Mesa 6L6 Tube Varients

[BoogieMKIIA]

I have been playing my MKIIA 60W out quite a bit the past year or two. Thinking that new power tubes may be a good idea sooner or later.  Anyone have first-hand experience with new Mesa 6L6? 

Mesa suggested their STR 445. They have at least three other variants, the description are so-so. I like to use Mesa power tubes since they match the fixed bias and they are screened. Not opposed to other brands. Not interested in expensive NOS tubes.

[Dutchman]

I used Phillips 7581A tubes in my Boogie. I think that's what the original Boogie tubes may have been.

They're making them again.

https://reverb.com/item/3378248-new-2x-tungsol-7581a-matched-pair-duet-two-tubes-free-ship

 

[BoogieMKIIA]

56 minutes ago, Dutchman said:

I used Phillips 7581A tubes in my Boogie. I think that's what the original Boogie tubes may have been.

They're making them again.

https://reverb.com/item/3378248-new-2x-tungsol-7581a-matched-pair-duet-two-tubes-free-ship

 

Wonder if they can select them for Mesa fixed bias? Can ask.  

Need to do some research. There are very few tube factories anymore. I think several “brands” may use the same factory, not sure how many true variants there are.

[Cboss]

Scroll wayyyyyy down to the bottom of the white section, some of these are not very expensive

If you email Brent he will know what will work best in that amp

https://www.audiotubes.com/6l6.htm

[JGale]

Brent Jesse to the rescue.

Brent Jesse to the res-es-cue!

 

Tell him I sent you.

[tbonesullivan]

2 hours ago, BoogieMKIIA said:

Wonder if they can select them for Mesa fixed bias? Can ask.  

Need to do some research. There are very few tube factories anymore. I think several “brands” may use the same factory, not sure how many true variants there are.

There are some smaller tube factories in central / eastern Europe as well as some in China. Psvane is one in china that comes to mind. Unfortunately the Shuguang factory that really worked with Tube Amp Doctor and others to make some great tubes has been shut down since a fire, and I would guess will not be coming back.

The tube factories still in large scale production are just JJ electronics in Czechia and the Reflektor / X-pul plant in Saratov, Russia. Both of these make multiple variants of the 6L6 tube types.

Mesa currently has the following types:

• 6L6 STR 443 - These are the same as the Sovtek 6L6WXT and Electro Harmonix 6L6GC. I think these are actually a variant of the Russian 3PS tube.

• 6L6 STR 445 - These are JJ 6L6GC tubes. A lot of people like these for various uses. I think they are "rounder" sounding than the Russian tubes.

• 6L6 STR 441 - These are Russian, and most people believe that these are the Tung-Sol 6L6GC-STR tubes, which are part of their reissue series.

• 6L6 STR 448 - These are, I believe, the same as the TAD Redbase, and are made by PSvane in China. I've heard VERY good things about these tubes.

So, you can get these tubes elsewhere, however you need to make sure you can get a pair that will bias correctly in a Mesa, which probably came stock with the STR 415 tubes which were I believe Sylvania. Ruby Tubes and Groove Tubes may also market many of these same tubes.

Groove tubes are rated, and the Mesa rating system covers groove tubes ratings from 4 to 6.

[BoogieMKIIA]

Thanks for the Boogie to mfg cross reference. I was looking at photos trying to tell by structure. Seems most are made by EH (Russia) and JJ (Slovakia).

Brent Jesse doesn’t have anything in stock at my price range at the moment.  I need a windfall so I can get some Sylvania tubes, STR 415 Mesa and equivalent.

[Dutchman]

13 hours ago, BoogieMKIIA said:

Wonder if they can select them for Mesa fixed bias

Matched tubes will work. I've run not matching but close when I had my Mark llB and it sounded great. I really miss that amp....

[tbonesullivan]

5 hours ago, BoogieMKIIA said:

Thanks for the Boogie to mfg cross reference. I was looking at photos trying to tell by structure. Seems most are made by EH (Russia) and JJ (Slovakia).

Brent Jesse doesn’t have anything in stock at my price range at the moment.  I need a windfall so I can get some Sylvania tubes, STR 415 Mesa and equivalent.

What power tubes are currently in the amp? Also, how long have the preamp tubes been in there?

[BoogieMKIIA]

I need to see what is in there, some Boogie tubes. I have a few other sets without much time.  For preamp tubes, believe I have one old RCA 12ax7, the others are likely Boogie.

I have rolled preamp tubes in the past and couldn’t tell much difference. For power tubes, I hadn’t played it out much until the past couple of years, don’t know what difference I will hear.  Reliability is important to me.

[tbonesullivan]

1 hour ago, BoogieMKIIA said:

I need to see what is in there, some Boogie tubes. I have a few other sets without much time.  For preamp tubes, believe I have one old RCA 12ax7, the others are likely Boogie.

I have rolled preamp tubes in the past and couldn’t tell much difference. For power tubes, I hadn’t played it out much until the past couple of years, don’t know what difference I will hear.  Reliability is important to me.

Well, if the power tubes are old production, they may still have lots of life on them. Preamp tubes as well. Boogie used to use 6N4J Beijing Square Foil Getter preamp tubes, which also hold up very well compared to new production.

I actually have a spreadsheet saying what's in every amp I own because I'm OCD.

[JGale]

22 minutes ago, tbonesullivan said:

I actually have a spreadsheet saying what's in every amp I own because I'm OCD.

Dude! You are my new Hero!

[tbonesullivan]

20 minutes ago, JGale said:

Dude! You are my new Hero!

It has helped SO much. I don't have many "old production" tubes, but I definitely like to keep track of them. It also makes sure I don't put Russian Spiral filament tubes into amps that don't play well with them.

The Russian Reissue tubes like Tung-Sol, Mullard, and Sovtek LPS tubes, they use a spiral filament design that is a bit delicate. They don't like being in cathode follower positions, as the plate to heater voltage is too high. Also some amps have a voltage reduction feature, and the spiral filament doesn't heat up enough if it isn't at the correct voltage.

[BoogieMKIIA]

My stock of 6L6GC tubes. Can’t say for sure how old they are or how much use.

• Mesa STR 420, had to tack the bases with high temp epoxy. Chinese from what I can find
• Mesa STR 430, think by Sovtek
• Ruby 6L6GCMSTR, think Chinese. Doug’s Tubes say the same as Mesa STR 440. Both have a small top flashed getter
• Mesa STR 440 currently installed
• No JJ, no NOS