Long term update:
I can not recommend this amp highly enough. You guys hit this one out of the park!
After almost 3 years and hundreds of hours of playtime, there has been zero problems with my Triptop. The only issue is that the KT88s are too close together and it sounds like Trinity has addressed this point with wider spacing between tubes on the chassis. On the original chassis, I have the tubes separated using the red gasket rings but so much heat is generated that they have melted. The tubes have not exhibited any problems though.
I ran 6L6GCs in it for the first year. It has been run for the last 2 years on KT88s. Even with the KT88s, the power transformer is barely warming.
In case anyone is interested, I took some bench measurements on it tonight.
All measurements were taken using the normal channel.
Fixed bias was used, cathode bias resulted in lower values.
Bias on each set of tubes was set to 70% dissipation.
Voltage output did not vary much when frequency was varied but both tubes lost a bit of output as frequency dropped below 500Hz. In both cases it was less than a volt down to 50Hz.
A 4 ohm resistor was used as the output load.
Measurements were taken using an oscilloscope at the point of visible distortion in the waveform.
Higher power is possible with distorted waveforms.
I used the following formula to calculate power out: (Vp-p/2 * 0.707)^2 / 4 ohms
To summarize my results:
KT88Diode Rectification
Plate Voltage = 490 Vp-p
Bias Current = 50 mA
Peak voltage = 46.0 Vp-p at 1KHz
Output Power = 66.1 Watts6L6GCGZ34 Rectifier
Plate Voltage = 473 Vp-p
Bias Current = 43 mA
Peak voltage = 40.4 Vp-p at 500Hz
Output Power = 51 Wattstldr: Great amp. Great Sound. Buy one.