The best thing you can do for those amps is turn them into CL-150's. Triode connect the outputs. It will sound better and make it more reliable.
KT120 tubes in AudioResearch ref 300 MK2
Hi
I own the ARC ref 300mk2 mono-amps and i wonder if someone have any experience with replacing the powertubes for the Tungsol KT120.
More specific: Is there enough room because the KT 120 is a bit bigger?
Does it gives problem with the heat?
Is it necessary to replace the filament-transformer,
because the Tungsol needs more current?
What is the soundexperience?