Leaky presence cap - again
Posted: Sat Nov 14, 2015 4:41 pm
For some reason I keep burning through presence caps.
Let me tell you what I got. It's basically a 2204 amp with a PPIMV.
Started its life as a plexi, so it has the plexi-type presence circuit with a .68 cap instead of the .1 there.
What it does is, every now and then, I start to hear some noise creep in. It starts to get worse and worse. I identified it by tapping around on the boaard with a chopstick, the presence cap sounded microphonic, so I replaced it and the noise went away ... for several months. Now it's back again.
I've used good quality caps, like Mallory M150, and a CDE DME 1KV.
Should I rewire the presence control to the newer type? What's the story with the change? I'm sure there's a reason why they switched.
Let me tell you what I got. It's basically a 2204 amp with a PPIMV.
Started its life as a plexi, so it has the plexi-type presence circuit with a .68 cap instead of the .1 there.
What it does is, every now and then, I start to hear some noise creep in. It starts to get worse and worse. I identified it by tapping around on the boaard with a chopstick, the presence cap sounded microphonic, so I replaced it and the noise went away ... for several months. Now it's back again.
I've used good quality caps, like Mallory M150, and a CDE DME 1KV.
Should I rewire the presence control to the newer type? What's the story with the change? I'm sure there's a reason why they switched.