What would happen if I did this to a Mesa/Boogie head?

Contra · #1 06-10-2002, 04:34 AM

What if I changed the 6L6 power tubes to EL84s? What about EL34's?
How would the wattage be affected? Could I even do it?
I just read the Biasing article on the Mesa site, Do I HAVE to buy Mesa tubes? Can I buy Ruby EL tubes instead?
Any clarification on this would really help me out.
I'm used to just buying 12AX7's for my JMP-1, Ive never dealt with power tubes before...

7 Dying Trees · #2 06-10-2002, 07:54 AM

Get someone professional to rebias the amp for you once you've decided to change tubes. In general EL34's have a very classic british rock sound. EL84's I don't know, but I guess that's going more towards vox type of stuff and the like (I think, I may be very wrong on that one). Generally I'd describe changing from ^l^'s away to the tubes you've named as making the amp sound less american, possibly a bit more loose. But that's just me

BrianH · #3 06-10-2002, 10:31 AM

my tri. rect(well was mine) will do this out of the box. It has a switch to select which tubes you have put in it. as far as other mesa gear I don't know.

texshred777 · #4 06-10-2002, 12:27 PM

yeah, dual recs have the ability to take el34's instead of 6ls's. You just need to rebias it to the tubes you have, and flick the bias select switch. (take it to a professional..mesas dont have the bias points on the exterior like 5150s. That'd be cool though!)
NOW, to answer your other question. Mesa not only has their own tubes (chinese pos's i think) but they also offer svetlana el34s and 6l6s, and since they're distributed by mesa, they're already matched exactly the same straight from the mesa distributor. SO, once you bias your dual rec to the el34's you dont have to bias it again if you get mesa distributed svetlanas!! That's great! You can use ruby's if you prefer, but hey, svets are great and if you can get them to where every single one you buy is the same...rock on! Mesa believes that tubes should match the amp, and they should be set up to be the same everytime...that the tubes are set up to match the amp in the most economical and consistent way possible straight from them. El84s? no...not unless you get one of those el84 adapter 'Bone Plug in Play' or something like that. i wouldnt recommend that unless you want to run it at 50 watts and get power amp overdrive. I think el34s would be a nice thing to try in a dual rec, it would tighten up the bass some and give it some more musical mids. (something i think they need) but they overdrive easier...and i think preamp distortion by itself is a plenty in recs w/out power amp distortion on top of that. (talk about muddy...)

Contra · #5 06-10-2002, 08:46 PM

"Since a bias supply needs to put out the right voltage and never vary, I wanted to build amplifiers that were individually hard wired to the correct values and NEVER needed adjustment. And for 25 years, that's how Mesa/Boogies have been built."

"Time to change tubes? Just plug our tubes into any one of our amps and you're DONE. No tech needed. NO bills and no BS about biasing. And most important: The bias is RIGHT because it can't change!"

Those quotes were taken from:

http://www.mesaboogie.com/US/Smith/biasadjust.html

So I'm a little confused...

Contra · #6 06-10-2002, 08:48 PM

The head I'm talking about is a DC-3 by the way four EL84 power tubes stock.

jonrayl · #7 06-10-2002, 09:01 PM

*********************do NOT rebias the amp*******************

Mesa permantly sets the bias at the factory... you *never need to have them biased. To switch from 6L6 to EL34, simply slide the switch in the back to the appropriate tube type. As far as el84's...you would have to have a serious mod done to the amp as they are the size of 12ax7's and would never fit in the socket for a 6l6 or el34

jeffrey · #8 06-10-2002, 09:37 PM

I prefer the sound of EL34's over 6L6's by a large margin. Just like the tone better.

texshred777 · #9 06-10-2002, 11:01 PM

Quote:

Originally Posted by jonrayl

*********************do NOT rebias the amp*******************

Mesa permantly sets the bias at the factory... you *never need to have them biased. To switch from 6L6 to EL34, simply slide the switch in the back to the appropriate tube type. As far as el84's...you would have to have a serious mod done to the amp as they are the size of 12ax7's and would never fit in the socket for a 6l6 or el34

...As long as you're using tubes matched for the bias on a mesa amp. C'mon...how would it work if you bought a set of ruby el34's that are matched COMPLETELY DIFFERENT from mesa tubes. If you use the tubes they match up for mesa amps everything's cool. BUT if not then it's a different story. As far as the EL84 point you are absolutely correct except for the fact that you're forgetting about the adapter tubes i mentioned. You can find them in most musicians friend magazines. of course if it's made for EL84's and you want 6l6's or el34'd then forget it.

bammbamm · #10 06-11-2002, 04:26 PM

The boogies are fixed bias, they don't run that hot so you don't need to worry about the bias settings. This actually prolopngs tube life a bit by not having them run balls-out when you turn on the amp. Boogies Rock despite the low bias settings, don't worry about biasing the amp unless you swap tubes and have a switch specifically for that, otherwise let em be, most tubes that are matched have a set and predictable way that they react so when you swap between one or the other, yes, they will vary a bit, but it will not hurt your amp in the least. Plug n' play !

Bamm

Contra · #11 06-12-2002, 01:24 AM

Okay, thanks everyone.

So Basicly if I get a matched quad of Ruby El84's I will be fine??

texshred777 · #12 06-12-2002, 01:32 AM

well, you're in luck. amps that take el 84's are self biasing..so no matter what el84's you use its all good

BZ Beetle · #13 06-15-2002, 09:46 PM

personally, i prefer JJ tubes to any EL84's ive ever played. www.eurotubes.com has em, and they are reaaaaaaally nice. bob from eurotubes is a ncie feller too

texshred777 · #14 06-15-2002, 10:13 PM

Quote:

Originally Posted by BZ Beetle

personally, i prefer JJ tubes to any EL84's ive ever played. www.eurotubes.com has em, and they are reaaaaaaally nice. bob from eurotubes is a ncie feller too

jj tubes are just a brand...where as EL84s are a tube type...so I dont really understand what you mean. You can get EL84's from many different makers. I guess you mean jj tubes el34's...