What Happens When Replacing Pre-amp Tubes?
Mon, 06/18/2012 - 12:41
Okay, so you drop the input V1 from 12AX7 to 12AU7/ECC802S, or something like that? I've done this and my amp is lust quieter throughout the volume range. The 6L6's don't go into overdrive until the volume knob is up around 8-10. Used to be 4-5 with the 12AX7's. The amp is still at the same SPL when breakup occurs. So really what is the purpose of this mod?
Thanks!
Hello Krowe- The whole point of changing to lower-gain preamp tubes is to make the amp easier to play. Feedback is always a problem for harp players and subbing preamp tubes can help, especially when we are talking about an amp that was made for guitar (like almost all classic harp amps). Remember that guitar pickups put out a MUCH lower signal than a microphone, and the lower-gain tube will make the amp's volume control less "touchy"- a big problem especially for beginning players. I might suggest trying a 12AT7 or 12AY7 rather than the 12AU7 which has the very lowest amount of gain, but the right tube is the tube that YOU like in the amp. Rick Estrin favored a bone-stock Super Reverb, but his decades of experience in controlling feedback might have something to do with it!
Skip Simmons