Did the tube glow at all? The pin configuration of a rectifier puts no voltage to the KT150 plate and does not complete the heater circuit. In other words a tube with no voltage to glow the base or the top. No glow means no power and therefore a dead channel. Unless the preamp has a solid state backup in case a tube rectifier fails which would cause problems if both channels are fed from one transformer.
Crucial TUBE question
I placed a KT 150 power tube into a Prima Luna Evo 300 preamp rectifier slot. I know. But what happened was surprising. The sound was, well, magnificent glorious. Nothing burned out. No smoke. No arc lights. I asked Upscale Audio to advise me as to what damage I may have done or could have done to the PL. They only said they would not advise placing anything but the original tubes in the slot. They would not commit to whether or not that power tube could be used in place of a rectifier to tube. So, is it an absolute or not? If so, why? I’d appreciate feedback (please, no slams) from anyone having any experience with this. Thanks!