71

CP5176 FET compressor / Re: No sound CP5176

« Last post by JPK on January 22, 2026, 03:20:25 PM »

I suppose that you mean the fingers on CN3a?
No. I mean the card edge connector at the back of the card with golden fingers (connecting to the lunchbox).

And without any power I suppose?
Correct

72

CP5176 FET compressor / Re: No sound CP5176

« Last post by Stam on January 22, 2026, 02:40:55 PM »

Hi!

Does this voltage vary, from 0 to max) with the P1 rotation?
 Yes. But still just 0.11 VAC at maximum P1 on TP1. On L1 I get from 0 VAC on P1 at minimum and 10.8 VAC when P1 at maximum. (1Khz 1VAC)
 
The resistance between side pins of P1 read 1.69 K when front PCB is attached to main PCB.
 
I´m really confused when it comes to check the input transformer coils resistance …
I suppose that you mean the fingers on CN3a? Shall the front PCB be attached? And without any power I suppose? When I see the main PCB so I can read text “SOUNDSKULPTOR” on It. I got one upper row of 10 solder joints and one row under with 10 solder joints on CN3a. If the upper row is 1-10, and the lower row is 11-20. Between which numbers shall I test the resistance?  
 
I have balanced cable in and out. Checked with another 500 series module on the XT500 extender and it sounds fine.
 

73

EQ250 stereo equalizer / Re: EQ 250 setup question

« Last post by JPK on January 22, 2026, 11:55:24 AM »

Yes correct.

74

CP5176 FET compressor / Re: No sound CP5176

« Last post by JPK on January 22, 2026, 11:54:08 AM »

With the P1 set max I can also read 0.11 VAC on TP1
Does this voltage vary, from 0 to max) with the P1 rotation?

Check the input transformer coils resistance:
Between edge connector fingers 8 & 10 (counting down, including absent fingers): 2k
Between side pins of P1: 1k6

But the signal is lacking all bass
Are you sure you are connecting the output with a balanced cable? This lack of bass happens when only one phase is connected.

75

EQ250 stereo equalizer / Re: EQ 250 setup question

« Last post by TheWoodman on January 22, 2026, 07:33:41 AM »

Thanks for your rapid response!

Just checking if I understand this correctly, is this the method?
-         I want to check the mid frequency band of the EQ250 (central frequency for this band = approx 540 Hz)
-         I send a 540 Hz tone from a tone generator (I use Tolvan Tone) from computer to both inputs of the EQ250
-         I send the outputs back to the computer to measure the levels (in db or lufs)
-         I sweep the signal from the tone generator up and down (between 500 – 600 Hz roughly) and check the output levels for both channels
-         I make a note of the highest output level for each channel to get fmin and fmax
-         Now I can calculate k

76

CP5176 FET compressor / Re: No sound CP5176

« Last post by Stam on January 21, 2026, 07:55:25 PM »

Hi again!

I found a bad solder joint on the transformer T1 and resolder it. The connectors CN3a and CN3b are fine and solder joints on P1 also. Now there are signal coming through the compressor. But the signal is weak and lack all bass. When I send a 1khz sine 1VAC to the compressor I get only 0.11 VAC in the pot P1 top pin. With the P1 set max I can also read 0.11 VAC on TP1. I also did the checking Nr.4 again. This time there was I very weak signal AC coming through on TP3 and also a very weak DC level on JMP1. All other test was okey like it were before. I tested the compressor with the GR installed with the jumper on pin 1 and 2 an it seems as it kind of works. But the signal is lacking all bass.

77

Discussions about the products / MOVED: EQ 250 setup question

« Last post by JPK on January 21, 2026, 06:16:01 PM »

This topic has been moved to EQ250 stereo equalizer.

https://www.soundskulptor.com/forum/index.php?topic=7394.0

78

EQ250 stereo equalizer / Re: EQ 250 setup question

« Last post by JPK on January 21, 2026, 06:13:13 PM »

You can use a plugin in your DAW that generates a variable frequency sine wave (there are several free plugins available like tonegenerator) and adjust the frequency for the maximum output signal.

79

EQ250 stereo equalizer / EQ 250 setup question

« Last post by TheWoodman on January 21, 2026, 03:48:27 PM »

Hi, I want to build a 250 stereo EQ and I wonder how to test the left / right balance. The setup manual says: Do the test with the frequency adjustment potentiometer in the middle of the band, at about 12 o’clock. Measure the central frequencies of the two channels. you get fmin and fmax.

My question is: how to measure this? Do I send an audio signal through the unit and turn (for example) the mid band volume up? And then use a frequency analyzer on the computer and look for 'bump' differences in both channels? If I use an audio signal, what kind (white, sine etc)? So, any tips how to do this measurement?

I understand the part about adding caps when channels don't match. My question is how to measure wether they match or not.

80

CP5176 FET compressor / Re: No sound CP5176

« Last post by JPK on January 21, 2026, 11:14:57 AM »

I have put a 1VAC sine 1 Khz signal to the input of the compressor and I don´t get any VAC reading on TP1
Check the solder joints on transformer T1, connectors CN3a and CN3b, potentiometer P1.

With a signal at the input, check that you get an AC volts reading on pot P1 top pin, against 0V, then on TP1 with P1 set at max.