Lowfreq

1176LN Rev D DIY
« Reply #20 on: January 03, 2007, 05:46:36 AM »
Quote from: "Shenes"
Hi,

I'm thinking of building a couple of G1176 based on boards from Mnats. But this thread is making me a bit confused. The current version for sale in the black market is the rev J and this new version is rev D? Why "D", am I missing something? In what way is this new version different?

Mako can probably fill you in on this better than me, but the Rev D refers to one of the models of the origional units. There are a few different versions out there. The G1176 is based off a Rev F or G I think?

There's a few threads around here explaining the differences of the different revs.

Quote from: "edanderson"
oh dear, has everyone now done the homework that jens assigned? i don't like to see this question come up over and over either, but it is confusing. here are some cliffs notes that i hope will be helpful:

the rev A and B units (blue stripe) have a total of ~50db of system gain, with a 5db lower threshold point than the rev C-F (black face) which have ~45db of system gain (the F has a class AB output amp, C-E class A). this means that if you were to turn the input knob to the same place on both a blackface and a bluestripe, and send them the same signal, the blue stripe would go into action first. so you would naturally set the input control lower on a blue stripe (to get a similar threshold), and that is what the extra 5db of gain is for... to make up for the extra attenuation at the input.

the purple and the UA are both based on the rev D/E units, so they both should have 45db of system gain. the purple MC76 and MC77 are tested for that before they leave the shop. the earlier and perhaps present UA units probably do, but they had that "mid era" where they re-did the front end, so who knows for sure.

the g1176 is based on the later rev G (the first silverface). revs F-H used an output transformer (B11148) that was configured as 1:3.5 (10db gain) for the domestic market or 1:1 (unity gain) for export to europe. the gyraf PCB uses a lundahl output as a 2:1 stepdown (6db loss). some people modified the PCB to reverse the transformer. the mnats PCB has options for various 1:2 stepup (6db gain) transformers. and the front end is either an opamp (rev G) or a bridging transformer before a pot, similar to the solution UA used in their "mid era" reissues (to be contrasted with an attenuator before the transformer, as in the rev F and earlier). finally, the threshold sensitivity is again different on the rev G, so the input knob settings do not translate well from a rev G to the D/E units.

ANYWAY, there are many options with the g1176, and yes you can make something mighty close to a rev G or even a rev F if you source all the right parts. i think experimentation is great and you can certainly make some interesting custom units. try a 31267 on the input and a lo2567 on the output, for example. or a cinemag version. or the OEP versions on the mnats PCB. lots of options.

that said, the class A output section of the rev D/E, as found in the purple units/kit, is different from what you can do with the g1176. and that is the sound some people are after.

ed


Here's the full thread wth a lot of discussion on the various 1176's
http://www.groupdiy.com/index.php?topic=18160&postdays=0&postorder=asc&highlight=1176&start=0

As for the rev J, it's Mako's own naming for his pcb version of the G1176(with some very handy additonal features)


Rob Flinn

1176LN Rev D DIY
« Reply #21 on: January 03, 2007, 06:48:14 AM »
Quote from: "mnats"
Quote from: "Rob Flinn"
I would guess that many people are using the iron that Andrew supplies with the kits.

You are rough on a guy who just drove 700 kms.


Sorry about that, but I thought I'd say it before anyone else got in with it !!
regards Rob

raysolinski

1176LN Rev D DIY
« Reply #22 on: January 03, 2007, 09:12:52 AM »
Go Mako Go!
I don't mind the off board transformers  :grin: ..Just curious, What type of output iron would we use? I am assuming without an output  cap we would need a gapped transformer?

Cheers.
Ray
"orange whip?..orange whip?...3 orange whips please"

flaheu

1176LN Rev D DIY
« Reply #23 on: January 03, 2007, 02:30:48 PM »
Quote
What sort of iron are people using in their Purples?


Personally, I would use the EDCOR that tony dB has tested recently:
 http://www.edcorusa.com/downloads/other_documents/XS1100_sheet.pdf

for output and maybe the usual suspect like OEP on input or maybe a Lundahl (like in the G1176.

I'ver already bought some iron's from tony and I should say I'm very pleased with them  

Mnats: again great job  :thumb:  :thumb:
I can not wait to buy 2 boards.
As MagnetoSound said:
"Sad lack of balls in today's bands, IMO"

Rob Flinn

1176LN Rev D DIY
« Reply #24 on: January 03, 2007, 03:04:37 PM »
Quote from: "flaheu"
Quote
What sort of iron are people using in their Purples?


Personally, I would use the EDCOR that tony dB has tested recently:
 http://www.edcorusa.com/downloads/other_documents/XS1100_sheet.pdf

for output and maybe the usual suspect like OEP on input or maybe a Lundahl (like in the G1176.

I'ver already bought some iron's from tony and I should say I'm very pleased with them  

Mnats: again great job  :thumb:  :thumb:
I can not wait to buy 2 boards.


Yes, but you are totally forgetting that the class A UREI's need an output transformer with a tertiary feedback winding.  This is the main reason why there aren't too many clones out there  of the class A 1176.  This is why Jakobs board isn't cloning the class A 1176 in the first place.

I am quite interested to find out how well Mnats board works without this feedback winding in place.  Does it sound right ?  Iguess ultimately it oesn't matter too much whether it sounds exactly like a rev d/e, it is just another flavour
regards Rob

mnats

1176LN Rev D DIY
« Reply #25 on: January 03, 2007, 08:42:15 PM »
Too friggin' hot to venture into my workshop today. But when I had it hooked up to the CJ output transformer last week it sounded fine to me.

