New JJ KT-77 power tubes - got a set!

[CaughtLikeFire]

Just received a pair of JJ KT-77 tubes from Eurotubes this past Friday and installed them in my Rectoverb head. I (at least temporarily) replaced a relatively new set of Groove Tubes SED 6L6s.

For those of you who aren't familiar with the KT-77, its an older tube that hasn't been made in quite awhile and its in the EL34 family. KT stands for kinkless tetrode. The KT77 is to the EL34 what the KT66 is to the 6L6 and the KT88 is to the 6550.

I've never used EL34's in the Recto before so I can't say for sure how much better the KT-77 is compared to a typical SED, JJ, EH, etc. EL34. I will say that this tube is a beast though. Bass response is killer and the upper mids aren't spikey. Its hard for me to really get a chance to crank the #$%% out of my amp, but the KT-77's break up nice and smooth when they start to distort. Next week, once the honeymoon phase is over, I'll put the SED 6L6's back in and see if I still like the KT-77s better.

I'm really enjoying the tubes so far and for $35 plus shipping, they're definitely worth experimenting with. As far as I know, only Eurotubes has them right now, but they'll be making there way to other tube vendors in the next month or so.

Anyways, just wanted to share my experience. Anybody else get a set of these yet?

 

[NoGlassNoClass]

....Bass response is killer....Anybody else get a set of these yet?

Not yet but I'm really taking a hard look! I really tried to like EL34's in my Triple...the tone was sweet, but the amp responded like one of it's testicles had been cut off. How would you compare the bass freq's to a 6L6 ? Not so much the woofy sub-lows, but that "recto whallop" that defines why most of us use these amps to begin with.

I was going to try one of those integrated sets (4x6L6 2xE34L) but I'm kind of leary about them being so far out of spec (to all run at same bias) that it could damage the amp in some way...horror stories I know, and FWIW Bob has never done wrong by me in my several dealings with Eurotubes.

If these KT77's are the missing link between the 6L6 slam-factor and EL34 singing solo tones, I would definately give them a shot.

Awaiting your thorough review (and clips vs 6L6 if you can!)
Jon

 

[Brewski]

Please give more details as you get a chance to crank the amp up. I had been toying with trying a pair of them, but if they sound too much like 6L6's, then it might be better to get a pair EL34L's. Can you get a Brit type of sound with them or are they too fat sounding?

 

[jbird]

How'd they fit into the tube sockets?

 

[CaughtLikeFire]

I would say that the KT-77s in a Recto have the characteristic EL34 crunch w/ strong upper mids but are overall "thicker" in the low mids than most EL34 amps I've listened to/played. Your Recto should still be able to pack punch - it won't suddenly turn into a JCM 900 or something like that :shock: With the output at 2 oclock and the Master at 11, I had to keep the bass below 11. Its pretty thick. I'll limit my comments to that since I haven't used any other EL34s in my Recto.

As far as sounding British, the Recto will never sound like an EL34 Marshall. Like I said above though, the KT-77 maintains most of the EL34 sound characteristics. When I swapped out the 6L6s, I immediately noticed (even at low volume) the raised fundamental frequency of the bass, increased upper mids, and the removal of some of sizzle at the extreme top end of the frequency range. The KT-77 does not sound like another 6L6.

As far as fitment goes, the KT-77s were barely taller than the SED 6L6 - they fit perfectly.

I don't agree with Bob @ Eurotubes in that I don't think the JJ preamp tubes sound good in Rectos. I will say that he has an excellent reputation for selecting, matching, and grading power tubes and some JJ power tubes do work well in Rectos. I told him that I'd be running them in a Mesa and he sent me a pair that don't run too hot. Simple as that. No problems at all so far.

 

[jbird]

I was hoping to hear the KT77's would have some of that 6L6 sizzle with other characteristics of an EL34. It's that sizzle, my nizzle, dat I gots to have up here in dis hizzle. Yo! :lol:

 

[Brewski]

CaughtLikeFire-Thanks for the additional info. It sounds like you're liking them. I'll probably still try a pair, and like you say, experiment with them. If they still maintain the EL34 characteristics, have a nice breakup, a little more bottom end is not necessarily a bad thing. I can always put it back the way it was. It comes down to what each player likes and dislikes. Thanks Again. It's good to get an impartial impression.

