'm sure they'll be more questions- I better move up to the front row  :green:

--Richie
Title: 525 build thread
Post by: babyhead on July 07, 2007, 12:02:35 AM
I really really like the 'nod to the skeptics'

Very nice touch.

So how do we mount the meter board?

 :guinness:  :guinness:  :guinness:
Title: 525 build thread
Post by: kazper on July 07, 2007, 01:14:20 AM
Quote from: "babyhead"
I really really like the 'nod to the skeptics'

Very nice touch.

So how do we mount the meter board?

 :guinness:  :guinness:  :guinness:


Kazper raises his hand and get's called on..

The 3 pots are connected to it and it's held in place by them. Check out peters pic's on page 7 or 8 of this very thread.



Cap-N-Spoony it looks like your stuff finally arrived, Hopefully unscavenged by the natives where it was held up at.

I started stuffing mine today, with what's in my hiddy hole and see where that get's me till it's next time for a store run.

Kevin
Title: no it is:
Post by: shabtek on July 07, 2007, 08:55:43 AM
mine says

nod to the septics

will it still work?
Title: Re: no it is:
Post by: peter purpose on July 07, 2007, 09:19:05 AM
Quote from: "shabtek"
mine says

nod to the septics

will it still work?


Haha  :green: ... highly unlikely.

I was wondering when you lot would notice that.
Title: 525
Post by: thestudio on July 08, 2007, 02:04:54 PM
I received the 525 pcbs and like to say  "very nice work"  :wink:  
Where is everyone getting transformers :?:  I know search the form but just thought I'd ask :oops:

Thanks Peter

Cheers  :guinness:
Title: 525 build thread
Post by: peter purpose on July 09, 2007, 06:49:21 AM
You're welcome. :thumb:
I'll be going for Ed's transformers. Look back a few pages.
I can't tell any difference between them and the originals.

peter
Title: peter
Post by: thestudio on July 10, 2007, 09:11:03 PM
Yep, going with Ed's transformers..........thanks again....cheers  :guinness:
Title: 525 build thread
Post by: kazper on July 11, 2007, 01:43:20 AM
Any idea where to find the switches in the states?

I still hadn't found what I'm looking for.

Kevin
Title: 525 build thread
Post by: peter purpose on July 12, 2007, 05:53:28 AM
Kevin,
Ask the capn where he got his.
Otherwise, search for sub miniature push buttons.

peter
Title: 525 build thread
Post by: kazper on July 12, 2007, 08:25:11 AM
Thanks peter

I think I was missing the sub miniture

Mouser

one of the E-Switch models starting with PBH2UEE

Need to chose what cap color you want when you order.....


Note these may or may not work....
Title: cap questions
Post by: king-rb on July 12, 2007, 12:05:04 PM
hi!...

what are the values for follow caps:
CD5
CD6
and these two caps behind the vertical opamp and c14/r49
   
I would like to use the 990 opamp...
do I have to change some resistor values or anything else=?

thank you!
Title: 525 build thread
Post by: capnspoony on July 12, 2007, 12:56:17 PM
Kazper... Do you mean the 5* 2-pole pushbutton switches?

I got some in my kits but those were missing for a while in the mail and I went ahead and ordered extras from mouser.  I'm not sure if mine are the right kind either but IF they are I'll be glad to send'em to you .. be in touch later tonight.
Title: 525 build thread
Post by: capnspoony on July 12, 2007, 01:01:40 PM
King Rb:

"what are the values for follow caps:
CD5
CD6 "

CD6/5 are both 33pf

Quote
and these two caps behind the vertical opamp and c14/r49


R49 is a resistor - 47K

C14 is a cap - .1UF or 100nF

Pretty sure you don't have to change resistor values using a 990... my understanding is all of those DOA's with the 2520 footprint will work

best

Richie
Title: Re: cap questions
Post by: peter purpose on July 12, 2007, 01:02:38 PM
Quote from: "king-rb"
hi!...

what are the values for follow caps:
CD5
CD6
and these two caps behind the vertical opamp and c14/r49
   
I would like to use the 990 opamp...
do I have to change some resistor values or anything else=?

thank you!


Check the updated bom.
Not entirely sure of any changes needed when using 990s.

peter
Title: 525 build thread
Post by: capnspoony on July 12, 2007, 01:07:25 PM
Questions of my own:

1) What does "Led Dependent" mean for RL1 and RL2 ?

2) What is "200uA FSD meter" ?

3) Can someone give me an example or part number for a "tri color cathode of choice" that will work for this project?

4) Also is there a part I need for mono strap and mode or is that taken care of through wiring?

best

Richie
Title: Re: cap questions
Post by: delaymix on July 12, 2007, 01:57:22 PM
Quote from: "peter purpose"
Quote from: "king-rb"
hi!...

what are the values for follow caps:
CD5
CD6
and these two caps behind the vertical opamp and c14/r49
   
I would like to use the 990 opamp...
do I have to change some resistor values or anything else=?

thank you!


Check the updated bom.
Not entirely sure of any changes needed when using 990s.

peter


Hi,    

In the boom the two caps behind the vertical opamp and c14/r49 they do not have reference nor value in the boom.

(http://www.dropshots.com/photos/308235/20070712/193926.jpg)

What is the value for these capacitors?

Thanks.
Title: Re: cap questions
Post by: peter purpose on July 12, 2007, 03:24:56 PM
Quote from: "delaymix"

What is the value for these capacitors?

Thanks.


100nF
Title: 525 build thread
Post by: peter purpose on July 12, 2007, 03:25:43 PM
Come on you lazy bastards..... read the forgen thread.
Title: 525 build thread
Post by: peter purpose on July 12, 2007, 03:30:10 PM
<<1) What does "Led Dependent" mean for RL1 and RL2 ? >>

Read the forgen thread

<<2) What is "200uA FSD meter" ? >>

It is a meter with a 'full scale deflection" of 200uA.
If you're using the led meter, you need not trouble yourself with this.
Read the forgen BOM.

<<4) Also is there a part I need for mono strap and mode or is that taken care of through wiring?>>

Piece of wire or jumper.
If going stereo with these things, then wires are attached at the strap points and for the mode... strap for full lighting, or leave for single led lighting.
Read the forgen thread.

peter
Title: 525 build thread
Post by: capnspoony on July 12, 2007, 07:31:49 PM
<<rl1/rl2 led dependent.what`s this?.i`m ashamed to ask. >>

"Don't be.
The in/bypass switch has provision for a tricolour led. Use whatever floats your boat to get the desired brightness.

peter"

I read this before and I'm still not sure, sorry.  I just don't want to hurt the circuit the first time I turn it on

<<2) What is "200uA FSD meter" ? >>

"It is a meter with a 'full scale deflection" of 200uA.
If you're using the led meter, you need not trouble yourself with this.
Read the forgen BOM. "

sorry, I wasn't sure if it was an either or situation.

thanks

Richie
Title: 525 build thread
Post by: Brizco on July 13, 2007, 02:39:30 AM
Quote from: "capnspoony"
<<rl1/rl2 led dependent.what`s this?.i`m ashamed to ask. >>

"Don't be.
The in/bypass switch has provision for a tricolour led. Use whatever floats your boat to get the desired brightness.

peter"

I read this before and I'm still not sure, sorry.  I just don't want to hurt the circuit the first time I turn it on


led: something like this: http://www.distrelec.com:80/ishopWebFront/catalog/product.do/para/language/is/de/and/shop/is/CH/and/id/is/01/and/node/is/acaaadaaacai/and/series/is/1.html;jsessionid=2171EE854200F65EB30606A5F5199967.chdist54

and then the resistors depends on the led you have used, and the brightness you want.
Title: harr
Post by: king-rb on July 13, 2007, 04:04:58 AM
yeahhha... thanxx
Title: 525 build thread
Post by: peter purpose on July 13, 2007, 09:14:32 AM
Quote from: "capnspoony"

I read this before and I'm still not sure, sorry.  I just don't want to hurt the circuit the first time I turn it on


LEDs come in many varieties. Colour, size, brightness and so on.

For 'your needs' Richie, they all need to be of the 3mm variety.
10 of them being one type for the meter and 1 of another type for the in/bypass switch.

For the meter they will be single colour 2 leg. Get the colour and brightness of your choice. Play with RM1 to get the desired brightness.

For the in/bypass switch, the pcb has provision for a tri colour, common cathode led. That is a 3 leg jobbie, with the centre leg being common.
Get whatever colours float your boat and use the appropriate resistors for each colours requirement.

peter
Title: 525 build thread
Post by: peter purpose on July 13, 2007, 11:22:50 AM
OK boys, I'm taking a week off.. :thumb:
Title: sockets
Post by: king-rb on July 15, 2007, 06:41:30 PM
anyone know a produkt# forthe vcr2 sockets at farnell=?

thanks
Title: 525 build thread
Post by: louder on July 15, 2007, 06:48:15 PM
alo
farnell p/n:177128
best regards
pedro
Title: 525 build thread
Post by: kazper on July 15, 2007, 06:56:22 PM
Quote from: "peter purpose"
OK boys, I'm taking a week off.. :thumb:


I think you need it!

Enjoy...
Title: 525 build thread
Post by: peter purpose on July 18, 2007, 08:22:19 AM
Quick wiring dagram.
This does not mean I'm back..!!

(http://www.twin-x.com/groupdiy/albums/userpics/normal_525wiring.jpg)

Large version...
http://www.twin-x.com/groupdiy/albums/userpics/525wiring.jpg
Title: diagramm
Post by: king-rb on July 18, 2007, 11:17:17 AM
wow thanks ..thats what i deeded!
Title: 525 build thread
Post by: capnspoony on July 18, 2007, 01:05:28 PM
cheers peter...

I opted for this...

You deserve a present for all your hard work Peter!  whatchoo want

--Richie
Title: 525 build thread
Post by: peter purpose on July 18, 2007, 02:18:03 PM
Quote from: "capnspoony"
 whatchoo want


A week off.
Title: voltage
Post by: king-rb on July 21, 2007, 07:18:20 AM
moin! on which voltage should i run the 525...
ther are 3 990opamps integrated
Title: 525 build thread
Post by: peter purpose on July 21, 2007, 07:39:13 AM
As standard, the 525 wants to see +&-15V.
If you have 990Cs, then they really want to see +&-24V(I think).
The upright opamp can also handle 24v, so it really depends on how brave you are.
I'd start out at standard voltage and push on up until your sphincter puckers up tight.
Title: 525 build thread
Post by: king-rb on July 21, 2007, 11:46:02 AM
yeahahh!!! first channel finished and it works.. haha
3x 990opamp stable with psu voltage 20V

now i have to build the other 3 ... haha
and a 19" case...
Title: 525 build thread
Post by: chester on July 21, 2007, 01:01:19 PM
Quote from: "king-rb"
yeahahh!!! first channel finished and it works.. haha
3x 990opamp stable with psu voltage 20V

now i have to build the other 3 ... haha
and a 19" case...


pictures please!!  :wink:
Title: 525 build thread
Post by: peter purpose on July 21, 2007, 08:54:11 PM
(http://www.twin-x.com/groupdiy/albums/userpics/normal_built525.jpg)

Bigun.. http://www.twin-x.com/groupdiy/albums/userpics/built525.jpg
Title: 525 build thread
Post by: king-rb on July 22, 2007, 05:52:47 AM
wow.... this is a good looking one!
Title: ok
Post by: shabtek on July 22, 2007, 09:23:17 PM
I know I saw some discussion of this but I could not find it on this thread.

What is the gain of the upright op-amp? I have not traced it out to see what the resistor network is.

I think I want to bal->unbal the input with a trafo...1:1 hi.z input...?

 Somebody had mentioned doing this before.
Title: 525 build thread
Post by: peter purpose on July 23, 2007, 08:29:02 AM
It's a differential input. So, balanced or unbalanced. Amplifying only the difference.
Here's the schematic of the op amp.
(http://www.twin-x.com/groupdiy/albums/userpics/uroa~0.jpg)

If you're sticking a transformer on the front, bring the secondary signal to the point marked RB1.
Leave out....
CD1-6
RD1-4
A4 and the two unmarked caps
CB1
RB1

peter
Title: 525 build thread
Post by: babyhead on July 23, 2007, 03:51:33 PM
Quote from: "king-rb"
yeahahh!!! first channel finished and it works.. haha
3x 990opamp stable with psu voltage 20V

now i have to build the other 3 ... haha
and a 19" case...


Watch out for DC across the primaries with the 990c's. Every application on the JH website calls for DC blocking on the output... you could slowly fry the output iron.

Am I correct?

Otherwise congrats!
Title: !!
Post by: shabtek on July 23, 2007, 05:45:06 PM
many thanks again peter.

babyhead: i believe the xfmrs ought to be gapped, if there is DC offset on the DOA out, it  should not cause a winding to burn open...if ungapped there is always a possibility...and frequency response will suffer as the core could be saturated by the DC
Title: 525 build thread
Post by: babyhead on July 23, 2007, 09:08:51 PM
Quote from: "peter purpose"
Quote from: "babyhead"

It is either that the 2623 is DC capable or the DC output of the 2520 negligible.


The latter.


I'm going by this...
Title: 525 build thread
Post by: CJ on July 23, 2007, 10:48:19 PM
thats a steel core, so dc will not be a problem as with the Ni alloys, but turns are low, so any dc will go right thru the xfmr, so make sure your offset is low enough so that you dont burn up your op amp. it will do as its told, if this means pumping dc thru the output transconitinentals, so have your nearest tech buddy standing by with a soldering iron.

What happens to DC offset during the rise of an 8 hz sqaure edged bass note?
 

I mean, if the dc is really ac, but still sucks  amps, do we consider it?

Measure DC offset while you play music thru it, and you will see what I mean.

People who bypass the output cap are either askin for trouble, or from the UK. Near London probably.
Hopefully not Twekesbury.
Title: dc
Post by: king-rb on July 24, 2007, 03:33:09 AM
sooo.... im using the cinemag cmoq-2s and the 990s what should i do against this dc problem
Title: 525 build thread
Post by: Greg on July 24, 2007, 08:40:31 AM
An easy solution would be to add a DC blocking cap between the opamp and output transformer.
Title: 525 build thread
Post by: babyhead on July 24, 2007, 12:49:27 PM
Quote from: "Greg"
An easy solution would be to add a DC blocking cap between the opamp and output transformer.


While you are at it, minus well throw the output isolator in there...
Title: 525 tranformers
Post by: thestudio on July 24, 2007, 09:27:14 PM
Are the transformers ready for the 525 meaing are they for sale  :?:

Looking for (4)  :roll:
Title: 525 build thread
Post by: CJ on July 25, 2007, 09:11:29 PM
yeah, there five quid a piece.
Title: 525 build thread
Post by: Reptil on July 25, 2007, 11:15:08 PM
:grin:
I have that!
happy happy joy joy
Title: Re: 525 tranformers
Post by: edanderson on July 26, 2007, 11:01:07 AM
Quote from: "thestudio"
Are the transformers ready for the 525 meaing are they for sale  :?:

Looking for (4)  :roll:


i should have some for sale within two weeks.  i will post when they are available.  please don't PM me.

ed
Title: 525 build thread
Post by: Rob Flinn on July 27, 2007, 06:00:26 AM
Peter

Any chance you could post the last parts list as a spreadsheet matey ?
Title: 525 build thread
Post by: peter purpose on July 27, 2007, 10:00:09 AM
Quote from: "Rob Flinn"
Peter

Any chance you could post the last parts list as a spreadsheet matey ?


Have you lost the use of your fingers?
Title: 525 build thread
Post by: Rob Flinn on July 27, 2007, 12:34:55 PM
Quote from: "peter purpose"
Quote from: "Rob Flinn"
Peter

Any chance you could post the last parts list as a spreadsheet matey ?


Have you lost the use of your fingers?


No, not if the progress I'm making on these 525's is anything to go by !!!!
Title: 525 build thread
Post by: gar381 on July 30, 2007, 09:30:49 PM
A quick note to your guys and gals ordering your VCR2N
from Goldmine.. they have 10k and 50k (use for 47k) "y" format Bourns trimmers if you need them for this project...Cheap!! :grin:

GARY
Title: 525 build thread
Post by: Brizco on July 31, 2007, 02:05:42 AM
goldmine does not ship to europe, right?

oh thats bad, here in switzerland, one piece vcr2n costs 12 dollars plus shipping! yes, a single piece!!

any chance to trade fine chocolate for two vcr2n ? :grin:
or is there another good source in europe for this part?

another question to peter: can you please post a picture of your 525 frontpanel? thaaaaanx!!

 :sam:
Title: 525 build thread
Post by: peter purpose on July 31, 2007, 09:00:44 AM
If you're getting your transformers from Ed, he'll throw in the fet.

(http://www.twin-x.com/groupdiy/albums/userpics/boxuc1.jpg)
Title: 525 build thread
Post by: Brizco on August 07, 2007, 11:38:27 AM
can someone please explain me how the stereo link works?

tnanks!
Title: 525 build thread
Post by: peter purpose on August 07, 2007, 03:32:18 PM
(http://www.twin-x.com/groupdiy/albums/userpics/normal_525STQU.jpg)

BIGGUN.. http://www.twin-x.com/groupdiy/albums/userpics/525STQU.jpg
Title: 525 build thread
Post by: thestudio on August 07, 2007, 05:33:36 PM
To Ed,

 Please post here when transformers are ready  :wink:
Title: 525 build thread
Post by: Rob Flinn on August 07, 2007, 06:09:33 PM
Here is a probably really dumb, & answered in a previous thread that didn`t come up when I used the search facility question:

Is there any information on how to calibrate these boards anywhere ??  I just  spent an hour wading through the 525 threads & came up with nothing !
Title: 525 build thread
Post by: peter purpose on August 07, 2007, 06:45:08 PM
(http://www.twin-x.com/groupdiy/albums/userpics/normal_525_Page_10.jpg)

biggun.. http://www.twin-x.com/groupdiy/albums/userpics/525_Page_10.jpg


(http://www.twin-x.com/groupdiy/albums/userpics/normal_525_Page_11.jpg)

biggun.. http://www.twin-x.com/groupdiy/albums/userpics/525_Page_11.jpg
Title: 525 build thread
Post by: Rob Flinn on August 07, 2007, 07:28:15 PM
Thanks Peter
Title: 525 build thread
Post by: Greg on August 07, 2007, 08:37:31 PM
Don't hold out on us, Peter.

I'm waiting for my opamps to come in from Fabio then I'm going to start pestering you!

Gulp, Gulp!   :guinness:
Title: 525 build thread
Post by: CJ on August 07, 2007, 08:59:52 PM
I've got something on my peter.

Greg, don't drink the water.
Pipes are corroded from salt water, leakin like a sieve.
Both ways.
Flush twice and pray.
 :green:
Title: 525 build thread
Post by: Greg on August 07, 2007, 10:52:03 PM
Yea, they had a blurb in the WSJ today about it.  Does drinking the water while taking a shower count? Gotta get hydrated in the morning, ya know. Drink too much at night.  :guinness:

Our pipes have been leaking for years. Decades, in fact.

But really, Entergy (natural gas and electricity company here) is replacing all the underground gas lines in my neighborhood with higher pressure lines to prevent back flow in case of another flood. Apparently water got into the gas lines from the storm. Oops.

This is really of topic... sorry, Peter. Maybe we should ramble on in The Brewery.
Title: 525 build thread
Post by: Brizco on August 08, 2007, 04:12:33 AM
thanks peter! you are a hero!
Title: 525 build thread
Post by: peter purpose on August 08, 2007, 11:31:29 AM
Quote from: "Brizco"
thanks peter! you are a hero!


Got to look after my Swiss brethren.
Title: 525 build thread
Post by: peter purpose on August 08, 2007, 11:32:51 AM
Quote from: "Greg"
I'm going to start pestering you!


No change there then.
Title: 525 build thread
Post by: peter purpose on August 08, 2007, 11:33:42 AM
Quote from: "CJ"
I've got something on my peter.


