Just built a couple CP5's. They sound good, but when I plug in a Coulour module they no longer pass signal.

Also, one of them was working then made a pop and was hissing an unusable. Now it won't pass signal at all and when I turn up the gain at the highest setting it is making an audible high pitched tone. I don't know if that is typical for a part that has been damaged.

Any help would be appreciated.

Thanks,
Jeff

Look over all your Electrolytic Capacitor and make sure their polarity is correct. if just one is wrong it may be damaged and needs replaced.

Thanks Rick. I will double check

UPDATE: I had two preamps that were having problems. With the help of DIYRE support, it was suggested that I check all solder joints carefully. He even used pics I sent to illustrate which type of issue to hunt down. I repaired many of them for a third time and one of the preamps is now functioning properly. The other one is working, but is still not passing signal when the Colour module is engaged. I will make an attempt to hunt down that issue by looking at those points involved in that circuit. Sufficed to say, I need to work on soldering skills. Still this has been a worthwhile project.