All things G1176 - the new "repost" thread.

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galileon

New member
Joined
Oct 24, 2021
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2
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PL
hello Everyone,

Just finished my first 1176 clone made on basis of Mnats rev J.
First i have used in and out OEP transformers and ratio 2:1 for both. Then tested my build against TRacks plugin and ActionComp ( 500 series fet ).
The results i got were average i mean i was able to recreate the same character on plugin. So i removed the input transformer ( as some of U suggested ) and left only output OEP 2:1 one. Its more clean but still i cannot achieve exciting effect.
I have used most parts as suggested at BOM list and double checked. ( so no any additional mods )

Meybe some of U have some thougths about - the ratio or some changes i can do for components to make this build more exciting :)
Meybe i shoud try to use output as 1:1 ? When i have 2:1 looks like gain is very low.

Any suggestions are welcome!
Thank U for all of this great things here.

Rafal
 

gyraf

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Rafal,

To get an answer for a question like this, you need to specify exactly what you mean by "exiting" - otherwise we would each have our own guess as to what you mean (and if this is on purpose, it would probably be better to ask over at gearslutz or similar place)

/Jakob E.
 

galileon

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Joined
Oct 24, 2021
Messages
2
Location
PL
hah sorry Jakob :) My sense of humour is very specific :) Just to be honest i have simple issue about this gain and just looking for some advice if there is the best answer what combination works - i mean regading transformers and ratios and eventually some changes at the board - i know i am lazy bastard who won't experiment by himself but currently have even no place to do tests/experiments etc. I found when i settled 2 oep in 2:1 the sound of midrange was really nice - somehow bright and little distorted - that was significant on female vocals. Now 2:1 just out. gain decreased and i am little lost.

About the gain i have used 120p ( C101 and C102 ) because they havent 100p - it could be the reason?

It is excting already to make diy 1176 - we all know it !
Thank U

Rafal
 

MrG

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Joined
Jul 22, 2018
Messages
125
Location
Nashville, TN
Hello Folks,

About 15 years ago, I built the Rev J project to completion, and it's been working well since. I recently decided to replace the input transformer with the 0-12, and the output with an original B11148. I also found my value for R87 was wrong and had slowly burned up, so I replaced that. Just to confirm, the unit still sounded normal/fine with that resistor burnt.

I read many threads and Mnats website, and tried to figure out exactly what I needed to do to use these transformers, and I think I did it right. I'm using the 0-12 as a 2:1, and the B11148 as a 1:3.5 (I believe that's correct).

Here's the issue: the output seems like it's about the correct gain I was hoping for (similar to the original configuration), however the low end is completely rolled off. I'm guessing this is something simple/stupid I'm not considering, but I haven't been able to figure out what. One thought is, neither transformer is grounded to the PCB, as I'm not sure where or if I need to do that.

Any help, or steering me towards info would be very greatly appreciated.

Thanks!
MG
 

MrG

Well-known member
Joined
Jul 22, 2018
Messages
125
Location
Nashville, TN
Hello Folks,

About 15 years ago, I built the Rev J project to completion, and it's been working well since. I recently decided to replace the input transformer with the 0-12, and the output with an original B11148. I also found my value for R87 was wrong and had slowly burned up, so I replaced that. Just to confirm, the unit still sounded normal/fine with that resistor burnt.

I read many threads and Mnats website, and tried to figure out exactly what I needed to do to use these transformers, and I think I did it right. I'm using the 0-12 as a 2:1, and the B11148 as a 1:3.5 (I believe that's correct).

Here's the issue: the output seems like it's about the correct gain I was hoping for (similar to the original configuration), however the low end is completely rolled off. I'm guessing this is something simple/stupid I'm not considering, but I haven't been able to figure out what. One thought is, neither transformer is grounded to the PCB, as I'm not sure where or if I need to do that.

Any help, or steering me towards info would be very greatly appreciated.

Thanks!
MG
UPDATE: I discovered that the connection from the board to the output had become severed on one of the two audio paths - re-attached and I am now good to go!

For anyone who might benefit from this info, I think this sounds absolutely killer with the original transformers in it. On it's own, the compression is so instantly classic and recognizable that it puts it in a whole different use category for me. Slightly less lows and low mids, less midrange dynamics, grabbier and glassier in a really rich way. In a mix, it sets the track into the mix much more naturally, makes it less obtrusive, etc... It's like a better-sounding, more leveled version of the performance, with some vintage rolloff going on.

Thanks to mnats once again for this project.

Best,
Mark
 

sodastereo

Member
Joined
Apr 26, 2022
Messages
5
Location
argentina
Buenos días a todos, ha pasado mucho tiempo desde el comienzo de este hilo, sin embargo, necesito su ayuda.
Construí el 1176 rev H, todos los voltajes están ahí, algunos cerca de 1v más o menos, pero están cerca del esquema, el OT se enrolló de acuerdo con las especificaciones requeridas, mi versión usa opamp en la entrada.
Ahora, el problema es que no hay audio, sin embargo, si hago una sonda conectada al potenciómetro de salida, hay audio allí, además de eso, la VU no se mueve, solo puedo moverla en Bypass con qbias preestablecido y cero ajustar. los unicos reemplazos fueron los fdh333, que usaban otros bf245 soldados como diodos (en un post de este foro), el pin 19 es negativo y tambien varia si giro q bias, igual que el pin7.
¿Por dónde podría empezar?
 