I'm no circuit reader like some of the experts around here but glancing at the schematic it seems as though there is the usual negative feedback happening in the circuit before the transformer and the tertiary winding simply applies overall feedback back to the first stage. Seems as though this might be to compensate mainly for distortion due to the transformer? Aren't there plenty of designs out there that don't bother compensating for the output transformer (like the later versions of the 1176 itself)?

...edited to add schematic...

So maybe if you aren't too concerned about this overall feedback and use a gapped transformer or block the DC with a big cap you can be happy with an ordinary transformer. When the Purple 'reissue' shows up I will do a with and without test.

I'm surprised with all the people that appear to be interested that no one has encouraged edanderson with his group buy suggestion. Lots of folks seem happy with their Purples and with the same output iron this might be a simple way to get there now that the kit has been discontinued. Maybe he could even be pursuaded into doing an input transformer and attenuator group buy?

tommypiper

1176LN Rev D DIY
« Reply #26 on: January 03, 2007, 09:14:21 PM »
Mako,
great shtuff, man.  I've been waiting for this!  Dual in a 2U, yes!  

...edited...

cheers
Imagine a wet, slightly chilled from its gas release and decompression, with water droplets condensing, sucking surface tension, slowly sliding down the side, capped by a healthy virgin froth on top..

kato

1176LN Rev D DIY
« Reply #27 on: January 03, 2007, 09:50:04 PM »
Gorgeous layout. It's art.
Your wife doesn't understand the obsession? I would think women are more attuned to the importance of pleasing visuals.

My wife once said (about a partially stuffed board, only resistors,) "I like the little blue beads."   :grin:

tommypiper

1176LN Rev D DIY
« Reply #28 on: January 07, 2007, 12:34:36 AM »
edited...  :grin:   showing my support.
Imagine a wet, slightly chilled from its gas release and decompression, with water droplets condensing, sucking surface tension, slowly sliding down the side, capped by a healthy virgin froth on top..

Sleeper

1176LN Rev D DIY
« Reply #29 on: January 07, 2007, 03:35:33 AM »
http://cinemag.biz/application_notes/AN-106.pdf
this is pretty close I'll bet.  I'm sure they could do it. for a group order. I'd be in for two transformers and two boards.  

MNats. I have a few of your other boards.  are all the switching arrangements basically the same...  
seems like there aren't any major differences between the g1176 and the RevD, but i haven't looked too closely. Reckon you have.

 I'd be into a couple of those boards too... I haven't stuffed the revJ boards I bought from you, but this would be for my second dual 1176. a different flavor, and the purple style class A with the terteriary winding does sound different and I've been told "better-bigger-stronger " by mixers with a lot more hours on their ears than mine.

Why not right. :sam:  :thumb:
Kelly


mnats

1176LN Rev D DIY
« Reply #30 on: January 07, 2007, 03:11:49 PM »
Cinemag have done it. No need to try to reinvent the wheel - Purple and Cinemag have already sorted it out. Please see the last post on page one.

I've sent off the files and am having a small batch of boards made which I'll offer on the Black Market. Meanwhile I'm working on a PDF file and a page describing the project with top and bottom layers for home-etchers.

rascalseven

1176LN Rev D DIY
« Reply #31 on: January 07, 2007, 03:48:20 PM »
That's awesome!  If you decide to make a run of PCB's available, I'm in for 2 boards and 2 trannies.

:thumb:

JC
"If you dig the gig, do it. -But listen to the signal, not the person talking."  -Keef

Orleanska

1176LN Rev D DIY
« Reply #32 on: January 07, 2007, 03:51:18 PM »
I'd be in for two transformers and two boards.

regards
Denis
we teach what we need to learn.

radiance

1176LN Rev D DIY
« Reply #33 on: January 07, 2007, 04:04:38 PM »
I'm in for boards AND transformers..........
"Knowing that you are dreaming, however, does not automatically guarantee full rationality.
Then again, being awake doesn't ensure good thinking, either." -  Lynne Levitan

1176LN Rev D DIY
« Reply #34 on: January 07, 2007, 04:25:23 PM »
I am definenytly in for two boards and two transformers!

flaheu

1176LN Rev D DIY
« Reply #35 on: January 07, 2007, 05:03:13 PM »
I'm in for 2 boards and 2 tranies  :grin:  :grin:

Keep us updated  :thumb:  :thumb:
As MagnetoSound said:
"Sad lack of balls in today's bands, IMO"

HarryH

1176LN Rev D DIY
« Reply #36 on: January 08, 2007, 05:43:14 PM »
I think a group buy would be great,Im in for 2 boards.
Harry

BladeSG

1176LN Rev D DIY
« Reply #37 on: January 08, 2007, 06:46:10 PM »
Beautiful work there Mako  :thumb:

I don't know how I've missed this thread so far, but anyhow if boards are made available I'll be in for 1 board and 1 transformer too.

Steve

Sleeper

1176LN Rev D DIY
« Reply #38 on: January 08, 2007, 10:42:51 PM »
Quote
Cinemag have done it. No need to try to reinvent the wheel - Purple and Cinemag have already sorted it out. Please see the last post on page one

I see the altran numbers, but not a cinemag one, though edanderson says it's posted somewhere...  I'll have to have a look around.
FYI
If there is a group buy in play, I've been told that Altran will also probably do smallish runs(like 50)
It looks like everyone is thinking there is a group buy hapenning for the transformers, I'm not sure if this is really the case is it?


I'm in for 2boards and 2 transformers as well.
at least 2 boards from you mnats.
Thanks
Kelly

OK I looked, I see some cinemag numbers, but I really don't know
if I'm looking at the right one.  edanderson?

Prophonic

1176LN Rev D DIY
« Reply #39 on: January 09, 2007, 06:03:47 AM »
Hi Mako,

I would be also in for 2 boards and trannies if a group buy takes place.

cheers

prophonic


 

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