Recommendation Needed: Durable EL34’s

[braintheory]

So as some of you guys may have seen, I got a Megalith Beta amp that came with KT88’s. I wanna try EL34’s in it, but according to the maker himself, he said that EL34’s are actually to him the best sounding tubes in it, but the ones he’s used only lasted a few days in the amp because of the super high plate voltage of the amp even though in theory the 34’s should be able to handle way more than the amp has. Are there any current production EL34’s that you guys think can last ok in this amp and still have that more raunchy EL34 flavor that I like? I asked also about KT90’s in it, but he said they also don’t last that long in it and don’t sound that different from the 88’s in it

 

[harddriver]

KT88's are pretty much like a big bottle slightly more linear EL34's IMHO but the KT88 does has emphasized mids unlike 6550's, that's why Marshall used the KT88 in the 200 watt Marshall Majors because it was the most EL34 like big bottle tubes at the time. I don't recommend the JJ KT88 they really have a compressed bottom end that I don't like but yo might dig it YMMV. For new production KT88's I like EH or Sovtek KT88's they are well built a quite robust. I've heard great things about the new production reissue Gold Lion KT88's but I have no experience with them.

That being said I love 6550's, GE and old Svetlana SED 6550's in my Marshalls as well as Sylvania 6CA7's. The EH6ca7 might last a while due to the more rugged construction but if you have plate voltages above 450, like 480 and 500 DCV bias them cold like 50%/60% dissipation and you will be golden.... KT88's and 6550's don't like a hot bias, they can get mushy on the lows and less defined sounding if biased hot.

If the amp has high voltages above 450 DCV stick with the KT88's nothing besides the Ruby EL34BHT's can handle it well but it seems the Ruby Shuguang EL34BHT is no longer being made and they were the only modern EL34's that could handle higher plate voltages.

 

[MetalHeadMike]

JJ E34L is what Rick uses in his amps and they're supposed to be pushing 500v on the plates. I was told Tesla black base EL34 are also capable of holding up under those plate voltages but they're over $400 a quad.

 

[Nigel]

JJ KT77’s take high voltage and are EL34 like in the mids.

 

[braintheory]

JJ KT77’s take high voltage and are EL34 like in the mids.

I’ll ask him if those will last in it. They do sound very good in my Gjika and are the stock tubes for that amp

 

[braintheory]

JJ E34L is what Rick uses in his amps and they're supposed to be pushing 500v on the plates. I was told Tesla black base EL34 are also capable of holding up under those plate voltages but they're over $400 a quad.

I gotta double check, but I think I remember hearing that this Beta is in the 600v range. It’s a crazy amp. Those E34L’s do have a midrange voicing that I think could really benefit this amp

I’d be scared to try NOS tubes in it and risk them breaking from not handling the amps crazy plate voltage

 

[RedB4Black]

I came to say JJ e34Ls but Mike took care of that already!

 

[Nigel]

I’ll ask him if those will last in it. They do sound very good in my Gjika and are the stock tubes for that amp

Talked to Bob a while back. We both prefer JJ KT77’s and 50’s Mullard f91/f92 ling plate 12AX7’s. I know I need to get a 10n quarter stack, it’s likely the ultimate for what I love.

 

[Exo-metal]

TADs

 

[psychodave]

I thought the EL34BHT was good for high voltage.

 

[fusedbrain]

You should be OK with these.

 

[Racerxrated]

Siemens will hold up, but like you said they are spendy...KT90s though, sound pretty different to me vs 88s...very EL34-like in the midrange. I'm surprised he thought they sounded that similar. The VHT D60 took on a whole new dimension when I swapped 90s in place of the 88s.
Go with the JJ EL34L as others have said...if they fail you aren't out too much. KT90s aren't cheap either.

 

[braintheory]

Siemens will hold up, but like you said they are spendy...KT90s though, sound pretty different to me vs 88s...very EL34-like in the midrange. I'm surprised he thought they sounded that similar. The VHT D60 took on a whole new dimension when I swapped 90s in place of the 88s.
Go with the JJ EL34L as others have said...if they fail you aren't out too much. KT90s aren't cheap either.

I’ve got Siemens in my Hiwatt I could use, but that would be a real bummer if my Beta kills them, so don’t wanna risk that. I was surprised too that he said that about the 90’s, but who knows, it’s a different amp than others I’ve been through. The JJ EL34L’s or KT77’s seem like solid choices from what I’m gathering. Because it’s a new 2020 amp and not a raw, organic kinda amp, I’m guessing it’s not one of those amps that’ll really sound better with vintage tubes. From my experience these kinda amps actually often sounded worse to me with vintage tubes vs generic tubes

 

[braintheory]

You should be OK with these.View attachment 81982

Yeah that seems like one of the contenders, but the maker himself mentioned that even EL34’s that supposedly could do 800v didn’t last in his amps, but maybe these KT77’s would be better. I asked in the MI Audio Facebook group and him if they’ll do the trick. Waiting to hear back

 

[harddriver]

Yeah that seems like one of the contenders, but the maker himself mentioned that even EL34’s that supposedly could do 800v didn’t last in his amps, but maybe these KT77’s would be better. I asked in the MI Audio Facebook group and him if they’ll do the trick. Waiting to hear back

If the builder himself told you that he tried new production EL34's in his amp and they didn't last then there is a design reason why he had to use a more robust tube like the KT88 in his amps. (plate voltage above 500DCV- I think you stated earlier 600DCV)

I guess if you really have to hear EL34's in this amp then be prepared if they go poof and damage the amp. Sounds like the builder has made it pretty clear.

It has been stated by other builders that new production tubes due to the materials used in construction these days anything above 450DCV can really shorten the longevity of them.