1176 "Ratio 4:1" problem

[ForthMonkey]

I' built my own 1176 but i have problem about Ratio.I'm getting variable signal because of Ratio.Lowest signal with 4 and highest signal with 20.What is problem?

I fixed this problem.

Now another problem...Ratio 4 sounds like not compress.I'm researching forum but can't find,yet.Any idea?

Thanks.

 

[ForthMonkey]

8:1,12:1 and 20:1 compressing but 4:1 not.Can't find problem.About bias adjustment?

 

[gswan]

Have you measured the compression ratio curves to see what they really are?
Have you performed proper tests on the unit to confirm correct operation?
Or are you just putting signal through it and thinking it sounds ok or not?

Perform the tests and measurements and come back with the numbers to see if there is a problem.
Here are some hints.
http://axtsystems.com/joomla31/index.php/projects/11-cat-1176ln-audio-compressor/13-art-1176ln-compression-ratios
http://axtsystems.com/joomla31/index.php/projects/11-cat-1176ln-audio-compressor/15-art-1176ln-troubleshooting

 

[ForthMonkey]

Thanks for reply.

I didn't measure anything.Just trying to hear compression with only signal.With 4:1 no compression.

But first of all i just measured psu voltage before sending this reply,my positive voltage around 22V.Negative is -10V.I believe it's serious voltage difference between 22V and 30V.Right?

I will try another trafo.I guess my trafo is faulty.

 

[gswan]

Fix your PSU first . Is the regulator getting warm? Check the resistors around the 30V rail regulator too.
Then you need to perform the tests and measurements to ensure that everything is operating as expected.
Putting audio signal through it and listening is not good enough.
When you have confirmed that everything passed teh tests, then you can try measuring teh actual ratios and confirm where the threshold is and what the comression ratio actually is.

 

[gyraf]

..we have a very-very long help thread for the G1176 already...

Jakob E.

 

[ForthMonkey]

Fix your PSU first . Is the regulator getting warm? Check the resistors around the 30V rail regulator too.
Then you need to perform the tests and measurements to ensure that everything is operating as expected.
Putting audio signal through it and listening is not good enough.
When you have confirmed that everything passed teh tests, then you can try measuring teh actual ratios and confirm where the threshold is and what the comression ratio actually is.

Thanks.I will change my trafo to get voltage for 1176.There is nothing get warm.Everything is stable.I believe it's about weak trafo.I used 18V trafo and got 22V after power supply.I guess,with 24V trafo,i will get correct voltage.When i get trafo,i will try it with measurements.

By the way i tried Ltspice to simulate circuit before build it.I tried 22V psu in Ltspice and i got result like real world.Nothing stable with ratios.

..we have a very-very long help thread for the G1176 already...

Jakob E.

Sorry but i researched and can't find anything about specific ratio problem.Mosty people had problem about weak compression with 20:1 ratio but mine is different.No compression with 4:1.

And i found lots of in in G1179 thread.After this issue,i will re-read all thread to fix my problem.

Sorry again.

 

[gswan]

Thanks.I will change my trafo to get voltage for 1176.There is nothing get warm.Everything is stable.I believe it's about weak trafo.I used 18V trafo and got 22V after power supply.I guess,with 24V trafo,i will get correct voltage.When i get trafo,i will try it with measurements.

Well it is usual practise to use the correct parts if you want it to work correctly.
An 18V transformer secondary will only give you about 22V regulated DC. A 24V transformer will result in around 30V regulated DC. Multiply the transformer secondary voltage by 1.4 and subtract 2-3V for the regulator.

Sorry but i researched and can't find anything about specific ratio problem.Mosty people had problem about weak compression with 20:1 ratio but mine is different.No compression with 4:1.

Until you actually perform all the tests and measurements, including measuring the ratio curves, you really don;t know what is going on. Verification is an important step in the built and test process.