All things G1176 - the new "repost" thread.

[JonnathanLopes]

I did all the links but it does not seem to compress, does not alter the sound by pressing the buttons. The only connection that not  did was turn on the VU. Can anyone help me get my compressor to compress?

 

[soulitude]

I'm looking for a G1176 parts list for Europe (I live in Sweden).
I'm going to build a Mnats Rev J. Seems like a good place to start. Really excited.

I've searched the forum with no result (except from Mnats BOM), and as a total newbie I really need some help with sourcing the parts.

Has anyone got a Mouser cart or something similar that could be helpful to me?
Would be highly appreciated.

 

[Spencerleehorton]

Hi Guys,

soulitude probably best to go onto the mnats threads about this and ask, other than that your just gonna have to put one together yourself.

regards

Spence.

 

[Spencerleehorton]

HI Guys,

My G1176 seems to have a little hum and i wanted to try the hitchhikers cut but am struggling to find any info on exactly where to make the cut.
Can anyone post in the info please?

regards

Spence.

 

[gyraf]

Googling G1176 trace cut finds e.g.: http://www.gearslutz.com/board/geekslutz-forum/870144-gyraf-1176-rev7-compressor-hum-problem.html

I'm pretty sure the topic has come up at least 10-15 times in this thread

Jakob E.

 

[Spencerleehorton]

Hi Jacob,

thanks for that all the links i found where out of date, perfect will try it all out.

regards

Spence.

 

[Spencerleehorton]

HI Jacob,

still slightly confused about eh 2.5mm wire for removing this hum, where is this placed?

regards

Spence.

 

[gyraf]

eh 2.5mm wire

Does not compute - the easy version of this mod just implies cutting the copper traces at the shown places. If you want more, you could reinforce ground trace with additional copper/wire, but I haven't found need for that.

Jakob E.

 

[Spencerleehorton]

Ah Ok, thanks jacob, mine is a rev 8 version so im unsure of whether to do this now as it looks like the ground doesnt go all the way round, so i think my problem is somewhere else?

Spence.

 

[gyraf]

yes, if you have the new pcb, your problem must be something else...

Jakob E.

 

[Spencerleehorton]

HI Jacob,

Its seems my problem is 50/60 cycle hum so i need to find a way of tracing where this is coming from.
The hum actual note is somewhere between a G and A on a bass guitar on the E string which is normally 50/60 cycle.

regards

Spence.

 

[Spencerleehorton]

HI Guys,

just a quick question which might hopefully solve my problem with hum, on input and output jacks i have earth wire direct from case and connected to IEC.
Should i be connecting the earth wire on the input plugs or output plugs which go to main pcb or should i be taking a main earth from the main pcb from somewhere else?

hope this is clear?

regards

Spence.

 

[gyraf]

Ground is taken from input XLR pin1, split:
1 - to power ground
2 - to chassis. All parts.
3 - to PCB input ground
4 - to output XLR pin1

Jakob E.

 

[Spencerleehorton]

HI Jacob,

thanks, i have done this and there is still a slight hum which appears and gets worse when i engage the slam function, all hiss seems to come up really high when slam mode is engaged? is this normal?
the only thing i can compare it to is the bombfactory BF-76

regards

Spence.

 

[Aleguitarpro]

Hi to all.
I've just finished a stereo G1176.
This is my sixth 1176, so I've experienced a lot this project and never had problems.

After having calibrated both channels (with 4 matched BF254) I discovered that one channel react to RELEASE control: it change output signal also with compression disabled and changed also in GR mode the needle of the meter.
I seen that this problem is quite common and I've already read everything related to this problem in this support thread but I haven't find ideas to fix mine...

Obiouvsly I've checked all the voltages and all are ok.

1. changed the two FH333 -> nothing changed
2. removed Q12-13-14-15 in the GR CONTROL AMP and power on the unit: cheched the RELEASE pot -> nothing changed. The needle moved as before.
3. tried to clean both boards (main board-ratio board) -> problem still here
4. replaced ratio board, rewire the pots (attack-release) ->problem still here
5. replaced release pot ->problem still here
6. checked all the resistors
7. checked all the caps

The only situation in wich the release pot doesn't affect the meter in GR mode/output is when I disconnect point "7" in main pcb.
I've tried to disconnect points 18 and after 19 but with point 7 connected the problem is still there...

Any ideas from someone that had the same problem and solved???
Thank you very much... too many sleepless nights spent.

A.

 

[mats-odm]

Without having had this problem let me throw out some ideas;

Just to be sure, does the release knob change both the signal level (as measure on the output XLR) and move the needle or just one of the two?
Perhaps try with Q10 removed / the whole meter circuit disconnected.

Check to see what's happening on Q1 gate, check also without signal and while moving the release pot.

I would check around connection 18, as I understand it the charge in C22 will flow through the release pot and then the q-bias network there.
Measure the voltage there (18) without signal while turning the release knob, if I understand it right the voltage should be a constant negative there (the Q bias)..



