2. amps-preamps
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New KT150 tubes?

Has anyone any experience with these pretty new tubes. There are already one or 2 amps I know of, that use them. The review of one of these amps in a UK magazine suggested they were a little warmer and more natural sounding than the nearly new KT120's

The article also suggested they were a straight swap for KT120 based amps, with no adjustment necessary. They are more than twice the cost of KT120's, but still not too costly compared with NOS tubes. I know changing from KT88's or 90's to 120's. did require some amp modification. I have an ARC reference 75 and might want to try the new tubes at some point, ARC don't seem to have a customer E-mail service, to ask the question
david12
wolf_garcia
6,644 posts
 
I just ordered a quad of KT150s for my Jolida 502p because I live on the edge...also they hit my magic cheapness number on Ebay, so I guess I live on the edge of cheapness.
wolf_garcia
6,644 posts
 
I completely forgot how old this thread was, and I just re-read the whole thing (something I never do)...I've been using some Sovtek kt88s and Tung Sol 6550s from my "barely used" tube stash once I sensed recently that the 120s might have been finally losing it...I'd like to publicly thank those tubes for stepping in before they're sadly put back in the drawer. I might make some sort of LED lit display for my collection of spent tubes since I love the way they look. I just stuck some new Gold Lion Premium "matched everything" 12Ax7s in my amp and although they sound amazing (really), they DON'T GLOW worth a damn, a fact thetubestore warned about in their hype...they're worth every penny though. Also, in case anybody is keeping track, the 150s cost $269 a quad including shipping.
xti16
1,525 posts
 
Wow great price Wolf. But sue to write how they sound especially compared to the KT120's.
tsushima1
1,165 posts
 
Wolf_ whilst In no way insinuating you to be a Numb Nutz....around valve gear, however, i'd be inclined to back the bias right off of the incumbent valves, insert the 150's, then steadily increase bias back to to circuit spec or close to on the conservative side for a while.
wolf_garcia
6,644 posts
 
I've been using tube amps since about 1962 (albeit that was my cousin's white Bandmaster guitar amp), and anytime my Nutz get into a thread, well, it's a good thing...note that with all of those tube guitar amps nobody cared one bit about warm up or bias...we silly kids had no idea what bias was (I assume the repair dudes did). In any case, I've swapped the tubes out of my Jolida plenty and always turn the bias WAY down...after dialing the bias back and sticking new tubes in (and looking out for explosions or large flames) I wait a while and reset it, then check it again hours later...most tubes seem to stay in bias fairly well after the first warmup tweak, but I'm a serial tube finger burning bias freak anyway so I'll be poking it with my meter probes willy nilly.
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