Use a cheese grater.
Title: 525 build thread
Post by: CJ on August 08, 2007, 03:12:31 PM
yummm...linburger!
but i took me foreskin off.
.
.
hey, no more AIDS!
 :thumb:  :green:
Title: 525 build thread
Post by: kazper on August 08, 2007, 03:35:57 PM
Hey Peter how long ago did you do the Eq's?

Was that a kit like the 525?
Title: 525 build thread
Post by: peter purpose on August 08, 2007, 03:59:25 PM
Quote from: "CJ"
yummm...linburger!
but i took me foreskin off


I see where you're going wrong.
It is called 'organzola' Christopher and is found 'under' the foreskin..  :green:
Title: 525 build thread
Post by: peter purpose on August 08, 2007, 04:00:59 PM
Quote from: "kazper"
Hey Peter how long ago did you do the Eq's?

Was that a kit like the 525?


Feels like I made em when God was a boy and was, or is not a kit.
Title: 525 build thread
Post by: edanderson on August 13, 2007, 02:41:47 PM
Quote from: "thestudio"
To Ed,

 Please post here when transformers are ready


the page to order should go up in the next few days.  i will post again when all is in readyness.

ed
Title: 525 build thread
Post by: louder on August 16, 2007, 10:08:47 AM
Hi Peter
sorry for being a pita,but i just can`t seem to find the switch`s for this project.
if you could drop a hint.....
best regards
pedro
Title: 525 build thread
Post by: peter purpose on August 16, 2007, 10:54:20 AM
Rotary...        RS 352-187
Wafers X2...   RS 352-244

Pushbutton
5X  Rapid  78-0060 2 pole
1X  Rapid  78-0061  4 pole

peter
Title: 525 build thread
Post by: CJ on August 16, 2007, 05:03:58 PM
speaking of when God was a boy, i got this api output ready to send back to the nice guy from the uk,
so apologies, its coming back with some extra stuff.
cj
remember when we took that apart?

hey, i was thinking, which is a miracle in itself, why has not any one tried running an aPI without the output xfmr?
its 1:1, or 1:2, or is it 2:1, i don't know , but i do know you would not lost much gain to a ratio step up?

just stick a cap in there, and make sure whatever your running into, well, you have your chassis grounds all kosher.
Title: 525 build thread
Post by: Greg on August 16, 2007, 07:30:29 PM
Give me iron or give me death.
Title: 525 build thread
Post by: jensenmann on August 17, 2007, 05:23:55 AM
Quote from: "Greg"
Give me iron or give me death.


 :grin:  :thumb:  :thumb:  :thumb:

 :guinness:
Title: 525 build thread
Post by: peter purpose on August 22, 2007, 08:46:44 AM
IMPORTANT

Boys,
I've just found another boo-boo.  :oops:
The output transformer termination switch/jumper is wrongly implimented.
Leave out the switch/jumper, or you'll be shorting the output when switched or jumped.
If you have the 600R resistor fitted, it will be permanently across the secondary.
If you want the next piece of gear to terminate the transformer, then leave out the 600R resistor.
If you need the switching capability, then a little trace cutting and rewiring is called for.
Sorry peeps.. :oops:  :oops:
Title: 525 build thread
Post by: CJ on August 22, 2007, 02:55:59 PM
bastard.

.
.
.
 :green:
get it right.
.
.or else.
.
.
.
 :razz:
Title: 525 build thread
Post by: peter purpose on August 22, 2007, 07:48:31 PM
Look ere you soft Californian soak.... I reckon at 5 foot nothing I could still knock seven shades of sh*te out of you... even if you pulled the bayonet.
Title: 525 build thread
Post by: Greg on August 22, 2007, 07:51:54 PM
hah... I've seen that picture.

Don't underestimate a Californian with a bayonet.
Title: 525 build thread
Post by: peter purpose on August 22, 2007, 07:54:29 PM
Bollox.. All (coastal) Californians could, and should be put down with a hammer.
Title: 525 build thread
Post by: conleycd on August 23, 2007, 11:20:19 PM
Quote from: "Siegfried Meier"
I'm thinking of doing just this - make a single rack space, Front Panel Express file, get EDAC connectors, or whatever, and just rack the 2 units.  Only thing is the P/S.  Anyone know what I need?  Or maybe just buy the JLM powerstation, and that will most likely work for what I need.

Thanks,
Sig


A lessor known powersupply that I think would work fine here is a kit made by PAIA.  It avoids the whole AC connection head ache.

http://www.paia.com/proddetail.asp?prod=9770R%2D15

CC
Title: 2623 transformers for PP 525 compressor
Post by: edanderson on August 27, 2007, 08:54:02 PM
now sold out:

http://www.groupdiy.com/index.php?topic=286214

ed
Title: 525 build thread
Post by: okgb on September 18, 2007, 07:48:14 AM
Hey Ed , did you mention something about the xfmr colors being
different ?
 Although it is awhile off , i'm looking at how to wire up the xfmrs so i can keep the parts together

thanks & regards Greg
Title: 525 build thread
Post by: edanderson on September 18, 2007, 09:19:18 AM
from:

http://www.groupdiy.com/index.php?topic=24087

Quote from: "edanderson"
the main difference is that where the originals had striped lead wires for the "cold" ends of each winding, these have solid colors.

primary: red to orange
secondary1: blue to green
secondary2: brown to black
Title: 525 build thread
Post by: peter purpose on September 18, 2007, 01:02:39 PM
He's Canadian Ed, you'll have to trot that one out another few times before he grasps it.
Title: 525 build thread
Post by: okgb on September 19, 2007, 08:20:42 AM
Nah  , it's a combo of being in a hurry , behind and needing glasses ,

but i gotta say we're all a little tired of keeping houses for the Queen when she comes to visit , can you let her know we've had enough ? !
Title: 525 build thread
Post by: peter purpose on September 19, 2007, 09:09:16 AM
That's odd Greg, Her Majesty speaks very highly of you.
Title: 525 build thread
Post by: okgb on September 19, 2007, 09:21:34 AM
That's cause we spend so much money to keep her isloated from the masses [ and the truth  ] in high style .
and anyway she never calls , so it's lip service i think !

 Before we distract the thread though thanks again for your fine offer of compression to the
 masses , through your boards .

btw , what is the status of the metal work & kits now that you are on a 2nd round of pcbs ?

take care regards Greg
Title: 525 build thread
Post by: peter purpose on September 20, 2007, 07:25:18 AM
Quote from: "okgb"

btw , what is the status of the metal work & kits now that you are on a 2nd round of pcbs ?

take care regards Greg


Got three sets left and one is spoken for.
Not really a second round of pcbs, just what I have left.
Title: 525 build thread
Post by: peter purpose on September 24, 2007, 10:06:50 AM
The mod to rectify the output termination blunder is a breeze.
Cut the two traces at the red marks and bring the resistor leg (pink) to the switch/jumper.

(http://www.twin-x.com/groupdiy/albums/userpics/525mod2.jpg)
Title: 525
Post by: thestudio on September 26, 2007, 11:53:07 AM
What's the status on the second run of transformers for the 525  :?:
Title: 525 build thread
Post by: peter purpose on November 28, 2007, 07:01:45 AM
Gentlemen,

ATTACK MOD
If you've built one of these and are wondering why the attack pot does bugger all... well I'm afraid you're going to have to add a resistor.
If running a 10k pot, stick a 10k resistor at the pot return-to ground.
This will halve the control voltage to the fet at full clockwise.
If this is too much for you, experiment by going up in value with this resistor.

(http://www.twin-x.com/groupdiy/albums/userpics/attmod.jpg)

If it's already built and you don't want to take things apart, you can add the resistor on the pot/meter board. Just make sure to add it to the pot return pad.

peter
Title: 525 build thread
Post by: peter purpose on November 28, 2007, 08:03:47 AM
Oh yeah.... Some comments from a UK number one producer on the 525 copy.

"Absolutely LOVIN' the compressor to bits! In a word - AWESOME! Not exactly sure what is different to my original 525. Something not quite right in the input pot/"more"switch department. Probably the alignment/FET business. Sounds BETTER than mine ever  did. Especially on vocals! not so sucky as the old one, but [email protected]@k me! I love it to bits! Great on bass guitar, stand-up, and synth b-lines. Should sound much more compressed when you crank the switch up, but who cares? I could never have used mine on a lead vox before! Attack makes virtually no difference surprisingly, so perhaps if a longer attack is possible, it would be a good thing (addressed above). Loving the LED's!!!!! Looks perfect to me. Seriously cool in the lunchbox, easy to see across the room, and for once, blue is COOL. - Oooh Yeah! Given the option to make this one more like the original in response, I think I would would have to say no, even if this is not quite authentic. It is so smooth, and yet so filthy at the same time."

It's all in the alignment.
If you want it like the above, align it as in the notes.
If you want a standard response, adjust R7 for 0db.

peter
Title: 525 build thread
Post by: mich on November 28, 2007, 10:41:02 AM
Great info......thanks!

im finishing mine now,- have a question about the bypass switch/board:

what do the B G R points stand for? im guesing G is ground and B and R goes to the led (Blue - Red?) with the corresponding rl1 and rl2?

also,the calibration notes says "make sure R63 is 150" - but if using just one unit(mono) this resistor is bypassed with the jumper?

thanks
Title: 525 build thread
Post by: mich on November 28, 2007, 10:59:38 AM
if you are using peter c's melcor for A3 - it oscilates teribly - changing C4 to 180 pF solved the problem for me. :thumb:
Title: 525 build thread
Post by: peter purpose on November 28, 2007, 11:01:48 AM
Quote from: "mich"
Great info......thanks!

im finishing mine now,- have a question about the bypass switch/board:

what do the B G R points stand for? im guesing G is ground and B and R goes to the led (Blue - Red?) with the corresponding rl1 and rl2?

also,the calibration notes says "make sure R63 is 150" - but if using just one unit(mono) this resistor is bypassed with the jumper?

thanks


Correct on both counts.. :thumb:
Title: 525 build thread
Post by: mich on November 28, 2007, 11:38:26 AM
great.   but one last thingy..........

the bypass switch does not show on your coloured schemo - i checked if it is implemented as in the original schematic but i dont see how....
in other words: i've got compresion going on but the bypass does nothing...(i left out the meter board and using a 200uA meter)

pics to follow...
Title: 525 build thread
Post by: peter purpose on November 28, 2007, 11:43:15 AM
(http://www.twin-x.com/groupdiy/albums/userpics/normal_525Cschem2.jpg)

Biggun.. http://www.twin-x.com/groupdiy/albums/userpics/525Cschem2.jpg
Title: 525 build thread
Post by: peter purpose on November 28, 2007, 11:53:17 AM
(http://www.twin-x.com/groupdiy/albums/userpics/nu525.jpg)
Title: 525 build thread
Post by: mich on November 28, 2007, 12:15:04 PM
(http://i14.photobucket.com/albums/a345/mich4/525front.jpg)

(http://i14.photobucket.com/albums/a345/mich4/525inside.jpg)

(http://i14.photobucket.com/albums/a345/mich4/525insidedetail.jpg)

Quote
the bypass switch does not show on your coloured schemo - i checked if it is implemented as in the original schematic but i dont see how..
 ??
Title: 525 build thread
Post by: peter purpose on November 28, 2007, 12:21:41 PM
Quote from: "mich"
??


Have you seen the new schematic?

Congrats on being first to post your build.. :thumb:
Title: 525 build thread
Post by: mich on November 28, 2007, 12:28:59 PM
yes!

now it all comes clearer.... :thumb:  :thumb:
Title: 525 build thread
Post by: mich on November 29, 2007, 03:50:39 PM
the compressor now works - after i added R64 on the switch..... :green:

calibration goes well,but i have some dirt on the signal when compressing and even more with limiting.its not a lot but i think it should not be there.

when i have the out pot fully C.C.W (where it should be zero output) i can hear this distortion, and it increases as i turn up the input pot.

could it be a layout problem? (taking the negative input of A2 to ground eliminates it)
Title: 525 build thread
Post by: peter purpose on November 29, 2007, 05:11:24 PM
Quote from: "mich"
the compressor now works - after i added R64 on the switch..... :green:

calibration goes well,but i have some dirt on the signal when compressing and even more with limiting.its not a lot but i think it should not be there.

when i have the out pot fully C.C.W (where it should be zero output) i can hear this distortion, and it increases as i turn up the input pot.

could it be a layout problem? (taking the negative input of A2 to ground eliminates it)


Mine behave the same way. These things distort easily (part of their charm), but the more clockwise your rotary switch is, the less distortion appears to be present. So I'm thinking this is a fet anomaly.
PRR had something to say on the matter a while back. I'll see if I can find it.
PRR... "Because the FET sees the pre-limiting signal voltage, it overloads on strong signal. To make it work on typical line levels you have to attenuate the input, forcing a compromise with noise. It also is highly sensitive to FET parameters."

peter
Title: 525 build thread
Post by: mich on November 29, 2007, 05:29:09 PM
Quote
So I'm thinking this is a fet anomaly.


if only i would have a couple more of them to swap..... :sad:

i was cheap ordering only one (10 pounds and 2 weeks to get here) - and now i have to pay for it  :mad:
Title: 525 build thread
Post by: peter purpose on November 29, 2007, 05:31:33 PM
Nah, I've tried a few and they all behave the same.
Title: 525 build thread
Post by: Brizco on November 30, 2007, 08:01:50 AM
can someone pleas check if im doin it right?

the colour code for ed´s transformers:

primary -   : Orange
primary +  : Red



secondary - : black
socandary +: blue



secondary - : green
     I
secondary +: brown

thanks a lot!!
Title: 525 build thread
Post by: edanderson on November 30, 2007, 08:48:15 AM
this is what i wrote in the thread where you ordered the transformers:

Quote from: "edanderson"
primary: red to orange
secondary1: blue to green
secondary2: brown to black


so you've got the primary correct, but the secondary leads mixed up, i think.

ed
Title: 525 build thread
Post by: Brizco on November 30, 2007, 11:25:43 AM
Quote from: "edanderson"
this is what i wrote in the thread where you ordered the transformers:

Quote from: "edanderson"
primary: red to orange
secondary1: blue to green
secondary2: brown to black


so you've got the primary correct, but the secondary leads mixed up, i think.

ed


thanks ed! ive read that, an i thought i should make it as you suggested, but than ive seen peter´s pictures of his unit and on these pictures it looks different from your explanation.

hmm and now i´m confused   :?
Title: 525 build thread
Post by: peter purpose on November 30, 2007, 11:33:38 AM
(http://www.twin-x.com/groupdiy/albums/userpics/tw.jpg)
Title: 525 build thread
Post by: Brizco on December 01, 2007, 04:23:45 AM
thanks!! what a nice view!  :thumb:
Title: 525 build thread
Post by: Reptil on December 13, 2007, 08:29:32 AM
Quote from: "edanderson"
this is what i wrote in the thread where you ordered the transformers:

Quote from: "edanderson"
primary: red to orange
secondary1: blue to green
secondary2: brown to black


so you've got the primary correct, but the secondary leads mixed up, i think.

ed


Trannies & FETs recieved, they look very nice.
Thank You!!
 :grin:
Title: 525 build thread
Post by: peter purpose on December 18, 2007, 01:51:58 AM
OK boys... I think after attacking the crack, I've cracked the attack.
Leave C3 off the main board and move it to the attack pot wiper and take it to ground. If using the pot board, you'll have to seperate the pot pads and attach a wire.
Oh...lose that extra resistor too.

(http://img218.imageshack.us/img218/6937/xx1zd2.jpg)
Title: 525 build thread
Post by: Rob Flinn on December 18, 2007, 07:17:43 AM
Quote from: "peter purpose"
OK boys... I think after attacking the crack, I've cracked the attack.
Leave C3 off the main board and move it to the attack pot wiper and take it to ground. If using the pot board, you'll have to seperate the pot pads and attach a wire.
Oh...lose that extra resistor too.
If I could upload a pic I would, but I can't.


Peter is this with the original value pot      ? was it 22k?
Title: 525 build thread
Post by: mata_haze on December 19, 2007, 06:57:53 PM
Quote from: "peter purpose"
Oh...lose that extra resistor too.


are you referring to R63?

ps =I am getting ready to test my 525  :grin:
Title: 525 build thread
Post by: peter purpose on December 19, 2007, 09:58:49 PM
Rob... use whatever you've got.

Mata... No, I mean this one....

(http://www.twin-x.com/groupdiy/albums/userpics/attmod.jpg)
Title: 525 build thread
Post by: mata_haze on December 22, 2007, 08:06:42 AM
thanks Peter,got it working.
Title: 525 build thread
Post by: mata_haze on December 22, 2007, 08:06:52 AM
thanks Peter,got it working.


Best,
Mattia.
Title: 525
Post by: king-rb on December 29, 2007, 02:37:32 PM
what happens with this attack mod=? faster attack=?
an another quesion ..
should i connect the term jumper=?

i build a stereo version with controlls for each channel ..so i connected the mono strap on led pcb.. is this ok=?

thanks for help..

greetings, ludwig!
Title: 525 build thread
Post by: peter purpose on January 01, 2008, 07:52:17 AM
what happens with this attack mod=? faster attack=?
As originally implemented, the attack pot had little effect. The first mod (the extra resistor) only reduces the control voltage to the fet. The last mod should give true attack control.

should i connect the term jumper=?
i build a stereo version with controlls for each channel ..so i connected the mono strap on led pcb.. is this ok=?


Check back in the thread somewhere. There you'll find instructions for stereo operation.


peter
Title: 525 build thread
Post by: mata_haze on January 15, 2008, 03:02:39 PM
Quote from: "peter purpose"
should i connect the term jumper=?
i build a stereo version with controlls for each channel ..so i connected the mono strap on led pcb.. is this ok=?

Check back in the thread somewhere. There you'll find instructions for stereo operation.



I checked in the previous pages but could not find anything. I have encountered the same issue while wiring for stereo: shall I connect the "mono strap"?

Mattia.
Title: 525 build thread
Post by: peter purpose on January 15, 2008, 06:39:38 PM
You're not looking hard enough son. Page 15.

(http://www.twin-x.com/groupdiy/albums/userpics/normal_525STQU.jpg)

BIGGUN.. http://www.twin-x.com/groupdiy/albums/userpics/525STQU.jpg

while wiring for stereo: shall I connect the "mono strap"?

You connect to those points, but don't strap em.
Title: 525 build thread
Post by: king-rb on February 11, 2008, 10:05:50 AM
my 525 is working good no noys and the amp stage is working but
its not reacting to attack, release and macke-up gain and no
change in the signal if im switching comp & limit ...

i found out that in the schematik is a comment "SW1A,B,C
Mechanically interlocked SW2,3&4 are alt action" i think tis is
the reason..

i used switches instead of pushbuttons.. so this means to connect both "side" of the switch togeter that 4 pins are everytime connectet together=?
and where is sw1a =?

thank you very much!
Title: 525 build thread
Post by: king-rb on February 11, 2008, 10:28:46 AM
ahh .. found sw1a in the orginal schematik this switch dont exist in the new version right=?
Title: 525 build thread
Post by: peter purpose on February 11, 2008, 12:32:13 PM
Quote from: "king-rb"
ahh .. found sw1a in the orginal schematik this switch dont exist in the new version right=?


Right.
As to your other problems... double check your connections.
Title: 525 build thread
Post by: king-rb on February 11, 2008, 12:50:48 PM
thank you.. i will do the connections in the sw1b & sw1c then it should work perfect!
Title: 525 build thread
Post by: louder on February 19, 2008, 05:21:38 PM
Hi Peter
as for the 600r resistor across the out tranny,you said some pages ago,to leave it if you want the next piece of gear to terminat the tranny.
i will use the 525 connected to the sound cards,as a insert for mixing,or after a preamp to track.
should i leave it,or should i not?.
once again,thank you so much.
best regards
Pedro
Title: 525 build thread
Post by: peter purpose on February 20, 2008, 06:57:43 AM
Stick it in, do the mod and fit the switch. Try em both for preferred flavour.
A standard 525 does not have 600R across the output.
Title: 525 build thread
Post by: Rob Flinn on March 14, 2008, 02:39:50 PM
I'm looking at the inter wiring diagram.  Particularly the hook up to the rotary switch.