 

[Brewski]

I ordered a pair of the KT77's to give them a try, and got them on Friday. CaughtLikeFire described them very accurately. They are punchier and are thicker. I changed them out last night and although I only got a couple of hours in with them, so far I really like what I'm hearing. They are not 6L6's in a EL34 shape. But if you're looking for something that has beefier presence, harmonics, and dynamics than the standard EL34, give 'em a try.

 

[Boogiebabies]

Sounds like a Sylvania/ GE 6CA7 test to me. I have no idea why JJ would issue a KT77. How many amps do you remember coming with them.
I may have to get a set and run the piss out of them before I sound like a
cork sniffer.

Thanks for the review.

 

[Brewski]

I may have to get a set and run the piss out of them before I sound like a
cork sniffer.

HAHAHAHA! Funny. You may just have to! I really don't consider myself a cork sniffer. I'm just trying them out like the next guy.

BTW-jbird, they fit the sockets just fine. No issues, so far.

 

[musicbox]

bob put up a set of nos genelex for the reissue. they developed them for the same reason as any company. they saw an opportunity to make some money.

 

[SgtThump]

I just got a set of JJ KT77's yesterday and put them in my Stiletto. I got a short while on them last night and a good solid 1 1/2 hours of LOUD jamming tonight. I'll admit, I'm impressed. They're exactly as the others described. Smoothed out this Stiletto, but not so smooth it lost it's balls. The highs are more pleasant and not nearly as hard on the ears as the stock Mesa branded EL34's that came in the amp.

Now the JJ preamp tubes on the other hand, I don't like 'em. They cut off this amps balls and make it mushy sounding. I never liked those JJ preamp tubes in the past either (tried them a few times), but I got a wild hair up my arse and ordered three of them with these KT77's. I don't know what I was thinking. I never liked them before and don't now.

But yeah, the KT77's are worth it, I think. They sound great in this amp. I may get some for my Marshall next.

 

[oyster]

would these replace 6L6s or EL34's ( ie. for bias setting on my single rec - which should I set it to?)
Have tried EL34s before in my single rec. but went back to 6L6 for the tighter attack.

 

[CaughtLikeFire]

would these replace 6L6s or EL34's ( ie. for bias setting on my single rec - which should I set it to?)
Have tried EL34s before in my single rec. but went back to 6L6 for the tighter attack.

These are an EL34 replacement (put the bias switch on "EL34") but are thicker-sounding than standard EL34 tubes.

 

[Crunchyriff]

I'm about to try the KT77's in my TOV.

I may get REAL twisted...and try the KT77/6V6 integrated set.

YEAH!

 

[Crunchyriff]

I just ordered the KT77/6V6/GZ34 package for my TOV.

will give an update when it arrives and gets tested.

 

[screamingdaisy]

When I swapped out the 6L6s, I immediately noticed (even at low volume) the raised fundamental frequency of the bass, increased upper mids, and the removal of some of sizzle at the extreme top end of the frequency range.

That's pretty much my opinion of EL34s in a Recto. They were cool, but I didn't like them because they removed quite a bit of the "thump" I like when I palm mute.

 

[CaughtLikeFire]

When I swapped out the 6L6s, I immediately noticed (even at low volume) the raised fundamental frequency of the bass, increased upper mids, and the removal of some of sizzle at the extreme top end of the frequency range.

That's pretty much my opinion of EL34s in a Recto. They were cool, but I didn't like them because they removed quite a bit of the "thump" I like when I palm mute.

just realized that I never gave an update on this. as cool as the KT-77 sound was, I decided that in a Single Rec at least, a 6L6 type tube is best for me. I put the SED 6L6 back in. I can't describe it exactly, but you're right - it loses some of that Recifier "thump" that attracted me to the amp in the first place.

 

[NoGlassNoClass]

it loses some of that Recifier "thump" that attracted me to the amp in the first place.

Good to know! You may have just saved me a hundred bucks. I do like the tone of the EL34 types, but not willing to give up the sledgehammer effect that sold me on this amp in the beginning.

 

[Crunchyriff]

it loses some of that Recifier "thump" that attracted me to the amp in the first place.

Good to know! You may have just saved me a hundred bucks. I do like the tone of the EL34 types, but not willing to give up the sledgehammer effect that sold me on this amp in the beginning.

You might well want to try a KT77/6L6 integrated quad.