Retubing an ARC VT100 mkll


Thinking of tube rolling my VT100 mkll. Currently using EH for both the 6922 input and 6550 output tubes. Less than 800 hours on the entire set, so its not that I need an entire retube, just looking to improve the sound if possible. What would give the biggest improvement, changing out the input or output tubes to KT88/90? Bear in mind I would need a closely matched OCTECT of either so bizarre/rare vintage tubes are out of the question. Thinking of Gold Lions or similar, any thoughts from the scholars?
spinaker01
Thanks Gary -- will do.

Gary and Johnsonwu -- I'll probably regret this question, but what is the significance of a triode amp? Btw, with KT-120 tubes, the VS-115 can push out 130 wpc, but my ears would bleed if I pushed my amp and speakers that hard.

Thanks again,

Bruce
Triode-wired tubes give a more refined sound. Richer in inner detail as many would call it. I would describe the sound as more linear, the microdynamics of low level passages are better preserved so you wont spent time hunting for the right listening volume.

In pentode or likely Ultra linear in the VS115 config, you get better bang for the buck esp in the dept of bass dynamics. if you like gut punching bass, keep it as it is. If you love violins, female vocals, and choral music, AND your speakers are 89dB/W/m or better, go triode.

Triode-wired tetrode or pentode tubes can last longer assuming same B+ and bias in both modes.

Many amps can be rewired to run the power tubes in triode mode. Pull the screen grid input resistor and connect the screen grid to the plate via a 100Ohm flameproof resistor. But it really depends on whether the biasing circuit has enough range to get the tubes biased to the 55-65mA per spec after triode conversion.