Mark III question

Hey Guys,

so i picked up a mark III chassis... el34's in the power section ( all 4 tubes ) and looks like the bias mod is installed

amp clean sounds great can crank this up with no noise or hiss... the lead channel sounds a bit weird to me .. kind of brittle.. maybe its just me..

anyway, was thinking of going back to the original configuration and was wondering what the tubes should be biased at kind of thinking that the bias mod was just for the set that was switched to el34's im aware that it should have one pair of 6l and one pair of el34

its a non simulclass 60 - 100 watt version

any help would be appreciated !!!

thanks,

Joe
LONG LIVE THE BOOGIE !!!!!

That's got to be one of the most interesting mods I've heard of on a MkIII. All EL34s??!! Sounds interesting. The bias, if I were to hazard a guess, is probably in the 30mV range for the EL34s. But honestly, I've never measured bias on my Boogie...ever.

DeathMagnetic said:

im aware that it should have one pair of 6l and one pair of el34
its a non simulclass 60 - 100 watt version

Click to expand...

Can't answer your question as I don't recall the numbers off the top of my head, but what I can tell you is this, DO NOT run 6L6s AND EL34s at the same time with your amp!! Only the Simul Class version is capable of running 6L6s on the inside pair and EL34s on the outside pair, if the power switch on your amp says 60/100 it's NOT Simul Class and therefore you should run all 6L6s or all EL34s (in fact, if you didn't have the bias mod you could only run 6L6s).

I saw that amp for sale and wondered, why? EL34 v. 6L6? Just buy a friggin Marshall already.

thanks for the replies!

as with all my other Mesa's i feel that the amp should be run with the tubes it was designed for.

This was a great purchase ... it ROARS and is dead quiet between notes... and the price couldn't be beat !!!! I had the Mark II pretty sure it was the a version ... lt had the 15" EV and was an anchor... the loop is great on the III and the channel switching is much better

Fortunately i have an old Ampeg 2 x 12 combo at my rehearsal space so i'm just jacking in to the speakers with whatever head i bring.... (nothing against the ampeg, but it is REALLY old and does some funky stuff... probably needs caps and tubes)

on that note.. the front says full power / half power on the switch isn't the simul class switch on the back ( if it had it )

Joe

Yes the switch would be on the back right side next to the heat sink. I've never heard of all el34s in a mark before. Strange to me but if it ain't broke, don't fix it. :mrgreen:

I have a Mark III blue stripe 60w with El34's - I love it when it works

Its broken again - this time I think it needs a full rebuild - I am debating to just get it put back to normal, but I reckon it sounds really good like it is, I just wished it was more reliable -

Regards


Casey

Not wanting to jynx myself... have been taking this to practice for a couple weeks now.. and some time noodling with it seems to be working great ! not sure the mods done to it other than the bias mod

It does kick butt..

Joe