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CP5176 FET compressor / No sound CP5176
« Last post by Stam on January 19, 2026, 12:09:15 PM » I have built the main PCB and the front PCB on the CP5176. I connected them and did the setup test. I connected to my 500 box with XT500. Pushed the red button-the green led lighted up. I connected the multimeter black probe to OV and the red probe to the V+. Perhaps I did something wrong and made some connection with something because it came smoke from the area where the red probe sat. Unfortunately (it was late at night) I moved the red prob to the V- test pin and did get another smoke from the big transformer area. I saw that the R57 was burned. I replaced R56 and R57. Started the process again. The green led light up, but it turned off after a while. I measured direct on the replaced resistor R56 volt and it was +16.03v in, and +0.04 v out. On the R57 was -16.12 in and -0.54 v out. They were broken again. I replaced them again and also replaced the two TL074CN Quad Op-Amp. Started up the compressor again. Now I did get the right measurement on V+, V- and on TP7. Everything seems okey so far.
I build the SK25 and put it in place and send the 1khz sinewave to the compressor. Turned the in and out potentiometer up. No signal passed through the compressor. I measured the L1 with DC and did get 0,057 V, and the SK25 became warm after some minutes. Can’t find any misplaced components on the SK25 or obviously bad joints, but something is wrong I suppose. I also did the measurement on the resistors A to G without the SK25 described in the forum: https://www.soundskulptor.com/forum/index.php?topic=402.0
Every value was right except D: that should be - 0.2 V, and I did get - 0.133 V.
I have also checked this: https://www.soundskulptor.com/forum/index.php?topic=9.0
Can’t find any problem so far. How Should I proceed?
I build the SK25 and put it in place and send the 1khz sinewave to the compressor. Turned the in and out potentiometer up. No signal passed through the compressor. I measured the L1 with DC and did get 0,057 V, and the SK25 became warm after some minutes. Can’t find any misplaced components on the SK25 or obviously bad joints, but something is wrong I suppose. I also did the measurement on the resistors A to G without the SK25 described in the forum: https://www.soundskulptor.com/forum/index.php?topic=402.0
Every value was right except D: that should be - 0.2 V, and I did get - 0.133 V.
I have also checked this: https://www.soundskulptor.com/forum/index.php?topic=9.0
Can’t find any problem so far. How Should I proceed?