Good luck, I wish I could help more.

 

[Aleguitarpro]

Without having had this problem let me throw out some ideas;

Just to be sure, does the release knob change both the signal level (as measure on the output XLR) and move the needle or just one of the two?
Perhaps try with Q10 removed / the whole meter circuit disconnected.

Check to see what's happening on Q1 gate, check also without signal and while moving the release pot.

I would check around connection 18, as I understand it the charge in C22 will flow through the release pot and then the q-bias network there.
Measure the voltage there (18) without signal while turning the release knob, if I understand it right the voltage should be a constant negative there (the Q bias)..



Good luck, I wish I could help more.

Thanks for answering.
The RELEASE POT change both the signal level (as measure on the output XLR) and move the needle in GR mode.
The short RELEASE time give me a normal behaviour of the compressor, but moving the pot to the short RELEASE time the output signal decrease and the meter in GR mode shows a big amount of GR (corresponding to the decreasing of the output signal).

I measured the change in V in FET's GATE, moving the release pot:

Fully working channel:
-0,938 slow release
-1,501 fast release

Bad working channel:
- 0,786 slow release
- 1,475 fast release

I'm measuring after having calibrated the unit.
Wihout Q10, obiouvsly, the meter is not working in GR mode but the problem in the output is still there...
Measuring the V in point 18:

- 2,077V (slow release-fast release) - bad working channel

Working channel, point 18:

-2.098V (slow release-fast release)

I changed the FET with the ones in the working channel but it isn't problem due to bad matching...
Also in the working channel I see a little movement of the needle in GR mode moving the release pot, but it's not rilevant.

I noticed a strange thing and maybe it could help to solve the problem: blowing in the pcb (both in the component side and in the traces side I see the needle of the meter moving in GR... do the same drop that I see moving to SHORT RELEASE the pot.
I tried to blow in the working channel and nothing changed...

Any idea?

Thanks,
A.

 

[Aleguitarpro]

I noticed a strange thing and maybe it could help to solve the problem: blowing in the pcb (both in the component side and in the traces side I see the needle of the meter moving in GR... do the same drop that I see moving to SHORT RELEASE the pot.
I tried to blow in the working channel and nothing changed...

Any idea?

Thanks,
A.

I've repeated this "blowing" test: blowing in the pcb I've a voltage drop in the Gate of the 2 FETs...
I changed all the wirings, the FH333 again, the capacitors in the GR CONTROL AMP and the 4 transistors (Q12, Q13, Q14, Q15).
No results...
Blowing in the pcb the voltage drop consistently and the meter shows this change in GR moving the needle towars -20dB of GR.
Without blowing, moving the release pot to "slow" the voltage drop and the meter in GR shows this drop of about 5-10dB and sometimes 20dB (full scale drop).

Any idea?
Has anyone ever had this problem?
Otherwise I'll replace the main pcb with a new one...

Thanks,
A.

 

[mats-odm]

Ok  I simply had the switches in the wrong holes.  And I think the attack is working but I really can't tell much.  How do you know if the attack is working?  Is it a dramatic thing?  Also,  after a while of being on I get intermitent noise and low frequency pops;/crackling,  kinda sounds like a dirty pot turning.  If I move the unit it seems to go away a bit but not consistantly.  I checked the voltage regulator heatsink and, man,  it was hot!  I know this is not good.  It supposed to be hot but not to a temperature where you can't keep you finger on it,  right? I am thinking there is a connection between the voltage regulator getting hot after time and this noise.    I am testing out to see.

Do you have an decent size heat-sink attached to the regulator?
Mine would get quite hot and even shut down if I run it without additional heat sink (I used a 2x1 inch piece of aluminium plate 0.5 mm thick).

 

[mats-odm]

I noticed a strange thing and maybe it could help to solve the problem: blowing in the pcb (both in the component side and in the traces side I see the needle of the meter moving in GR... do the same drop that I see moving to SHORT RELEASE the pot.
I tried to blow in the working channel and nothing changed...

Any idea?

Thanks,
A.

I've repeated this "blowing" test: blowing in the pcb I've a voltage drop in the Gate of the 2 FETs...
I changed all the wirings, the FH333 again, the capacitors in the GR CONTROL AMP and the 4 transistors (Q12, Q13, Q14, Q15).
No results...
Blowing in the pcb the voltage drop consistently and the meter shows this change in GR moving the needle towars -20dB of GR.
Without blowing, moving the release pot to "slow" the voltage drop and the meter in GR shows this drop of about 5-10dB and sometimes 20dB (full scale drop).

Any idea?
Has anyone ever had this problem?
Otherwise I'll replace the main pcb with a new one...

Thanks,
A.

Do you have your FETs socketed?
I read somewhere else about this "blow test", in that case it turned out to be caused by dirt/contamination in the sockets causing problems (I think it caused capacitance in between the pins and the socket) - problem went away by soldering in the FETs.

Or maybe it could have to do with cooling, but I don't think the FETs should be running hot at all...