61

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

« Last post by MRMNW on January 07, 2026, 11:49:28 AM »

pictures:

62

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

« Last post by MRMNW on January 07, 2026, 11:42:32 AM »

Yes, sorry V- = -16.40

I've triple checked all diodes, BRs and polar caps are correct. Not seeing any solder bridges or forgotten joints - reflowed all the joints too.
I have R52 as 5K1 in the parts list, do you mean R41 and R42?
R41 and R42 both read 1.2 ohm.
I've given it a good clean too with Isopropyl alcohol.

I'm still getting the same results.

Trying to add pictures but the spam filter won't allow me to embed them or post a link.

Thanks

63

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

64

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.

65

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.

66

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.

67

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

68

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.

69

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

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

70

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.