Looking at the hook up diagram it appears that from the ground through R64 should be connected to sw5A position 0.    However when I look at the circuit diagram it shows it going to sw5B position 20.

Other than that can someone clarify some of the test procedure:
section 4

E) turn up the step control checking for 2dB steps......
F) adjust the in pot for 0DBm out.

so does one do F) with the step control on zero or 20  ??? Either way not a lot is happening for me here.

Does someone who has got these working have a list of all the corrections/erratas.  I compiled my own, trolling through this thread several times, but I suspect there is something I must have missed.
Title: 525 build thread
Post by: Siegfried Meier on March 16, 2008, 07:17:09 PM
Does anyone have a BOM with part numbers for Digikey and Mouser?

Thanks,
Sig
Title: 525 build thread
Post by: peter purpose on March 16, 2008, 09:54:26 PM
Jayzus Robert..!!
Ground goes through R64 to SW5B pos 20. Ground also goes direct to SW5A pos 0. If you nail R64 between those two switch positions, then take a wire from SW5A pos 0 to ground, you'll be hunky dory.
Title: 525 build thread
Post by: Rob Flinn on March 17, 2008, 07:20:03 AM
Quote from: "peter purpose"
Jayzus Robert..!!
Ground goes through R64 to SW5B pos 20. Ground also goes direct to SW5A pos 0. If you nail R64 between those two switch positions, then take a wire from SW5A pos 0 to ground, you'll be hunky dory.


Thanks Peter, I'll sort it this afternoon when I get back from bashing my drumkit !!
Title: 525 build thread
Post by: DAN_000 on April 01, 2008, 04:54:17 PM
LM3915 or  LM3916 ??

LM3915 is 3dB/led   and LM3916 is Vu scale.

If original meter is 200uA  I think 3915 is the choice,  what you think?

Dan.-
Title: 525 build thread
Post by: edanderson on April 16, 2008, 10:12:00 AM
more 2623 type transformers for sale:

http://groupdiy.com/index.php?topic=27318

ed
Title: 525 poly caps, i.e. red rectangles
Post by: scottlwilson on April 27, 2008, 09:48:07 PM
Hi Everyone

I'm going to begin building my 525 pair.....finally.  I am wondering if any of you gentlemen could help me with a supplier/part number for the rectangular poly red caps that Peter spec'd for these?  Not sure if they're poly or what specific manufacturer/supplier.

Thanks very much for any clues you can provide to the clueless.

cheers

Scott Wilson
Title: 525 build thread
Post by: kazper on April 28, 2008, 12:12:01 AM
Red poly cap's are generally Wima brand or a knock off and can be found from Taw electronics or mouser.

Taw will help you and stock a huge assortment. Make sure you specify what lead spacing your after. Mouser has less Wima stock but probably what is needed for a 525.
Title: 525 build thread
Post by: Rob Flinn on July 27, 2008, 12:45:42 PM
Having a bit of a problem with one of these.  The other 3 I have built are working really nicely.
I'm following the calibration procedure and all is fine up to step F.  when I set this to 0dB out the signal starts to creep up slowly, stopping maybe 3-5dB above where it was 30sec later.

When I turn down the gain switch it sort of reads 0dB out for most of the way then does some weird stuff at the lower end.  If I turn the switch from zero to 2dB the meter goes from nothing to about 3 leds below top gain reduction.  i.e all the meter action is on the top 3 led's when it is compressing.  Also when changing the switch postion I get the slow level creep aftr the switch postion is changed , like in the above paragraph.

SO I have checked the resistors on the switch.  The meter is on the top led when the switch is at 20dB gain reduction.  I have tried 3 of the VCN fet .

Anyone got any ideas, as I have spent a lot of time on this now, & am tearing what little hair I have out now ??
Title: 525 build thread
Post by: Rob Flinn on July 28, 2008, 12:20:14 PM
Ok so I found the problem with the signal creeping up & down.  It was  a fault in the sidechain OP Amp.  I swapped it out & now it is behaving nicely although the meter range is still a bit bunched.
Title: 525 build thread
Post by: Greg on September 17, 2008, 04:26:25 PM
Last component to source is sockets for the DOAs. I'm not sure what size will fit the board. A little help please? These ones I have in my shop are toooo big, and I'd prefer to not drill the PCB.
Title: 525 build thread
Post by: peter purpose on September 17, 2008, 04:38:30 PM
Greg,
Those are holes for 1mm pins. If you want sockets you're going to have to drill em out.
Just remember to solder the tops where traces run to the pads.

peter
Title: 525 build thread
Post by: Greg on September 17, 2008, 04:50:13 PM
Copy that!
Title: 525 build thread
Post by: Greg on September 22, 2008, 10:26:33 AM
hey Peter:

Can you take a peep and verify this for the 525 in/bypass LED? I ordered the wrong one first time around. And when you say tri, you mean tri-leaded (bi-color), right? There are only two current limiting resistors.

http://www.lumex.com/pdf/SSL-LX3059IYW.pdf

Finally making some good progress on my comp.  :guinness:
Title: 525 build thread
Post by: peter purpose on September 22, 2008, 10:30:24 AM
I'm sure that'll do ya.
Divvent forget that sparking up both colours creates a third.

Toodle pip
Title: 525 build thread
Post by: Greg on September 22, 2008, 01:48:25 PM
Oh yea, didn't think of think... some of my poly caps were waaay too big. One more small parts order and I should be happily FET squishing.

I'll have a handy parts list compiled for people here in the states when I'm done. Should help people avoid multiple parts orders.
Title: 525 build thread
Post by: Greg on September 23, 2008, 08:46:52 AM
(http://members.cox.net/ram3n/5252.jpg)
Title: 525 build thread
Post by: peter purpose on September 24, 2008, 08:04:58 AM
Coming along Gregory.. :thumb:
Title: Looks nice...
Post by: LewKellogg on September 24, 2008, 12:00:02 PM
Looks nice Greg. Looking forward to the US parts list.
Title: 525 build thread
Post by: Greg on October 04, 2008, 07:40:55 PM
Hey Peter:

My 525 is complete and happily squishing.

Gonna have  :guinness:  then get this thing calibrated.

Thanks for the doing all the leg work on this one!
Title: 525 build thread
Post by: peter purpose on October 05, 2008, 08:06:39 AM
:thumb:
Title: 525 build thread
Post by: Greg on October 06, 2008, 09:34:52 AM
OK Peter I'm all calibrated except for the release-time overide... but that can wait. Nice compressor !!!

(http://members.cox.net/dwee-bay/525Complete_Small.jpg)

Very fast FET. I love the feature that you can increase gain reduction without having to turn up the output. It really allows to hear the effect of the compressor and not having perception change due to a volume drop. Great design.

But first... I don't think I've quite cracked the attack. Here's what I did.

(http://members.cox.net/dwee-bay/525Attack_Small.jpg)
(sorry for the terrible camera picture)

1. Connected C3 across wiper and ground (you can see the WIMA on top the meter board).
2. Cut two traces... one on the underside of the meter board that connects the wiper to the end contact. The other on the top that connects the wiper to ATT.
3. Added a wire from the contact that was connected to the wiper to ATT.

Did I do something wrong? I'm not hearing much change... maybe a little but not drastic.
Title: 525 build thread
Post by: peter purpose on October 06, 2008, 10:31:52 AM
Quote from: "Greg"
Did I do something wrong? I'm not hearing much change... maybe a little but not drastic.


Hi Greg,
Nice build.

I haven't really messed around with the attack as much as I should have, but I reckon upping the cap size to 330nF might give you a bit more.
Give it a try and report back.
Also just seen that you haven't stuck a washer and wire on the chassis thingumyjig.

peter
Title: 525 build thread
Post by: Greg on October 06, 2008, 01:15:37 PM
Ah, safety first. Will add that tonight.

I'll also try and tinker with the Attack sometime this week.

Also, reading back... I preferred the alignment with R7 for -5dB (as in the notes) being sent to the sidechain. I felt at 0dB the compressor was way to aggressive. Any additional thoughts on this?
Title: 525 build thread
Post by: peter purpose on October 06, 2008, 01:50:19 PM
Quote from: "Greg"
Any additional thoughts on this?


Set it where you like it,
Title: 525 build thread
Post by: janvanvolt on October 20, 2008, 07:28:00 PM
Hey there,

i just started on the 525. Short question regarding the rotary. how should this be assembled ? i am absolutely clueless (as i can read the schematics, but no pro in building stuff together). any help appreciated.
Title: 525 build thread
Post by: peter purpose on October 21, 2008, 08:59:26 AM
Here's how I do mine, but you can nail em straight across if you have smaller resistors.

(http://www.lazpro.com/rs.jpg)

peter
Title: 525 build thread
Post by: janvanvolt on October 21, 2008, 06:19:26 PM
Well. That give me a bit of insight view :-) from which direction i need to do which values is now the question ? pinout ?

(sorry for my dub question, this is my first 5xx module)
Title: 525 build thread
Post by: mistadschan on October 22, 2008, 09:00:04 AM
Hey janczmok,

...But you are not alone, For I am here with you, Though we're far apart..."

I guess, Pete is kickin' my ass - so I was waiting for another person to post first - felt too ashamed :-(

Maybe I have to search more carefully...I just cannot find any hint!! Any...

Pete! Just paypaled the metal work - late!! Sorry!!
Title: 525 build thread
Post by: peter purpose on October 22, 2008, 10:26:18 AM
Prepare for arses to be kicked.

Assemble the switch. When it is in the fully counterclockwise position, that is POS 0.
Look at the wafer... there is one contact that is clamping the circular slide. That is POS 0. Mark it 0.
Now if you're looking at it from the rear and you turn the switch clockwise to POS 2, the circular jobbie will move anticlockwise to the next contact. That is POS 2. Mark it, and mark em all. Mark one wafer A and tother B.
Slide em off the switch and nail the resistors on in the order that the schematic tells you.
Assemble the switch.

If that makes no sense.... you're in the wrong game.. :green:
Title: 525 build thread
Post by: mistadschan on October 22, 2008, 10:29:07 AM
Quote from: "peter purpose"


If that makes no sense.... you're in the wrong game.. :green:


 TRUE! :grin:
Title: 525 build thread
Post by: Greg on October 22, 2008, 10:59:19 AM
Peter:

Been using the compressor alot the past couple weeks. Bass, vocals, even on some whacky guitar solos. This is the only FET compressor I've used other than 1176s... very different. Good stuff !!!  :thumb:

Still playing with the attack crack...
Title: 525 build thread
Post by: peter purpose on October 22, 2008, 11:40:32 AM
Quote from: Greg
Still playing with the attack crack...

I'll have to build another to get to the bottom of this.
Thinking that we might have to go to a much larger attack pot, say 100K.

peter
Title: 525 build thread
Post by: janvanvolt on October 22, 2008, 08:04:26 PM
another question:

C10 .39UF/35V (150N+220N) SEE C21


is this polarized or normal capacitor ?
Title: 525 build thread
Post by: peter purpose on October 23, 2008, 08:25:09 AM
Either/or
Title: 525 build thread
Post by: janvanvolt on October 23, 2008, 08:34:39 PM
can you draw the position into the flickr post ?

http://flickr.com/photos/jczmok/2967504343/
Title: 525 build thread
Post by: Greg on October 24, 2008, 09:17:02 AM
The contact directly above the left screw is the pole... see how it is always in contact with the inner wafer in all positions.

hey Peter, you an America football fan? My howetown team is playing at Wembley Sunday !!! Who Dat !!!
Title: 525 build thread
Post by: peter purpose on October 24, 2008, 09:46:26 AM
(http://www.lazpro.com/wafermark.jpg)
Title: 525 build thread
Post by: peter purpose on October 24, 2008, 09:52:07 AM
Quote from: "Greg"
hey Peter, you an America football fan? My howetown team is playing at Wembley Sunday !!! Who Dat !!!


Wembley is our national sports stadium.
NFL: New Orleans Saints v San Diego Chargers
Football is played with the feet.
Title: 525 build thread
Post by: Greg on October 24, 2008, 10:07:29 AM
C'mon, Peter... don't fall into the semantics crowd. If you don't like the game, hey that's fine. But you guys have to get over the name... it happened before I was even born. I at least said "American Football" to draw a clear distinction.

Should be a good game.

Cheers.  :guinness:
Title: 525 build thread
Post by: peter purpose on October 24, 2008, 10:15:32 AM
Go Saints.. :thumb:
Title: 525 build thread
Post by: peter purpose on October 25, 2008, 12:50:37 PM
Quote from: "janczmok"
can you draw the position into the flickr post ?


No.. really.. it was no trouble at all.
Just had to do a screen grab, because you can't save from flickr.
Edit that, import into photoshop, add some text, upload to my site and make the post.
Took no more than 10 minutes.
There really is no need for thanks. It was my pleasure.
Title: 525 build thread
Post by: janvanvolt on October 25, 2008, 08:01:47 PM
muchas gracias... nearly finished with the main pcb.
another sidequestion: the LED's are those 3mm or 5 mm  ones? (on the metalwork)
Title: 525 build thread
Post by: peter purpose on October 26, 2008, 10:44:04 AM
3mm
Title: 525 build thread
Post by: janvanvolt on October 27, 2008, 08:23:07 PM
Quote from: "peter purpose"
3mm


Thanks for the info. Will put in those later on.
I've completed the main board today:

(http://farm4.static.flickr.com/3189/2980028068_eab9b37b47.jpg)

More photos here in my Flickr! Account (http://flickr.com/photos/jczmok/sets/72157608427357352/)
Title: 525 build thread
Post by: peter purpose on October 27, 2008, 08:29:50 PM
Coming along, but you should have left C3 off the board.
It also looks like you haven't done the upright op amp mod.
Have you read the thread?
Title: 525 build thread
Post by: janvanvolt on October 27, 2008, 09:14:51 PM
Quote from: "peter purpose"
Coming along, but you should have left C3 off the board.
It also looks like you haven't done the upright op amp mod.
Have you read the thread?


the cable on the addon board ? that is done. see the more "detailed" photos.
removing C3 now ...

any other changes ?

p.s.: just finished the switch :-) now the metalwork just needs to arrive to finish that lovething board.
Title: 525 build thread
Post by: Siegfried Meier on October 29, 2008, 08:58:23 PM
I hate to do this...but does anyone that's already made these have a BOM with actual part #'s from Digikey or Mouser?  Everytime I try to order something, I always end up getting wrong parts and wasting a bunch of money, no matter how much I read or accurate I think I am.  It would help a bunch.

Thanks!
Sig
Title: 525 build thread
Post by: Greg on October 30, 2008, 11:02:30 AM
I have one (Mouser), but I still need to make a few updates for that very reason. I ordered a couple wrong parts... but that's DIY. It's unavoidable.  :cool:
Title: 525 build thread
Post by: RedNoise on November 07, 2008, 06:10:53 PM
Very interesting pics and "draws"...
Thx guys :thumb:
Back to iron!
Title: 525 build thread
Post by: RedNoise on November 10, 2008, 01:13:19 PM
May I ask about the LM 39XX...
Has someone a farnell ref please??I'm lost with this one , don't know which one I need....
Thx.
Title: 525 build thread
Post by: Greg on November 10, 2008, 01:44:50 PM
I order my LM3914s from some dood on e-bay. Couldn't find them at Mouser or Digikey.
Title: 525 build thread
Post by: RedNoise on November 10, 2008, 02:27:55 PM
thx greg , I'll investigate!!
Cheers!!
Title: Re: 525 build thread
Post by: Siegfried Meier on December 11, 2008, 10:42:31 AM
How easy is it to adapt the original 525 GR meter into this circuit?  What needs to be done?

Does anyone have any leads on where one can get this meter?

Thanks!
Sig
Title: Re: 525 build thread
Post by: peter purpose on December 11, 2008, 01:10:17 PM
What needs to be done?

Leave out the meter/pot pcb and connect your rare as rocking horse poo meter to the hole marked 12.
Title: Re: 525 build thread
Post by: Siegfried Meier on December 11, 2008, 02:13:57 PM
Just to hole 12?  And ground, I assume.

Are there any other meters that can be used?  I don't suppose API would sell these meters from their new reissue units...

Thanks!
Sig
Title: Re: 525 build thread
Post by: Siegfried Meier on December 11, 2008, 06:18:22 PM
What about all the other stuff that exists on the meter board?  R/ATT, Mono Strap etc. - where does this stuff now connect to if I use the other meter?

Thanks,
Sig
Title: Re: 525 build thread
Post by: Denyle Guitars on December 11, 2008, 07:51:00 PM
Solder pad 15 on the meter board goes where?
Title: Re: 525 build thread
Post by: peter purpose on December 12, 2008, 06:44:07 AM
Solder pad 15 on the meter board goes where?

Page 10 of this thread.
Title: Re: 525 build thread
Post by: Denyle Guitars on December 12, 2008, 10:12:04 AM
Thanks.
Title: Re: 525 build thread
Post by: gar381 on December 13, 2008, 10:18:28 PM
gar381's version of peter's wonderful 525.

(http://gar381interests.com/new_525_front.jpg)

(http://gar381interests.com/new_525_top.jpg)

Much still to do.

GARY


Title: Re: 525 build thread
Post by: RedNoise on December 14, 2008, 02:51:24 AM
Hey Gar381...It's a Grayhill??
Title: Re: 525 build thread
Post by: peter purpose on December 14, 2008, 10:33:44 AM
V nice Gary... you could have asked for the drawings ya know..!!

Here's a little mod for the meter signal. As is, the meter still operates in bypass, so why not use the spare side to switch the signal in and out.

(http://lazpro.com/metermod.JPG)
Title: Re: 525 build thread
Post by: gar381 on December 14, 2008, 02:46:30 PM
V nice Gary... you could have asked for the drawings ya know..!!

Thanks peter.  I will remember that next time but I actually had a great time backwards
engineering your metal work.  Fun project !!

Hey Gar381...It's a Grayhill??

(http://gar381interests.com/525_switches.jpg)

Yha Rednoise its a Grayhill and e-switch replacements for the wellbuying.

GARY
Title: Re: 525 build thread
Post by: bradb on December 21, 2008, 02:30:32 AM
How is this project going?

Are boards / kits / trannies still available?  I know I'm late to the party?

Any bummers or un-sussed problems still lurking?

thanks, looks totally awesome.
Title: Re: 525 build thread
Post by: okgb on December 21, 2008, 08:28:40 AM
Hey brad  , i believe Baltimore was selling a couple kits

Peter , i'm not in a hurry but curious to lnow  , did the fixed metalwork
kits ship out ? [ haven't seen mine ]
Title: Re: 525 build thread
Post by: Siegfried Meier on January 16, 2009, 06:03:05 PM
Hey Peter,

Is the front panel supposed to sit tight against the chassis?  I suppose it can't, since the nuts from the pots is there.  What holds the panel in place, the Sifam knobs?

EDIT - or, the nuts are supposed to go on the actual front panel, not on the aluminum sub panel...?

Sig
Title: Re: 525 build thread
Post by: peter purpose on January 17, 2009, 06:54:59 AM
The youth of today, eh!
Title: Re: 525 build thread
Post by: Siegfried Meier on January 18, 2009, 03:34:36 PM
I guess that more or less answers my question, and thank you for calling me youth.  Makes me feel good.  You old bastard.   :D

Sig
Title: Re: 525 build thread
Post by: wowi on March 22, 2009, 08:10:37 AM
Hi Peter,

i nearly finished this project. Thank you for this wonderful compressor.

I am not sure about the attack mod. You send me the 100k pot for the attack pot.
Is the attack mod still necessary ?

If yes, is this approach from greg ok:

Quote
1. Connected C3 across wiper and ground (you can see the WIMA on top the meter board).
2. Cut two traces... one on the underside of the meter board that connects the wiper to the end contact. The other on the top that connects the wiper to ATT.
3. Added a wire from the contact that was connected to the wiper to ATT.

