Do we still need 6550 or KT88 tubes?

KT120s are absolutely reliable not only based on my own experience of using them daily for nearly 2 years, but also based on my having rarely ever seen anybody say otherwise even when I posted a question regarding longevity. I think we "need" 6550s and KT88s merely for tone options and not because KT120s are "terrible", because clearly that's nonesense if only based on the KT120's overwhelming popularity due to performance and an amazing lack of publicized tone or reliability issues. This (A'gon) crowd is hardly shy about opinions, and from what I've seen the KT120 is nothing if not utterly accepted. I've never seen a specific new-ish power tube (and until some recent Chinese versions these were a "one option" tube from Tung Sol only) be so quickly adopted by manufacturers where I can reasonably assume they wouldn't risk an amp design on an unreliable or "terrible" tube. I've also talked to service technicians from more than one local high end audio shop (and a few amp designers), and it "seems" KT120s are a well designed, reliable, and great sounding tube that has earned its place as a huge success in audio. Also, most professional guitar players (and high end guitar amp designers) use either 6V6, EL84, or EL34 based designs as the trend has moved away from KT88s and 6550s, except in a few higher power demanding bass amp designs.

I like the sound of my 6550 and KT88 sets, but KT120s seem to sound stronger in my rig, and they're larger, so there's that...I do wonder if Shuguang KT120s will be any different from Tung Sols, and recently noticed some Chinese "Gold Lion" branded 12AX7 tubes being made by license (so they say) from New Sensor...for about half the cost of Gold Lions. They really should make a KT120 with fancy gold lettering, gold pins, and a presentation box or they're missing an opportunity...my new Psvane 12AX7s had a great box which provides a comfortable home for the tubes they replaced, or a nice casket for burrying small twin rodents.

Regarding guitar amps, a lot of guitar players who have been around the tube amp block are going for lower wattage amps since you can squeeze the magic grease out of the power tube stage without relying on complete preamp tube saturation...I just bought an EL34 based Burriss Royal Bluesman that illustrates this wonderfully and will melt your brains if you push the 18 watts...my other fave amp (Reverend Goblin) has a "5 or 15 watt" switch and does the same with 6V6 power tubes. A beautiful thing.

It seems the number of people dissatisfied with KT 120s is up to 3. It's a mounting wave of dissatisafaction.

I think Wolf Garcia said something like that earlier.