6550 tube vs KT88


Was wondering what might be some of the differences between these 2 tubes. I've heard 2 sets of 88's and was not a tube that fits my music, classical. i found the sound too compressed, too flat on fq's, dynamics were thin. Too warm, not detailed like the KT90 tube.
Is the 6550 a middle of the road between the 2?
Hows the timber? bass/mids/high separation?
The KT88 seems to blend the 3 too much.
bartokfan
I found zero bass with the 2 88 tubes I tested. Just a falt response, flat like the Kansas landscape.
I can see how tubes get a bad reputation vs a big ss amp.
>>I found zero bass with the 2 88 tubes I tested. Just a falt response<<

Perhaps bad tubes (possible but not probable); more likely a weakness elsewhere in your system. "Zero bass" is not a general characteristic of the 88. Your amp might be the problem.
>> I found zero bass with the 2 88 tubes I tested
agree w/ commercial member "Audiofeil". The KT88 tubes are anything but bass shy! I'm using EH KT88 in my JoLida 502A to very good effect. They sound better (more balanced over the entire audio spectrum) than the original winged-C Svetlana 6550 tubes.

One thing that you *need* to realize is that different amps take to different tubes.
By this I mean, for example, just because KT88 sound great in my JoLida does not mean that they'll sound as great in your CJ 11a or some other amp.

For the particular amp that you have several people have tube-rolled before & probably catalogued somewhere in these archives which output tube sounds best, better, good & fair. Same deal w/ my JoLida - the EH KT88 is reputed to work really well in this amp & I can 2nd this from my experience.
You probably need to search these archives; it'll be worth your while.
The EH KT88 is a bit bass heavy (you are correct) but it's soundscape is not flat like KS!
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Thanks Tvad I'll order that issue. I think the issue here is that my Seas speakers area MTM design rated at 87db, so its just not a match for the KT88 I demoed nor the EH88's that I rolloed in my JOR.
db rating must be 90+ to be effective.
This is the one drawback with Seas speakers, few tube amps can bring out the dynamics. The Jadis is one that can meet these demands, as their web site says, "our amps can drive any speaker" and they can. I've put their smallest amp to the test.
Not sure how the Jadis 88 tubes image? vs the 90's I'm using.
The thing is, if I order a Jadis amp in the future, I may just stay with the 90, as I like the sound. And may not be willing to give up the characteristics of the 90 in order to gain some benifits of the 88's or 6550's.
Trade off's are a part of this audio realm. But if it isn't broke, don't fix it.