1

MP566 Tube microphone preamplifier / Re: 5.66 Problems

« on: May 20, 2026, 05:57:34 PM »

Thanks, what do you mean by sequenced?

It's one of your 501 Chassis, but does the same in my API lunchbox too.

2

MP566 Tube microphone preamplifier / Re: 5.66 Problems

« on: May 20, 2026, 01:56:41 PM »

I get 222v and -5v

3

MP566 Tube microphone preamplifier / 5.66 Problems

« on: May 18, 2026, 08:37:45 AM »

Hi, 
built this a month ago and it has worked fine,
Now when switching the chassis on it clicks on and off before eventually working after switching it off and on again.
There is also a very low and thin sound. I think it may have overheated. 
Any help much appreciated.
Thanks

4

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

« on: January 09, 2026, 06:51:03 PM »

All calibrated and working now, thanks JP

5

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

« on: January 09, 2026, 04:03:17 PM »

Bingo. Thank you. Another mistake! 

6

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

« on: January 08, 2026, 06:32:41 PM »

OK I'm up to step 8 on the setup guide. I have a reading of 0.5VAC on the DMM but the trimmer T4 isn't affecting the meter at all. Turned it a considerable amount in both directions. No movement at all. 

7

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

« on: January 08, 2026, 06:15:01 PM »

78L12 AND 79L12 were in the wrong place! 

Thanks for your patience and help. (I may be back once I get past the first stage of setup!)

8

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

« on: January 08, 2026, 01:23:11 PM »

Still getting the same readings when it's just PCB (A). 
R41 Doesn't seem to be getting hot. 
I've replaced all the 1N4004 diodes.
Still the same. 

9

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

« on: January 07, 2026, 11:49:28 AM »

pictures:

10

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

« 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

11

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

« 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.

12

CP4500 Stereo Bus Compressor / Bad power voltages and reversed THAT1246

« 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.

13

EQ573 Equaliser / Stereo Link

« on: June 05, 2025, 01:10:56 PM »

Is there any reasonable way to mod these in order to stereo link 2 of them?

14

EQ573 Equaliser / Re: Knob issue

« on: May 26, 2025, 06:56:23 PM »

That fixed it, thanks!

15

EQ573 Equaliser / Knob issue

« on: May 24, 2025, 11:13:38 AM »

Hi
I’m having an issue where the frequency dial often moves the gain knob with it, is there any way to avoid this? Is this normal behaviour? 
Thanks