All things G1176 - the new "repost" thread.

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Still haven't figured out why my VU meter only works in GR and not +4?
One channel gain wise looks close but the other is way too distorted.
Anyone got any suggestions please?
It's seems to be wired correctly to the transformer and I get output on both and signal to VU meter, if the phase was out would it not appear in the VU meter on +4?
I'm totally foxed!!!!

Regards

Spenc.
 
All sets up fine now, wire off on the attack control, could change txfs for some sowters and will need to change psu txf for a toroidal as this one is a little noisy. other than that works and sounds great!!!

regards

Spence.
 
HELP. I checked all voltages in the GR control amp and line-amp section and they are all on-point but there is no compression.
Checked bypass knob and it's working correct (ground when bypassed, 40k resistance when live).  Signal passes through nice with low noise.  Meter works.  Tracking pot works but zero adj does not.
Any advice is greatly appreciated.
 
has anyone done high-pass and/or tilt on the sidechain for 1176? i'm building a pair of (phat phet) and would quite like to at least include a high pass on the SC; wondering if it could be as simple as a capacitor and resistor in the path, or would there be more to it than that?
 
Spencerleehorton said:
check connection to attack control maybe, resolder, i had the no compression thing and it looked like connection to my attack control on the pcb was ok but resoldered and worked.
Thanks.  I checked it out and everything's ok there.  Going to replace Q bias and 0adj w/ 5k trimmers as I'm falling about 5db short of being able to reach 0 on the meter.  Maybe it has something to do with the lack of compression though I think something else is still off.  Just puzzling that the voltages check ok...
 
Hello good people! Today I finally finished my G1176 project. I am very happy with results.

Thank you Jakob and Mnats for making this possible!!!

Here are some pictures.






 
gyraf said:
Beautiful faceplate!

Jakob E.

Thank you Jakob so much! Your compliments means a lot. I just tried to make something different.  :)

This is 1,2 mm wood (Oak) veneer sheet glued on 3 mm aluminum plate. Everything is made by hand except laser engraving.

Greetings
Mihailo
 
OK people, after few days of non-stop recording I noticed some problems, similar on both channels. There is some noise (buzz, something magnetic) which disappears when output pot is on certain point, around 1 pm. :) Everything below or above is noisy. Good thing is that 1 pm position gives perfect signal to my AD converter, but still, I would like to solve this problem.

Somebody know what is happening?

Thanks in advance
Mihailo
 
Hello!  A couple of years ago I got a few unfinished compressors... And still can't understand... One of the problems is the UV-meter... As I understand it requires an additional amplifier... Instead I connected the oscilloscope... When I turn the "Q bias", the signal is increasing, there is no voltage drop... No compression... If I am applying 0.7 Volt to the input, then the "Q bias" turn to minimum (then part of the Release pin go to ground), then as in the manual turn INPUT and OUTPUT, so that on the output meter was 0.8-0.9 V...... If I start to rotate the "Q bias" signal is only growing...
 

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It must be like that, but how to work meter i dont understand...
chuk_1_sm.jpg
I turned on the meter using the diode... But if I submit directly on the meter 0 dB (0,77) from the generator, it shows - 10dB...
 
Yeah! :eek: I solved the problem! The ratio switch was broken and the signal not went to pin 22... Now i must understand - Can I use that inclusion of meter (through the diode)... Its correct? And how to set a compressor with an oscilloscope and generator by measuring voltages... It is now fully working, all switches, compress as it should... But I would like to configure it correctly... I did not understand what the initial position of the BIAS... In video on youtube from the resulting minimal gain... I set up opposite from the high resulting gain...

And what about VU meter. How must it work? If I take alone UV meter with diode bridge without resistors and conect to 0  db generator,  What should it show? 0 db?

My transformer is 1:1 it means my meter must show 0 dB if signal 0.775 V?
 
Hey folks.

I have this problem on just one of my 1176 builds (the MNATS RevJ board with IC input stage).
Basically input level is a long way off on this one. (too high)

I've built a few but this is the first time I experienced this issue.
I've triple checked in case I used any different components or wiring from the last one I built (working fine) to this one, but I can't find the problem).. 

Where usually I would have the input knob at say "24" (top centre) on my other unit, on this problem unit I get the same level coming in dialled right back down to "48" (ie. approx. 7 o'clock kinda position, almost off).

I've seen this problem mentioned quite a few times in relation to this build (mostly circa 2006/2007) and a few threads suggesting some thins to look at, but nothing really conclusive..

eg.  this ref thread:
http://groupdiy.com/index.php?topic=14234

Everything else on my units are working the same in terms of compression amount and threshold operating point, but I have to have the problem unit dialled way back down at the input to get that same operating level. 
I feel like I'm possibly hearing a bit of additional background noise which may be accompanying this too, but not sure at this point.

From what I have deduced across these various posts, it's looking like the change of R1A in the IC input stage (from 10k ohms to 3.7k ohms) is probably the most likely to sort out this issue on my unit, but wanted to ask if anyone worked out any other things that I really ought to check first?

Thanks!
Evan
 
UPDATE:  Tried swapping R1A to 3.7k ohms, to decrease input level.
I think it "helped" a bit, but not that much.  I suspect it's not the best way to properly fix my issue here.
I guess I could try an even lower value, say, 1.5k ohms .. but i suspect increased background noise will become more of a problem.
 
Did you perform any measurements for the gain of each stage?
This should be part of the final test after assembly, so you know each section is performing as it is supposed to.
With gain-reduction switched off, the first amplifier stage should be about 26dB gain, and the line driver amplifier about 10dB gain.
More post-build troubleshooting info here:
https://axtsystems.com/joomla31/index.php/projects/11-cat-1176ln-audio-compressor/15-art-1176ln-troubleshooting

- Geoff
 
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