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CP5176 FET compressor / Re: No sound CP5176

« Last post by Stam on January 21, 2026, 07:55:25 PM »

Hi again!

I found a bad solder joint on the transformer T1 and resolder it. The connectors CN3a and CN3b are fine and solder joints on P1 also. Now there are signal coming through the compressor. But the signal is weak and lack all bass. When I send a 1khz sine 1VAC to the compressor I get only 0.11 VAC in the pot P1 top pin. With the P1 set max I can also read 0.11 VAC on TP1. I also did the checking Nr.4 again. This time there was I very weak signal AC coming through on TP3 and also a very weak DC level on JMP1. All other test was okey like it were before. I tested the compressor with the GR installed with the jumper on pin 1 and 2 an it seems as it kind of works. But the signal is lacking all bass.

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Discussions about the products / MOVED: EQ 250 setup question

« Last post by JPK on January 21, 2026, 06:16:01 PM »

This topic has been moved to EQ250 stereo equalizer.

https://www.soundskulptor.com/forum/index.php?topic=7394.0

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EQ250 stereo equalizer / Re: EQ 250 setup question

« Last post by JPK on January 21, 2026, 06:13:13 PM »

You can use a plugin in your DAW that generates a variable frequency sine wave (there are several free plugins available like tonegenerator) and adjust the frequency for the maximum output signal.

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EQ250 stereo equalizer / EQ 250 setup question

« Last post by TheWoodman on January 21, 2026, 03:48:27 PM »

Hi, I want to build a 250 stereo EQ and I wonder how to test the left / right balance. The setup manual says: Do the test with the frequency adjustment potentiometer in the middle of the band, at about 12 o’clock. Measure the central frequencies of the two channels. you get fmin and fmax.

My question is: how to measure this? Do I send an audio signal through the unit and turn (for example) the mid band volume up? And then use a frequency analyzer on the computer and look for 'bump' differences in both channels? If I use an audio signal, what kind (white, sine etc)? So, any tips how to do this measurement?

I understand the part about adding caps when channels don't match. My question is how to measure wether they match or not.

75

CP5176 FET compressor / Re: No sound CP5176

« Last post by JPK on January 21, 2026, 11:14:57 AM »

I have put a 1VAC sine 1 Khz signal to the input of the compressor and I don´t get any VAC reading on TP1
Check the solder joints on transformer T1, connectors CN3a and CN3b, potentiometer P1.

With a signal at the input, check that you get an AC volts reading on pot P1 top pin, against 0V, then on TP1 with P1 set at max.

76

CP5176 FET compressor / Re: No sound CP5176

« Last post by Stam on January 20, 2026, 01:33:47 PM »

Hi!

Nr 3 on the checklist:

I have put a 1VAC sine 1 Khz signal to the input of the compressor and I don´t get any VAC reading on TP1, Tp2 and L1.

Nr 4:

I am not a skilled electrician and did not understand input sine 100hz at 100mVAC? Can’t even get that low signal from the software generator so did send a 100Hz at 1VAC instead. Maybe you can teach me there …

Ac level on TP3:
My multimeter read 0.04 VAC on every ratio.

DC level on PT4:
All value where correct on all ratio.

DC level on JMP1 pin 1:
Did not get any reading on any ratio

DC level on TP6:
Did get -2,7 VDC so it seems okey.

DC level on TP5 with jumpers JMP1 on 2-3 and 4-5:
 Was correct, I did get exactly 0.32 VDC

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MU524 Vari-Mu Tube Compressor / Re: STEP 6 OUT 1Vac

« Last post by JPK on January 20, 2026, 08:56:11 AM »

D'après les photos envoyées, sur le 1er MU524, les trimmers ne sont pas à la bonne place:
TR1 5k au lieu de 2k
TR2 5k au lieu de 1k
TR3 1k au lieu de 5k
TR4 2k au lieu de 5k

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MU524 Vari-Mu Tube Compressor / Re: STEP 6 OUT 1Vac

« Last post by FX on January 19, 2026, 06:00:22 PM »

IDEM SANS U4

R3=R4=2185 OHM
R5=2225
R6=R7=10K
R8=469

79

CP5176 FET compressor / Re: No sound CP5176

« Last post by JPK on January 19, 2026, 04:13:23 PM »

Every value was right except D: that should be - 0.2 V, and I did get - 0.133 V.
This is probably OK.

You must try to follow the signal as mentioned here.
It will tell you where the signal chain is broken.

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MU524 Vari-Mu Tube Compressor / Re: STEP 6 OUT 1Vac

« Last post by JPK on January 19, 2026, 03:35:34 PM »

TP1=41,4 VDC
TP2= 40 VDC
Est-ce le même résultat en retirant U4 ?
Vérifier les valeurs et soudures de R3...R8.