You wrote something about changing cap size to 330nF. Do you still recommend this ?

regards
Wolfgang
Title: Re: 525 build thread
Post by: peter purpose on March 22, 2009, 08:38:40 PM
Do you still recommend this ?
I haven't tried it. Why don't you... and report back.
Title: Re: 525 build thread
Post by: DAN_000 on April 15, 2009, 06:49:14 PM
Hey Peter,   I readed your BOM and is IC meter is marked as LM391X , but, there are differents law on this IC.
LM3914   Linear Version
LM3915     3 dB/step, 30 dB range
LM3916   Audio VU Version

and, what about DCR in original analog meter ?  any 391X is HIZ buffered. Maybe we can add a resistor in that place?
Best!
Title: Re: 525 build thread
Post by: benlindell on April 17, 2009, 03:18:17 PM
Crappy n00b question. I've order 2 sets of caps now, and keep getting the wrong casing of WIMA caps, which ones should I have gotten?

Also wondering which LM391X chip people used? I assume the Audio VU one?

-ben
http://www.benlindell.com
Title: Re: 525 build thread
Post by: benlindell on May 14, 2009, 03:10:40 PM
just finishing up my 525s and had a few quick questions to double check before I blow it up.

1. the output transformer termination mod. what is the best/most popular way of doing this? leaving the 600ohm resistor off or leaving it there and no jumper or do I have this all messed up.

2. the optional 10pf cap (C4) doesn't need to be jumped if not there correct (read the schematic and that looks to be true but just wanted to double check)

those are it for the moment.

thanks guys

-ben
Title: Re: 525 build thread
Post by: peter purpose on May 15, 2009, 08:16:06 AM
Hey Peter,   I readed your BOM and is IC meter is marked as LM391X , but, there are differents law on this IC.
LM3914   Linear Version
LM3915     3 dB/step, 30 dB range
LM3916   Audio VU Version

and, what about DCR in original analog meter ?  any 391X is HIZ buffered. Maybe we can add a resistor in that place?
Best!

I use 3916. Try what you will Dan.
Title: Re: 525 build thread
Post by: peter purpose on May 15, 2009, 08:17:16 AM
Crappy n00b question. I've order 2 sets of caps now, and keep getting the wrong casing of WIMA caps, which ones should I have gotten?

Also wondering which LM391X chip people used? I assume the Audio VU one?

-ben
http://www.benlindell.com

Look at the pcb footprint. It's small, with a 5mm spacing.
See above.
Title: Re: 525 build thread
Post by: peter purpose on May 15, 2009, 08:19:13 AM
just finishing up my 525s and had a few quick questions to double check before I blow it up.

1. the output transformer termination mod. what is the best/most popular way of doing this? leaving the 600ohm resistor off or leaving it there and no jumper or do I have this all messed up.

2. the optional 10pf cap (C4) doesn't need to be jumped if not there correct (read the schematic and that looks to be true but just wanted to double check)

those are it for the moment.

thanks guys

-ben

1. Do it as in the instructions, or leave it out altogether.
2. correct.
Title: Re: 525 build thread
Post by: T1M0N_5 on May 15, 2009, 01:34:45 PM
hi
are those kits still available?

timon
Title: Re: 525 build thread
Post by: peter purpose on May 16, 2009, 06:27:51 AM
I have a few of most things.
Title: Re: 525 build thread
Post by: memestudio on May 19, 2009, 06:05:15 AM
Hello,
has someone tried to install an input transformer instead of the discrete op amp? Maybe a Lundahl 1540 or a Neutrik will work... http://www.neutrik.com/fl/en/audio/210_197961/NTL1_detail.aspx
They are small, so probably it is possible to place them on the 525 board.
Ciao
Fabio
Title: Re: 525 build thread
Post by: substitute on May 19, 2009, 08:35:16 PM
Hey, I wanted to ask about the trimmer values.  The closest I can find is 50k, 2k, 5k, from mouser, I'm figuring these can be adjusted to the appropriate values.  Is this correct?
Title: Re: 525 build thread
Post by: substitute on May 26, 2009, 10:58:35 PM
for the record, Peter said those trimmer values should be cool.
Title: Re: 525 build thread
Post by: benlindell on May 31, 2009, 11:14:28 PM
Finished my first one tonight, haven't had time to calibrate it, I'm just super happy it didn't blow up when I first turned it on. It's squeezing and the in, out and less/more knobs are all working perfectly. There seems to be a little bit of difference on comp and limit, can't tell the difference in the releases.

Two things right of the bat:

1. The In and out button makes a bad scratch noise after it's been pressed in, any thoughts.

2. Peter shipped mine with a 100k pot for the attack, so I thought I'd try to make it work without any mods that have been put out, it doesn't do anything :( Did anyone find the most reliable mod to work for the attack knob?

I'll get a chance to calibrate it some time this week.

thanks

-ben
http://www.benlindell.com
Title: Re: 525 build thread
Post by: peter purpose on June 02, 2009, 07:24:25 AM
1. The In and out button makes a bad scratch noise after it's been pressed in, any thoughts.

2. Peter shipped mine with a 100k pot for the attack, so I thought I'd try to make it work without any mods that have been put out, it doesn't do anything :( Did anyone find the most reliable mod to work for the attack knob?


1. Are you saying you have a continuous sratching noise when switch engaged, or a momentary?
2. You're going to have to do the mod. It's only a couple of trace cuts and a bit of wire.
I still haven't tried it, but I beleive Greg has. Small/miniscule range though.

peter
Title: Re: 525 build thread
Post by: benlindell on June 02, 2009, 12:07:11 PM
1. It's a momentary scratch after the button is pressed, both in and out.

2. So even with the attack mods there is just a small variation of attack?

thanks

-ben
http://www.benlindell.com

Title: Re: 525 build thread
Post by: Greg on June 03, 2009, 03:02:33 PM
2. So even with the attack mods there is just a small variation of attack?

That was my experience. Fantastic compressor but the variable attack (so far) is a bust.
Title: Re: 525 build thread
Post by: peter purpose on June 03, 2009, 03:10:55 PM
I blame Joe Malone.. ;D
Ben, try a snubber on the switch if it bugs you.
Title: Re: 525 build thread
Post by: benlindell on June 04, 2009, 07:39:29 PM
I'm kinda fresh, how do I do a snubber?
Title: Re: 525 build thread
Post by: substitute on June 04, 2009, 11:27:13 PM
if you go to the drip site (dripelectronics.com) and download the instructions for his la2a there's some info and diagrams of snubbers.    I don't know how specific you need to be with the values though.
Title: Re: 525 build thread
Post by: SIXTYNINER on June 25, 2009, 02:11:48 PM
very cool project
 :o
Title: Re: 525 build thread
Post by: kazper on July 27, 2009, 02:23:38 AM
I've been pondering over the Attack issue since I'm in process of finally finishing up my 4 units.

In looking at the attack as it sits and appears it end up like this...?

Attack Time = 3.8 ms with the 38K (R5) and 100n cap.
Add the 10 K pot full value for a total Resistance of 48K we get 4.8 ms of Attack.
Using the optional 100 K pot + R5 we get 13.8 ms of attack.

Using a 330n cap we increase them to
38K =12.5 ms
48K=15.85 ms
138K =45.54ms

I'm using this calculator..
http://www.cvs1.uklinux.net/cgi-bin/calculators/time_const.cgi

I think peter originally designed this attack from Joe from JLM audio's post #18 on this thread http://www.groupdiy.com/index.php?topic=61.0

Overall I'm thinking that placement of the RC is the key factor, because of the added resistance of R5... so

The attack of the UREI 1176 is said to be 20-800 micro seconds, which is what were trying for in this circuit I believe.

Could you reorient the configuration of the parts to be something like the following?

Fet to junction (to other resistor) then 10K pot in reistat form, Cap(to Gnd), 38K (R5). This would provide Attack circuit from 0-1ms or 0-1000 micro seconds. Would this work just by moving the RC around? Would it be benifital to have a small resistance in front of the pot, say 200R...?

What would the effect be of the Fet with the cap straight to ground when the pot is adjusted to zero?

Sorry for all the basic question, I've been looking at lots of schematics to see what was done in other products and designs and came up with a few questions and ideas on how to make this work :)

Kaz
Title: Re: 525 build thread
Post by: benlindell on August 24, 2009, 11:44:26 PM
I'm finishing up a pair of these that I bought from another user here and I'm having some troubles.

One is smoking up one of the resistors on the upright opamp. I check for shorts at the pins and there's none so I'm wondering what I should look at to fix it.

The second one isn't passing audio when engaged and the meter isn't showing anything except some jumps when turning the big knob. I did a quick once over with a probe and am getting sound off the upright opamp.

Any help on tweaking these to get them working would be great.

thanks
Title: Re: 525 build thread
Post by: peter purpose on August 25, 2009, 12:21:33 PM
Ben,
Did you do the capacitor mod?
See page 3
Title: Re: 525 build thread
Post by: benlindell on August 25, 2009, 12:35:46 PM
yes I did.
Title: Re: 525 build thread
Post by: peter purpose on August 25, 2009, 01:36:28 PM
Check the transistors on the burny one. Check the wiring to the in/out switch on the other.
Title: Re: 525 build thread
Post by: benlindell on September 15, 2009, 04:10:31 PM
Checked the switch, everything is wired fine.

I think I'm going to take this one at a time rather than trying to fix two things at once, so I'm starting with the non-burny one

I double checked the wiring of the switch and probed it and it's working fine.

I took the 3 DOAs from my working one (one I built myself and using your DOAs) and put them in, still nothing.

probed the upright opamp and it has signal in and out. This one is not burning but the transistors are significantly hotter than my working one, but like I said there is signal coming out of it's output.

Here are pictures of the upright opamp.
(http://www.benlindell.com/500/IMG_3013.JPG)
(http://www.benlindell.com/500/IMG_3014.JPG)
(http://www.benlindell.com/500/IMG_3015.JPG)
Where should I be looking next.

Thanks,

Title: Re: 525 build thread
Post by: peter purpose on September 15, 2009, 04:27:14 PM
Grab the schematic and follow the signal through until it pops into the ether.
Title: Re: 525 build thread
Post by: benlindell on September 15, 2009, 04:30:46 PM
any ideas on why the upright opamp would be running hot?
Title: Re: 525 build thread
Post by: peter purpose on September 15, 2009, 04:38:03 PM
wrong components?
Title: Re: 525 build thread
Post by: ethervalve on October 05, 2009, 12:51:26 PM
Hi,
I'm nearly done assembling my 525, but i'm a tad confused about r64. Does anyone know where it should be connected?
Thanks in advance.
Title: Re: 525 build thread
Post by: peter purpose on October 05, 2009, 03:21:45 PM
On the rotary switch.
Title: Re: 525 build thread
Post by: ethervalve on October 05, 2009, 03:42:14 PM
cheers good sir. this demon monday smote my wits and senses.
incidentally, fine work on the boards/layout.
Title: Re: 525 build thread
Post by: kazper on October 09, 2009, 10:53:17 PM
http://www.apiaudio.com/nw_1090.html
(http://www.apiaudio.com/nw_1090_1.jpg)


It looks like something... just can't put my finger on it...
Title: Re: 525 build thread
Post by: benlindell on October 19, 2009, 11:11:34 PM
Peter, I went through the upright opamp and it's all the correct components and I checked all the components around it as well and they all seem to be the correct values.

Took it off from the back again, I'm not seeing any bridges or non connections.
Title: Re: 525 build thread
Post by: peter purpose on October 20, 2009, 09:37:07 AM
Troubleshooting is an art. I think we need someone who knows what they're talking about to pipe in.
Title: Re: 525 build thread
Post by: substitute on October 23, 2009, 08:52:41 PM
I don't know why it took me so long to do this project but I finally have one channel up and running with just one issue.
My leds for the meter started smoking so I adjusted the PSU to +/-15v (from 18), they stopped smoking but no longer light up.  Any idea what might cause that?

Also I have a basic usage question, what happens when you have both limit and compress buttons engaged?

Thanks for the cool project Pete!  I really dig the limiter on acoustic guitar.
 
 
Title: Re: 525 build thread
Post by: kazper on October 24, 2009, 01:45:58 AM
Too much current.... what resistor value did you use to limit the current to the LED/driver, and what driver IC did you use?



Title: Re: 525 build thread
Post by: substitute on October 25, 2009, 05:07:03 PM
Quote
Too much current.... what resistor value did you use to limit the current to the LED/driver, and what driver IC did you use?

That would be RM1 correct?  It's 1k and I'm using the NTE 1549 meter driver.

I also noticed that if I turn the ceiling knob all the way up (position 20) I loose signal.  I assume it's shorting to ground, I'll double check my wiring but if any one has any ideas please let me know.
Title: Re: 525 build thread
Post by: EmRR on October 28, 2009, 02:53:19 PM
I've been pondering over the Attack issue since I'm in process of finally finishing up my 4 units.

I think peter originally designed this attack from Joe from JLM audio's post #18 on this thread http://www.groupdiy.com/index.php?topic=61.0

To add attack control just cut into the track or wire that joins to the join of R5 & C3 and add a pot wired as a variable resistor. A 10k pot will give the same attack range as a 1176 has.

Joe

It looks like Peter designed as Joe described with one exception:  I think the additional rheostat (whatever value, 10K, 50K, 100K) should not be between r5 and c3, but inserted ahead in the line feeding their junction.  C3 holds the bias to Q1, and we want to slow down it's ability to fill.  As drawn, I think it fills just as quickly, and we are affecting it's drain rate.  I may be wrong.    
Title: Re: 525 build thread
Post by: peter purpose on October 29, 2009, 09:57:32 AM
Tried it both ways and with the wiper feeding the cap.... all NFG.
Title: Re: 525 build thread
Post by: peter purpose on October 29, 2009, 09:58:31 AM
That would be RM1 correct? 

Jess my preng.
Title: Re: 525 build thread
Post by: EmRR on October 30, 2009, 02:08:41 AM
ah, NFG.  Your avatar is still pretty hot. 
(http://lazpro.com/gene.jpg)
Even Dick is diggin' 'er. 
(http://www.lazpro.com/tricky.jpg)

Title: Re: 525 build thread
Post by: Grand Master Audio on November 05, 2009, 09:12:07 AM
Hi Peter,

I have all units ready to fit together, some thing does not seem right, the round black caps for the push switches (x6), do not fit though the front panel, and only just through the back plate, is there some thing im supposed to do here? before i go and drill things about..

All the best
Pete
Title: Re: 525 build thread
Post by: peter purpose on November 05, 2009, 09:22:33 AM
You must have early panels that need drilling.
Title: Re: 525 build thread
Post by: Grand Master Audio on November 05, 2009, 10:15:05 AM
cool, no sweat, easy peasy..

thanks!
Title: Re: 525 build thread
Post by: Grand Master Audio on November 20, 2009, 11:16:20 AM
Hi Peter,

OK, a bit of help needed, units powerd up ok, can hear a little normal hiss as you turn the LESS/MORE knob up so its def on and output stage seems OK.

As soon as you depress IN the test tone drops to -60dB , the INPUT control has no effect, the OUTPUT control does effect this small signal. The VR around A1 does alter the gain of this very small signal too

have i over looked some thing simple, both my units behave the same so i have done some thing not quite to both...any help much appreciated. 

(http://www.grandmasteraudio.com/525.jpg)
(http://www.grandmasteraudio.com/2525.jpg)
Title: Re: 525 build thread
Post by: peter purpose on November 20, 2009, 01:47:21 PM
Have you fixed it?
Title: Re: 525 build thread
Post by: Grand Master Audio on November 20, 2009, 01:55:17 PM
Hi Peter,

No, i traced the signal into A1, and its coming out of A1 very small, negitve gain out of A1, then i saw a post about C3, which i pulled out, did not help me though, all though if i wind the input right up and the compression full, the lights dance about and makes a sound like a digital phone! lol

but that maybe just done to all the VR's not being set up propely i dont know, as these are new to me.

so some thing is causing the output of A1 to be very small, like the side chain i guess, but im not sure what voltage are supposed to around there..

mmm tricky..
Title: Re: 525 build thread
Post by: peter purpose on November 20, 2009, 04:09:57 PM
Have you fixed it yet? :D
Title: Re: 525 build thread
Post by: Grand Master Audio on November 20, 2009, 05:06:59 PM
Ha! Lol, thanks, it must be some thing around the fet, pulling the gain of a1 down,

I've given up for now, look tomorrow.
Pete
Title: Re: 525 build thread
Post by: peter purpose on November 21, 2009, 08:49:23 AM
Have you fixed it yet?  ;D

I'm the worst troubeshooter on the planet.. isn't I.

Have you gone through any of the set-up procedure?
Title: Re: 525 build thread
Post by: Grand Master Audio on November 21, 2009, 01:16:56 PM
hey no problem, you are not here just to help me, im good, i need to think what i have done wrong in both cases, i cant think that i have, normally very good as this,

In the set up proc the first thing is to set the level, well i don't have any coming out so failed on the first thing,

it seems to me that the FET is being turned on all the time regardless of the side chain, but i need to look into it further, it has to be a wrong component value or wrong connection with the wiring, as its both units, its unlikely to be component failure.

the MORE/LESS pot is work like a kind of Gain at the moment, its increasing the small signal that i do have, and the hiss increases to, is that normal it should behave like that, as a gain? i guess so, whilst also feeding more signal to the sidechain, is that how it works?

Cheers
Pete
Title: Re: 525 build thread
Post by: peter purpose on November 21, 2009, 04:15:43 PM
The more/less pot increases/decreases compression and inc/dec gain accordingly for a constant output.
Title: Re: 525 build thread
Post by: Grand Master Audio on November 21, 2009, 05:54:08 PM
Thanks peter, as i thought, that's working then...ill look some more.
Title: Re: 525 build thread
Post by: Grand Master Audio on November 24, 2009, 05:56:59 AM
Hi,

is any one able to measure some voltages for me? so i can compare my unit to yours, I think the problem is around the input amp,

So any DC measurements around the FET, Q5 and A1 would be fantastic.

Best
Pete
Title: Re: 525 build thread
Post by: peter purpose on November 24, 2009, 06:26:59 AM
Pete... did you do the cap mod on the input amp?
Title: Re: 525 build thread
Post by: Grand Master Audio on November 24, 2009, 06:57:24 AM
EDIT : removed some posts for clarity.

Hi Peter,

I think i did correctly, ill check now again, looking at the back of the input amp the top leg of the cap reaches across to the base of Q4?

I have removed the input amp and replaced with a spare 2520 and it works just great!

I can not work out for the life of me whats wrong with the input amp, all components are correct. is there a diagram for the input amp? are there any other mods needs other than the cap mod?

this is the correct list of components to be used?

UPRIGHT OP AMP
 
Q1 BC184C
Q2 BC184C
Q3 BC560C
Q4 BC550C
Q5 BC560C
D1 1N4148
D2 1N4148
R1 33k
R2 47k
R3 10k
R4 47R
R5 47R
C1 5pF

so now im stuck, some thing some where is not adding up.

Cheers
Pete
Title: Re: 525 build thread
Post by: Grand Master Audio on November 24, 2009, 11:13:13 AM
But playing with out the input amp fitted it still sounds fab, loads of compression.

so what to do, Peter, do you have a spare working input amp available?
Title: Re: 525 build thread
Post by: benlindell on November 24, 2009, 02:59:18 PM
sinestar, been great reading your posts of trying to fix your problems. I've still got 2 of these dead in the water. I tried removing my upright opamp and I got no sound. I did however notice that it had a 100ohm resistor inplace of a 10k so I switched that out and put it back in. I still have no sound when in except for a heartbeat that has now developed that goes away when I switch to limiting.
Title: Re: 525 build thread
Post by: Grand Master Audio on November 24, 2009, 03:25:09 PM

Hi Ben,

Ah bummer, thats a shame, Check you have + & - on your Op amps,( touch the can of the two big Transistors, one should be + and the other -, if that ok you need to start tracing the audio (use a 1KZ tone then you can use your multi meter set to AC) from the back edge connector into the upright opamp, where it is marked + & - underneath, the level of the signel will be smaller here, thats normal. do you have tone here? if you do check the output of the input amp marked o underneath, do you have signal here?

