KT-88 KT-90 KT-100 6550 which has the best bass?

I may get 60 watt 2ch.amp and was wondering which tube will offer the most authority?
I play rock and need the most power and bass I can get out of tubes.
The amp can use all 4 tubes mentioned.
Im leaning towards Svetlana or Electro Harmonix.
Thank you for any info.
probably KT90, that's what I've found. EH or Ei makes decent KT90 tubes. There may be others.
It depends how you describe best bass. In my experince with a Graaf tube amp, the 6550 was a warmer more musical sound but the KT-90s were more dynamic and punchier, but lost the magic in the mids. Could be the brand of tubes used also.

Happy Listening
I went thru the 'tube flipping' phase several years ago. In a c-j premier 11, I replaced the 6550 with a quad of the the kt90 series. Yes, I had some extended bass, but lost some sound stage. I really recommend using the tubes recommended by the manufacture of the equipment. The sound will be different, but not necessarly better!
I'm with Bigkidz. It depends on how you define "better bass".

I have KT88 and KT90 tubes, and consider the bass of both to be excellent, though quite different. The KT88 is punchier, warmer, and bloomier in the midbass by a significant amount, and not as extend. It is more classically tube. The KT90 is more evenhanded, leaner, taut, and extended. It's kind of like comparing the tube and solid state sounds. KT88 tube, KT90, more like solid state.
Again, depends in part on the electronics, though Joe and I both have used Jadis as a reference. In my JA80s, Joe's (Trelja's) and Peter's (Bigkidz) descriptions of KT88 vs. KT90 are accurate; I found 6550s (Svetlanas and Philips) to be a little fuller and warmer than the KT90s (EI Type 3), but nowhere near as rich and full as the KT88s (Gold Lions) and lacking the finesse of the other types in the midrange and highs (more of a brute force-type tube, may have a little more power). For rock at loud volumes, I'd go with either the 6550s or KT90s, depending on how lean or rich you like your sound.
Oh, David(by the way, how have you been?), I forgot to talk about the tube companies, since you mentioned EH and Svetlana.

In my experience, I have only tried the Ei KT90. They are no longer produced, thanks to the NATO bombing in the former Yugoslavia, but still available. It looks like EH is beginning to make them. It only makes sense, whenever you see a group of people fret over something no longer being available, it's wise to bring that product to market.

As far as KT88 goes, I prefer the JJ, which seem to have that punchy bass and beautiful tone. Svetlanas sound more neutral and 6550/KT90ish to me, though still a recommended tube.
Joe-Thanks for your input, as well as everyone else.You ask how I've been? I was in a car wreck the 20th of July.Out of work for another 3 weeks.Other than that,alls well.No one has mentioned the KT-100.The amp I 'may' get is supplied with KT-100'sI'll take a guess.Its similar to the KT-90??Joe,I recently bought a Threshold S/300 stasis.This amp gets HOT when pushed.Im keeping my bare foot off this amp! :~)
Whoa, that is horrible news, David! I am so sorry to hear it. Is there anything we can do? Honest. I do hear a ray in your words that suggests you are improving, and I hope that is true.

Russ was also down for a while, but is now back, looking great. Hopefully, he will make this a trend, and you will follow.

Yes, keep the feet away from Threshold amps. No bare feet, and no kicking them, as they hurt either way.

I don't know much about this KT100, but think I saw a Houston amp using it. Is this possibly the amp you are considering? They made an 845 based SET that I always lusted after, but can never find on the used market. It's a Chinese company, but they seem to be OK. I know that recent ASL efforts, such as the 1009, are better than most anyone would expect.

Given you listening preferences, you may want to look into a pair of Granite monoblocks. I have a pair, and they can run just about any tube, those you listed, plus EL34 and 6L6, you can find a very wide range of sounds with it, and maybe whatever you are looking for. If you are set on a stereoblock, if the Rogue 150 sound trickles down to one of those, it may be one to think about also. I could be wrong, but it may already exist in the Model 90 - apologies for not keeping way up on these things.
Yes Joe,its the Houston amp on auction I am looking at.
I know of their reliability issues and have no customer support.But if I can get it for $300 it may be worth it.
Any thoughts on rolling the dice with the Houston?
BTW Joe,do you remember when I burned my foot on the Aleph-3?
Yes, I now remember it. Sorry, but I needed you to remind me to bring it up.

I think that the Houston at $300 is a no brainer. For less than the cost to retube a lot of amps, you are getting the whole kit and kaboodle. I think you should do very well with it. I have never heard about issues with their products, mainly because I have never really seen that many people using them. But, they look well built from their pictures. I have even considered them myself, though I have never run into the right deal, and after I got the Granites, there is no real point. The Granites are made to a great level, and sound excellent.

I think in the end, listen to the amp first, and get your bearings. Then, if you do want to retube, let us know the direction you want to take the sound, and we can probably give better insight. Still, the person who knows the most in these situations is you.
Thats Joe- I'll flip a coin tomorrow night to decide to bid on it or not.
My Threshold S/200 drives my Thiels with utter ease.The speakers have never sounded like they do now.Incredible!
The Houston probably would get limited use as Im a whaco metal head.
But the Houston is so pretty,and I miss the glow at night from big tubes.
I guess thats an irrational reason to buy,huh? :~)
S/300 sorry-
David, the Threshold were some of the finest solid state amps ever built. When I think of some of the junk sold for $10K, I realize how very intelligent people like you are. These new cosmetic heroes do not compare with the likes of what you have.

As far as the Houston goes, so long as the price doesn't get too high, my recommendation is to BUY IT!

Good luck,
The Houston went for ~$440 or so.I didnt bother to bid once it took off.
I remember when they were sold at close out prices NIB for ~ 5 bills.
For $300 it would have been a nice second amp though.
You're right Joe.The Threshold is awesome and I finally have a amp to drive my Thiels to my complete satisfaction.
Nice to hear from you again!