71

Discussions about the products / MOVED: Modification HPF cp5173

« Last post by JPK 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

72

CP5176 FET compressor / Re: Modification HPF cp5173

« Last post by JPK on January 07, 2026, 10:18:21 AM »

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

73

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

« Last post by JPK 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.

74

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

« Last post by MRMNW on January 06, 2026, 04:41:02 PM »

Thank you. Including the VCAs?

I'm now getting 

V+ 4.59
V- 16.40

+12: 3.55
-12: .682

with no IC's in their sockets.

75

CP5176 FET compressor / Modification HPF cp5173

« Last post by PMswing on January 06, 2026, 04:34:27 PM »

Bonjour, est il possible de modifier (simplement) le HPF du cp5173 en le faisant passer de 80Hz à 160hz ?

Merci

76

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

« Last post by JPK 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.

77

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

« Last post by JPK on January 06, 2026, 04:11:47 PM »

78

CP4500 Stereo Bus Compressor / Bad power voltages and reversed THAT1246

« Last post by MRMNW on January 06, 2026, 02:12:11 PM »

Hi,
I was getting bad readings in the first stage of the setup guide:


V+: .890
V-: 15.67

-12: .711
+12: .174

I checked everything over and realised the THAT1246 was in upside down.

I've since replaced the 1246 but it's the same - so I'm guessing something else has blown.

Not sure where to look,
Any help much appreciated.

79

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

« Last post by CGMix on January 05, 2026, 06:27:18 PM »

Well damn, that was it. Transformer was upside down…

80

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

« Last post by JPK 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