Best
Pete
Title: Re: 525 build thread
Post by: Grand Master Audio on November 25, 2009, 08:06:53 AM
Hi Peter,

I've checked the thread but cant find any thing, Is there a circuit drawing for the input amp available?

Cheers
Pete
Title: Re: 525 build thread
Post by: Sredna on November 25, 2009, 08:36:11 AM
Page 10, Reply #195.  ;)
Title: Re: 525 build thread
Post by: Grand Master Audio on November 25, 2009, 08:54:37 AM
my brain honestly!

thank you!

Now i have spotted my mistake! lets see if we can get this thing working....
Title: Re: 525 build thread
Post by: bdubya on November 25, 2009, 10:19:31 AM
Another Ben, here.  In the same boat, sort of.  I've completely built up one of my two units.  I can trace a tone into the opamp at 1.1V(started out with 3.9V at the input jack), then out of the upright opamp, i get 3.4V.  My symptoms are very low signal once the comp is engaged, but once I tweaked R7 a bit, i started to get normal levels of audio, but the signal is distorted and coming in bursts, not unlike something thats been gated and sent through a distortion box.  Which is cool, I ran some samples through and will use them, they sound F'd up.  But obviously, not the end result I'm going for.  

I'm thinking I need to crank more juice into this thing than my soundcard can push, either that or get a more sensitive meter to look at the AC.  There are other test points on the PCB, little spots for your probes, where I can tell there's SOME signal, but its too low for me to see with my meter, except for the one between T1/A2, which reads something crazily high, like 34VAC.  Anyone have a notion as to what "good" readings might be at these points?  I'm going to remove my rotary switch and replace it with some resistors temporarily to troubleshoot, as I may have screwed that up; at the very least it seems the most likely problem at this point. 

Also, I had C21(the tantalum) flipped around.  Didn't blow up or make anything smoke, but I replaced it with a new one in the correct orientation.  No noticeable change.  Could anything have been harmed elsewhere in the circuit from this mis-orientation?  I know enough to be dangerous to myself and my projects, but not enough to know the function of C21.   

 Anyhow, I'll post my findings as I fix things, but I'm sloooooowww.  Thanks for all the great information!

bw
Title: Re: 525 build thread
Post by: Grand Master Audio on November 25, 2009, 10:49:56 AM
Hi Ben,

Im not an expert at all but ill try and help,

when you mention bursts, are you using test tone or music whilst testing? tone im assuming...sounds like your input amp is fine so that's good, C21 should have not caused any thing else to go wrong looking at the drawing so that should be good, is it possible you have other components in backwards, maybe a diode somewhere? im trying to think what would be causing these bursts, obviously some sort of oscillation some where,

What are the meters doing whilst its bursting? when you turn the input control up do you get any GR shown on the meter?

Pete

Title: Re: 525 build thread
Post by: bdubya on November 25, 2009, 01:13:25 PM
Thanks for the response, I'll double check all diodes for proper orientation.  I haven't stuffed the meter portion of the circuit yet, basically just using that board for the In and Out Pots, I left off the attack pot, as it doesn't seem to do anything, by all accounts.  I've jumped both ATT pads and the "grnd" pad next to them together, in order to simulate one extremity of the attack pot.  I figured that since the 10k attack pot is close to zero ohms at the one end, a short would be okay.  I may have done this improperly.  I don't really have a permanent setup, so after thanksgiving I'll bust it back out and try everything I can think of.  I have most all of the parts in spare, so it'll get there.  Thanks again for your insight.

bw
Title: Re: 525 build thread
Post by: peter purpose on November 25, 2009, 03:01:41 PM
I've jumped both ATT pads and the "grnd" pad next to them together, in order to simulate one extremity of the attack pot.
bw

Wrong. Grounding the ATT pads will take the control signal to ground. NFG
Title: Re: 525 build thread
Post by: bdubya on November 25, 2009, 11:02:23 PM
I've jumped both ATT pads and the "grnd" pad next to them together, in order to simulate one extremity of the attack pot.
bw

Wrong. Grounding the ATT pads will take the control signal to ground. NFG

Yep, i now see what you mean.  I tried messing around with it a variety of ways, as I knew I wasn't making a very informed decision with that move, but in retrospect, all of them involved shorting one of the ATT pads to grnd, which is wrong.  Would jumping the two ATT pads together then be the correct approach, do i need SOME resistance between the two or am I barking up the wrong tree in thinking that I don't need to connect the ATT pads to the potentiometer/meter board if i'm leaving off the attack pot itself . . .  I have the correct pot on hand, I'm just a cheap unemployed bastard and want to save it for something where it does something.  Hell, I should give it away on the giveaway thread.  It's an Omeg, nice pot.  Thanks for the heads up peter.  cheers!

bw
Title: Re: 525 build thread
Post by: Grand Master Audio on November 26, 2009, 04:54:26 AM
HI Ben,

The easiest thing to do is wire up the meter board normally, then, where the Attack pot lives, it has 3 connections to the PCB, correct? to emulate the pot hard left or hard right just fit a 10k resistor between the middle and one of the outer pins, and short the one pin remaining to the middle pin again.

ok?

Title: Re: 525 build thread
Post by: peter purpose on November 26, 2009, 10:27:00 AM
Jump the two att pads on the main board together. This will give you standard a 525. Wireing the meter board normally will get you nothing without modifying it. And only very little attack when modified.
Title: Re: 525 build thread
Post by: bdubya on November 26, 2009, 11:57:09 AM
Gotcha.  To the rotary switch, then, and triple-checking the diodes.  I wired it up a year and a half ago, when i knew even less than I do now about this stuff (I dove into the shallow end with this one).  It's been a huge learning experience, though, and will be that much cooler once it works.  I'll take some readings at those test points once it works, as it seems like that would help out a bit with the trouble-shooting, at least in narrowing down the section of the circuit that's not performing, if we knew what "good" readings would be at those points. thanks again

bw 
Title: Re: 525 build thread
Post by: Grand Master Audio on November 28, 2009, 06:59:51 AM
Hi Peter,

Just to say i got both working, I misread the input op amp components, I missed the BC550c, i had all 560's in there, either my dyslexia or stupidity! If i had of got that right it would of worked on first power up.

So thanks for a great project.

Best
Pete
Title: Re: 525 build thread
Post by: Jim50hertz on November 28, 2009, 07:41:36 AM
Just to say i got both working

 8) 8) 8) 8)
Title: Re: 525 build thread
Post by: Grand Master Audio on November 28, 2009, 08:11:54 AM
You can buy em back if you need em!  ;)

hope all is well Jim,

Pete
Title: Re: 525 build thread
Post by: bdubya on February 11, 2010, 03:48:21 PM
So the main part of my problem ended up being a shoddy solder joint at the (-) input of A2.  Now the sound is nice and clean, but I have to reassemble the rotary switch that got sacrificed in the hunt in order to verify the rest of it.  What made me realize that it was a power issue was when I was listening through an equalizer that wasn't powered on.  I noticed that I could hear the signal, just very low and distorted.  Sounded a whole lot like what was happening with the 525, so I checked for continuity between the + and - inputs on each DOA to their corresponding power inputs on the edge connector (13,14,15) as well as verifying ground in the same manner,  I got thrown for a moment because I didn't have the red and black leads on my meter oriented in the right polarity (because of polar capacitors blocking the DC in one direction?).  After I got that brain-fart out, I found the lack of continuity on the (-) input of A2.  I'm checking all my builds in this manner from now on, which I'm sure for some of you is an obvious step, but revelations are relative.  Pretty rewarding, when things don't work.  Better education than college.  I was psyched and felt the need to share . . .take care, have fun in the snow, if it applies to you.
Title: Re: 525 build thread
Post by: substitute on February 17, 2010, 10:15:23 PM
Finally getting ready to push these towards the finish line, a little confused about calibration though.

step 4. c adjusting r7 for output from A1.  I don't understand what is meant by monitor from pin 8.  Does that mean the - input pin on the edge or something else? 

and just to be clear, I'm measuring 0db (0.774v) across + & - of the input xlr, then I should be adjusting R7 for the same measuring from pin 8 to ground?

Title: Re: 525 build thread
Post by: peter purpose on February 18, 2010, 04:43:34 AM
Pin designation in the calibration notes refer to the standard schematic.
You'll have to compare the two to find test points.
Title: Re: 525 build thread
Post by: substitute on February 18, 2010, 08:20:35 AM
Thanks, that would make sense, looking at the schem I can trace pin 8 back to the output of A1.  I'm sure when I sit down with the pcb I'll be able to trace around and find that location on the actual boards, but I'm still a little foggy on what and how I'm measuring.

Am I right in thinking I should be measuring from "pin 8" to ground and setting R7 to -5dbu (0.435v)?

How are other folks setting their quiescent current?

Title: Re: 525 build thread
Post by: peter purpose on February 18, 2010, 12:13:45 PM
Am I right in thinking I should be measuring from "pin 8" to ground and setting R7 to -5dbu (0.435v)?

Jess
Title: Re: 525 build thread
Post by: substitute on February 18, 2010, 05:22:28 PM
thank you my freng
Title: Re: 525 build thread
Post by: magruith on February 19, 2010, 03:06:42 PM
Hi everyone!

I have a problem I can't find out how to solder the switch. What do sw5a p20, sw5b p20, sw5b pole, sw5a po/r64 and sw5a pole mean please?
where are the pins on the switch please?

Thanks in advance guys!

Magruith
Title: Re: 525 build thread
Post by: bdubya on February 19, 2010, 05:36:07 PM
Look back in the thread, there's an excellent, labelled photo of the switch.  If you look at the schematic, you'll see that each of the positions on the rotary switch is designated 0,2,4 . . .18,20.  There's a contact on your switch for each.  There should be two wafers, "a" and "b" on your switch, each possessing 11 contacts and 1 pole.  the pole will be staggered in some fashion to set it apart from the switch contacts. 
Title: Re: 525 build thread
Post by: magruith on February 21, 2010, 03:52:26 AM
thanks
but what What do mean five in "sw5a p20"
please...
im noobs....
Title: Re: 525 build thread
Post by: peter purpose on February 21, 2010, 04:28:22 AM
Switch 5..wafer A.. position 20
Title: Re: 525 build thread
Post by: magruith on February 21, 2010, 10:40:56 AM
thanks a lot for replying
i m sorry but there is one thing i don't understand
on the picture we can only see the following position for the switch:
fccw 0 2 4 6 .... but no sw5...
where is sw5 and which one is waffer a and which one is waffer b please?
because i dont see indication on the switch rotary
if you have a new picture , that would be helping ;)
thank you guys
Title: Re: 525 build thread
Post by: peter purpose on February 21, 2010, 11:22:37 AM
SW5 is the Rotary switch designation in the schematic.
The wafers can be either way round, just know yourself which is which.
Title: Re: 525 build thread
Post by: magruith on February 22, 2010, 09:34:22 AM
thanks again
there are star for ground where is the connector on the waffer
and soldier to the box?
Title: Re: 525 build thread
Post by: peter purpose on February 22, 2010, 10:41:07 AM
All connections from the switch go to the pcbs.
Title: Re: 525 build thread
Post by: dmp on March 31, 2010, 12:27:29 PM
I'm just finishing building up a pair of these. Great project.
I've been messing around with the attack and switching the pot to 1Meg seems to work. I simulated this part of the sidechain and moved the 0.1uf cap (c3) between the attack pot and R5 and found that attack went from very fast to about 50 ms ,without noticably changing the release (the addition of 1meg will slow the discharge of C3, but the release resitances are large).This picture is from the simulation for a cv to the FET. The larger the attack pot, the slower C3 charges. A nice thing about this configuration is when the attack pot is fully ccw (fastest), the attack pot is fully shorted - like an original 525 with no attack mod.
Just listened this morning after calibrating, and I can tell the attack is slowing as the pot increases. I don't have a good enough ear to tell how much, but if I figure out a way to measure I'll report back.
Anyone know of a supplier for Omeg pots in the US? I think this would be good - ECO1MLIN
Title: Re: 525 build thread
Post by: peter purpose on March 31, 2010, 03:27:33 PM
Gimme an address dmp
Title: Re: 525 build thread
Post by: dmp on April 02, 2010, 08:08:58 PM
I measured the attack times for a few positions. Full cw (~0 ohms), 100k, 500k, and full ccw (1Meg). The pot in this config allows quite a but of adjustment. The fast attack time is probably faster than shown here because I measured this using a 1kHz sine wave and calculated the rms - so the minimum observable attack time was on the order of what is shown here.
Title: Re: 525 build thread
Post by: dmp on April 02, 2010, 08:14:36 PM
Another graph - 525 in compression.
Title: Re: 525 build thread
Post by: dmp on April 02, 2010, 08:15:22 PM
One more graph, this is in limiting mode
Title: Re: 525 build thread
Post by: EmRR on April 02, 2010, 09:29:34 PM
excellent; I was suspecting 1M might be the ticket, based on the other SC values. 
Title: Re: 525 build thread
Post by: dmp on April 03, 2010, 04:06:16 PM
Here's what I've learned trying to calibrate the LED meter for gain reduction.
If you set R55 as in the calibration notes, the full scale meter voltage goes from 0 to  about 200 mv, shown in the orange curve below (which is the measured meter voltage for an increasing sweep of compression, like I posted yesterday). The LEDs don't light except for really high levels of compression, if at all (this was my experience anyway). This range however is appx. as expected to go to a 200 uA meter as used in the original 525 (generally these meters have a 1kohm resistance, yes?).

The LM3916 circuit, however, is set to work with a full scale range of 0v-1.2v, shown by the brown line (this is from the comparator resitances in the datasheet). The markers show when the LEDs turn on.
The blue line is what I got for the meter voltage for the same sweep of compression with R55 cranked up. This gets all the LEDs working (again, in my experience). The horizontal dashed lines show when each LED turns on as the gain reduction and meter voltage increase. The first five LEDs turn on before reaching 2 dB of compression, then the next five roughly indicate 3,4,6,8,~12 dB of compression.

For future designs using this chip, I'd suggest adding a few more components to set the voltage range for the chip (R2 in the datasheet for setting the high voltage reference, pin6, and a voltage divider to set the low voltage reference, pin 4, instead of tied to ground).
This would allow the meter LEDs to be more effective in showing gain reduction. The way I have it now, the first 5 LEDS all go on together. But with the extra resistors, you could calbrate the 1st LED to turn on at low GR and the 10th LED to turn on at high GR, and be more spaced out in-between. The slope and offset of the brown curve could be shifted to align better with the blue line. Ideally, you would want a comparator chip that matches the curve of the blue line but I don't think any of the LM391x chips would do this perfectly (or better than the lm3916). 
Title: Re: 525 build thread
Post by: kazper on April 03, 2010, 04:42:22 PM
excellent; I was suspecting 1M might be the ticket, based on the other SC values.  

I had ran that number myself in my notes....

When I was looking into the stuff back on page 18 or so, I was shooting for attack times like a 1176 compressor. The 1176 specs call out 20-800us attack and from what I've seen on ther graphs it looks like the 1M pot gives a 400ms attack with the 0.1uf cap.
 
Edited for clerical error on the post...
Title: Re: 525 build thread
Post by: onlymeeee on April 03, 2010, 04:51:55 PM
excellent; I was suspecting 1M might be the ticket, based on the other SC values.  

I had ran that number myself in my notes....

When I was looking into the stuff back on page 18 or so, I was shooting for attack times like a 1176 compressor. The 1176 specs call out 20-800ms attack
 

Much less than that!  20-800μs
Title: Re: 525 build thread
Post by: dmp on April 03, 2010, 07:10:37 PM
Usually the specs for compressors say "attack as fast as" or something like that. I measured the attack for my DIY 1176 rev D (using the same method as for the 525) as 1ms to about 7ms. Bear in mind that the 525 is supposed to have frequency dependent attack/release and the graph just shows the response to a 1khz sine wave. 
Title: Re: 525 build thread
Post by: benlindell on April 03, 2010, 11:43:43 PM
Just wondering what you're using to measure and graph attack times. Always wanted to measure those myself.
Title: Re: 525 build thread
Post by: kazper on April 04, 2010, 01:45:02 AM
Specs for the 525 call for  Attack time is as fast as 15u/ or Attack Time:    15 micro seconds

Looking at the specifications of the LA2A it shows a attack of 10 Milliseconds and a release of 0.5-5 seconds.
 

What was your final attack measurement at pot max on the 1Meg Pot?  My guess was 400ms based on the first graph.

Realizing the original project modification design was having the pot adjusted to ground before. What does the provided 100K or 10 K pot give you for adjustment? I ask that because that was what was delivered to those who bought as kits. It may be nice to know what the difference attack ranges it makes if you change the pot's around as you have found to work.

If I get some time tomorrow I'll finish wiring mine now that I have all my tools found after the move.

Last are you checking this with a scope on the R5 and C3 junction?
Title: Re: 525 build thread
Post by: dmp on April 04, 2010, 03:30:08 AM
Ben-
I've been generating a signal to send to the 525 and acquiring the data from the output using National Instruments data acquisition cards. I wrote some test programs for this. (I work with this kind of thing in my real job...).
kazper-
If you put in the 100k pot tell us what you think. It is an easy mod - just move C3 off the main board and solder it onto the meter board below CM1, with one leg on GND and one on the inner ATT hookup. Both wires from the ATT pads go to the main board without change. Just a little mod on a fantastic project.
Looking at the graph, I agree it looks like the 1Meg slows attack to about 400ms & 100k about 20ms, but really someone with good ears will have to try it out - which isn't me ;). 
I did measure the voltage at the R5 & C3 junction a little bit, but that is not what I am using for the attack measurement. Just the regular output signal. 
Title: Re: 525 build thread
Post by: kazper on April 04, 2010, 11:59:22 AM
I'll try to get things together later today or early this week and try both the 10K and 100K version. I'll see if I can post something once I get them adjusted and up and running finally. I had to set these aside for other commitments and another housing move.

So a ruff estimate would be attack of 15us to 4ms with the 10K and 15us to 40ms with the 100k, comparison wise thats very useful but it's something that your ears must judge.

Thanks again for the information and graphs. I had looked at other schematics and was trying to get the same thing but I overlooked the simple fact that with the attack were trying to slow down that C3 cap time charging up. Thats really what this is about learning more and we get some cool tools out of it as well.

Cheers,

Kevin

Title: Re: 525 build thread
Post by: EmRR on April 04, 2010, 12:37:57 PM
Good observations on the metering.  Have to look into mod possibilities there; haven't yet. 
Title: Re: 525 build thread
Post by: dmp on April 05, 2010, 11:38:36 AM
I built up a seperate meter circuit on a breadboard but didn't get much improvement by adding components to change the voltage range for the chip. Did add a little bit more range in the first few LEDs as suspected, but not a big difference at all in practice. 
Title: Re: 525 build thread
Post by: EmRR on April 11, 2010, 05:48:35 PM
In your earlier comment about the first 5 LED's, are you seeing useful 0.4ish dB step resolution, or are they really all coming on at the same time, or something in between?  I'm not against super-res at the bottom, but all 5 at once would be crazy. 
Title: Re: 525 build thread
Post by: dmp on April 11, 2010, 11:44:38 PM
It is small dB steps for the first few LEDs in my experience. Only for certain settings (high compression) it appears they all go on at once. As I've been using these 525s over the last week for guitar and vocals the first LEDS are quite useful. High compression has a very unmusical distortion so they are limited to subtle use, ~5dB. In my experience so far for my builds.
As a rough measurement I recorded at what gain reduction (dB) the LEDs would go on (there is some measurement error for these):

LED          as original pcb            mod on breadboard
1               0.05                          0.58
2               0.76                          1.72
3               1.85                          2.15
4               3.14                          3.26
5               4.14                          4.51
6               6.42                          6.71
7               7.79                          8.33
8               9.47                          10.23
9               15                            14.63
10             20                             20
Title: Re: 525 build thread
Post by: benlindell on April 29, 2010, 02:38:31 AM
I got one of my two dead 525 working this evening. there were a few combinations of things that were causing the problems, I wasn't getting enough V- to the opamps, turned out to be the V- at A3 where I had drilled out the hole to fit sockets and the top side wasn't connecting to the socket, same thing happened with the Out of A1. Now it's working fine, just one last thing, when the 525 is powered on and in bypass it's dropping my signal by 6 db, when I power it off, it returns to unity, so I take it I have a loading problem correct? How should I fix it?

