18Watt.com

Hi all. I've converted over 60 PA/Hi-Fi amps and believe it or not I've never included a Trem. I would like to use the AA1164 Princeton style Trem that operates by changing the power tube bias. I dont want to use the Opto-Roach type found in the Deluxe/Twin, etc.
My question is: Because both of my 220K power tube grid resistors are separated (I always use 2 adjustable bias pots on my builds so I dont need to use matched tubes ) it looks like I might have to go with a single bias pot if I want to use the AA1164 Schematic. I'm not certain. Any suggestions or thoughts are very welcome. Schematic for Princeton is herehttps://robrobinette.com/images/Guitar/ ... ematic.png

Show us the schematic of your build. On an 18W we use preamp tubes for tremolo. If there is a spare triode in your amp it's normally possible. Or you can go the mosfet route too.. I have that type in my imperial clone and it sounds really awesome.

Checkout the Matchless Hurricane, which is a similar amp to the Marshall 18W but uses the "bias wiggler" approach - http://www.thetubestore.com/lib/thetube ... ematic.pdf To save a precious triode you could always use a high voltage FET or bipolar transistor for the trem oscillator.

So now you have two options, Marshall 18W preamp or Matchless power amp. Both are cathode-biased amps and don't need bias adjustments.

I'll once again say that matched power tubes are only required for hi-fi amps. In guitar amps, non-matched tubes help produce a richer tone, with more even-order harmonics.