EL34 vs KT77

[MikeS]

Yeah, I know, another tube question… The time has come, I think, to replace the power tubes in the DSL50. The tone just doesn’t seem to be there anymore, though I haven’t noticed anything visually off about the tubes. No weird colors or abnormal glowing... it just doesn't sound like it used to.

Originally I wasn’t thinking about going with anything other than EL34 (not sure whose EL34 yet, I might just go with OEM replacement once I open it up and see who made them) but then saw that the JJ KT77 fits the same socket. Tonally, what differences could I expect from the two tubes? Thus far I’ve read the KT77 has a flatter EQ than an EL34 and tonally sits between an EL34 and 6L6. The compression is supposedly also between 6L6 and EL34 as well. Anyone know about breakup with this tube? Clean tones?

I’m still leaning towards that classic EL34 Marshall sound, but I am interested in what the KT77 could do for me.

Thanks

 

[metlking]

Re: EL34 vs KT77

I was a big supporter of the JJ KT-77 when it first came out. I was using a Marshall 9100 poweramp at the time. When I switched to heads, including a DSL50 I popped them in to see how they'd sound. I personally didn't like them anymore.....too clean and tight. I was looking for more rawness and a 3D sound but didn't quite get it so I went back to the EL-34's. I'm using Shugaung EL-34-B right now and like them alot.........My DSL50 came stock with what looks like =C='s SED and Chinese preamp tubes..........I'm not using the KT-77's at the moment, I could send them your way to borrow and try out if you'd like.....Do you bias the amp yourself? It's real easy with only a volt metter. Marshall recomends 40-45mv but man thats high! I set mine around 37mv.......your tubes will last alot longer too!

 

[MikeS]

Re: EL34 vs KT77

Thanks. I don't want anything too clean and tight, and I do like the raw Marshall tone. I was a fan of it out of the box, so perhaps I should stick with the EL34 and try different variations of that. I thought the DSLs came with either Sovteks or Svets, but couldn't remember. If you say winged "C"/SED I believe you. Are you still running the stock preamp tubes?

I've never biased an amp before. I'm not opposed to learning how and I'm handy with a meter, but I recognize that doing it incorrectly can be an expensive mistake. So I don't know if I'm going to try it or not yet.

 

[idsnowdog]

Re: EL34 vs KT77

Does a KT-66 have the same socket and pinout?

 

[Lake Placid Blues]

Re: EL34 vs KT77

Does a KT-66 have the same socket and pinout?

Not the same pinout, but it uses the same octal socket. Pin-1 on the KT66 is internally connected. On EL34 amps its common to externally connect pin-1 to pin-8, the cathode, at the socket, so it doesn't matter to the KT66 if you put it in most EL34 wired sockets.

The same may not be true the other way around, however, so you must always use caution. The grid resistors on an amp designed to run 6L6/KT66 tubes exclusively may not be the right values, or the right connections for EL34's either. The KT66 will still run fine with grid resistors/connections of EL34 spec, however.