Thanks guys. I may look at this attack thing too now that I've got a working unit.
Title: Re: 525 build thread
Post by: dmp on April 29, 2010, 03:19:12 PM
I haven't checked if mine shows the same 6dB drop, but the input opamp has 10k resistors attached on the input that are not switched out when the bypass is engaged. A 10k / 10k voltage divider gives a -6 dB drop, so it could be part of the design. 20*log10(10k/20k).
The in/out switch is 4 pole, so with a little mod, the input opamp could be switched out on bypass.
Title: Re: 525 build thread
Post by: dmp on April 29, 2010, 03:34:02 PM
Oops, the voltage divider idea I just threw out doesn't make sense. It would depend on the source impedance.
Title: Re: 525 build thread
Post by: bdubya on April 29, 2010, 08:25:12 PM
I got one of my two dead 525 working this evening. there were a few combinations of things that were causing the problems, I wasn't getting enough V- to the opamps, turned out to be the V- at A3 where I had drilled out the hole to fit sockets and the top side wasn't connecting to the socket, same thing happened with the Out of A1. Now it's working fine, just one last thing, when the 525 is powered on and in bypass it's dropping my signal by 6 db, when I power it off, it returns to unity, so I take it I have a loading problem correct? How should I fix it?

Thanks guys. I may look at this attack thing too now that I've got a working unit.

Yeah, I drilled out the 2520 pads to accomodate sockets and had a little bit of the same fuss with getting the drilled pad to take the solder.  Once I found where the ground pin of one of the opamps(i can't remember exactly which one) wasn't seeing ground and got it reflowed, things started behaving.  One of them still sounds like it has a gentle low pass on it at around 2k, compression or no, which I'll trace out next time through.  Pretty satisfying to be listening to music through these after tweaking with them for so long, though.   
Title: Re: 525 build thread
Post by: dmp on May 19, 2010, 11:37:37 AM
I notice a little hum on both of my 525s... has anyone else noticed this?
With no input signal, the hum is most noticable with the ceiling at ccw positions. With the ceiling fully cw, at 20, it is gone. The output pot has no effect.
Title: Re: 525 build thread
Post by: dmp on May 21, 2010, 02:43:49 PM
I think I found the proverbial smoking gun with these 525s.
The ones I built both had hum and a non-musical distortion (same as discussed on  pg 14 by Mich and Peter). The distortion was not caused by the FET - it was caused by the meter circuit. After turning R55 all the way off (so the meter would not light at all), the distortion disappears. There's a ground problem when the meter circuit shares the same ground as the in/out pot grounds. I think the current from the meter circuit was causing a ground loop between in/out pots and A3. Easy fix - I cut the trace leading from the neg side of CM1 to the GND on the meter board, and ran a wire from Neg CM1 to audio ground at the hole by gold finger 5. With this change, both of my 525s are quiet & distortion free. Even at heavy compression they sound smooth - a huge improvement. And the hum is gone
A second mod I'd recommend - after tightening down the mounting nuts a few times (or a zillion in my case), the silkscreen over the ground plane developed shorts, which connects audio ground to the chassis, not desirable. Easy mod was to cut the traces by gold fingers 5 & 13 to disconnect the pcb ground plane from audio ground. Then the short to the chassis through the mounting bolts makes the pcb ground plane a chassis ground, which is better for noise rejection.
With these mods the 525s are fantastic. I just played through them with guitar and singing and they are smooth and clean.

Title: Re: 525 build thread
Post by: Brizco on July 11, 2010, 01:04:22 PM
first unit is finally (almost) working! after using a melcor opamp in A4 the unit is working when more/less switch is on pos 12 to 20.
wasnt able to build a working peter-opamp. but ill try again!

at positions 2 to 10, the meter isnt responding, and i cant hear any compression... maybe an error on the switch?

(btw: its not properly calibratet yet)

connecting both att points together brought just distortion...




Title: Re: 525 build thread
Post by: Brizco on July 22, 2010, 02:50:18 PM
first unit is finally (almost) working! after using a melcor opamp in A4 the unit is working when more/less switch is on pos 12 to 20.
wasnt able to build a working peter-opamp. but ill try again!

still no love for the a4... still using melcor 1731...
Quote
at positions 2 to 10, the meter isnt responding, and i cant hear any compression... maybe an error on the switch?

fixed: bad wiring caused this problem

now a new problem with this unit: meter doesnt work anymore, changed ic, nothing happened, there are +15.2V on the cap, but 0V at the LED's... have to check that when i have time.


good news: second unit worked from first start! (with melcor 1731 on A4)




Title: Re: 525 build thread
Post by: janvanvolt on September 12, 2010, 07:42:15 PM
Finally, after 2 years i finished the Module today. Unfortunately i have to wait until next week to get the backpanel from the 51X PSU to finish the PSU and wiring.

Thanks for all support.
Title: Re: 525 build thread
Post by: peter purpose on September 13, 2010, 07:13:18 AM
Briz,
You must have ignored the A4 mod.... there are so few components on there that it must be the case... or you're using the wrong nails.
Title: Re: 525 build thread
Post by: 12volts on September 13, 2010, 09:38:34 AM
Not being a cap snob and lacking the lug holes to tell the difference, I shove whatever I have in there.

peter


Yes, I know it's an old thread but I agree, like Keef, with what is said. I'm sick of tossers who know
more about adjectives & fashion than they will EVER know about electronics.


Frank
Title: Re: 525 build thread
Post by: duantro on September 15, 2010, 03:36:01 AM
Easy fix - I cut the trace leading from the neg side of CM1 to the GND on the meter board, and ran a wire from Neg CM1 to audio ground at the hole by gold finger 5.

Being a Noob or too blurry eyed from the solder, I'm not sure where the "gold finger 5" is that you're referring to in this mod. Could someone enlighten me? 
Title: Re: 525 build thread
Post by: peter purpose on September 15, 2010, 07:22:59 AM
Pin 5 on the edge connector son.
Title: Re: 525 build thread
Post by: duantro on October 04, 2010, 04:46:08 PM
Thanks Peter, I should have figured that out!

Anyone know of a supplier for Omeg pots in the US? I think this would be good - ECO1MLIN

Has anyone found a supplier for these Omeg 1meg pots in the states? Or anyone across the pond care to mail me a few? ;D
Title: Re: 525 build thread
Post by: kazper on October 04, 2010, 09:10:11 PM
Pm me with you qty, I'm ordering by Friday.
Title: Re: 525 build thread
Post by: janvanvolt on December 06, 2010, 07:30:25 PM
Okay, i need some help on debugging this baby.

It's powered up, the LED is green and i am getting audio thru the module (when IN/OUT is not pushed).
As soon IN/OUT switch is pushed, LED is red and i have a lot of static noise, literally it sounds like an Amp, but without input signal.
None of the controls have effect in either in/out. when powering up the Module (or power down) i get a short burst of signal on the LED's, so
i can assume i soldered them correctly.

Jumper set on TERM and on the MODE.

Any idea where to start debugging ?
Title: Re: 525 build thread
Post by: benlindell on December 06, 2010, 08:04:14 PM
Check for voltage getting to the 2520s.
Title: Re: 525 build thread
Post by: peter purpose on December 07, 2010, 08:17:04 AM

Any idea where to start debugging ?


Did you do the A4 mod?
Title: Re: 525 build thread
Post by: janvanvolt on December 07, 2010, 09:23:36 PM
Did you do the A4 mod?

which mod is this ? I did add the C3 in between the attack pot. Also i added the small wire on the add-on board
and also cut the two tracks and rewire the resistor on output.

Title: Re: 525 build thread
Post by: Sredna on December 07, 2010, 11:06:38 PM
I think he means the mod described on page 3, posting nr 43.

The PCB of the small upright DOA had an error, its an easy fix....
Title: Re: 525 build thread
Post by: peter purpose on December 08, 2010, 05:48:28 AM
I think he means the mod described on page 3, posting nr 43.

The PCB of the small upright DOA had an error, its an easy fix....

Datsdawunn
Title: Re: 525 build thread
Post by: janvanvolt on December 08, 2010, 04:33:00 PM
Dawunn was made. Loong ago.
so... i'll try to check the 2520's then.

Title: Re: 525 build thread
Post by: duantro on December 08, 2010, 06:32:56 PM
Good new is that I've got my pair built and squashing!
Still debugging a few things though.... ???
First: It appears that I have my switch wired up incorrectly. When I look at the Schematics in the BOM it appears that r64 goes from sw5B pos20 to ground. On this other wiring diagram that was posted Later in this thread, it states that r64 goes between ground and sw5A pos 20. I'm assuming that since my switch isn't behaving and I wired it up blindly by the second diagram, that it is indeed incorrect? Should ground go to SW5A pos 0, and r64 go from SW5A pos 0 to SW5B pos 20?

Here's the second diagram that I'm referring to:
Quick wiring dagram.
This does not mean I'm back..!!

(http://www.twin-x.com/groupdiy/albums/userpics/normal_525wiring.jpg)

Large version...
http://www.twin-x.com/groupdiy/albums/userpics/525wiring.jpg
Title: Re: 525 build thread
Post by: peter purpose on December 09, 2010, 07:02:13 AM
Do it as in the schematic and you'll be dandy.
Title: Re: 525 build thread
Post by: duantro on December 11, 2010, 03:08:51 PM
Thanks, I think I have it squared away now. I just nailed r64 from SW5b pos 20 to SW5a pos 0 (ground). seems hunky dory
Now just have to figure out why the led meters aren't lighting.

I wanted to add that this thing sounds amazing! Pretty versatile unit from the small amount of use that I've had with it so far.

I also Highly recommend the attack mod that DMP posted. It gives you plenty of adjustment range.
Title: Re: 525 build thread
Post by: Sredna on December 11, 2010, 07:05:33 PM
I also Highly recommend the attack mod that DMP posted. It gives you plenty of adjustment range.

Hmmm, so it does work after all?
Title: Re: 525 build thread
Post by: duantro on December 13, 2010, 10:53:41 PM
Yes it works great with plenty of adjustment. You can even get it to pump pretty good for an aggressive sound. I'm using the Omeg 1 Meg pots (thanks kazper).

I also Highly recommend the attack mod that DMP posted. It gives you plenty of adjustment range.

Hmmm, so it does work after all?
Title: Re: 525 build thread
Post by: JBVries on December 23, 2010, 01:59:13 PM
Anybody have a Mouser project built with this the BOM?
Title: Re: 525 build thread
Post by: duantro on December 24, 2010, 02:01:48 AM
Can anyone verify that the LED meters actually work to some degree with this design? I can't get any of them to light up with normal audio signal, but can with more voltage applied. It seems that there is too much resistance somewhere.
It appears that I have a bad Omeg input pot on one as it bypasses the compression if you futz with the pot shaft. Anyone source these in the states or is this only over seas?
Everything else is working great.
Title: Re: 525 build thread
Post by: dmp on January 14, 2011, 10:11:19 AM
The LED meters definitely work and can be adjusted to be very sensitive. Have you adjusted R55? This trimmer sets the level going to the meter.
Title: Re: 525 build thread
Post by: duantro on January 19, 2011, 02:56:13 PM
The LED meters definitely work and can be adjusted to be very sensitive. Have you adjusted R55? This trimmer sets the level going to the meter.

Yes I have adjusted r55 all the way up and still no LED's. I'm not sure what is going on.....

I'm very interested in your mod that you recommended from the "new" 525 thread:

About adding a FET to the meter circuit, I had this in mind. I didn't try it on a breadboard (which would have to be done) but it looks good when I plotted out the voltages.
Similar to a 1176, a second FET mirrors the one in the audio path. Both FETs would share the same cv, so you wouldn't need the meter path on the original schematic anymore (cr3, cr4, r53, r55, c12, r54,r68,cr6).
Since the resistance of the FET is loglinear with cv, the meter voltage from this divider has to go to a log scaled (dB) LED driver. Since you want to see GR steps, something like the LM3915 since it gives even dB increments.
I couldn't figure out how to change the fullscale range on the LM3915 this morning, however. 30dB fs is more than needed. Maybe it could be adjusted or a different chip would give the range you want...


I've ordered all of the parts to try this, just waiting on the LM3915's to show up. Hopefully this will fix my issues along with being an improvement with the LED scaling.
Thanks again for your input DMP, I'm appreciating the attack mod along with the audio ground mod's. : thumbs:
Title: Re: 525 build thread
Post by: JBVries on January 19, 2011, 03:20:42 PM
I like to order extra Parts and there may be some completely unrelated parts on here, but here is an already existing, mostly built mouser order.

Just check it against your BOM right quick and it should have you a little closer to being on your way to a 525..... ;D

http://www.mouser.com/ProjectManager/ProjectDetail.aspx?AccessID=2fdd070592
Title: Re: 525 build thread
Post by: peter purpose on January 19, 2011, 08:23:56 PM
duantro,
Maybe daft, but is the chip fitted on the underside?
Title: Re: 525 build thread
Post by: dmp on January 20, 2011, 11:24:45 AM
And maybe the LEDs are in backwards, try flipping one and see if it goes on.
Title: Re: 525 build thread
Post by: dmp on January 20, 2011, 11:27:51 AM
Quote
I've ordered all of the parts to try this, just waiting on the LM3915's to show up. Hopefully this will fix my issues along with being an improvement with the LED scaling.
Cool! Good luck experimenting.
Title: Re: 525 build thread
Post by: duantro on January 21, 2011, 02:55:11 PM
duantro,
Maybe daft, but is the chip fitted on the underside?
Chip is on the underside.

And maybe the LEDs are in backwards, try flipping one and see if it goes on.

And I have tried flipping one LED around after reading here about someone else doing this.

Still no go. I have a tech pal that helped calibrate these say that the LED's light up when you run more juice than the comp is capable of. He also double checked that I had the correct resisters inline for the meters. To quote Will Ferrell, "this is Mind bottling"
Title: Re: 525 build thread
Post by: dmp on January 21, 2011, 03:07:32 PM
Quote
I have a tech pal that helped calibrate these say that the LED's light up when you run more juice than the comp is capable of.
You have something wrong because this shouldn't be true. The only thing you can do is double check the components again and run more tests. Finding these kind of problems can be difficult. If I had this problem, I would insert a signal from a signal generator right at pin 5 of the lm3916 chip and determine that the metering is working (0 dbv lights the correct LEDs). Then you would know if the metering has a problem, or the sidechain feeding it. Perhaps CR6 is backwards or your trimmer is defective.
Title: Re: 525 build thread
Post by: duantro on January 24, 2011, 05:31:15 PM
Thanks for the suggestions. I think I have CR6 in correctly. Here's a quick pic. Let me know if you see anything that I'm missing. I'll run some signal and see how much juice it needs to light em up. Sorry for the crappy picture >:(

Edit: With a tone generator on input (pin 5), There are no LED's lighting. however with the tone generator connected to the LED's (pin 1, & pins 10-18) the individual LED's light up just fine.
Title: Re: 525 build thread
Post by: thestudio on January 24, 2011, 06:38:28 PM
I'm trying finish all my many projects this year and found another one which is the 525....  I would like know if there's a BOM available for this project??? Also, I have an older version because it looks like there was a pcb update?
Title: Re: 525 build thread
Post by: dmp on January 26, 2011, 01:02:05 PM
Quote
With a tone generator on input (pin 5), There are no LED's lighting. however with the tone generator connected to the LED's (pin 1, & pins 10-18) the individual LED's light up just fine
The LM3916 chip works as a current sink on the LEDs, meaning that if you put positive voltage on the pins to the chips, and the LEDs light up, they are in backwards. If this isn't the problem, you probably need a new chip.
Title: Re: 525 build thread
Post by: duantro on February 24, 2011, 01:01:25 AM
I've finally figured it out. I had a 330k resister in r53 instead of a 300ohm. Thanks for the help ive got meters now.
Title: Re: 525 build thread
Post by: EmRR on August 12, 2011, 03:07:46 PM
Have been trying to finish off one of these that someone else started.  Note to self:  NEVER buy anyone else's unfinished project.  Far more difficult, since you don't know what they did and didn't do correctly. 

Anyway.  Anyone have problems with the ceiling switch (sw5, more/less)?  This one wants to throw speaker cones across the room when changed, and also includes a lovely high pitched squeal.   Switch seems to have a good deal of rotational flex, and it's well tightened.  All seems properly built, and I've retouched all the joints.    May have to throw it out and start over with a new switch.  What will fit in? 

---EDIT-----

maybe answering my own question, maybe not. 

It appears from all available evidence that sw5 was part of the kits, maybe it wasn't?  And the sorry bastard before me ordered BBM switches?  That's how it's acting.   But it sure looks like the switches seen in everyones pics. 

The only other clue I can see is that Peter's switch layout picture shows an aluminum standoff between the inner wafer and the front of the switch body.  This one only has the screws as support.  Possibly that is the source of the additional flex, and contact failure? 
Title: Re: 525 build thread
Post by: peter purpose on August 12, 2011, 04:10:14 PM
1. What will fit in? 
2. This one only has the screws as support.  Possibly that is the source of the additional flex, and contact failure?

1. I've seen Grayhills used.... but you've got the thing there, take a stab at choice.
2. There should be steel sleeves and spacers, so soppy bollocks didn't do it right.
Title: Re: 525 build thread
Post by: EmRR on August 12, 2011, 04:27:19 PM
Yeah, got it in front of me, and definitely MBB.  Looks like I need to fit some spacers in and see how it plays. 
Title: Re: 525 build thread
Post by: jandoste on August 13, 2011, 04:56:36 AM
Hey Peter,
I received my package and Thanks [ also big thanks for the score  :]
Just I'm searching the Bom parts  and that I need to buy one more Transformer...
Can I use this one from Hairball ? http://hairballaudio.com/shop/product_info.php?cPath=24&products_id=82

Thanks
Title: Re: 525 build thread
Post by: peter purpose on August 13, 2011, 05:11:51 AM
Hey Peter,
I received my package and Thanks [ also big thanks for the score  :]
Just I'm searching the Bom parts  and that I need to buy one more Transformer...
Can I use this one from Hairball ? http://hairballaudio.com/shop/product_info.php?cPath=24&products_id=82

Thanks

No, you need the same thing. EA-2623-1 from Jeff. I thought you must have had one already.
And by the way.... a 'score' is what we English call £20.
Title: Re: 525 build thread
Post by: jandoste on August 13, 2011, 01:12:24 PM
Hi Peter,
I can't find BC161-16  :o
Can I use this one --> 2N5322 instead of BC161-16 ?
http://fr.mouser.com/ProductDetail/Central-Semiconductor/2N5322-LEADFREE/?qs=sGAEpiMZZMutXGli8Ay4kKcj8LVUp7Qv6fiOhiO6W%252bA%3d
Thanks
Title: Re: 525 build thread
Post by: peter purpose on August 13, 2011, 01:28:24 PM
I don't know if you can use them or not, but 2n3053 and 2n4037 are good for the driver Qs.
Title: Re: 525 build thread
Post by: jandoste on August 13, 2011, 02:07:08 PM
I don't know if you can use them or not, but 2n3053 and 2n4037 are good for the driver Qs.

