Ok so who the heck makes a good 6L6 anymore?

[The Dude]

I too have been quite happy with the Ruby 6L6GCM-STR. They have been sturdy and reliable, I think they sound fine, and not a single one has come back to me either defective or with a sound complaint.

Be careful when you say you like (or dislike) Mesa tubes. Mesa doesn't make tubes, so the Mesa 6L6 this month might be a Sovtek, but next month it might be a JJ. Calling a tube a Mesa doesn't tell us what it really is inside.

While this is certainly true, over and over I've had horrible luck with Mesa "branded" tubes. They are the worst I've seen, whether they make them or not. Maybe somebody is passing off seconds on them. Maybe somebody's taking the reject tubes out of the garbage and stamping them with the Mesa logo. I've no idea why and frankly don't care. I won't buy them,.. period. My experience is: On any given batch of Mesa tubes, more will be bad than good out of the box.

As a little side note: Just last week a customer brought in a TSL100 that was JUST re-tubed. The customer re-tubed it to see if he could fix it himself. All 4 preamp tubes were Mesa branded tubes. All 4 were bad (had at least one "dead" element- some both). Although I don't buy Mesa tubes, one of the local music stores here sells them, so I still see these crappy things all the time.

Edit: Another side note: Mesa's matching means they put them in the same kind of box. The last "matched set" of Mesa 6L6's a customer brought me for his amp at the identical bias voltage, current on one tube was 35ma and the other was 85ma.

[Enzo]

Oh, be fair, 85ma was a failed tube, not a mismatch.

[The Dude]

Oh, be fair, 85ma was a failed tube, not a mismatch.

Precisely.

[big_teee]

Has anyone else tried that 7581 Tung-Sol Yet?
Dying to hear another first hand report?
I think The Tube Companies should pick our Forum to test all the 6L6 Tubes.
We could start a list and rotate them around among us, to see which ones have the most Flavor!
What think Ye?
T

[Tone Meister]

Oh, be fair, 85ma was a failed tube, not a mismatch.

One good tube and one failed tube IS a mismatch, isn't it?

[wizard333]

While this is certainly true, over and over I've had horrible luck with Mesa "branded" tubes. They are the worst I've seen, whether they make them or not. Maybe somebody is passing off seconds on them. Maybe somebody's taking the reject tubes out of the garbage and stamping them with the Mesa logo. I've no idea why and frankly don't care. I won't buy them,.. period. My experience is: On any given batch of Mesa tubes, more will be bad than good out of the box.

As a little side note: Just last week a customer brought in a TSL100 that was JUST re-tubed. The customer re-tubed it to see if he could fix it himself. All 4 preamp tubes were Mesa branded tubes. All 4 were bad (had at least one "dead" element- some both). Although I don't buy Mesa tubes, one of the local music stores here sells them, so I still see these crappy things all the time.

Edit: Another side note: Mesa's matching means they put them in the same kind of box. The last "matched set" of Mesa 6L6's a customer brought me for his amp at the identical bias voltage, current on one tube was 35ma and the other was 85ma.

That is EXACTLY my experience with them. Every time.

I know who makes what, they seem to be mostly Sovtek, maybe they buy the ones Fender/GT rejects.

[Paleo Pete]

Me to, I also prefer to drive Ferraris and Bentleys, but I don't have the money for them. Nor do my customers. With RCA Blackplates selling at $200 PER TUBE, that is a non-starter.

Sorry, my bad, I should have also pointed out...and if you can afford them...you are right of course, those things are damn expensive...

enzo also pointed out something else I neglected, Mesa does not make tubes. But their QC must be getting sloppy, in earlier days, their tubes were always good and a pair was usually a good match. Then again that was 20 years ago...

[mikeboone]

I have been using Tung Sol 6L6 STR lately and I really like them. They are warm and compressed. They get my amp to a bluesy overdrive a little sooner than others I have tried. They don't fizz out in an amp with MV with some preamp gain going on if you're into that kinda thing.

I have recommended them to a few friends who all seem to like them as well.

[Cygnus X1]

Can't understand why Mesa branded tubes would be at a high rate of failure sold new.
Sure can't stock their amps that way and keep in biz, can they?
In a pinch for example I would always go for a Groove Tubes at a retail store because even
if they didn't sound the best I never had a reliability issue with GT's (except some oddball 12AT7's years ago).

I figured Mesa does their own testing and matching so they should have a low failure rate.

[Paleo Pete]

That's what I thought too, but according to comments here, maybe that's changed in the past few years...The friend I mentioned above has played Mesas for years, adn never had any trouble at all with replacement tubes, I've used them with no problems too and others I've talked to have given them good marks due to their reputation of reliable matched pairs. They supposedly do that so you can pop a new pair in your mesa and not worry about biasing. So they are not only supposed to be matched pairs, but close enough to factory specs to be user replaced on the fly with no hassles. If bad tubes are showing up that says Mesa QC is going downhill.

