1

MP566 Tube microphone preamplifier / Re: LED Goes Green, But Not Red

« on: December 06, 2023, 04:19:26 PM »

The issue seems to be between R45, R46, D11 or the LED.
Check the value, direction and solder joints.
Try shorting R46 with a wire. If the RED doesn't come, then the LED may be damaged.

2

CP4500 Stereo Bus Compressor / Re: Channels keep becoming unbalanced

« on: December 06, 2023, 04:10:25 PM »

@Dolbah
Do you get TP1=1.5VAC with 3VAC at the input?
Are the VCA's socketed or SMC?

3

CP4500 Stereo Bus Compressor / Re: Channels keep becoming unbalanced

« on: December 06, 2023, 04:06:19 PM »

@tvesneski
It could be a damaged T3 (Mouser 3266X-1-201LF)
Or an intermitent solder joint. Reflow any bad looking solder joints.

4

CP5176 FET compressor / Re: CP 5176 no output

« on: December 06, 2023, 03:42:39 PM »

The rail voltages supply the pream via R16 (for +) and R17 (for -).
Check the solder joints on these.

5

CP5176 FET compressor / Re: No audio passing on my 5176

« on: December 04, 2023, 08:04:16 AM »

Try installing a working meter board from another unit to know which board the issue comes from.

6

MP566 Tube microphone preamplifier / Re: LED Goes Green, But Not Red

« on: December 03, 2023, 08:56:53 AM »

With a strong input signal, when the LED should be full red, can you report the DC voltages on every pin of U3, against 0V?


(same principle for 14 pins)

7

CP5176 FET compressor / Re: CP 5176 no output

« on: December 03, 2023, 08:43:58 AM »

Does this short have effect on other components?
Only R56 and R57 could have been damaged.
Check they are not open circuit (no need to de-solder).

8

MU524 Vari-Mu Tube Compressor / Re: Is a THAT1246 a Suitable Substitute for OPA2134?

« on: December 03, 2023, 08:32:59 AM »

Sorry, this is a mistake.
We will send you a OPA2134 tomorrow.

9

MP566 Tube microphone preamplifier / Re: LED Goes Green, But Not Red

« on: December 02, 2023, 10:41:23 AM »

Something wrong around U3, R36...R46, D5...D11.
Check components value, direction and solder joints.

10

CP5176 FET compressor / Re: CP 5176 no output

« on: December 02, 2023, 10:39:14 AM »

Remove the DOA and check the voltages again in case the DOA is the issue.

11

CP5176 FET compressor / Re: Siamesed pads on Front PCB - is this correct?

« on: December 01, 2023, 08:45:40 AM »

The 2 pads are connected: Normal

12

First Aid / Re: MP566 - Missing DPDT Switches

« on: November 30, 2023, 08:52:08 AM »

We will send the switch immediately. I am sorry for the inconvenience.

13

SK25/SK99 Discrete Op-Amp / Re: SK-25 half as loud as it should be

« on: November 29, 2023, 05:50:15 PM »

Yes the fault is in the DOA.
Are you sure about your connections between the base and the vertical PCB's?

14

CP5176 FET compressor / Re: No audio passing on my 5176

« on: November 29, 2023, 05:45:39 PM »

Do you hear compression on the units with no metering.
Check that the Input and Out potentiometer pins do not touch the meter board (pins must be cut very short on the meter board).
Other than that, I can only think of a bad connection somewhere.

15

CP4500 Stereo Bus Compressor / Re: Reading 0v on -V (-16v indicator blinking on lunchbox)

« on: November 28, 2023, 05:11:51 PM »

16

SK25/SK99 Discrete Op-Amp / Re: SK-25 half as loud as it should be

« on: November 28, 2023, 05:10:28 PM »

Did you check these?
What values do you get for R2, R3? 
50 ohms would be correct.
Does the DOA sound OK outside the output level? The DOA gain is set by R19, R20 on the compressor.

17

CP4500 Stereo Bus Compressor / Re: Reading 0v on -V (-16v indicator blinking on lunchbox)

« on: November 28, 2023, 05:01:03 PM »

The 4 pins 7, 8, 9, 10 are all connected together to the ground. This is normal.
The V- issue is somethin different.
Do you have the same issue if the meter is disconnected?

18

CP5176 FET compressor / Re: No audio passing on my 5176

« on: November 27, 2023, 09:38:15 AM »

Do you get the correct DC voltages now in points A to G?
With 100mVAC at the input, do you get 
- 100mVAC at the output in bypass?
- 73mVAC on TP1 against 0V?
- 1.4VAC on TP2 against 0V?
- 8VAC on the top of L1 against 0V?

19

EQP501 Passive Equalizer / Re: PCB missing metalized pads?

« on: November 26, 2023, 09:43:48 AM »

This is not a pad but a via which connects top to bottom tracks.
No component should go there.

20

501 Single Host / Re: unable to entirely close switcher shield

« on: November 14, 2023, 06:33:32 PM »

No real problem because electrical continuity is provided by the connectors.

21

MC624 Monitor Controller / Re: REM624 Mono & Diff Not Functioning

« on: November 11, 2023, 12:21:48 PM »

It is because your microcontroller firmware is not up to date.
Please contact me here.

22

MP573 Microphone preamplifier / Re: Clicks and pops after couple days then failure

« on: November 11, 2023, 12:20:10 PM »

K being the only wrong value, I would check the solder joints on the connector CN2 (output transformer connection), both on the socket and wires to transformer.
What DC voltage do you get directly on the metal tab (collector) of Q6, against TP2?

23

CP4500 Stereo Bus Compressor / Re: R42 on PCB A immediately smoking after powering up

« on: November 07, 2023, 03:22:02 PM »

Please contact me here for a replacement.

24

CP4500 Stereo Bus Compressor / Re: R42 on PCB A immediately smoking after powering up

« on: November 04, 2023, 11:25:28 AM »

Unplug all IC's,
Disconnect the meter connector CN4,
Disconnect the front PCB,
Power on

If still the same, look for solder bridges.
If not, step back on at a time, front PCB, meter, ...

25

MU524 Vari-Mu Tube Compressor / Re: My Problems begin at step 6 of setup

« on: October 25, 2023, 09:28:30 AM »

Check the value of these components, by colour code or marking:
Pot P1 = 10kB
Pot P2 = 2k2C
trimmer TR1 = 2k
trimmer TR2 = 1k
R5 = 10k