1

CP5176 FET compressor / Re: No sound CP5176

« on: Today at 05:10:16 PM »

I am running short of ideas. 
Do you want to send it to us for a check? Contact me at jpk@soundskulptor.com

2

CP5176 FET compressor / Re: No sound CP5176

« on: Today at 09:47:41 AM »

The values are correct.
Check that the input transformer is inserted the right way around, with the markings facing upwards.
Check that the relay is inserted the right way around, with the white line down.
Check that the resistance between TP1 and ground goes from 0 to 1k6 when turning P1.

3

CP5176 FET compressor / Re: No sound CP5176

« on: January 22, 2026, 03:20:25 PM »

I suppose that you mean the fingers on CN3a?
No. I mean the card edge connector at the back of the card with golden fingers (connecting to the lunchbox).

And without any power I suppose?
Correct

4

EQ250 stereo equalizer / Re: EQ 250 setup question

« on: January 22, 2026, 11:55:24 AM »

Yes correct.

5

CP5176 FET compressor / Re: No sound CP5176

« on: January 22, 2026, 11:54:08 AM »

With the P1 set max I can also read 0.11 VAC on TP1
Does this voltage vary, from 0 to max) with the P1 rotation?

Check the input transformer coils resistance:
Between edge connector fingers 8 & 10 (counting down, including absent fingers): 2k
Between side pins of P1: 1k6

But the signal is lacking all bass
Are you sure you are connecting the output with a balanced cable? This lack of bass happens when only one phase is connected.

6

Discussions about the products / MOVED: EQ 250 setup question

« 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

7

EQ250 stereo equalizer / Re: EQ 250 setup question

« 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.

8

CP5176 FET compressor / Re: No sound CP5176

« 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.

9

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

« 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

10

CP5176 FET compressor / Re: No sound CP5176

« 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.

11

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

« 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.

12

MU524 Vari-Mu Tube Compressor / Re: MU524 is noisy

« on: January 19, 2026, 10:56:59 AM »

Check if any component is overheating, U2 in particular.

13

EQP501 Passive Equalizer / Re: Switch issue

« on: January 13, 2026, 03:19:40 PM »

14

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« on: January 10, 2026, 09:49:53 AM »

15

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« on: January 09, 2026, 03:25:25 PM »

This is because you have the wrong trimmer in T4. It should be a 5k (502), your photo shows a 200R (201).

16

CP5176 FET compressor / Re: Modification HPF cp5173

« on: January 09, 2026, 03:13:48 PM »

que représente la valeur R= 2x3900 ohms
R25 + R27

Qu'entendez-vous par "valeurs standard" ?
Ce sont les valeurs des composants du CP5176.

204Hz correspond au passe-haut du cp5173, ou au début de l'atténuation ?
C'est la fréquence du coupe bas pour laquelle l'atténuation est de -3dB, donc le début de l'atténuation.

80Hz est la fréquence aproximative pour laquelle l'insertion du passe-haut crée une variation de 6dB de la compression.

17

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« on: January 08, 2026, 05:59:28 PM »

Are the fingers on the back connector clean and making a good contact?
Check that you didn't break the vias between the top and bottom pads of the components you replaced.
Is U23 getting hot? This is the last active device connected to V+.
If true, remove it.

18

CP5176 FET compressor / Re: Modification HPF cp5173

« on: January 08, 2026, 12:16:10 PM »

R = 2 x 3900 = 7800 ohms
C en Farad
Avec les valeurs standard: 204Hz

19

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« on: January 08, 2026, 11:57:03 AM »

do you mean R41 and R42?
Yes, sorry.

Do you still get V+ at +4.59 when you only power the left PCB (A), without the front PCB being connected?
Check the diode D4.
Is R41 getting hot?

20

Discussions about the products / MOVED: Modification HPF cp5173

« on: January 07, 2026, 10:19:32 AM »

This topic has been moved to CP5176 FET compressor.

https://www.soundskulptor.com/forum/index.php?topic=7388.0

21

CP5176 FET compressor / Re: Modification HPF cp5173

« on: January 07, 2026, 10:18:21 AM »

Oui, en modifiant C24 de 100nF à 47nF.

22

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« on: January 07, 2026, 10:16:37 AM »

Including the VCAs?
Yes.

I'm now getting
V+ 4.59
V- 16.40



Do you mean V- equals minus 16.40V

Check that all the diodes are in the correct direction.
Check that all the diodes bridges BR1, BR2 are in the correct direction.
Check that all the electrolytic caps are in the correct direction.
Check that the 1R resistors R41, R52 are still at 1 ohm.
Look for solder bridges, forgotten solder joints, cold solder joints.

23

CP4500 Stereo Bus Compressor / Re: Bad power voltages and reversed THAT1246

« on: January 06, 2026, 04:19:31 PM »

Remove all IC's from their sockets and check again.
If V+ and V- are correct, put the integrated circuits back in place, one by one, checking the voltages each time.
This will show you which one has failed.

24

MU524 Vari-Mu Tube Compressor / Re: Initial AC voltage jump

« on: January 06, 2026, 04:11:47 PM »

25

MU524 Vari-Mu Tube Compressor / Re: Initial AC voltage jump

« on: January 05, 2026, 10:06:16 AM »

Is the label on the transformer facing towards the back of the module?
Check the input transformer coils resistance (in circuit with potentiometer IN on 10):
pin2-pin4 : 37ohms
pin3-pin5 : 37ohms
pin7-pin9 : 98ohms
pin8-pin10: 98ohms
pin7-pin10: 194ohms