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I've noticed a similarity (possibly intentional given the pedigree of the Tramp) with a P1eX from AX84 (Phil?) Would the use of 12BZ7 instead of a 12AX7 be okay with the same changes in values mentioned by Phil? Has anybody tried this?

Thanks,
Gene

Pedigree is yes but a lot more features in the Tramp. Sure, don't see why not, to use that tube with appropriate mods. Lets see what Phil says. I haven't tried it. Why is it suggested?

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

It's a 12AX7 with but with half the internal plate resistance (rp), roughly 30K. The plate can also dissipate 0.5W more.

With no mods you should get more gain out of the amp. What are the Phil mods?

_________________
http://pdfelectronics.com

Phil's mods are as follows:

"First get yourself a 12BZ7 and change R7 to 10k (last voltage dropping resistor in B+ power supply) and R18 to 1.2k (second stage preamp cathode resistor).

"Then use my lower-loss tone stack mods (jalapeno tone stack already incorporated with voltage divider for VR4):
R11 = 56k (slope)
C10 = 0.01uF (mid)
VR4 = 50k (mid)
VR3 = 500k (bass)

"See how you like that. The combination of this tone stack with the lower output impedance of the 12BZ7 means you get much reduced attenuation in the stack. The increased preamp voltage (360V) means the power tube also gets driven a lot harder, and you get more preamp headroom. With the increased preamp voltage, you can also boost the preamp gain a little more if you want, by reducing R21 to 180k (part of preamp first stage load resistance in series with VR1 rather than optionally paralleling VR1)."

I tried to give you the changes referenced to the Tramp schematic. Some of the parenthetical comments are mine. I may not be 100% correct, so please forgive me.

Gene (edited for clarity)