Loading…
29
Just spent 2 years building amps with undersized filter caps without realizing it
I was working on a 5E3 Deluxe clone last month and it had this weird hum that wouldn't go away no matter what I did. A guy on the Hoffman Amps forum pointed out my filter caps were only 16uF when the original schematic calls for 20uF at the first stage. I went back and checked my last 4 builds and every single one had the same mistake because I misread the values on a parts list from 2021.
2 comments
Log in to join the discussion
Log In2 Comments
anthony_fox902mo ago
16uF is fine for a 5E3" - maybe, but it changes the feel of the amp a lot more than people think. Smaller caps drop the voltage faster under load, so you get more sag and a spongier response that can mask other issues like phase inverter problems. I'd bet that hum was actually the smaller caps letting more ripple through on the preamp plates, not a ground loop or wiring mistake like everyone assumes.
6