Tubes for a JVM?

B

B2D

SDUGF Riffologist Supremö
So I'm messing around with my JVM and one of the power tubes goes down. White flashing inside the tube (arcing?) accompanied with a lot of ugly bursts of noise and static.

I check the amp's s/n and it's a 2008, and they look like the original tubes - no idea how many hours were on them before I got the amp so it's probably due for a new set.

There's a good local tech in town so I'll probably take it in for a quick rebias and a new set of power tubes.

I'd planned to go look over in the JVM forum for some advice on this as well, but what are the JVM users on here doing for pre and power tubes these days? I've always been fond of JJ's in both for most amps I've had save for Boogies.
 
Re: Tubes for a JVM?

I like Svetlana for EL34's. Still running the stock set in my 210H though. Only amp I've ever owned that I didnt feel the need/urge to do tube swapping before any failures occurred.
 
Re: Tubes for a JVM?

I know I'm really pushing it with these tubes, but I still have the original SED Winged C tubes in my 2007 JVM. But I end up playing through my little practice amp more than I do through my heads, so they really don't have too much use on them.

I have been seriously considering doing the KT88 Mod, but if I don't, I'll probably go with Tung-Sol EL34s when I get new power tubes for it.

Go to TheTubeStore.com and read their reviews, they're pretty accurate in their descriptions.
 
Re: Tubes for a JVM?

KT88s in a Marshall are nice. Albeit a little stiff vocally and feeling. I prefer EL34s as I like a bit of power section...flex.
 
Re: Tubes for a JVM?

I have never found KT-88's to be stiff, though certainly solid. I suppose if you really have them pumping, they might loosen up just a bit. But then so won't the foundation of the building that they are being played in.
 
Re: Tubes for a JVM?

Gone_Shootin said:
I know I'm really pushing it with these tubes, but I still have the original SED Winged C tubes in my 2007 JVM. But I end up playing through my little practice amp more than I do through my heads, so they really don't have too much use on them.

I have been seriously considering doing the KT88 Mod, but if I don't, I'll probably go with Tung-Sol EL34s when I get new power tubes for it.

Go to TheTubeStore.com and read their reviews, they're pretty accurate in their descriptions.
Click to expand...

I know it isn't exactly the same, but I briefly tried running KT-88s in my Marshall Jubilee. Compared to EL-34s they were louder, less bright, and little bit bassier, but the overall changes were pretty minimal. Unless you're playing near the breakup point of EL-34s (or beyond) I doubt modding your amp for KT-88s will be worth the extra expense.
 
Re: Tubes for a JVM?

I threw a set of Mullards in my DSL. To my ear I am getting a lot more grind on my high gain stuff. I am also noticing a more singing sustain.
 
Re: Tubes for a JVM?

dystrust said:
I know it isn't exactly the same, but I briefly tried running KT-88s in my Marshall Jubilee. Compared to EL-34s they were louder, less bright, and little bit bassier, but the overall changes were pretty minimal. Unless you're playing near the breakup point of EL-34s (or beyond) I doubt modding your amp for KT-88s will be worth the extra expense.
Click to expand...

Thanks for the info. The mod only requires swapping out a few resistors since the transformers in the 100 watt JVMs are the same transformers that Marshall used in the JCM800KK, which came from the factory with KT88s.

But the slight difference you mentioned is why I'm still on the fence about it, and is why I'm also considering Tung-Sol EL34s.
 
Re: Tubes for a JVM?

I don't think you can install kt-88's in the jvm without upgrading various other components. I found the jvm to be very bright, so I threw in some JJ's in the preamp and left the power tubes with the stock =c=. head on over to jvmforum.com for detailed results of various combinations
 
Re: Tubes for a JVM?

Kais said:
my mistake. I have so many mods I'd like to try on the jvm, but no where near the amount of electronics knowledge to attempt
Click to expand...

No worries, man. And now that I think about it, I think we talked about this a few months ago. Lol
 
Re: Tubes for a JVM?

I've never replace mine, but I've read on the JVM forum that those winged C's are just superb.
 
Re: Tubes for a JVM?

JOLLY said:
I've never replace mine, but I've read on the JVM forum that those winged C's are just superb.
Click to expand...

They were superb, probably were the very best current production EL-34 available. But the factory quit making tubes in 2012, which is why they're so expensive, and I've read complaints about the quality of the remaining stock.
 
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