Retubing an ARC VT100 mkll

Just waiting for the first report of someone popping the filament winding.

OregonPapa, you mean you can hear a big difference after you replace that regulator pass element 6550 in the PH8 and Ref 3 Preamp? How old was the 6550 that was replaced?

No way the vs115 is triode. 4 tubes push pull per ch will not get you 110wpc even if you push B+ all the way to 550v.

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.