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Tubes 101

I'm very new to tubes. Is there a sonic signature to different tubes? For instance, do Kt-88's have more highs and bass? Do 6550's have better midrange?

It seems like KT-88's, 6550's, EL-34's are the most common, or at least those are the ones that I keep seeing pop up.

I can use KT-88, 6550, KT-90, EL-34, 6L6GC, 7581A, KT66...

In terms of sound, I want it all, and why save $100-$200 on tubes when I'm already this deep in the rabbit hole?

To further complicate things, which brands are better? I'm thinking a matched quad set of Cyro'ed Gold Lion Kt-88's might look pretty sitting in my PrimaLuna Prologue 5....
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mapman's avatar
mapman
21,975 posts
 
TUbe #s/model merely identify a set of standard parameters that enable different ones to be used interchangeably. These alone do not assure a certain "sound", only that certain models are more likely to work best in a particular design, case by case.

Probably more often than not, two different models of the same tube #/type will deliver sonic differences. How much and to what extent it matters still depends.
b_limo's avatar
b_limo OP
2,273 posts
 
Beautiful! Thank you everyone! Please keep the info coming. I think it will be helpful to many others, now, and in the future.

Thank you XTI, that was very helpful, you too Mapman, thank you!
xti16
1,525 posts
 
B_limo - what tubes are in your amp now? What change would you like to hear? Are your current tubes new or pre owned? If used give them 25 hrs before making a judgement. If new they could take 100 - 200 - 350hrs before they settle down which is why I asked what tube are in there now.
b_limo's avatar
b_limo OP
2,273 posts
 
I have been switching between some svetlanna 6550's and electro harmonix el88's. I prefer the el88's bass and highs. The svetlanna 6550's can make some vocals sound really nice, and possibly image better, but they make some rock music sound awful.

My input tubes are a mix of g.e. and others with no names... I have the regular input tubes that came with the prima luna but prefer these others.

I'm thinking that some bugle boy input tubes with some golden lion kt88's might be good...

Ultimately, I'd like extension at both ends; sparkling highs, tight bass and good imaging are probably my priorities.
xti16
1,525 posts
 
B limo
I have SED 6550 and KT88's. Not sure how close the Svetlana sounds compared to SED. But from what you are describing I would suggest Ei KT90's (type 2 or 3). Besides great extension at both ends it has great mids too not to mention a huge soundstage. They are a little pricey but nothing like original vintage 6550's or KT88's. I also have no experience with EH but a local tube seller prefers the Ei KT90 over the Eh KT90 by a long shot. Finding Ei KT90's can be a little difficult since production was halted in the early 90's. Ending in a few hrs - no affiliation
http://app.audiogon.com/listings/tubes-kt90-ei-nos-amazing-sound-kt-version-ei-kt90-second-generation-quad-2-spares-new-in-2014-01-04-accessories-33441-deerfield-beach-fl
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