[bob p]

> "One that sounds good and is reliable? "

... and is stable over 500 VDC?

[wizard333]

They supposedly do that so you can pop a new pair in your mesa and not worry about biasing. So they are not only supposed to be matched pairs, but close enough to factory specs to be user replaced on the fly with no hassles. If bad tubes are showing up that says Mesa QC is going downhill.

They sell tubes in a certain bias range, so that yes, if you buy those tubes, you don't have to bias. But then Fender sells amps with GTs in the 4-6 range, so if you buy those, you don't have to re-bias either. And if you know what that range is on anyone else's scale, you can buy tubes anywhere you know the scale and not have re-bias. They aren't any better matched than anyone else's in theory, and in practice, I've found them to be, at least as often as not, woefully mismatched.

The other way Mesa gets around that issue is that they bias amps very cold. Ever checked factory bias on a 6L6 or EL-34 Mesa running Mesa tubes? I've seen them in the 25% at idle range quite often. That is to preserve tube life, and also I guess so that if someone stuck a hot set of tubes in there, they'd still be too cold to cause red plating. Does nothing for the sound though, changing the bias on those amps to something more reasonable makes them sound a whole lot better, on the clean channel especially.

Maybe they match up ok at super cold bias, IDK. If so, then using a normal 50-70% may throw them off, and that's what we're seeing.

They do burn their EL84s to hell like everyone else though. Over 100% at idle.

They occasionally seem to sell an acceptable set of tubes, but my experience when someone brings me Mesa tubes to put in something is that less than 50% are something I'd put in an amp.

[bob p]

They sell tubes in a certain bias range, so that yes, if you buy those tubes, you don't have to bias. But then Fender sells amps with GTs in the 4-6 range, so if you buy those, you don't have to re-bias either. And if you know what that range is on anyone else's scale, you can buy tubes anywhere you know the scale and not have re-bias. They aren't any better matched than anyone else's in theory, and in practice, I've found them to be, at least as often as not, woefully mismatched.

My experience with Mesa tubes is limited to a Mark IV that I've had for over a decade. It's got the Green-Dot STR in it from the 1990s. they work fine, and they've been totally reliable. No complaints. And those tubes are older than dirt. I don't think I've ever changed them. cold bias definitely prolongs tube life.

The other way Mesa gets around that issue is that they bias amps very cold. Ever checked factory bias on a 6L6 or EL-34 Mesa running Mesa tubes? I've seen them in the 25% at idle range quite often. That is to preserve tube life, and also I guess so that if someone stuck a hot set of tubes in there, they'd still be too cold to cause red plating. Does nothing for the sound though, changing the bias on those amps to something more reasonable makes them sound a whole lot better, on the clean channel especially.

I agree completely that cold biasing preserves tube life, but I wouldn't go so far as to say that Mesa's cold bias approach does nothing for the sound, as it does provide for remarkable consistency in the amp;s sonic signature as it migrates from low output to high output.

Mesa's approach to voicing an amp like the Mk IV is to do most of the tone shaping in the preamp, not so much in the power amp. This is especially apparent in the multiple channel amps that use cascaded distortion in the preamps. In those amps, the objective is to tweak knobs in the preamp section to control the amp's tone. With a cold biased power section, it becomes very easy to tweak the preamp at bedroom levels to find your tonal settings with the power amp turned down about as far as it will go. When it's time to play the amp LOUD, just turn up the master volume and the sound doesn't change all that much, it just gets louder. IMO that's a VIRTUE of cold biasing -- it allows the power amp not to act as as much of a tone colouration device as if it were biased hot.

In my case, I don't really have a problem with the fact that the Mk IV has it's power section biased as cold as it's biased by the factory. When I first got the amp I was eager to rip out the factory bias circuit and replace it with a conventional bias setup so that I could bias the amp hotter. It took a couple of years of playing to gain enough familiarity with the amp to figure out that that was a mistake.

[Enzo]

One good tube and one failed tube IS a mismatch, isn't it?

True, but it differentiates from Mesa just throwing random tubes in boxes and calling them matched.

[Steve Conner]

I disagree, I think when a tube power amp is biased too cold, it makes the sound more inconsistent as you vary the power. It sounds all thin and fizzly at low volume, only to come to life as you crank it.

You might have to go colder than 25% dissipation before that becomes a real problem, though.

I agree in the case of a Mesa, the cold bias is intentional and part of the sound. The whole amp was tuned as a package to sound the way they wanted. If the tone stays consistent between bedroom level and gig level, that's because it's a well-designed package of a master volume amp, not simply because it's biased cold.