Rev Blue with KT88's

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jc986

jc986

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Swapped out the EL34L's in my Rev Blue today for a set of JJ KT88's and am very pleased with the change. They tighten up the bottom end, take away some of the mid honk and everything just sounds clearer, bigger and meaner.

I had read a bunch of threads that mentioned you'd have to widen the bias range to be able to do it, but I was able to get around that by having Eurotubes send me their coolest set of KT88's. They biased up just fine to 35ma and everything I love about the Uber just got bigger and better. Figured I'd post this in case any of you have decided against trying this because of the bias range.
 
Cool idea and good move in my opinion
I def am in love with the kt88's in my twin jet. Beast of an amp, huge but just tight enough for my playing.
 
Folks, try the EH6CA7 power tubes ;) suits the Uberschalls insanely !!!!
 
I agree that the EH 6CA7 tubes are an improvement over the EL34 or EL34L, but for me the KT88's suit the amp better.
 
Very cool, I heard this was possible but some folks suggested it might not sound good with cool KT88s. Glad to see the contrary and I may have to give this a shot at some point.
 
I meant to ask since you have some time with it, any problems with the KT88s? And have you stuck with them?
 
Nice :thumbsup:

Thinking at some point of possibly trying Kt88s in the Savage 120. Pretty happy with the stock 6550s in there now though.

All these recent Uber threads are stiring up the GAS you fuckers :lol: :LOL:
 
I've used KT88s in my Rev 2 with no issues. It's a monster with those tubes. They should've used those in the first place instead of EL34s.
 
Is there a specific mA range I need to look for when ordering? And does the Rev2 have a higher plate voltage. Not sure if that makes it better or worse than a Rev Blue for handling KT88s, I'm pretty new to this.
 
Rev2 has higher plate voltage than the Blue. You'll need to do a simple (and reversible) resister mod to get the mA into spec.
 
Thought I had read that and feared that was the case. While the mod looks pretty easy, I'm not quite ready to start molesting the innards yet.

Would a cool set as the OP stated work without the resistor change? I by no means need to do anything, just trying to learn what I can. Thanks!
 
I got my info straight from Charlie at Bogner, so yes, as long as you get a set that will work within the stock bias range you do not need to change the resistor. I ordered mine from Eurotubes and just asked that they send the coolest grade they had available. There was plenty of room within the stock bias range to get them to an acceptable ma reading. 35ma is what Bogner recommends for KT88's, and the stock bias range would have allowed me to get to as low as around 18ma. The eurotubes rating on the boxes of KT88's they sent was "37".
 
Great info. I need to chill for a bit on the purchases, but would be interested in trying some KT88s and am glad to know Bogner would support cool tubes without having to mod the amp. Thank you sir!
 
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