#1
Hey, I just bought a used Mesa Single Rectifier, and the power tubes need replacing. As you most likely know, Mesa Rectifiers use 6L6's, and Mesa tubes should only be replaced with Mesa tubes. That being said, the tubes currently in the amp (the old ones) are Mesa 6L6 STR 420's, while the new tubes (on mesaboogie.com), are Mesa 6L6 440's. What's the difference, and what does STR and the number mean?
Gear:
Fender Stratocaster
Gibson SG w/ Bigsby
Ibanez Roadster Bass
Sovtek MiG 60
Marshall 1965B
Maestro Echoplex EP-3
MXR Ten Band EQ
EHX Russian Big Muff
Ross Phaser
Boss DD-6
#2
Hmm..Im not quite sure...it could be the bias. As in 420 or 440 plate volts. But Im not sure...
#3
Quote by fitzyfantastic
Hey, I just bought a used Mesa Single Rectifier, and the power tubes need replacing. As you most likely know, Mesa Rectifiers use 6L6's, and Mesa tubes should only be replaced with Mesa tubes.

Not in the least bit true. You can replace your Mesa tubes with any other brand as long as they're 6L6s. You might even like another brand more. That being said, it's hard to find a warranty that beats Mesa's. I've had the same tubes in my Mesa (Mark IV) for about 7 years. They're JUST starting to die on me.
That being said, the tubes currently in the amp (the old ones) are Mesa 6L6 STR 420's, while the new tubes (on mesaboogie.com), are Mesa 6L6 440's. What's the difference, and what does STR and the number mean?

As long as they're 6L6s or 5881s, don't worry about it. You'll get lost in the sea of acronyms they put on tubes. But yeah, check out www.tubestore.com. They have a good explanation section and they do ratings of a lot of different tube manufacturers.
Hi, I'm Peter
#4
I guess it's head games and what-not.... but I had STR 430's in the first Dual Rec I had. Then I purchased the one I have now with STR 440's, and the sound is still sweet.... but it's a little thinned out sound more than before. Like I said, could be me?
Mesa Dual Rec/ Mesa 4X12 cab
01 PRS Custom 22
06 PRS Singlecut Ann.
1965 Fender Mustang
Ibanez acoustic
AceFrehley Epiphone LP
Takamine Explorer
tr-2 tu-2 / EHX DMM / MXR Script Phase 90 / SMM w/ HAZR
WH-1 Whammy / 535Q Crybaby
#5
Mesa tubes are nothing more than rebranded Sovteks. Other tubes will infact most likely sound better.

Try SED 6l6s. They work great in Mesas.
#6
they may just be re-branded, but they are tested also to be within their factory bias specs. If I had a mod to adjust the bias, I would have probably experimented with other brands. But besides the warranty, that also means that you can replace just one if you needed to by matching up their color code. I used different preamp tubes, but I think I'm going to stick with Mesa power tubes.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 14, 2006,
#8
Quote by Erock503
they may just be re-branded, but they are tested also to be within their factory bias specs. If I had a mod to adjust the bias, I would have probably experimented with other brands. But besides the warranty, that also means that you can replace just one if you needed to by matching up their color code. I used different preamp tubes, but I think I'm going to stick with Mesa power tubes.

Suit yourself... They really come to life with SED's. I need to get some myself.
#9
Quote by electrik
Suit yourself... They really come to life with SED's. I need to get some myself.

what are SED's anyway? I'm just really happy with the sound of my Mark right now, but they are also basically new tubes. I used JJ's in the preamp section, and I tried a few different kinds before I settled on them. They had the smoothest gain IMO, and they seemed to work well with the Mesa power section.

I'm all for improvement though, if they actually test them or something specifically for Mesa's fixed bias, that would be great. For me personally, I really like the powertube overdrive you get from these amps. I know you said you really don't like driving your tubes that hard, but I like when my power section is cooking. I've found that it's really easy to get into that crossover distortion if the bias isn't set correctly for those tubes when they are really cooking though, I saw it first hand on the Framus. I also don't want to go throught tubes like candy if the bias is too hot.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#10
Quote by Erock503
what are SED's anyway? I'm just really happy with the sound of my Mark right now, but they are also basically new tubes. I used JJ's in the preamp section, and I tried a few different kinds before I settled on them. They had the smoothest gain IMO, and they seemed to work well with the Mesa power section.