Thanks Peter,
is it right that;
BC141-16 => 2n3053 
BC161-16 => 2n4037
I guess my last question... :)
Title: Re: 525 build thread
Post by: peter purpose on August 13, 2011, 02:09:45 PM
work it out yourself.
Title: Re: 525 build thread
Post by: zayance on August 13, 2011, 05:12:50 PM
Hi Peter,
I can't find BC161-16  :o
Can I use this one --> 2N5322 instead of BC161-16 ?
http://fr.mouser.com/ProductDetail/Central-Semiconductor/2N5322-LEADFREE/?qs=sGAEpiMZZMutXGli8Ay4kKcj8LVUp7Qv6fiOhiO6W%252bA%3d
Thanks

http://fr.farnell.com/multicomp/bc161-16/transistor-pnp-boitier-to-39/dp/9207694?Ntt=BC161-16

http://fr.farnell.com/multicomp/bc141-16/transistor-npn-boitier-to-39/dp/9207678?crosssellid=9207678&crosssell=true&in_merch=true&
Title: Re: 525 build thread
Post by: jandoste on August 13, 2011, 06:21:07 PM
Hi Peter,
I can't find BC161-16  :o
Can I use this one --> 2N5322 instead of BC161-16 ?
http://fr.mouser.com/ProductDetail/Central-Semiconductor/2N5322-LEADFREE/?qs=sGAEpiMZZMutXGli8Ay4kKcj8LVUp7Qv6fiOhiO6W%252bA%3d
Thanks

http://fr.farnell.com/multicomp/bc161-16/transistor-pnp-boitier-to-39/dp/9207694?Ntt=BC161-16

http://fr.farnell.com/multicomp/bc141-16/transistor-npn-boitier-to-39/dp/9207678?crosssellid=9207678&crosssell=true&in_merch=true&

Merci Zayance :)
Title: Re: 525 build thread
Post by: jandoste on August 13, 2011, 07:21:09 PM
Hey Guys,
I just finishing my mouser list and on the Vu meter board I see CM1 what is that? Any idea? :o
Thanks :-*
Title: Re: 525 build thread
Post by: zayance on August 14, 2011, 02:53:59 AM
Hey Guys,
I just finishing my mouser list and on the Vu meter board I see CM1 what is that? Any idea? :o
Thanks :-*

On the BOM:

Quote
CAPACITORS
(WHAT I USED)
CM1 1000UF/16V
Title: Re: 525 build thread
Post by: jandoste on August 15, 2011, 02:33:52 PM
Thanks Zayance!

for VCR2N I received an email from Goldmine sales "We do not ship to France"  :o
Do you have any other idea?
Thanks
Title: Re: 525 build thread
Post by: peter purpose on August 16, 2011, 05:11:06 AM
I have some, but only if you ask really nicely and you check back to see what 'score' means.
Title: Re: 525 build thread
Post by: EmRR on August 16, 2011, 11:30:59 PM
Three more things to confirm in my troubleshooting of an inherited build:

1) I jumpered sw5B sweeper to r64, and confirmed that the unit otherwise appears to behave properly.  This kills the giant thumps since it effectively bypasses the switch section, so something is up in this switch deck.   (I did put in the spacers from another switch, and it tightened it up mechanically, but not sonically)  Specific question: With sw5B jumpered out, switching from '0' to '2' the unit mutes entirely, then comes back up.  Is this normal behavior for sw5A, or evidence of other issues? 

2) following dmp's advice on meter trim, I discovered relatively similar steps in meter/GR correspondence.   What I don't see addressed anywhere, is what the attack control does to meter behavior.  In this unit, a slower attack causes the meter to show greater gain reduction than it does at the stock (fastest) setting.  As expected, the actual result of slower attack is that more transients pass through, and output level rises as expected.  A 1M attack control does work, but does the meter misbehave because of it, or is this unit also funky in this way?

3) I aligned the GR meter following dmp's clues, with the ceiling control set to position 10.  I then checked the measurements with it set on 2 and 20, and found that I got slightly less GR per LED on 2, and even less on 20.  At 7 LED's in particular I measured -4.6dB GR on 20, -5.8dB GR on 2, and -6.3dB GR on 10. 

Thanks for clues and observations. 
Title: Re: 525 build thread
Post by: dmp on August 17, 2011, 12:13:06 AM
Quote
1) I jumpered sw5B sweeper to r64, and confirmed that the unit otherwise appears to behave properly.  This kills the giant thumps since it effectively bypasses the switch section, so something is up in this switch deck.   (I did put in the spacers from another switch, and it tightened it up mechanically, but not sonically)  Specific question: With sw5B jumpered out, switching from '0' to '2' the unit mutes entirely, then comes back up.  Is this normal behavior for sw5A, or evidence of other issues? 
I haven't seen this behavior. The 'A' side of the switch is going to the sidechain input. At '0' the input is grounded, at '2' it is being fed to the sidechain. It sounds like there might be a big DC voltage from the output of the A1 doa? This would cause a sudden spike to go into the sidechain and trigger it to compress the signal. A DC voltage on the input was the first thing I thought of for the thumps on your output 'B' side switch as well, since the resistors connect each switch position, and effectively make the 'B' side of the switch a voltage divider. You can check the switch pretty easily - disconnect the input and wiper from the 'B' side, attach R64, and measure the resistance of the wiper to ground as you turn the switch. Verify that it matches the schematic.
I'd try a different doa and check the components around it for proper value / connection. Check that the in/out pots are correct and grounded correctly. Since both sides of the switch are showing some funny behavior I'd look at the doa output.
Title: Re: 525 build thread
Post by: dmp on August 17, 2011, 12:32:50 AM
Quote
2) following dmp's advice on meter trim, I discovered relatively similar steps in meter/GR correspondence.   What I don't see addressed anywhere, is what the attack control does to meter behavior.  In this unit, a slower attack causes the meter to show greater gain reduction than it does at the stock (fastest) setting.  As expected, the actual result of slower attack is that more transients pass through, and output level rises as expected.  A 1M attack control does work, but does the meter misbehave because of it, or is this unit also funky in this way?

3) I aligned the GR meter following dmp's clues, with the ceiling control set to position 10.  I then checked the measurements with it set on 2 and 20, and found that I got slightly less GR per LED on 2, and even less on 20.  At 7 LED's in particular I measured -4.6dB GR on 20, -5.8dB GR on 2, and -6.3dB GR on 10.

I'll preface this with... I spent HOURS trying to figure out how the sidechain of this compressor worked, including simulations, which just crashed - I eventually gave up.  But I can confirm the observation that the meter shows much different gain reduction as the attack is changed. I can't recall if it is the same as you describe (slower attack, more LEDs).
As to #3, the meter circuit in this compressor does not really capture the compression behavior of the FET and gain reduction structure of the first DOA. I wouldn't be terribly surprised to learn of odd behavior like this. In order for the meter to really track GR correctly, it would need a matching VCR2N to capture the functional form of the attenuation behavior. Since it is a feedback compressor it is possible I suppose that the input to the sidechain might change the relationship between the meter and actual gain reduction. 
Title: Re: 525 build thread
Post by: dmp on August 17, 2011, 12:44:20 AM
Just remembered about the attack pot / GR meter - the attack pot is AFTER the meter in the sidechain circuit. In a feedback compressor, the sidechain reacts to the audio, generates a voltage which then has to go through the attack resistance and charge the attack capacitor BEFORE the fet attenuates the signal. But the GR meter indicates the sidechain voltage BEFORE the attack RC circuit, not the voltage on the base of the FET, which is what actually correlates with GR.
Because it is a feedback compressor, the sidechain voltage actually increases as you slow down the attack (before the attack RC), because more audio signal actually slips by the GR doa on a slow attack. So, long confusing explanation aside, it is another error due to a poorly designed meter circuit.
 
Title: Re: 525 build thread
Post by: EmRR on August 17, 2011, 02:05:46 AM
Thanks, confirms many things.  I think you're right; need to try a different A1 and also pull SW5 enough to measure it fully.  SC voltage increase with attack R change is making sense.  Input level to SC affecting metering is probably also correct, and would be fudged in the original with it's tiny low resolution meter movement.  We may see more here, and it may be less satisfying to know the limitations. 


----------edit--------

Switch is correct, and wired in properly.

DC at output of any A1 2520 I try is around 10mV on average, largest seen during switching is about 30mV.

A3 removed, sw5 thumps and chirps at every position.
A3 removed, sw5B jumpered sweeper to r64, 0-2 thumps, gain higher on 0.
A3 removed, sw5A jumpered sweeper to ground, less chirps, lower thumps.

Obviously something more to yet discover....
Title: Re: 525 build thread
Post by: jandoste on August 21, 2011, 12:53:50 PM
Hey Guys,
I am searching A Rotary Switch [1X 2 POLE 11 WAY MBB ROTARY] and found it here --> http://www.banzaimusic.com/Rotary-Switch-2-level-2x1x12.html
Can I use it? and I didn't find any info which resistor I'll use for the Rotary Switch ?
Thanks for any feedback...
Cheers,
Title: Re: 525 build thread
Post by: peter purpose on August 21, 2011, 01:43:56 PM
2 levels, 2x1 pole 12 positions, without stop end position. Switching: Make-before-break.
Looks ok, but not sure what they mean above.
Title: Re: 525 build thread
Post by: benlindell on August 21, 2011, 01:46:55 PM
It'll just keep rotating around,going from pos12 to pos1
Title: Re: 525 build thread
Post by: jandoste on August 21, 2011, 02:39:39 PM
Thanks Pete and Ben !

I already have  used this one for Pete's Tr**dnt project  --->http://fr.mouser.com/ProductDetail/Alpha-Taiwan/SR2921F-0112-19R0B-E9-S-W/?qs=sGAEpiMZZMuLS1mv1rPY1mZCAvtEStLP
and works fine... if you say it's ok I am buying it  :-*
Second thing is what resistor I will solder on this resistor? if you have any idea or document and if you share it I will be very happy  :)
Thank you gentlemans!

Cheers,
Title: Re: 525 build thread
Post by: peter purpose on August 22, 2011, 05:19:24 AM
I used http://uk.rs-online.com
352-187 & 352-244, but looks like the wafers are out of stock for the moment.

Second thing is what resistor I will solder on this resistor?
On the switch? 1/4w metal film are just fine.
Title: Re: 525 build thread
Post by: jandoste on August 22, 2011, 06:35:19 AM
Second thing is what resistor I will solder on this resistor?
On the switch? 1/4w metal film are just fine.

Thanks Peter,
I meant what value of resistors I neeed to solder? I searching and already searched on all pages but I just found this picture :-X :-[
(http://i1236.photobucket.com/albums/ff442/jandoste/wafermark.jpg)

Thanks again!

Title: Re: 525 build thread
Post by: peter purpose on August 22, 2011, 06:59:32 AM
The schematic on the first page.
Title: Re: 525 build thread
Post by: jandoste on September 01, 2011, 06:05:45 AM
Second thing is what resistor I will solder on this resistor?
On the switch? 1/4w metal film are just fine.

Thanks Peter,
I meant what value of resistors I neeed to solder? I searching and already searched on all pages but I just found this picture :-X :-[
(http://i1236.photobucket.com/albums/ff442/jandoste/wafermark.jpg)

Thanks again!

Thanks again!

Hi Peter,
I really can't read [ because of my eyes ]  the schematic :o
I read like this [ I may be wrong but my wife helped me :]
2= 47k    ->8k2
4= 16k    ->6k8
6= 5k1    ->5k1
8= 5k6    ->4k3
10=3k8   ->3k8
12=2k7   ->2k7
12=1k8   ->2k2
14=1k5   ->1k6
16=1k1   ->1k3
              ->1k1
am I write?
Thanks
Title: Re: 525 build thread
Post by: peter purpose on September 01, 2011, 10:29:40 AM
(http://www.twin-x.com/groupdiy/albums/userpics/525.jpg)
Title: Re: 525 build thread
Post by: jandoste on September 01, 2011, 03:19:02 PM
Thanks Peter!
You're a great man!
Now I see that I was wrong with the some values:)
Best
Title: Re: 525 build thread
Post by: jandoste on September 01, 2011, 06:51:00 PM
Hi again  ::)
I'm sorry for my stupid question but I can't find on mouser 9k1 resistor so can I use 10k instead of 9k1?
Thanks for any advance.
cheers,
Title: Re: 525 build thread
Post by: benlindell on September 01, 2011, 06:58:45 PM
Hi again  ::)
I'm sorry for my stupid question but I can't find on mouser 9k1 resistor so can I use 10k instead of 9k1?
Thanks for any advance.
cheers,
http://www.mouser.com/Search/Refine.aspx?Keyword=271-9.1k-rc
Title: Re: 525 build thread
Post by: jandoste on September 01, 2011, 07:48:23 PM

http://www.mouser.com/Search/Refine.aspx?Keyword=271-9.1k-rc

Thanks Ben :) Awesome!
Title: Re: 525 build thread
Post by: jandoste on September 05, 2011, 05:58:43 AM
Hey Peter,
I'm finishing the build but just got some questions...
33nf is missing for C11 but I already have 47nf what do you think that  can I use 47n instead of 33n?
Thanks
Title: Re: 525 build thread
Post by: peter purpose on September 05, 2011, 06:54:35 AM
I would use the right part, but it will not explode if you use 47n. Your choice.
Title: Re: 525 build thread
Post by: jandoste on September 05, 2011, 07:05:40 AM
I would use the right part, but it will not explode if you use 47n. Your choice.

Thanks Peter!
I'll try 47n and we will see if it works or not :)
cheers,
Title: Re: 525 build thread
Post by: jandoste on September 05, 2011, 08:59:27 AM
Hi again Peter,
last questions and I hope if you have a bit time you can save me...

1- I must cut the two traces?
 (http://i1236.photobucket.com/albums/ff442/jandoste/525mod2-1.jpg)

2- I am using the sowter 9935 trnx and I read again all thread but didn't find any info for wire connection :-\...

Do you have any idea?
and big thanks again Sir!

Title: Re: 525 build thread
Post by: peter purpose on September 05, 2011, 10:29:07 AM
1. yes.... as per the instructions.
2. I've no idea of the colour codes on the Sowters.
They usualy print them on the reverse of the invoice.
Title: Re: 525 build thread
Post by: jandoste on September 05, 2011, 10:38:55 AM
1. yes.... as per the instructions.
2. I've no idea of the colour codes on the Sowters.
They usualy print them on the reverse of the invoice.

Thanks Peter,
They didn't send me the colour codes :(... I sent an email them and any one didn't use the sowters for their build?
Cheers,
Title: Re: 525 build thread
Post by: peter purpose on September 05, 2011, 10:43:36 AM
any one didn't use the sowters for their build?

As far as I know we all used Ed's.
Title: Re: 525 build thread
Post by: jandoste on September 05, 2011, 12:40:05 PM
Good news :) They sent it me...
Now I got the colour codes but I am not sure about +/- which colour?
any advance?
(http://i1236.photobucket.com/albums/ff442/jandoste/9935x1.jpg)

Thanks
Title: Re: 525 build thread
Post by: peter purpose on September 05, 2011, 04:18:43 PM
Try this... or the exact opposite.

(http://lazpro.com/OLa.jpg)
Title: Re: 525 build thread
Post by: jandoste on September 05, 2011, 05:34:44 PM
Merci beaucoup Peter
Title: Re: 525 build thread
Post by: jandoste on September 08, 2011, 06:05:56 AM
Hi Peter,
finished :) but  I guess I got some bugs with my build. if you have a bit time for helping me I'll be very happy man!
- Fist; the LED meter is not working [ didn't do the calibration]
- Comp and Lim don't work [ or just calibration problem ]
- More & Less don't...
- more two questions;
(http://i1236.photobucket.com/albums/ff442/jandoste/OL-1.jpg)
(http://i1236.photobucket.com/albums/ff442/jandoste/metermod.jpg)

I don't know if I wired on the right way for the att but something wrong:(
Merci
Title: Re: 525 build thread
Post by: peter purpose on September 08, 2011, 06:49:58 AM
The two you have marked as 10k are probably too high. Measure your led and use an online led calculator.
R63 is indeed 150R, but you can leave it off for mono.
Meter board 12 to 12... you're just putting a switch in the path.

Most problems with these are down to the wiring. Check your work again.
Title: Re: 525 build thread
Post by: jandoste on September 08, 2011, 08:41:05 AM
The two you have marked as 10k are probably too high. Measure your led and use an online led calculator.
R63 is indeed 150R, but you can leave it off for mono.
Meter board 12 to 12... you're just putting a switch in the path.

Most problems with these are down to the wiring. Check your work again.

Thanks for replied Peter!
I changed the resistors and I put 47r 0.25W and I already wired between 12->12. :-\
I used three colours maybe the problem comes by this way?
(http://i1236.photobucket.com/albums/ff442/jandoste/-1-9.jpg)

Thanks
Title: Re: 525 build thread
Post by: jandoste on September 08, 2011, 01:49:19 PM
Ok, It was not easy this build for me but I am finishing it[ slowly:]
Ok here my calcule and I just need it's right or wrong...
I used:
5 green LEd :2.2V
2 yellow: 2.4v
3 red: 2.1V
So it was wrong 47ohm! and It's must to be 1k 1W?
if I am not wrong?
any idea?
Thanks
Title: Re: 525 build thread
Post by: jandoste on September 09, 2011, 05:48:53 AM
Ok, I'm not a good home worker :o
Title: Re: 525 build thread
Post by: peter purpose on September 09, 2011, 05:54:09 AM
You're talking of RM1? Stick 1k5 in there. 1/2W is plenty.
Title: Re: 525 build thread
Post by: jandoste on September 09, 2011, 06:14:41 AM
RL 1 and RL 2
Title: Re: 525 build thread
Post by: peter purpose on September 09, 2011, 07:11:04 AM
It would help if you mentioned the parts you are talking about.
Stick a couple of 2k2 in there and be done with it.
Title: Re: 525 build thread
Post by: jandoste on September 09, 2011, 08:23:06 AM
It would help if you mentioned the parts you are talking about.
Stick a couple of 2k2 in there and be done with it.

I put there two 2k2 and no chance :-[
Title: Re: 525 build thread
Post by: peter purpose on September 09, 2011, 09:39:37 AM
No chance of what?
Title: Re: 525 build thread
Post by: jandoste on September 09, 2011, 09:45:03 AM
No chance of what?

Sorry, I meant the leds don't  work...
Title: Re: 525 build thread
Post by: peter purpose on September 09, 2011, 10:17:11 AM
Is there power going to them?
And is it a common cathode led?
Title: Re: 525 build thread
Post by: jandoste on September 09, 2011, 10:40:29 AM
Quote from: peter purpose
Is there power going to them?

Nothing comes to them

And is it a common cathode led?
    LED, 3MM, GAP, GREEN
    Bulb Size:3mm
    LED Colour:Green
    Luminous Intensity:40mcd
    Viewing Angle:45°
    Forward Current If:20mA
    Forward Voltage:2.2V
    Lens Shape:Round
    Wavelength Typ:576.5nm
    SVHC:No SVHC (15-Dec-2010)
    Lens Style:Tinted Non-diffused
Title: Re: 525 build thread
Post by: peter purpose on September 09, 2011, 11:38:30 AM
You need a three legged, common cathode led for the in/out switch.
Title: Re: 525 build thread
Post by: jandoste on September 09, 2011, 02:20:49 PM
You need a three legged, common cathode led for the in/out switch.

Bien compris maintenant :) Thanks Peter!
I was asking that myself "maybe something is missing with this switch" :)
Now I understand this connection:)
(http://i1236.photobucket.com/albums/ff442/jandoste/metermod.jpg)
Title: Re: 525 build thread
Post by: jandoste on September 13, 2011, 10:26:41 AM
Ok, I received a three legged! and wired it! but I just wanted to be sure for the wire connection!
I already wired 12 to 12 and I just need to connect like in this picture? and I guess it's my last question :) hope :-\
(http://i1236.photobucket.com/albums/ff442/jandoste/OLwire.jpg)

Thanks for any advance!
Cheers

Title: Re: 525 build thread
Post by: peter purpose on September 13, 2011, 12:33:00 PM
2nd and third back. Apart from that, lose the blue.
Title: Re: 525 build thread
Post by: jandoste on September 13, 2011, 01:30:42 PM
2nd and third back. Apart from that, lose the blue.

