A good read

[MesaENGR412]

http://www.eurotubes.com/euro-n.htm

I am currently looking at getting a KT-66/88 integrated sextet for my Triple, and I stumbled up this on Eurotubes' site. I just wanted to post it here for anyone's information, and to see if there are any discrepancies with it that you guys see.

-AJH

 

[CaughtLikeFire]

I commented on this in another post just yesterday.

Bob likes to push limits with amps - you may burn through tubes a little faster or if there's the smallest issue with any of the circuitry in your amp, running that setup will bring it out of the woodwork. Not that something bad will happen, just that you need to be prepared. It's like running a car with a modified performance engine. His logic is correct - nothing downright crazy he's trying to accomplish - not like your amp will instantly blow up or anything.

I'm not a fan of Kt-88s in guitar amps in general - very hi-fi and lots of headroom - not good if you like harmonics from power tube distortion (although in a Triple Rec, you don't get much of that anyways :wink: )
Kt-66s can sound cool but I'm not 100% confident in the new production ones yet - they might be worth a try though.

Unless you've already decided that neither 6L6s nor EL34s do it for you, this would be an expensive experiment. I'm not sure what you really gain from using KT88s - not like you ever run out of clean headroom in a TR and their sound characteristic is nothing exceptional - they're great for hi-fi and bass amps b/c they color the sound much less than an EL34 or 6L6 when the volume is cranked. A set of all KT-66s might be worth a try although you may find the bottom end way too loose (moreso than 6L6s)

my $0.02

 

[MesaENGR412]

hmm interesting, I may save some money and just get some EL-34L's then, I've heard a lot of good things from people using those. I dunno, we'll see what goes. Thanks for your info

-AJH

 

[CaughtLikeFire]

hmm interesting, I may save some money and just get some EL-34L's then, I've heard a lot of good things from people using those. I dunno, we'll see what goes. Thanks for your info

-AJH

get the Groove Tubes version if you want to try that tube. It's a true 30W tube no matter what Bob claims (JJ factory has a deal with GT - you can physically see the difference between GT E34Ls and the ones from Eurotubes).

Anyways, they do bias differently so you won't be able to run them in a GT rated 6 or 7 like you normally do in a Recto. I think you need to go with a GT #4 rating but it never hurts to give GT a call to check. their tech staff are all cool people and happy to help (used to call them all the time when I worked at Guitar Center).

let us know how it works out 8)

 

[MetalHorse442]

hmm interesting, I may save some money and just get some EL-34L's then, I've heard a lot of good things from people using those. I dunno, we'll see what goes. Thanks for your info

-AJH

get the Groove Tubes version if you want to try that tube. It's a true 30W tube no matter what Bob claims (JJ factory has a deal with GT - you can physically see the difference between GT E34Ls and the ones from Eurotubes).

Anyways, they do bias differently so you won't be able to run them in a GT rated 6 or 7 like you normally do in a Recto. I think you need to go with a GT #4 rating but it never hurts to give GT a call to check. their tech staff are all cool people and happy to help (used to call them all the time when I worked at Guitar Center).

let us know how it works out 8)

Gasp! you worked at guitar center? I can see how that can be a really fun or really aweful job all at the same time.


MesaENGR412, read my thread titled 2 ch triple rec with EL34's, CaughtLikeFire and I had an extensive bit of info sharing on that one as far as power tubes go, check it out, there is a lot worth reading.

 

[stephen sawall]

I like KT-88 a lot. I have not used them in a Boogie. But they have a huge bottem and crunch at a lower freq than a EL-34. I run old 6CA7 in my tremoveb {like the tube Groove Tube makes in the US}. They have a better clean and bottem more like a 6L6 with cruch more like EL34. More than one person at Boogie told me they are the best tubes for the rectifers. I have never heard anything I like better. This a matter of taste. I do use other tubes if I am going for that voice I like KT-66 and if you try them well you post what you think? Or what ever you put in there

 

[MesaENGR412]

I'll let ya'll know first thing when I make my decision. I appreciate all of your info. I don't think i'm going to get them until next month though, just to make sure no one has picked up the idea for a Christmas gift.....

-AJH

 

[stokes]

Just a warning to you guys who want to "fire up" your power tube distortion in your Boogies.I am a big fan of the adjustable bias mod in Boogies and have done quite a few.I also like a lot of power tube saturation in most amps.But amps like Boogies and some other high gain amps develop a lot of distortion in the preamp,if I bias up a Boogies power tubes as hot as I would most other Fender types it gets real ugly,especially in the lead mode.Boogies are biased on the cold side for a reason,too cold for my tastes,but too hot and it will get ugly.

 

[fishyfishfish]

I think the "Biasing on the cold side" started with Howard Dumble. His amps had a reputation of never breaking down, being a little on the cold side puts less stress on the power tubes, which just amplify what it gets from the pre-amp. My friend did a bias mod in his Solo Rec, experimented with all kinds of tubes, and came full circle back to just about where he started. So, being a super smart dude, I to spent lots of time and money on the tube chase just to see if it would be different for me! NOPE. IMO, the reason Boogies are so good is that they are just a good, solid tube amp without all the hassles that older tube amps have. Just a thought.

 

[stokes]

To me Mesa's scheme is twofold.They bias on the cold side to keep the output clean since the preamp produces enough distortion for most,but it is also so their tubes can safely vary some within the same grading.Over the years I have seen tubes with the same coding vary as much as 10-15ma's.Now if they were to try to use a bias point much hotter and the tube you put in there without checking the bias were to fall 10 ma's higher,it could be out of the "safe" range and something could fry.Not very conducive to their system of selling tubes you can safely just plug and play.Years ago when I first got my IIC+ I purchased a new set of Mesa tubes of the same grade I had in there.The new tubes were cold as hell,the amp had a solid state feel.The new tubes were drawing 21 ma's,while the old tubes idled at 34ma's,big difference.I did the adjustable bias mod,threw away both sets of Mesa tubes,got some NOS RCA's and havent used anything but NOS in any of my amps since.

 

[CaughtLikeFire]

and havent used anything but NOS in any of my amps since.

I'm headed in that direction too. I can't afford the super rare stuff but even the 1970s/early 80s US military valves are miles ahead of the current production tubes. No matter how amazing and how close to the orignals all these Russian/Chinese reproductions claim to be, they all seem to be just average tubes that cost 30-50% more.

And you don't even need to do the adj bias mod necessarily. Until the NOS supplies really dry out, most vendors can select power tubes that drop right in a Mesa (I'm holding out until my warranty is up).