# Mesa Power Tube Replacement



## mrfiftyfour (Jun 29, 2008)

I want to swap out the tubes in my TA-30. EL84's and 12AX7's.
Mostly because I want to keep the old ones so I have backups in case of failure.
Mesa doesn't provide anyway of biasing the power tubes. They want the owner to purchased Mesa branded power tubes that have been matched, thus not needing to be biased.
Can I install any brand of matched power tubes?
Has anyone installed a bias trim pot on a Mesa amp? Any benefits or is Randall correct that biasing is a waste of time?
My last question is this: Is it worth while to put NOS tubes in V1 and V2 in modern amplifiers?
I'm torn if I should just buy Mesa branded preamp and power tubes or if I should try something else.
I can't remember who makes Mesa's tubes.


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## sammyr (May 7, 2013)

For simplicity it is easiest to just buy a set of mesa branded tubes that match the ones you took out. That's sorta what randall smith was going for I assume.

However, rebranded tubes (mesa/gt) are more expensive so if you have the ability to check the bias with a multimeter or bias probe and solder/desolder you can buy whatever tubes you like and then adjust the bias by tweaking the range resistor I believe.

Re: preamp tubes. I wouldn't bother spending big money on NOS tubes unless you have a source that you can get them at a good price. If the store near you sells new production tubes for almost 30 bucks after tax but you can get a NOS short plate GE tube for the same price.... However, personally I find that NOS tubes are more worth it in simpler amps where the each individual component has more of an effect on the tone. In an amp with many channels and tons of preamp gain it seems kinda like overkill.


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## keto (May 23, 2006)

Yeah, lots of Mesa amps have had adjustable biases added (though certainly not the majority by any means). Randall knows more about amps than my by a factor of hundreds, but I still think he's full of crap if he actually said that biasing is a waste of time. More like, he builds his amps that way so users don't screw crap up, plus he can make additional income selling his own rebranded tubes.

Yes, any brand of matched power tubes will work. You might even get a pair recommended for Mesa's bias range if you shop from a tube specialty place (tubestore.ca or others)

NOS preamp, if you have some lying around you can try them but I agree w Sammy, I wouldnt go out and spend $ to acquire any. That said, I disagree with him about the impact a single tube can have even in a complicated amp. They all sound different, particularly in what is traditionally V1, and in the inverter spot.


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## knight_yyz (Mar 14, 2015)

I'm pretty sure if you called a place that sells tubes and you tell them you want matched pairs for a MESA they would be able to give you something that would work perfectly for you. 

Or you could just buy a set of tubes as a "kit" from a tube store. For example the tube store in Hamilton has 3 different value packages, ranging from a full set of tubes at 100 all the way up to almost 700 USD if you want to spend the big bucks for NOS stuff.


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## sammyr (May 7, 2013)

Keto I definitely agree with you on v1. If you are gonna add some secret sauce to your amp v1 is usually the place to do it and the PI. Knight_yyz makes a good point as well. if you arent married to buying locally you plenty of places offer tube kits specifically for different mesa models.


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## High/Deaf (Aug 19, 2009)

If you have a bunch of old matched EL84's you want to use in the amp, then it might be worthwhile to have adjustable bias, so the amp can be adjusted to the tubes. Other than that, if you're buying tubes, just buy the ones that work within Mesa's range.

Or trade your amp for an LSS (cathode biased) and never have to worry about it.


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## Kerry Brown (Mar 31, 2014)

I put these in my TA-30.

www.thetubestore.com - Preferred Series 7189 (Premium EL84) Audio Tubes

Very happy with them. Gave a little fuller sound than the Mesa tubes which are now backup. I specified the amp when ordering them and they said they would make sure they met the Mesa specs. I've tried a few different 12ax7's but like the original Mesa ones the best.


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## keto (May 23, 2006)

Preamp, if you want more clarity and top end ZING, TungSols are the way to go. If you want the opposite, but more gain, go JJ's.


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## mrfiftyfour (Jun 29, 2008)

Thanks for the replies. 
I had already looked up the tube kit for my amp at the tubestore.com and had picked out the Preferred kit that Kerry linked to. I'll probably go with that.
Is that the same place based in Hamilton that Knight mentioned?
Just as an aside, I don't have any spare tubes kicking around to try out. 
Are there any shops in the Vancouver area that carry a good selection? L&M and Tom Lee don't really have any stock of tubes it seems.


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## Boogieman (Apr 6, 2009)

I have two old Mesa combos, a Mk.I and a Mk.II, with no bias mods added. I have been buying tubes from thetubestore.com in Hamilton for years. Just mention in your order what model your amp is and they will take care of it.


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## keto (May 23, 2006)

And yes, tubestore is in Hamilton. They are fabulous to deal with, most of us around here who have used them have nothing but good things to say about their products and services. You can save a few bucks going ebay or whatever, but their service etc is worth that to me.


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## knight_yyz (Mar 14, 2015)

They do ship.


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## mrfiftyfour (Jun 29, 2008)

Boogieman said:


> I have two old Mesa combos, a Mk.I and a Mk.II, with no bias mods added. I have been buying tubes from thetubestore.com in Hamilton for years. Just mention in your order what model your amp is and they will take care of it.


Hey Boogieman, I was wondering if you used the amp specific kits or did you hand select the tubes?


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## knight_yyz (Mar 14, 2015)

You can call them up and ask them for a matched quad for your Ta-30, then buy 12ax7's anywhere you choose depending on the tone you want. Only the 4 power tubes are biased.


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## Boogieman (Apr 6, 2009)

mrfiftyfour said:


> Hey Boogieman, I was wondering if you used the amp specific kits or did you hand select the tubes?


My Mesa amps are not listed in their Mesa section, so the amp-specific packages that I used as reference was the Mk.I Reissue. I have not done an amp-specific package order with them, though, as the Mk.I Reissue was not a dead-on copy of the original. I think thetubestore tend to recommend the Preferred Series brand, which I have never tried on any of my amps. 

My go-to power tube for those Mesa amps has been the SED Winged "C" 6L6GC. I bought some more before production ceased, so I am good for a few more years.

For preamp tubes, especially for V1, I ordered several different 12AX7 brands (JJ, EHX, Tung Sol, etc.) to try out for both tone and microphonics. Once I decided which one I liked best, I ordered a bunch of them for quality discount. For the Mesa amps, I picked the Tong Sol. The rest became "taste test" tubes for my other amps. What sounds good on one model's V1 socket may not retain its magic on another brand or model of amp's V1.

It would be nice to have a good NOS tube in V1 of any vintage amp. For phase inverter, etc., I would rather use current production tubes. For amps that were designed after the West stopped making tubes, I wonder if there is much benefit to use NOS tubes. I reckon most of the modern amps are likely designed with currently available tubes in mind. I do have a few NOS tubes lying around, but I tend to save them for my pre-90's amps.

That said, I don't have Eric Johnson's ears (or chops), so YMMV.


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## Tone Chaser (Mar 2, 2014)

I have a stash of JAN tubes. I installed them in my Mesa Mini Rec 25, and Dr Z Maz 18NR. No issues; in fact the amps sounds better than the Preferred Series tubes that I had previously ordered and used with satisfaction.

There was an increase in volume and tone. The premium Preferred Series had about 40 hours or less on them.

No effort was made to match or bias.


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## mrfiftyfour (Jun 29, 2008)

Thanks Boogieman and Tonechaser (and everyone else for that matter). It's helpful to hear from a Mesa guy who has rolled different tubes in his amps.
Lots of good info in this thread.
Super stoked that tubestore is based in Canada. They're going to have a new customer.


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