Cold-running EL34s in outer sockets of Mark III?

[Whoopysnorp]

I was experimenting with the configuration of my Mark III today, and noticed the Svetlana EL34s I had in the outer sockets were only drawing about 13 mA. I replaced them with a pair of JJ E34Ls that were drawing more like 24 mA and figured that would work better. However, I think it had an adverse effect on my tone...after the change, the same settings that were giving me a nice undistorted clean before were giving a kind barky breakup. The tone wasn't even coming from the Mark III's preamp in that scenario; I had my Studio Pre patched into the effects return. I replaced them with the Svetlana EL34s and got my tone back the way it was. Should I, then, be running colder EL34s in those sockets on purpose?

One variable here is that neither pair of tubes was new. The Svetlanas were stock in a Marshall TSL601 I used to have, and the JJs came from the inner sockets of my Rivera M100. Perhaps with fresh tubes, I wouldn't get this unwanted breakup, or perhaps these brands aren't ideal for the Mark III? Basically, I'm trying to find out whether I can get some hotter-running EL34s in those sockets without losing my cleans (or maybe I should use 6L6s instead).

 

[MrMarkIII]

Obviously, the "correct" tubes to use are the ones that sound good, regardless of brand, hot / cold bias, etc. Oscilloscopes and multi-meters don't measure tone. Ears do.
Of course, it's always nice if your amp doesn't actually catch fire.

 

[CoG]

Welcome to my nightmare :lol: With EL34s the Mark III will give you two of: crystal cleans, nice distortion, or volume. Choose.

There's a lot to be said for 4x6L6 if you aren't doing a lot of lead stuff.

I use either SED =C= or NOS Siemens EL34s and just try rolling the guitar volume back a little. I don't really like my green stripe's cleans, period. My purple's cleans are much nicer-- this is with the same tube in V1, even swapping the same tube back and forth. I think they did something to increase the gain in the later stripes.

 

[6L6C]

You might find this interesting it’s a Word Document with readings I got on my Mark IV before a bias mod I had done The tubes are SED’s, as you will see the 4x6l6 are pretty much on par. However the 2xEl34/6l6 are a bit different, those 34’s are cold! But like it was already said sounds great so I really could not complain.

http://www.box.net/shared/thtamz9jr6

 

[CoG]

yo rabies if you are ever rolling in cash sometime, try siemens/rft NOS EL34s. (these are the same as STR-450s from Mesa.) You want some grind, mang? If you ever decide you deserve a present (like, $200 for a quad of EL34s) this is a good one. I just can't really get on the NOS preamp bandwagon, but **** these things sound good.

 

[kiff]

I dunno... I play mostly hard rock/metal so I rely on the preamp's gain and the clean channel stays clean. I did the same when I used my marshall jcm800 and a tube preamp.

Bottom line is, the boogie just sounds awesome that way... so I'm not sure I should even care about how hot the tubes run..