JJ KT77's in your Marshall??

[doomsdaymachine]

Anybody dig these in their Marshall?? My JVM came with SED EL34's, but I've since tried EH 6CA7's, and received some KT77's from Bob yesterday.. Thinking about giving them a shot!

 

[diesel king]

I loved them in my dsl. Big fat low end, real chunky sounding and great for metal

 

[diesect20022000]

yeah they're my favorite power tubes for modern heavy style. otherwise E34L's are my close second. the E34L's are a bit more of an old school tone with tighter response and bigger lows than standard EL34's but, KT's are like EL's on HULK imo. You get the highes and lows of a 6l6 with the lush mids of a 34

 

[big dooley]

i've tried EL34's, E34L's and KT77's in both my JVM and DSL... the KT77's were the winner, hands down... never tried a 6CA7 though

 

[Rahlstin]

I have a set of the early run of JJkt77 and they have the smaller pins. Had a real hard time keeping them connected. Sound was good. Havent tried a new set.

 

[doomsdaymachine]

Well, KT77's have won the trials. I prefer them to the SED's, & EH 6CA7's. The SED's are a great sounding tube, but I find a little bright. The 6CA7's have a "bigger" sound, very clear, but not as harmonically rich. The KT77's have both a big sound, and additional warmth, as well as rich harmonics & THUMP. These sound VERY nice, indeed!! More low end than the other 2, and tight! I have a pair of E34L's as well, but I think I'll just hang on to them for spares.

 

[Marshall Mann]

Well, KT77's have won the trials. I prefer them to the SED's, & EH 6CA7's. The SED's are a great sounding tube, but I find a little bright. The 6CA7's have a "bigger" sound, very clear, but not as harmonically rich. The KT77's have both a big sound, and additional warmth, as well as rich harmonics & THUMP. These sound VERY nice, indeed!! More low end than the other 2, and tight! I have a pair of E34L's as well, but I think I'll just hang on to them for spares.

I had JJ KT-77's in my 6100 for a long time before switching it back to KT-66's. I liked them allot, and would take them over a standard EL-34 or EL-34L any day. I do like the JJ 6CA7'a quite a bit as well though, it just depends on the application.

 

[carrots]

So if you like classic Rock and Blues which power tube would best suit the players style?

I'm currently using SED EL34's.

I love my sound now that I've installed old preamp tubes.

Your opinions are appreciated......

 

[Lederstrumpf]

My aging set of KT77s could not hold the bias anymore and I had to replace them with EL34s temporarily. No matter what I did, I couldn't get that lovely clean sound out of my TSL122 that the KT77s gave me anymore.
I am definitely ordering new ones this week.

 

[big dooley]

you sure it's the tubes and not the amp??? the TSL122 has a reputation you know...
how old are those KT77's?

 

[Lederstrumpf]

So if you like classic Rock and Blues which power tube would best suit the players style?

I'm currently using SED EL34's.

I love my sound now that I've installed old preamp tubes.

Your opinions are appreciated......

KT77s give you a cleaner, more complex clean sound.
Overdriven however, it depends on personal preference IMO.
KT77s have a less pronounced midrange than EL34s but add more low end and smooth out the top end. As such, my alt & prog benefit from the heavier, modern sound I get with them.
However, you desire a classic rock & blues overdrive sound, so I'd recommend sticking with EL34s or perhaps giving E34Ls a try.
But feel free to give KT77s a try, they're great tubes

 

[Lederstrumpf]

you sure it's the tubes and not the amp??? the TSL122 has a reputation you know...
how old are those KT77's?

Yes, I have the Issue5 Mainboard that loses its isolating capabilities when exposed to high temperatures. Over the weekend, I managed to repair this (The Marshall TSL122 TSL100 thermal bias drift repair page).
The KT77s were about a year old and I could not bias both sides lower than 95mV, regardless of amp temperature. Because of the bias drift problem, they were often exposed to a bias of 100-120mV a side, possibly causing the aforementioned issue.
The EL34s I chucked in can be biased down to ~50mV a side and the amp's temperature now stays consistent for at least two hours, without the use of an external fan . I'll do some further testing regarding the issue once I receive new KT77s.