I'm all for improvement though, if they actually test them or something specifically for Mesa's fixed bias, that would be great. For me personally, I really like the powertube overdrive you get from these amps. I know you said you really don't like driving your tubes that hard, but I like when my power section is cooking. I've found that it's really easy to get into that crossover distortion if the bias isn't set correctly for those tubes when they are really cooking though, I saw it first hand on the Framus. I also don't want to go throught tubes like candy if the bias is too hot.

All tubes work fine in the Mesa amps. You don't have to worry about bias, and you really won't experiance any of those problems. In any case, this is what Doug at Doug's tubes reccomends for a Mark IV if you're ever interested in trying somthing new or whatever:

Hi,

The best time to reach me is after 11am and before 9pm.

I have just the setup for the MKIV, I've done this in a bunch with some happy customers
v1 - Tung Sol reissue (some people like a JJ ECC83S in here too)
v2 - high gain JJ or sovtek 12ax7lp
v3 - shuguang 12ax7c9
v4 shuguang 12ax7c9
v5 balanced shuguang 12ax7c9

Regards,
Doug
http://www.dougstubes.com

Oh and SED 6L6s sound great in the power section!
#11
Quote by electrik
All tubes work fine in the Mesa amps. You don't have to worry about bias, and you really won't experiance any of those problems. In any case, this is what Doug at Doug's tubes reccomends for a Mark IV if you're ever interested in trying somthing new or whatever:

Hi,

The best time to reach me is after 11am and before 9pm.

I have just the setup for the MKIV, I've done this in a bunch with some happy customers
v1 - Tung Sol reissue (some people like a JJ ECC83S in here too)
v2 - high gain JJ or sovtek 12ax7lp
v3 - shuguang 12ax7c9
v4 shuguang 12ax7c9
v5 balanced shuguang 12ax7c9

Regards,
Doug
http://www.dougstubes.com

Oh and SED 6L6s sound great in the power section!

hmm, very interesting. So he uses a 12AX7 in the driver instead of a 12AT7. Mine came stock with a Mesa 12AT7, but I swapped a balanced 12AX7 in for a little rattier sound. My circuit is a little different than the current Marks though, it's a 1991 model, the original circuit. You have me interested in what those specific tubes have to offer though. I went with a high gain kit of JJ preamp tubes from Eurotubes.

The only thing I'm worried about with the power tubes, is getting that flubby buzzy sound when I'm really pushing the power section hard, I really LOVE to push them like I said. I have a really tight high gain sound when I'm cranking it right now, so I'm hesitant to mess with it. I know you can use any tubes, but I've heard what some other brands sound like in this amp, and it didn't sound NEARLY as good.

Is there any clips I could check out that you know are using those SED? Also, when people are getting the SED, are they also getting a bias pot added?
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#12
I don't have any clips of people with them, but no, no mods are done. Just pop em in... And yeah, I know you like your power tube breakup, but I don't think these tubes will in any way hinder that... at all.

You seem pretty hung up on the fact that Mesa says they factory bias their tubes or whatever, but its nothing, they just want you to buy their tubes, they make it sound like their tubes are the only thing that work in their amps, which is far from the truth.
Last edited by electrik at Aug 14, 2006,
#13
You don't have to adjust the bias in any way. You can just tweak it so you get the best out of them. You don't have to have a bias pot added(though I've done it to myself my amps and I recommend it).

One thing that IS IMPORTANT though, is to have matched tubes. This makes a big difference.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#14
Oh and by the way, whats your idea of cranked for tube break up? I run my master at 3 and my output volume at 3-4, and thats my ideal kind of sound. Anything higher than 5 on the output and I don't dig, at least for metal, and playing alone. I haven't played the Mark IV with the band yet though.
#15
I hear what you're saying electrik, but I've seen first hand what a perfectly biased amp sounds like compared to one that isn't, especially when you are pushing it hard like I do. That's why I'm hung up on it, but I'm willing to look at other alternatives. I know there is always room for improvement with anything, I'm not so arrogant to think mine is the only way.

