1

CP4500 Stereo Bus Compressor / Re: No output when engaged

« on: September 19, 2024, 10:06:16 AM »

2

CP4500 Stereo Bus Compressor / Re: No output when engaged

« on: September 17, 2024, 10:23:54 AM »

TP12 14.54V
Does the DC voltage on TP12 goes to 0V when turning the MIX pot CCW to 0?
Check value, direction and solder joints of U22, P3, R90...R94.

3

First Aid / Re: sk49 missing neoprene tubing and copper wire

« on: September 16, 2024, 11:10:34 AM »

Sorry for this.
We will send you the missing parts today.

4

CP4500 Stereo Bus Compressor / Re: No output when engaged

« on: September 14, 2024, 12:21:55 PM »

Do you have the jumper JMP1 inserted ?
Can you report the voltages you get from here?

5

CP4500 Stereo Bus Compressor / Re: Meter lights dont turn off when in bypass

« on: September 13, 2024, 03:16:22 PM »

This is normal. The meter light stays on when the lunchbox is on, independently from the bypass.

When in auto release, the needle creeps back to 0 veeeeeery slowly.
Check that capacitor C2 is in the correct direction.

6

EQ573 Equaliser / Re: 12-position switch has too many legs?... (Three pole switch, one pole on PCB)

« on: September 10, 2024, 10:13:43 AM »

am i right in the assumption that cutting any leg would have worked, but resulted in the wrong sequence of 
frequencies?
Absolutely right.

7

EQ573 Equaliser / Re: 12-position switch has too many legs?... (Three pole switch, one pole on PCB)

« on: September 09, 2024, 08:56:04 AM »

Sorry for the confusion.
You have to cut two pins, but not just any pins.
First make sure the switch is rotated all the way counter clockwise.
Then locate the stops which prevent the switch to rotate continuously (circled in blue in the picture).
The pin you want to keep is the one closest to the stops on the inner circle (circled in green).
Cut the 2 other pins on the inner circle (circled in red).

8

MU524 Vari-Mu Tube Compressor / Re: Light Hiss/Noise

« on: September 09, 2024, 08:16:38 AM »

Thank you for the update.
Did you try with a different lunchbox?
We are currently using API, Lindell, IGS lunchboxes without a noise problem.
We also work at strong line levels which helps.

9

CP554 Diode bridge compressor / Re: What is the correct way to stereo link two CP554 units?

« on: September 02, 2024, 06:09:06 PM »

10

MP573 Microphone preamplifier / Re: Short circuit check, brief readings.

« on: August 28, 2024, 06:33:26 PM »

Is it really dropping to 0, displaying a 0 or is it displaying an out of range sign like an L?
In the second case you are ok.

11

AB528 Microphone preamplifier / Re: Problème de gain sur AB528

« on: August 25, 2024, 06:15:41 PM »

12

AB528 Microphone preamplifier / Re: Problème de gain sur AB528

« on: August 23, 2024, 01:19:50 AM »

Est-ce que cette erreur explique les symptômes décrits
A 100%

et, surtout, cela a-t-il pu provoquer un endommagement quelconque ?
Non.

13

AB528 Microphone preamplifier / Re: Problème de gain sur AB528

« on: August 22, 2024, 08:18:30 PM »

You must start by checking the solder joints on SW3, R9...R14, J1a, J1b.
Next, you can check the DC voltages as shoxn here: https://www.soundskulptor.com/forum/index.php?topic=498.msg2966#msg2966

14

CP554 Diode bridge compressor / Re: What is the correct way to stereo link two CP554 units?

« on: August 21, 2024, 02:46:43 AM »

I have selected the 'stereo' button on both units.
Correct.
My inputs/outputs are 7 XLR in & out, and 9 XLR in & out.
Correct.

You also need to set the COMP BUS 8-9 switch to ON. This will link the 2 side chains together.

15

MU524 Vari-Mu Tube Compressor / Re: Different output levels

« on: August 21, 2024, 02:31:13 AM »

It will work with the 25k pots, with a smaller range in the max attenuation area. The 18k resistor won't change the result much so I wouldn't care.

16

MU524 Vari-Mu Tube Compressor / Re: Different output levels

« on: August 19, 2024, 06:52:45 PM »

The input pot difference could be caused by the tolerance on the pot resistance value (20%). You can check the resistance value of the pots between the 2 side pins, pot at max.

Regarding the 20VAC output it might be OK. Simply check that the input transformer is mounted in the correct orientation, label facing towards the back of the module.

17

MU524 Vari-Mu Tube Compressor / Re: MU524- output potentiometer voltage, meter adjustment, and ringing in audio

« on: August 18, 2024, 06:10:35 PM »

Actually this is fine. The 12VAC value mentionned in a previous post was for one single phase of the output. When measuring accross the two phases, you can reach 20V. Sorry for the confusion.

18

MP573 Microphone preamplifier / Re: Blown capacitor

« on: August 14, 2024, 06:21:37 PM »

Yes it happens. Electrolytic capacitors are the most fragile components, especially if their temperature is high.

19

MP573 Microphone preamplifier / Re: Blown capacitor

« on: August 12, 2024, 11:27:40 AM »

These voltages must be measured against TP2.
So they don't look so bad.
Can you redo these measurements relatively to TP2 from A to L ?

20

MP573 Microphone preamplifier / Re: Blown capacitor

« on: August 10, 2024, 06:00:30 PM »

Could be caused by a bad input?
No.

I would start by just replacing the cap which is the most likely to fail.
The other parts replacements are only if this doesn't work.

21

MP573 Microphone preamplifier / Re: Blown capacitor

« on: August 07, 2024, 12:17:17 PM »

TP2: 13.1
The minus voltage doesn't go through.
Check the diode D4 (DMM in diode mode), resistor R27 (ohmmeter), U1 and U2 (by replacing).

22

MP573 Microphone preamplifier / Re: Blown capacitor

« on: August 06, 2024, 03:52:53 PM »

The dead cap could be the symptom of something else.
Check the DC voltage on TP2 against the 0V pin. It should be -9VDC.
If OK, replace the cap and make a check of the other DC voltages: 

23

MP573 Microphone preamplifier / Re: MP573, Ripped up pad at R39, location of GND(V) ?

« on: August 06, 2024, 03:46:19 PM »

Should I still proceed with connecting the top of R39 to the right side of R37?
Not necessary as you've already restored the ground connection via R38.

will that affect the entire ground connection for other components connected to GND(V)
No. You are OK now. The ground connections are made via the ground plane on the top side of the PCB.

24

MP573 Microphone preamplifier / Re: MP573 problems with new build

« on: August 06, 2024, 03:37:50 PM »

25

MP573 Microphone preamplifier / Re: MP573, Ripped up pad at R39, location of GND(V) ?

« on: August 05, 2024, 05:54:17 PM »

I just wanted to confirm if connecting a wire between these two is indeed correct
Yes correct.
Be carefull this circuit uses 2 different grounds, separated by 9VDC.
The ground you want on R39 is the one connected to TP2, different from the 0V ground of the lunchbox.
The closest ground point from R39 top is R37 right.