Thanks Peter,
Didn't work  :o
I guess I got a problem but now I'm not sure where is it?
I wired like this and I used 2k2 for  RL 1 RL2 and nothing soldered on "mode"
(http://i1236.photobucket.com/albums/ff442/jandoste/OLLED.jpg)
Title: Re: 525 build thread
Post by: peter purpose on September 14, 2011, 03:43:12 AM
Correct.
Is the led is a common cathode type?
Title: Re: 525 build thread
Post by: jandoste on September 14, 2011, 05:21:19 AM
Correct.
Is the led is a common cathode type?

Yes, it is.
Title: Re: 525 build thread
Post by: peter purpose on September 14, 2011, 09:02:54 AM
Well... tis not rocket surgery. If you have the right amount of power at the resistors, the led should light.
Title: Re: 525 build thread
Post by: jandoste on September 14, 2011, 11:08:23 AM
Thanks Peter,
I didn't wire anything from LM39 to Pin 13? Maybe I need to change LM3916N ??? everything is ok! I all checked twice.
(http://i1236.photobucket.com/albums/ff442/jandoste/PBM.jpg)
Thanks
Title: Re: 525 build thread
Post by: peter purpose on September 15, 2011, 03:32:37 AM
Have you got power and ground connections to the in/out switch board?

You get 5 more questions..... make them count.
Title: Re: 525 build thread
Post by: jandoste on September 15, 2011, 12:25:45 PM
Have you got power and ground connections to the in/out switch board?

You get 5 more questions..... make them count.

Thanks Peter,
Everything is working except the Leds. in/out Led is also working...
Title: Omeg 1Meg specs
Post by: scottlwilson on September 16, 2011, 10:37:08 AM
Hi Everyone

Does anyone have the model number or specs for the replacement 1Meg Omeg pot? 

Thanks!!

Scott Wilson
Title: Re: 525 build thread
Post by: peter purpose on September 16, 2011, 02:40:26 PM
ECO 1M A
Title: Omeg ECO pots
Post by: scottlwilson on September 19, 2011, 02:54:06 PM
thanks Peter.  Does anyone know where these can be had in USA?  Damn Yanks....lol
Title: Re: 525 build thread
Post by: benlindell on November 19, 2011, 04:31:04 PM
So I'm trying to clear my bench off and I have 2 of these sitting here, I have one working now but both in bypass and with no power I'm getting a loss of ~8db. Any idea why I'd be getting that? That's symptoms of a bad cable, It's all good now.
Title: Re: 525 build thread
Post by: mitsos on November 29, 2011, 12:35:49 PM
ECO 1M A
Is this the attack pot? 1M linear?


no one carries these. Order direct from Omeg (they'll send a couple of samples if you ask nicely, otherwise you have to buy 10 I think).


does anyone carry the GH rotary switch?


Seems the pots and switch are the only difficult to source parts? Interested in a couple of these and doing some homework cuz I don't wanna have them stuck on my bench for a year waiting on a part! 

cheers, looks nice Peter!
Title: Re: 525 build thread
Post by: peter purpose on November 30, 2011, 10:41:41 AM
Mitsos, do you have the old version 525?
Title: Re: 525 build thread
Post by: mitsos on November 30, 2011, 10:57:05 AM
no, I have none atm!  Just doing homework cuz I think I have everything besides pots and that switch.  Pots I can get but switch I don't know. (It's 2x 1K log for In/Out as far as I could see, is the 1M linear (A is linear at Omeg right?) you mention above is for the attack pot?

ummm.... I just realized this thread might be about the old version? oops...

sorry, either no coffee or too much...

Title: Re: 525 build thread
Post by: peter purpose on November 30, 2011, 11:02:04 AM
You need small format pots for the new build. Omegs are way too big.
I'll start a new thread for the latest version.
Title: Re: 525 build thread
Post by: Rafita on March 06, 2012, 08:42:41 PM
finally finished just one problem , when compressing the audio crackle as the leds turn on , even with no output  as you increase the input pot the leds begin to turn on and hear crakling as the leds turn on and off  , any thoughs  thank's
Title: Re: 525 build thread
Post by: peter purpose on March 07, 2012, 07:40:45 AM
Have you done the mod... wire to edge connector?
Title: Re: 525 build thread
Post by: Rafita on March 07, 2012, 10:25:05 AM
yes peter done the mod , removing A3 the input pot has no function and no reduction , but the output works great lots of gain
thank's
Title: Re: 525 build thread
Post by: mitsos on July 21, 2012, 10:44:02 AM
hey peter, got one of your older kits here.  hope to get it together soon... are the VCR2Ns available anywhere besides goldmine?  If not, is there a workable replacement that you know of?  Didn't seem to find anything here..  cheers!
Title: Re: 525 build thread
Post by: peter purpose on July 21, 2012, 10:57:53 AM
Goldmine is the only place I've ever seen them.
A better man than I will have to pipe up with an alternative.
Title: Re: 525 build thread
Post by: zayance on July 21, 2012, 11:05:17 AM
electrochronic's web store, a little more expensive tough:

https://sites.google.com/site/diypartsstore/catalog/misc-components
Title: Re: 525 build thread
Post by: jplebre on January 29, 2013, 03:43:19 AM
Hey guys

I've seen most of the 2520 opamps with 1/2w or greater resistors.
Is this a requirement?
Title: Re: 525 build thread
Post by: peter purpose on January 29, 2013, 08:45:49 AM
Only Rs 16 & 17.
Title: Re: 525 build thread
Post by: duantro on February 12, 2013, 11:30:57 PM
I really like how these comps sound, thanks again
Title: Re: 525 build thread
Post by: Indecline on March 10, 2013, 03:27:42 PM
Does anyone have a source (or spares laying around) for the trimmers?

I've checked Mouser, Digikey, and Farnell and can't find any in stock that fit the board.

Thanks!!
Title: Re: 525 build thread
Post by: jplebre on March 10, 2013, 03:38:43 PM
I've used the small round vishay (other brand make them).
The issue they are 1 turn which makes it tricky to callibrate btu it's doable.

Title: Re: 525 build thread
Post by: Indecline on March 11, 2013, 09:25:36 PM
Ah, I'm an idiot.. I didn't realized I could get a slightly larger trimmer and "trim" it back.

Hardy, harr harr :)
Title: Re: 525 build thread
Post by: Indecline on July 29, 2013, 10:22:24 AM
Got mine all fired up and working yesterday. These things sound pretty damn good!

The only thing that's not functioning correctly is the ceiling control. I get more compression as I turn it up but the ouput doesn't automatically compensate for the extra compression. Also the output knob itself has a very low gain range (maybe 10dB at most) that seems to change with the ceiling control. Step 20 is also weird, I get way less compression and the output knob fully functions. I looked over the rotary and all is correct. I think it might be a short between the two wafers or with the switch board right above it.

I haven't done the meter board grounding mod or the attack mod but I haven't noticed any hum or noise and I do get a little attack control so I'll probably leave as is (100k pot).

Great project Peter!!  8)

Edit: I found two solder blobs on the rotary connecting the wafers. Works great, now I'll probably try out the attack mod.
Title: Re: 525 build thread
Post by: jplebre on August 06, 2013, 11:46:45 AM

I haven't done the meter board grounding mod
Which one are you referring to? please do tell more as mine doesn't work well with fast attack times.


Works great, now I'll probably try out the attack mod.
Let us know what you think. I think with the mod the pot works as you expect and gets the ridiculous fast factory setting.
Title: Re: 525 build thread
Post by: Indecline on August 06, 2013, 12:12:34 PM

I haven't done the meter board grounding mod
Which one are you referring to? please do tell more as mine doesn't work well with fast attack times.


Works great, now I'll probably try out the attack mod.
Let us know what you think. I think with the mod the pot works as you expect and gets the ridiculous fast factory setting.
The grounding mod for the meter board is to seperate the pot ground from the meter cap ground, running a wire from the cap to the edge card ground. The information is posted in the thread around page 22 or so. In my OSA rack and CAPI's rack mine work fine, but in my buddies OSA rack he gets an unuseable amout of noise. I'll probably investigate that further to find the discrepencies between our OSA racks, but that's a different thread.

I really like the fastest attack setting when you really want to clamp on something like rap vocals or distorted guitars. To me the attack (the way it sits unmodded) feels a bit weird. It works enought to notice the change but it feels like the envelope isn't quite right. Besides that they are insanely good and honestly I'd be fine with just the factory fast attack.

I'd love to pickup another for 2 bus duties if anyone has one for sale ;)
Title: Re: 525 build thread
Post by: jplebre on August 06, 2013, 06:40:29 PM
Quote
To me the attack (the way it sits unmodded) feels a bit weird. It works enought to notice the change but it feels like the envelope isn't quite right.

Yes, exactly what I felt. THe mod I suggested makes it 1176 ish stupid fast (factory) or something less, but the meter starts working weirdly.
Might try to see if the meter mod solves the issue
Title: Re: 525 build thread
Post by: EmRR on August 06, 2013, 07:12:34 PM
We addressed why the meter acts weirdly with slower attack earlier in the thread. No easy way around it, basically variable attack is a hack at this point, which would require greater redesign to have the meter follow properly.
Title: Re: 525 build thread
Post by: brianadams09 on November 07, 2013, 01:07:59 PM
Hello all,

I just finished building one of these cool compressors. I am seeing one bug.
My In (Threshold) pot does nothing if the Ceiling is down at zero.
I am not sure if this is normal or if I still need to trouble shoot a bit more.
Otherwise, it sounds wicked.

Thanks
Title: Re: 525 build thread
Post by: duantro on July 19, 2019, 07:45:11 PM
I recently picked up a pair of these that a previous member tried to assemble and couldn't get working. I've rewired everything and get signal. I see gain reduction on the meter, but not hearing output gain reduction, just keeps getting louder as I turn up the 20 pos switch. Any ideas where to look for issues?
Title: Re: 525 build thread
Post by: Potato Cakes on July 21, 2019, 03:35:20 PM
The ceiling control is an odd bird. Turning up the ceiling control will cause and increase in level that will in turn feed the compression circuit. Start with the ceiling control all the way up and then feed it signal. Then adjust the threshold to see if you can hear gain reduction. Also, just to be sure, make sure the circuit is engaged and the compressor is engaged (I've neglected to do this before).

Is this the first or second revision? Do you have a known working VCR2N?

Thanks!

Paul
Title: Re: 525 build thread
Post by: duantro on July 21, 2019, 04:07:12 PM
The ceiling control is an odd bird. Turning up the ceiling control will cause and increase in level that will in turn feed the compression circuit. Start with the ceiling control all the way up and then feed it signal. Then adjust the threshold to see if you can hear gain reduction. Also, just to be sure, make sure the circuit is engaged and the compressor is engaged (I've neglected to do this before).

Is this the first or second revision? Do you have a known working VCR2N?

Thanks!

Paul
Thanks for the comments. It’s a first version. I do have 3 others that work. Maybe I’ll swap out the vcr2n and see if that does anything.
The amplifier portion of the ceiling control is working as it gets louder, but doesn’t compress. Switches are engaged (in and compress)  I know it’s got to be something I’m overlooking.
Title: Re: 525 build thread
Post by: Potato Cakes on July 21, 2019, 04:18:03 PM
I have four of the first versions as well. One thing that I kept coming across is on some of the units, the wire I was using kept breaking from it's connections in different spots as they were started from another person as well (Peter's prototypes to be exact).

Thanks!

Paul
Title: Re: 525 build thread
Post by: duantro on July 21, 2019, 04:26:02 PM
Yeah, the person I got this from used solid core wire that kept breaking also, so I replaced all of the wires. We are truly glutton's for punishment trying to resurrect someones projects.
Edit: tried with a different vcr2n and still no compression, only volume boost
Title: Re: 525 build thread
Post by: duantro on July 28, 2019, 06:55:04 PM
I've been staring at the schematics trying to figure out how this side chain works. It makes it pretty hard to trouble shoot without this knowlege. The comp and limit switches seem to be connecting the circuit and showing changes on the meter, but I can't deduct where the gain reduction should be attenuating.  I'm also noticing about a 30% volume output, even with the output volume turned all the way down. I've searched for solder bridges and don't see anything ...
Title: Re: 525 build thread
Post by: Potato Cakes on July 28, 2019, 07:38:57 PM
Did you make all the board corrections since you're using a first version? I believe there are some besides the fixes for the attack control. I also remember having some transformers wired incorrectly when I first made mine. The volume should be working correctly if you have the right value for the potentiometer and it is free of connection errors. I had to use the schematic and do a fair amount of continuity tests when I was troubleshooting. It always came down to a misplaced/bad/no connection with at least one solder bridge I think.

Thanks!

Paul
Title: Re: 525 build thread
Post by: duantro on July 28, 2019, 08:01:01 PM
Yes, I think I have all of the fixes done. The Attack mod, the Meter ground mod, The termination blunder mod, etc... I didn't have to do the A4 mod as the previous builder of this lot lost the A4 board. Very generous member Ivan was kind enough to send me one of his version 2 A4 boards, that I retro fitted. This was quite a task as V2 A4 boards had lots more of the passive input components on it.  I had to jumper those, as I already had them installed on the main board.
So I've just got to find where this 30% signal is making it to the output. I'm guessing that this is where the compression isn't making it back in the circuit somewhere
Title: Re: 525 build thread
Post by: Potato Cakes on July 28, 2019, 11:25:41 PM
Did you socket your A4 boards? I am guessing you swapped op amp boards out of habit.

Thanks!

Paul
Title: Re: 525 build thread
Post by: duantro on July 28, 2019, 11:40:00 PM
Did you socket your A4 boards? I am guessing you swapped op amp boards out of habit.

Thanks!

Paul
On my other v1 builds I soldered them in. The last one that I’m trouble shooting, I socketed it in. Mainly because it is a v2 A4 board, and I wasn’t sure if it’d be an issue.
Title: Re: 525 build thread
Post by: AudioCommand on October 16, 2019, 06:17:59 PM
Hey guy's,

any one have the calibration guid for me...?


Thank's Dom
Title: Re: 525 build thread
Post by: duantro on October 16, 2019, 06:31:48 PM
Hey guy's,

any one have the calibration guid for me...?


Thank's Dom
Title: Re: 525 build thread
Post by: duantro on October 16, 2019, 06:32:29 PM
Here's part 2
Title: Re: 525 build thread
Post by: Potato Cakes on October 16, 2019, 06:33:12 PM
Hey guy's,

any one have the calibration guid for me...?


Thank's Dom

It should be attached somewhere in the this thread. It's just the original API 525  calibration guide. The controls and trimmer designation match up with Peter's design. There isn't another guide written for the ACL.

Thanks!

Paul
Title: Re: 525 build thread
Post by: AudioCommand on October 17, 2019, 06:17:51 PM
Thank's a lot!!!

Dom
Title: Re: 525 build thread
Post by: Potato Cakes on October 17, 2019, 10:54:12 PM
Thank's a lot!!!

Dom

Yes
Title: Re: 525 build thread
Post by: AudioCommand on November 25, 2019, 04:40:07 AM
I'm dominic from germany.

I build the lazpro 525 V2 and have them since years... and now I whant to finish them.

But my problem is that I lost all files with a hd crash!

I'm realy thankfull for posting the calibration files! But I need more infos and all files/links in the building trades are death...

Any one can send me his info pack with schematics, overlay, bom, and the calibration guid...

My [email protected]

That's realy helpfull!

Thank's for your time

Dominic
Title: Re: 525 build thread
Post by: duantro on December 01, 2019, 05:03:23 PM
I emailed all of my files, you might check for the V2 thread for more info.
Title: Re: 525 build thread
Post by: duantro on December 02, 2019, 03:08:05 PM
Can anyone enlighten me on how the sidechain works here? I'm still trying to get the unit I got from another member resurrected. The meter shows compression, but output isn't attenuating, audio just gets louder as I increase the more/ less switch. I've ran all new wiring, and have checked all of it, as well as the components many many times.
Title: Re: 525 build thread
Post by: shabtek on December 03, 2019, 11:10:55 AM
Looks like a bridge rectifier after the sidechain XFMR . Positive v drives meter neg is cv to vcr2n in yellow.

Check diode orientation.
Maybe isolate that branch going over to the variable release thing.

OT :Seems like a weird way to switch 2 release time resistors either 1M or 24M
—what goes on over there in the bottom right?  If there is a really big peak those transistors turn and ? The release time?
Title: Re: 525 build thread
Post by: duantro on December 03, 2019, 12:19:29 PM
Thanks Shabtek. I must have kept overlooking that yellow line back to the vcr2n. All of the diode orientation are correct. I think I have a spare vcr2n to try and see if that works.
Title: Re: 525 build thread
Post by: dmp on December 03, 2019, 12:49:10 PM
Can you  measure for the control voltage?
If you feed a audio wave to the unit and measure the DC voltage at the attack pot, you should see the control voltage go up as you increase the signal level feeding the unit.
Title: Re: 525 build thread
Post by: duantro on December 05, 2019, 12:37:16 PM
I swapped out a fresh vcr2n, and no difference. DMP are you saying measure the dc voltage at the attack pot, while increasing signal level?
Title: Re: 525 build thread
Post by: dmp on December 05, 2019, 01:40:35 PM
Yes - I would start out measuring on the attack pot (the side that faces the VCR2N) for the control voltage.  You probably will not have any voltage there. If you don't, then work your way back through the sidechain to see where things are getting messed up.
The basic operation is an audio signal goes to the ceiling control, which sends a signal to the sidechain (the ceiling changes a dual voltage divider to adjust the threshold and output together) . The signal to the sidechain  is amplified and rectified to a DC control voltage. That voltage changes the resistance of the FET (VCR2N) in the first 2520 amp circuit, to modify the gain of the amp.
Title: Re: 525 build thread
Post by: duantro on December 16, 2019, 06:53:28 PM
Thanks so much DMP, for the detail explanation. I was sick over the weekend and now am backed up with work, but will check this asap!
Title: Re: 525 build thread
Post by: duantro on January 07, 2020, 06:00:18 PM
I finally got around to looking at this. Spent about 5 hours searching for components and retracing wiring, etc. Still the same results. I'm not getting any dc voltage at the att connection on the meter board. I am getting between -2vdc to -12vdc on the top lead of r50 depending on how hard I send input audio. I double checked the wiring and solder joints going to the release time board. Input pot changes the meter reduction, but does nothing to the sound. Output pot is working, but when it is ccw there is still like 30 % audio coming through. Sw5 just makes out put gain hotter as turned cw. So frustrating...
Title: Re: 525 build thread
Post by: dmp on January 08, 2020, 11:09:19 AM
You have a negative control voltage on R50 but not on the attack pot???
Which side of R50: CR5 or CR12/CR11?
Title: Re: 525 build thread
Post by: duantro on January 08, 2020, 12:42:26 PM
You have a negative control voltage on R50 but not on the attack pot???
Which side of R50: CR5 or CR12/CR11?
On the CR11/CR12 side. I'm wondering if I should just jumper a wire from R50 to the inside att/c3 junction on the meter board, as it seems to die en route somewhere. The previous owner attempted a few repairs, perhaps a solder trace got too hot.
Title: Re: 525 build thread
Post by: dmp on January 08, 2020, 12:48:12 PM

From the schematic the R50/CR11/CR12 node should connect to the Attack pot / C3  - so yeah something seems funny
I don't remember what the routing looks like and I don't have one of mine with me to look at now, so can't be much help.
Title: Re: 525 build thread
Post by: duantro on January 08, 2020, 12:59:31 PM
That fixed the side chain! Compression at last! ....However, I'm still getting around 20-30% signal passing through, with the output pot turned off. Time to search for that and calibrate.
Title: Re: 525 build thread
Post by: dmp on January 08, 2020, 01:08:23 PM
Nice!

The ceiling also attenuates the signal
Title: Re: 525 build thread
Post by: duantro on January 08, 2020, 01:18:04 PM
Nice!

The ceiling also attenuates the signal
Right. I'm talking about the output pot itself. Regardless of the ceiling control position, I still get signal with output off. I think it might be time to double check the calibration now. Thinking of making sure R7 isn't way off.
Also, i need to do the mounting screw mod to disconnect gold finger 5 and 13 from each other. Does this image look correct to cut the red line?
Edit: i cut that and the same section from pin 13.