I'm going to replace my 2x12 LSC's 6L6 tubes coming up here and I've always put JJ tubes in other amps that I own. No particular reason, just liked the good folks out at eurotubes. So I've read that Mesa Boogie tubes are self biasing, is this only true of Mesa tubes? If I just stick a quad of a different brand of tube in there is the bias going to seem too cold/hot? Also, any recommendation of 6L6's to check out? I've been getting some pretty bad rattle with these Mesa tubes (I know that happens to most tubes in a combo). Thanks everyone! Take care.
6L6 Tube Replacement Self Biasing Question
- Thread starter zwish
- Start date
Help Support The Boogie Board:
plan-x
Well-known member
Tubes don't self bias. Mesa tubes are just tested and labeled by their specs....cold, hot, etc. Just like JJ's. You could virtually put any tube in there because the amp is self bias. I went with Eurotubes. They know the specs and will set you up with alot more details than mesa will. I asked for a high headroom set (pre & power tubes) for maximal vol without break up. Also, the JJ's seem to last alot longer than the mesa tubes. They sound better too! You know the drill, call Bob at Eurotubes.
These are the LSC kits. But as I said, you can customize the qualities you desire. The high gain kit is a hot tube set and probably will make a LSC snarl. We got this amp for its big, bold smoothness. The standard kit should be adequate and certainly surpass mesas kit. I retubed with mesa once and was disappointed. The amp just sounded flat. Got the JJ's and it's bouncy character was restored beyond the original set of mesa's.
https://ssl.eurotubes.com/cart/index.php?page=view_products&category_id=6&sub_category_id=139
These are the LSC kits. But as I said, you can customize the qualities you desire. The high gain kit is a hot tube set and probably will make a LSC snarl. We got this amp for its big, bold smoothness. The standard kit should be adequate and certainly surpass mesas kit. I retubed with mesa once and was disappointed. The amp just sounded flat. Got the JJ's and it's bouncy character was restored beyond the original set of mesa's.
https://ssl.eurotubes.com/cart/index.php?page=view_products&category_id=6&sub_category_id=139
djw
Well-known member
I concur wholeheartedly with plan-x, except on one point: It's my understanding that Mesa amps are FIXED bias, which means the amps' bias values do not change, and are non-adjustable. The exception here of course is the switch for 6L6 or EL34 bias settings. But that just switches between two fixed values that match up with Mesa's idea of what good biases for 6L6 or EL34 type tubes ought to be.
You can order tubes that will run hotter than the Mesa-specified tubes generally do. Tubes that run hotter than the Mesas will probably not last quite as long as a result, but lots of folks think these amps sound better when running a little hotter than spec. As plan-x says, talk to your tube dealer about it, they should know something about this. You will also, by the way, technically void the warrantee using non-Mesa approved tubes, but that's something we all deal with in our own way...
Yellow Jackets are self-biasing, by the way. But tubes are not.
You can order tubes that will run hotter than the Mesa-specified tubes generally do. Tubes that run hotter than the Mesas will probably not last quite as long as a result, but lots of folks think these amps sound better when running a little hotter than spec. As plan-x says, talk to your tube dealer about it, they should know something about this. You will also, by the way, technically void the warrantee using non-Mesa approved tubes, but that's something we all deal with in our own way...
Yellow Jackets are self-biasing, by the way. But tubes are not.
Telemaster
Well-known member
- Joined
- Oct 21, 2008
- Messages
- 117
- Reaction score
- 5
The amp is self biasing. Buy the tubes you prefer, in matched pairs, and put them in.
PS: It's a lot easier if you turn the amp upside down...really. I put a towel over my road case and turn the amp upside down on the top of the case...get's it at a working height and takes about 2 min to change out the tubes. Also: Don't do it while the old tubes are hot or you won't be picking licks for a few days.
PS: It's a lot easier if you turn the amp upside down...really. I put a towel over my road case and turn the amp upside down on the top of the case...get's it at a working height and takes about 2 min to change out the tubes. Also: Don't do it while the old tubes are hot or you won't be picking licks for a few days.
Yet if you put a matched set of tubes that are too far away from mesa specs they will redplate and usually last
sometimes weeks, days , or hours, if you even can stand the way they sound.
Fixed bias and "self bias" are said by a few as being the same, yet if you understood what fixed and self bias meant,
you would usually apply self bias to a cathode biased amp.
There is "non adjustable" fixed bias, most mesa's, and adjustable fixed bias, marshalls , some fenders, and plenty others,
if you are putting tubes in a mesa, with fixed bias it is best to get a matched set or quad in the bias range that mesa
sets their amps at. That would be what most call the middle. Groove tube numbers 4/5/6. So forth.
You can indeed stick any match set or quad in the amp, yet if they redplate, ruining your tubes, perhaps you
will lose your grid resistors, and even with alot of luck you might damage the transformer.
They might be out of spec and not redplate but run so cold that your amp lacks much of its performance and sound.
/cheers
sometimes weeks, days , or hours, if you even can stand the way they sound.
Fixed bias and "self bias" are said by a few as being the same, yet if you understood what fixed and self bias meant,
you would usually apply self bias to a cathode biased amp.
There is "non adjustable" fixed bias, most mesa's, and adjustable fixed bias, marshalls , some fenders, and plenty others,
if you are putting tubes in a mesa, with fixed bias it is best to get a matched set or quad in the bias range that mesa
sets their amps at. That would be what most call the middle. Groove tube numbers 4/5/6. So forth.
You can indeed stick any match set or quad in the amp, yet if they redplate, ruining your tubes, perhaps you
will lose your grid resistors, and even with alot of luck you might damage the transformer.
They might be out of spec and not redplate but run so cold that your amp lacks much of its performance and sound.
/cheers
