Will report back on my EL34s vs KT77s once I have a couple of hundred hours on the KT77s. Long-term, I'll likely have CJ rebias the amp for KT88/6550s and set it for triode operation, which is my favored flavor.
Opinions on Reissue 6CA7 and KT77 tubes
- Thread starter Tom Bombadil
- Start date
BillWojo
Addicted Member
I have a Dennis Had SE amp that shows a big difference in the sound quality of tubes. Between my EL34 JJ tubes and my vintage Mullard EL34/6CA7 tubes it's no contest. I just wish I could find a stash of those Mullards.
Over the wintertime Kevin (Kev777) and I went to a Carver meetup down in VA. I brought the Dennis Had amp along and used the Mullards. As luck would have it there was a set of Klipsch speakers there. Fortes I think. I pointed to those knowing the combo would kick butt. When the music came on everyone quieted down and just stared at it, I think they were amazed that this little SE amp could sound so good. There was some nice synergy going on between the amp, the Mullards and the Fortes.
I just picked up a VTA SP9 tube preamp, came with four JJ 12AX7 tubes in the preamp section. Yuk, they lasted one song, now it's loaded with two Telefunkens and two Sylvanias, all vintage stock. It's magical now. Detail is fantastic, sounds amazing. Need to find some more vintage stock to try out, I'd be surprised if my first try with what I had on hand can't be bettered but I'm pretty happy as it sits.
I've picked up several sets of JJ tubes along the way, they always seem to come in amps I pick up. Nobody wants to get rid of there good stuff so they always fill it up with JJ tubes. And that's how I will get rid of them to. I call them "filler tubes", fills the holes.
BillWojo
Over the wintertime Kevin (Kev777) and I went to a Carver meetup down in VA. I brought the Dennis Had amp along and used the Mullards. As luck would have it there was a set of Klipsch speakers there. Fortes I think. I pointed to those knowing the combo would kick butt. When the music came on everyone quieted down and just stared at it, I think they were amazed that this little SE amp could sound so good. There was some nice synergy going on between the amp, the Mullards and the Fortes.
I just picked up a VTA SP9 tube preamp, came with four JJ 12AX7 tubes in the preamp section. Yuk, they lasted one song, now it's loaded with two Telefunkens and two Sylvanias, all vintage stock. It's magical now. Detail is fantastic, sounds amazing. Need to find some more vintage stock to try out, I'd be surprised if my first try with what I had on hand can't be bettered but I'm pretty happy as it sits.
I've picked up several sets of JJ tubes along the way, they always seem to come in amps I pick up. Nobody wants to get rid of there good stuff so they always fill it up with JJ tubes. And that's how I will get rid of them to. I call them "filler tubes", fills the holes.
BillWojo
My experience with JJ tubes has been similar. There are so many reasonably priced reissue tubes from Russia that sound good (my experience with GL, Mullard & Tung-sol & Winged C power tubes has been excellent) and so many reasonably priced, great sounding NOS small tubes ($30 for an RCA black plate 6189) that I see no reason to listen to JJ. When I sell an amp or preamp the buyer is always 'gifted' with as many JJ tubes as I've inherited. Obviously, YMMV.
I tried both reissued tube Gold Lion KT77 and Electro Harmonic 6CA7EH (the high current version) on the same amplifier.
I had great hope for the KT77 and was very disappointed. The sound was very analytic and flat. Clear but no body.
I had mixed feeling about the 6CA7EH but when I tried them, the result was excellent. Deep sound very dynamic.
Since then, the EH 6CA7EH is my EL34 tube.
I had great hope for the KT77 and was very disappointed. The sound was very analytic and flat. Clear but no body.
I had mixed feeling about the 6CA7EH but when I tried them, the result was excellent. Deep sound very dynamic.
Since then, the EH 6CA7EH is my EL34 tube.
How long did you let the KT77's break in? I know Upscale Audio says they can take up to 100 hours, and how they sound before break in is about what you're describing. I admit that's rather frustrating, as its pretty lame to sit around listening to your music sounding bad in hopes it eventually doesn't. I have a quad of RFT EL34s I think sound bad and can't really bring myself to give them a fair shake.
That they do. I wish so many people hadn't warned me that they're going to explode and take my amp with them, I'm scared to use them now.
I have sold hundreds of these, and so far every customer is satisfied.
Lavane
Lunatic Member
Ive read about failures with new manufacture tubes. A lot to do with EH and JJ. But many are old posts, as In several years old. Then there are people that read this stuff and just repeat it without trying them out personally. I can see tubes melting down in some guitar amps since they tend to be pushed hard. I have yet to have a new manufacture tube pop on me. Many may not sound as good as the originals, but the new tube manufacturers for the most part must be getting better at it by now. I only buy tubes from a short list of vendors. That way my chances of getting a tube made several years ago with defects is pretty low. Thats my thinking anyway, could be wrong im sure. The only problems with new tubes I've had are with signal tubes. EH brand. Ive had several that were noisy right out of the box. Microphonics and hum problems.
arts
Addicted Member
I've gone through hundreds of JJ E34L,not EL34, with no catastrophic failures.The only difference is the higher drive requirement with the E34L.Can't see there being much difference between the two types vis a vis reliability. One of the only ''modern'' EL34 types that can survive in a Hiwatt 200,which runs over 700 on the plates.Probably the only octal-based JJ I trust....
They have 3 !
EL34 , conforming to phillips spec, E34L which needs another bias and EL34 II a new model recently introduced.
I deal so far only in EL34 ( i have not seen any benefits in the others, but i may be mistaken and is willing
to be proved wrong)
I have heard people say JJ has improved over the years. I think any new-production tubes I purchase will come from Upscale Audio, as they seem to charge a few dollars more in exchange for a better grading and burn in process.
Giving my JJ EL34's a run now. Initial impressions are that they aren't bad but I like the EH 6CA7 more. This Pilot SA-260 is very tubey sounding to begin with, and the JJ's seem to add to that a bit. The EH tubes are a little bit more crisp sounding and this amp benefits from that. Still, not a bad sounding tube and I wouldn't have any particular qualms about running them if these were all I had.
Rest of the tube compliment are Sylvania 12AX7 phase inverters, an Amperex 12AU7 voltage amp, and RCA 5U4GB rectifiers.
Rest of the tube compliment are Sylvania 12AX7 phase inverters, an Amperex 12AU7 voltage amp, and RCA 5U4GB rectifiers.
Tom Bombadil
AK Member
The OP posed these questions a couple of years ago. Since then I have acquired several different types of EL34/6CA7/KT77 tubes and tried them in three different amps, to different results. I appreciate the suggestions posted here. Now pretty much have all of the information I need.
arts
Addicted Member
The original 6CA7 was a beam tube,are the reissues also? I had the same preference with the original 6CA7 over the EL34 too,and for the same reasons.
Pio1980
AK Member
Afaik, yes. The EH big bottle 6CA7 innards look just like the Sylvanias, just like 6550.