Upscale audio burns tubes in for 72 hrs then matches them.
AR needs tightly matched output tubes to perform at best.
Upscale would be fine
I have a AR 610T amp
AR factory wants 12K for a tube set. 48 tubes
ARC Select Worth Price?
Sovtek 6H30Ps are sounding woolly. Upscale offers replacement quads (apparently not matched) in various grades up to ARC Select cryo, all priced accordingly. (I have not inquired directly with ARC).
My only past experience is with 6SN7s, which can be rolled infinitely. What would veterans buy, and from whom?