KT88's any good for guitar?
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Re: KT88's any good for guitar?
I've got a single ended rig with an 88 that puts out very close to 23 watts. It sounds pretty good but it's all happening up front - the 88 never gets close to being pushed.
Re: KT88's any good for guitar?
Not sure about that... with a max Pda of 35W and typical Class A efficiency of say 40%, a single KT88 is unlikely to get you 23W, but it's plenty loud nevertheless.sepulchre wrote:I've got a single ended rig with an 88 that puts out very close to 23 watts. It sounds pretty good but it's all happening up front - the 88 never gets close to being pushed.
OTOH, to get 23W in push-pull, Divided by 13 is probably using a low plate/screen voltage as mentioned - it sounds pretty darn good - but a bit extravagent to use the KT88 for such low output power IMO.Re: KT88's any good for guitar?
I think my scope's pretty accurate. And the sheets I have put the KT88 at 42 watts. When I checked it I had everything balls to the wall with a 1 volt 1Khz sine signal. It was hovering around 22 watts. Of course I'd never get that in actual playing, nor do I want it (he's got a big brother for the heavy lifting).
Oops, scratch that. I just checked my notes. It was running 20 watts, not 22. But that was some time ago and I've changed the tube and rebiased a bit cooler - the first tube bit the dust; I got it used. So I don't really know what it does now wattage wise, but it does still sound good.
I agree though; why use a pair of 88s for 23 watts?
Oops, scratch that. I just checked my notes. It was running 20 watts, not 22. But that was some time ago and I've changed the tube and rebiased a bit cooler - the first tube bit the dust; I got it used. So I don't really know what it does now wattage wise, but it does still sound good.
I agree though; why use a pair of 88s for 23 watts?
Re: KT88's any good for guitar?
I see, I was looking at the old datasheets, but it appears that JJ spec'd its KT88 at 42W, so I guess it is possible to get over 20W Po.sepulchre wrote:I think my scope's pretty accurate. And the sheets I have put the KT88 at 42 watts. When I checked it I had everything balls to the wall with a 1 volt 1Khz sine signal. It was hovering around 22 watts. Of course I'd never get that in actual playing, nor do I want it (he's got a big brother for the heavy lifting).
Re: KT88's any good for guitar?
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Last edited by matt h on Fri Mar 27, 2015 6:44 am, edited 1 time in total.
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Stevem
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Re: KT88's any good for guitar?
Dependant on the tubes used I like the Mesa thing with 4 tubes of 2 in pentode and 2 in triode mode, nice sweet sound with a non Mesa preamp in front of it!
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Not screaming like the passengers in his car!
Cutting out a man's tongue does not mean he’s a liar, but it does show that you fear the truth he might speak about you!
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Andy Le Blanc
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Re: KT88's any good for guitar?
kt88, kt90 and kt100 are wonderful in guitar rigs.
your not gonna see the potential power output unless your PS can provided the current for them
but you can use them all the same, they work nice with fender circuits.
mind that you don't over bias the PS looking for the current that the data sheet says they can handle.
and mind the screen grid voltages, keep them less than the plate at idle when you set up bias.
your not gonna see the potential power output unless your PS can provided the current for them
but you can use them all the same, they work nice with fender circuits.
mind that you don't over bias the PS looking for the current that the data sheet says they can handle.
and mind the screen grid voltages, keep them less than the plate at idle when you set up bias.
lazymaryamps
Re: KT88's any good for guitar?
Points well taken!matt h wrote:
Because you like the way it sounds better than a pair of 88s at 90W.
Because you like the way it sounds better than a pair of 6V6/EL34 at 23W.
Not everything is about efficiency... and given the other ways people blow way, way too much money on ineffective crap in builds, it's not fair to call dropping an extra 40 bucks on glass a waste for expense.