My rig can only handle up to KT 120's (4 per each monoblock), That would be neat if I could go to a 150...anyway, how's your voltage? My voltage is all over the place since we live across the river from a nuclear power plant...some times of the day - usually going into evening, it spikes to about 127v, normally during the day time it's at 120v or 118v. I was blowing tubes regularly, then installed variac transormers at each monoblock and problem solved. no more melting tubes.
Chasing distortion
I have an Audio Hungary Qualiton A50i. Recently, one of the power tubes (KT120) red-plated and I purchased a replacement. When installed, I heard distortion, along with music, coming out of both channels. The distortion sounds similar to a blown speaker.
Thinking maybe the replacement tube was no good, I swapped the entire quad of power tubes with a set of KT150s. After installing them I found that the sound was significantly lower, but I could still hear the distortion.
What should I try next? Start swapping the input tubes (2) or the driver tubes (4)?
Thanks!