1

CP5176 FET compressor / Re: CP 5176 no output

« on: December 05, 2023, 12:12:23 AM »

replaced c31 and c32 but still no difference. i still measure the same voltages or i can say better almost nothing.
R56 and R57 are measured around 5,9 ohms inside so that should be good.
I'm no pro, but it looks like I dont have any voltage in the beginning of the scheme.

could not find a short or open circuit and don't know how search for one aswell.

2

CP5176 FET compressor / Re: CP 5176 no output

« on: December 02, 2023, 09:11:32 PM »

I took them out, one of the two is defect. no uprising in ohms when measuring with DMM it stays very low.
I will get another one this monday. 

Does this short have effect on other components?

3

CP5176 FET compressor / Re: CP 5176 no output

« on: December 02, 2023, 03:56:11 PM »

Forgot to mention aswell, i think i saw some smoke coming out of c31 or c32 when trying to reach 0V to V+ / V- with the DMM. Could this be the problem?

4

CP5176 FET compressor / Re: CP 5176 no output

« on: December 02, 2023, 01:04:11 PM »

I forgot to mention. I checked without the DOA aswell

5

CP5176 FET compressor / CP 5176 no output

« on: December 02, 2023, 02:48:09 AM »

I was done with assembling the cp5176 I had a good feeling about it, but unfortunately it didn't work as excpected.

I followed the setup guide

0V with V+ was 15.61
0V with V- was -15.61

0V with TP 7 was -5.41

i got no output when measured the 1khz sine through the XLR output, i thought i was doing something wrong.
Eventually i plugged in my MP573 and set all the MP573 settings low. On the XLR ouput i saw that the voltage in MVAC  was coming through like it supposed to be... When turning down DAW-output level the AC voltage turned down aswell.

I checked  Topic: In case your CP5176 doesn't work as expected

I've got no forgotten solder, i reflowed every joint, no reversed components or flipped ic's and everything is trimmed enough so i doesn't touch the board or ground.

I did measurement DC voltage A till G:
A=   0.0
B= -0.39
C=  0.0
D=  0.0
E=  0.0
F= -0.39
G=  0.0

ofcourse this is not how it should be.

Maybe a defective component?
Is there a short early in the circuit?
What to test?

PS. the DIY package was incomplete..  i miss one of the control knobs (on the outside of the module for:  attack, relase, ratio, input, output) i received 4 from the 5.

6

MP573 Microphone preamplifier / Re: MP573 No input after assembling

« on: October 13, 2023, 10:49:43 PM »

excuses me i used the 20V scale so nothing happened on the MM.. 
The left side of R42 says 23.9V
Both sides of R24 with OV = -14.9V (- on R24 L/R and + on OV)
TP2 against OV is 8.98V (- on TP2 and + on OV)

7

MP573 Microphone preamplifier / Re: MP573 No input after assembling

« on: October 13, 2023, 02:23:29 PM »

The values are as described.
The directions are right.
and the solder joints are checked like 50 times and reheated a couple of times to make sure the solder flows deep enough.

with output transformer disconected 
G- jumps around between 0.00 and at max 0.06 that does not look good.
H=0.33
I=0.33
J=0.35
Left side of R42 stays at 1

what does this mean?

8

MP573 Microphone preamplifier / Re: MP573 No input after assembling

« on: October 12, 2023, 11:14:40 PM »

That was a little mistake the '-' should have been a '='. It is positive. Any suggestions about what else i can do?

9

MP573 Microphone preamplifier / Re: MP573 No input after assembling

« on: October 12, 2023, 02:42:38 AM »

I checked the values as much as i know how to do, nothing strange.
I resoldered al the  old points again, a few times the TP2 with V+ dropped till 13.8V.
After trying a lot I got the main voltage on 23.9V again.
But the measurepoints after point "G" still get the same volt values.

No shorts at the transformer and the ohms were all correct.

Measurements:
Yellow-Orange : 7.8 ohms,
Red-Brown : 6.6 ohms,
Blue-Green : 21.3 ohms,
Violet-Black : 21.1 ohms

I do get some output now. The mic is coming through and the mp573 knobs are working.
Unfortunately it does not amp enough.

My audient has +60db built-in pre amp.
The MP573 has +70db (60 + 10) but does not get half as loud as my audient.

10

MP573 Microphone preamplifier / Re: MP573 No input after assembling

« on: October 10, 2023, 12:42:34 AM »

I soldered about every solder again to make sure everyrhing was good, even though i did not see something strange.
I plugged it into my power supply and for 5 seconds my mic input came through.
I was so happy that i immediatly took it out and screw everything together, to eventually find out: no input again..

I really don't know whats wrong. I measured again and again, but  after point G, i'm measuring way different then it should (I guess).

A=2.62
B=4.11
c=22.0
D=12.81
E=2.02
F=12.20
G= 0.82
H= 1.71
I= 1.10
J= 1.80
K=23.10
L=1.31


hope you can help me out.

11

MP573 Microphone preamplifier / MP573 No input after assembling

« on: October 09, 2023, 05:00:24 PM »

I recently finished my MP573 unfortunately without succes.

After testing (TP2 with V+) I measured 23.9V (on 200V scale)

The same 23.9V was also measured with output transformer connected.

I thought it would be close enough to test the module, unfortunately no input signal.

When I went through the troubleshoot checklist i measured the points
A till L

The points were all good except the following points:
D= 12.83V (within 10% range but still)
H=1.71V
I= couldn't measure within power supply
J =couldn't measure within power supply
K= don't know how to measure
L=0.0

What can i do to fix it?
Does this mean i have some weak or missed solders?
Does this mean some components are not placed correctly?

I hope you can help me out!