Pink, what do you mean by tweaking it, you mean what EQ I'm using when I'm pushing it? And yeah, that's on my shortlist actually, I'm going to add a bias pot to the Mark eventually. I was planning to when it's time to change these Mesa's, but that won't be for a while.

Quote by electrik
Oh and by the way, whats your idea of cranked for tube break up? I run my master at 3 and my output volume at 3-4, and thats my ideal kind of sound. Anything higher than 5 on the output and I don't dig, at least for metal, and playing alone. I haven't played the Mark IV with the band yet though.



electrik: when I'm really pushing it, sometimes to even record, I run my channel volume at 7-8 and my master at about 11:00. I had to get a different knob for my output level, so I don't have numbers on it, lol.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 14, 2006,
#16
Hm, well when I crank it it gets real bright real fast. But then again I have a naturally bright speaker too (EV). Probably have to compensate a bit with the settings and EQ sliders... I'll give it a try tomorrow. Not to mention it just plain hurts the ears at such high volumes, thats why I don't do it when I don't need to.
#17
Quote by electrik
Hm, well when I crank it it gets real bright real fast. But then again I have a naturally bright speaker too (EV). Probably have to compensate a bit with the settings and EQ sliders... I'll give it a try tomorrow. Not to mention it just plain hurts the ears at such high volumes, thats why I don't do it when I don't need to.


haha, yeah, I have a earphones and a mixer, or earplugs if I'm going it "usually", at least with the 70 or 85W setting. I do it quite a bit on the 30W setting though, so it's only pushing the 2 tubes really hard. you want to hear your Mark roar though, try it sometime.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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#18
The bias is just for fine tweaking the cathode current flow on the tubes. You don't need to change the bias for different tube brands(however don't go and plug EL34s or 6V6's or anything in).
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#19
Quote by That_Pink_Queen
The bias is just for fine tweaking the cathode current flow on the tubes. You don't need to change the bias for different tube brands(however don't go and plug EL34s or 6V6's or anything in).

hmm, it made a big difference on my Framus. Do certain amps just drift on their own or something? By bumping up the bias on my Framus to 34mA with the EH tubes, it really made a positive diffence in the tone. This is good to know though, I will try out some different power tubes when I change mine next.

edit: and Pink, that cathode current flow, isn't that what determines when the tubes are running into crossover distortion, or when they start to burn up?


oh, and BTW Pink, you can use the EL34 or 6V6 with the Mark IV, it's ""simulclass" as Mesa likes to call it. You can run all 6V6 or sub in 2 EL34 with 2 6L6.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 14, 2006,
#20
Oh, well if the amp is built for it, it's fine.
Don't get the idea it's alright with any amp though.
I'm not very active here on UG currently.
I'm a retired Supermod off to the greener pastures of the real world.
#21
Quote by That_Pink_Queen
Oh, well if the amp is built for it, it's fine.
Don't get the idea it's alright with any amp though.

haha, yeah, I know better, but thanks

you answered before I edited, just in case you didn't see it. very curious about this, thanks.

edit: and Pink, that cathode current flow, isn't that what determines when the tubes are running into crossover distortion, or when they start to burn up?
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 14, 2006,
#22
Quote by That_Pink_Queen
The bias is just for fine tweaking the cathode current flow on the tubes. You don't need to change the bias for different tube brands(however don't go and plug EL34s or 6V6's or anything in).

Yeah, thats what I thought too. I didn't want to say it though because I wasn't sure.
#23
I talked to PF, and he confirmed you are better off either getting them from someone that tests the tubes for Mesa's fixed bias, like Eurotubes, or getting them from Mesa. You can wind up with either the sound being too harsh(overbiased), or very short tube life(underbiased) if you just get an off the shelf set of matched tubes from another company. It would be luck to get a set that was biased pefectly.
"The fool doth think he is wise, but the wiseman knows himself to be a fool." - W.S.
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Last edited by Erock503 at Aug 15, 2006,
#24
i work at a shop that carries mesa and idk if im the only one but at least in the rectifiers i hate the way the stock tubes sound, is that just me, o yea and we have recieved amps with bad tubes recently no breaks just wont light up, i much prefer changing out mesa tubes as soon as i can.