Dualflip

Electronic monk
Joined
Nov 15, 2008
Messages
1,639
Location
Mexico City, MX
Buenos días a todos, ha pasado mucho tiempo desde el comienzo de este hilo, sin embargo, necesito su ayuda.
Construí el 1176 rev H, todos los voltajes están ahí, algunos cerca de 1v más o menos, pero están cerca del esquema, el OT se enrolló de acuerdo con las especificaciones requeridas, mi versión usa opamp en la entrada.
Ahora, el problema es que no hay audio, sin embargo, si hago una sonda conectada al potenciómetro de salida, hay audio allí, además de eso, la VU no se mueve, solo puedo moverla en Bypass con qbias preestablecido y cero ajustar. los unicos reemplazos fueron los fdh333, que usaban otros bf245 soldados como diodos (en un post de este foro), el pin 19 es negativo y tambien varia si giro q bias, igual que el pin7.
¿Por dónde podría empezar?
Marcelo, this is an english only forum (en el foro se habla inglés solamente).

(Te van a llamar la atención si sigues hablando en español. Si no sabes hablar inglés, usa Google Translate.)

Saludos!
 
Last edited:

sodastereo

Member
Joined
Apr 26, 2022
Messages
5
Location
argentina
good morning, yes, my mistake, I used the wrong column of google translator, please accept my apologies
the message is as follows:

Good morning everyone, it's been a long time since the beginning of this thread, however, I need your help.
I built the 1176 rev H, all the voltages are there, some close to 1v or so, but they are close to the schematic, the OT was wound according to the required specs, my version uses opamp on the input.
Now the problem is that there is no audio, however if I make a probe connected to the output pot there is audio there, on top of that the VU doesn't move, I can only move it in Bypass with qbias preset and zero adjust. the only replacements were the fdh333, which used other soldered bf245 as diodes (in a post on this forum), pin 19 is negative and also varies if I turn q bias, just like pin7.
Where could I start?
 

gyraf

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pin19 should vary with q bias

no output signal even with signal after output pot puts the error in the output amplifier (Q5-6-7-8-9), wireing, or output transformer. VU won't move without output signal
 

sodastereo

Member
Joined
Apr 26, 2022
Messages
5
Location
argentina
You are a genius, the error was in Q6 (bc560) the stamp was not clear, if it was bc560 or bc550, apparently it is bc550, I replaced it with a 2n5087, connected my cell phone (a quick test changing the xlr plug) and the VU moved his needle .. a joy invaded me.
Today I decided to try it, I have sound, finally!, but I have no compression... and the needle does not move when there is sound, strange, I just turned it off and on, there were no changes.
Q bias is set.
Now, the problem may be in gr control amp? Should I search for that area? What do you recommend? Thank you very much for your time.
 

sodastereo

Member
Joined
Apr 26, 2022
Messages
5
Location
argentina
Good morning everyone, after checking everything, board, components, welds, that everything is fine, (at least on the board) it occurs to me to check the VU rotary key, and I notice that the needle was whipping, when checking with better light, I find that one of the 4 central pins had broken the track with the solder... I set out to reinforce the solder, and a piece of the track came off, a simple soldered wire solved the problems.
In short, in case someone else experiences the same thing in the future:
Fault: no sound on output: in my case the fault was Q5, another type.
Fault: no compression: values, voltages, false contact, welds were checked, the fault was a broken track in the VU selector key.
Now it only remains to adjust Q bias, and I noticed that at maximum gain it distorts, surely the Q bias influences, but at least it compresses!
Gyraf, very grateful for your time, it's a shame we're far away, otherwise I'd buy you a few beers, grateful for your good disposition.
 

fauxjazz

Member
Joined
Aug 5, 2020
Messages
12
Hi all, I am in the process of building a G1176 using a Gyraf Rev 7 board and rack front panel from Pusherman. I have fitted a fused IEC on the back of the unit and plan to have a small SPST rocker switch for power on the front panel, to make/break the mains live contact, pre-power transformer.

I am in the UK (230V) and the switch I have bought is rated at 250v 6A. Will this be safe and sufficient for my needs? The torroidal power transformer I have bought is 230V 30VA, 25V, 25V. I have built several Marshall-style guitar amps previously and I would normally use a switch with a higher amp rating for this purpose, but they seem difficult to source in a small circular size.

Out of interest does anyone know the rating for the push-button (ratio style) power button used in the Hairball kits (although I understand the implementation of the switch is a bit different)?

Many thanks and apologies for the basic question! I have done some searching/reading, but am struggling to find any conculsive answers.

Ben
 

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