Technical question - Mesa Boogies and valve's..

nick79

Hi guys, i'm after replacing the el84's in my Mini Rectifier, they've been in since it was new back in 2012 and it's been used in anger a fair bit. 
I've heard good things about JJ's in these, but do i need to get a pair that are within a certain range? I understand Mesa branded valves are colour coded to specify how hot or cold they run, thus changing the tone slightly? (That could all be bollocks though  ) 
I like the way it sounds and just worried if i buy a random matched pair it might change it.
Thanks

ecc83

I am pretty sure I have seen ICBM &Co state that power valves are less responsible for 'tone' than some (mainly valve suppliers?) would have us believe! Pre amp valves have more effect I think. I would be more inclined to go for value for money and reliability....('These £100pr Cryo jobs give FABULOUS tdfor tone! When they work. )

Dave.

Beexter

As I understand it,  all of the Mesa branded valves measure within a certain tolerance and if you fit Mesa branded valves,  you don't have to worry about biasing.
Of course,  you can fit other valves and some suppliers can supply valves that fall in the same tolerance bracket as the Mesa valves - i just don't know what this is as it doesn't seem to be published anywhere.
 I'm sure some of the more technically proficient peeps on here,  ( I'm looking at you ICBM) can shed a bit more light...

ICBM

It's true that Mesa amps are not adjustable, but as far as I remember I've never come across any decent, tested set of valves of any make that didn't bias in the right range in one. Not always 'perfect', but perfectly good - the amps are usually biased quite conservatively so there's a fair tolerance range.

Power valves don't have as much of an effect on the tone, no - some, but nowhere near as much as preamp valves. JJs are among the better power valves, and are usually reliable - I'm not a fan of their preamp valves though.

nick79

Thanks chaps, i'll order a pair of JJ's. £23 as opposed to more than double that for ones with Mesa stamped on.  

ICBM

nick79 said:

Thanks chaps, i'll order a pair of JJ's. £23 as opposed to more than double that for ones with Mesa stamped on.  

It may literally be that - I could be wrong, but I think Mesa are currently using JJs anyway! I never buy Mesa-branded valves so I'm not certain.

nick79

Thanks @ICBM       Just ordered them, it will be interesting to hear any difference. The valves in there at the mo are 3 to 4 years old and it's been used a fair bit. And cranked up pretty loud by me in the last 6 months, pretty much every week for a few hours. 

nick79

Just an update... I went ahead and got a pair of JJ's, and it's made a nice difference. It feel's punchier now and a bit louder - Last gig i didn't have to have the volume up as much as normal, although that might be because it cut through the mix better. 
Thanks again for the advice