trinityamps.com

I've been enjoying my Plexi 18W (with VRM) for a few years now, but have noticed that there's a fizzy/buzzy decay to the notes. A quick google search..apparently this is a known issue with EL84 18-Watters, crossover distortion perhaps?

Has anyone else experienced this issue? Apparently there's a Paul Ruby mod that employs a few Zeners to help snub crossover distortion.

There’s a whole thread on this. forum about chasing down the fizzies. I’ve never had the pleasure!

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I've changed many new mica caps in the last few months. Whenever I get a strange sound that puzzles me It's usually the mica cap in the tone stack. Even in locations where there is no voltage (treble bleed), their just noisy, maybe I bought a bad batch. Fixed the problem every time. I'm not saying this is your problem but it's with looking into, or to keep in your pocket.

What are you using to replace Silver Mica?

_________________
Stephen
Web: www.trinityamps.com. Facebook: facebook.com/trinityamps. Twitter: @trinityamps

I'm either finding a good one or using used ceramic disc.

I think I should look for used ceramic dishes, it will save quite a bit of money.
among us

The Paul Ruby mod you mentioned is a popular modification that aims to reduce or eliminate crossover distortion in EL84 amplifiers. This mod typically involves adding wordle a few Zener diodes to the circuit to help snub the distortion and improve the overall tone and response.

The fizzy or buzzy decay in the notes of your amplifier's sound could indeed be related to crossover distortion, which is a phenomenon that occurs when the signal transitions between pizza tower the two halves of a push-pull amplifier stage, such as the output stage in a tube amplifier like your Plexi 18W. Crossover distortion can cause the signal to sound clipped or distorted during these transitions.