Amplifier Power tubes - important to sound?

@brownred6 -

        The Svetlana Winged 'C' tubes were a very nice tube and I hated to see the company shut down after the St Petersburg plant burned, with all it's equipment.

        If you do manage to find any remaining stock; there's a 99% chance, they'll be factory seconds, as all the first quality tubes went years ago.

@carlsbad2 ​​​& @dogearedaudio -

                                             +1 (each)

       As usual: the resident imitation of a fictitious Intelligence Operative, knows nothing.

     I went through a few octets of  Sylvania's 6550s, until Upscale ran out and I couldn't find any more.

      Uncle Kev recommended the Winged 'C' and those were a nice replacement, until the plant burned.

       The GE 6550 variants were my next stop and I loved 'em, until they got too salty for my wallet.

        I kept a good testing quad, that I've used for comparison against a few other brands and found the Russian Gold Lion KT88s to provide fairly close to the same presentation.

                                    Roll on and happy listening!

Just to be clear, I was certainly not recommending anything other than the correct tube type for the OP’s amplifier. I was simply pointing out that the quality of the output tubes can make a difference, in terms of both power output and the amount of distortion they produce.

Curious, I read herein that the feedback level related to the amplifier is important to consider for purposes of evaluating whether it really makes much of a difference to tube roll power tubes. Anyone know why that would be?

Further, I am biamping with mc 901 monos and since the solid state part of it handles the bass drivers maybe power tubes are not that important since it appears it impacts the bass area more so.

But since I love spending so much money on everything audio even the slightest change might be worth considering. Maybe power tubes would impact the mid driver.

There are some people posting herein who know a hell of a lot about tubes. It’s actually kind of scary.