91 dB 6 ohm nominal load speaker, generally speaking, should not be that hard to drive unless the impedance has really low dips. Again generally speaking, tube amps tend to be able to provide more current than similarly priced SS amps. So, depending upon what tube amp you are using for these speakers, it doesn't sound, to me, like this is an amp problem, per se. However, as one commenter suggested, it might be a bad tube. Maybe it's time to roll out those tubes? If that doesn't do it, I would check and re-check all the basic stuff (e.g. connections). Maybe this is a speaker problem. If not, my next attack would be a good power line conditioner. Good luck!
What does clipping sound like?
I have been wondering if the break up distortion I hear with my 60 watt tube amps is because I have insufficient power for my 91db 6 ohm minimal speakers. I do question if that rating of my speakers is correct.
When the music swells, I get break up sound. It is not on low notes or high volume. I do wonder how my speakers would perform with a lot more power. I have always thought that any speaker likes more power.
When the music swells, I get break up sound. It is not on low notes or high volume. I do wonder how my speakers would perform with a lot more power. I have always thought that any speaker likes more power.