Non Mesa power tubes question

[dearco19]

Hello,

I'm wondering if I can use these tubes in a Mesa head.

https://www.dropbox.com/s/rkmkgnr0uwy1a9o/IMG_4142.JPG?dl=0

How can I know when I can or can't use other power tubes (non Mesa)? What should be the measure? What is PC, TC and the 13AV thing?
I appreciate your help!!

 

[Nick Lehman]

You'll have to be more specific on which Mesa head you're talking about. If its a rectifier then absolutely, just make sure to set the bias switch to the EL34 setting.
Im not sure what the other numbers mean, maybe someone else will chime in??

 

[bandit2013]

The PC # is the plate current in mA,
the TC # is the trans conductance in micro-mhos

As for the 13AV, this is part of the tube serial number system.

I had to find out for myself what the 13AV meant, the TAD website has more information.

http://www.tubeampdoctor.com/en/shop_TAD_Tubes_amp_Accessoires_TAD_Premium_Tubes/

 

[dearco19]

Thanks for the information all! But Unfortunately I still don't know if I can use these tubes in a Recto, Roadster, Mark V, or any other Mesa amp that allows EL34 tubes. You should know that MESA amps works only with Mesa Power Tubes because of the bias matter, unless you order the set of tubes of any other brand but with Mesa requirements/specifications....

 

[domct203]

Hello,

I'm wondering if I can use these tubes in a Mesa head.

https://www.dropbox.com/s/rkmkgnr0uwy1a9o/IMG_4142.JPG?dl=0

How can I know when I can or can't use other power tubes (non Mesa)? What should be the measure? What is PC, TC and the 13AV thing?
I appreciate your help!!

Thanks for the information all! But Unfortunately I still don't know if I can use these tubes in a Recto, Roadster, Mark V, or any other Mesa amp that allows EL34 tubes. You should know that MESA amps works only with Mesa Power Tubes because of the bias matter, unless you order the set of tubes of any other brand but with Mesa requirements/specifications....

If you really want to run non-Mesa tubes all you need to do is get yourself a bias probe and check the bias yourself. No guessing, no "in-accurate" advise.

There are a few different versions, with different features.

Eurotubes has a few:
https://www.eurotubes.com/cart/index.php?page=view_products&category_id=108&sub_category_id=109
There is a video on that site as well that shows the probe in use.

As well as Amp Head:
http://www.amp-head.com/index.php?cPath=21

Dom

 

[MrMarkIII]

Thanks for the information all! But Unfortunately I still don't know if I can use these tubes in a Recto, Roadster, Mark V, or any other Mesa amp that allows EL34 tubes. You should know that MESA amps works only with Mesa Power Tubes because of the bias matter, unless you order the set of tubes of any other brand but with Mesa requirements/specifications....

... And if you tell the guy selling you the tubes which Mesa amp you have, he will sell you tubes to match the amp. If he can't do that, he is not the tube seller you are looking for.

 

[peterdenny]

Hello,

I'm wondering if I can use these tubes in a Mesa head.

https://www.dropbox.com/s/rkmkgnr0uwy1a9o/IMG_4142.JPG?dl=0

How can I know when I can or can't use other power tubes (non Mesa)? What should be the measure? What is PC, TC and the 13AV thing?
I appreciate your help!!

It looks like an EL34 variant which should work so long as you flip the bias setting to match. I think if you put em in and try it you should be ok. Just watch em and if they get bright red (like crazy bright) or start to do a flumming noise you will know to power down and remove once they cool. I had a RCA blackplate 6L6 that flipped out on me and it was obvious but no harm was done to the amp bc I was watching. Really just put em in and see. Amps are not that delicate really IMO.

 

[dearco19]

Thanks a lot guys! I will consider to buy a bias tester because i think it is very useful. :mrgreen:

 

[peterdenny]

Why buy a bias tester? In mesa its hard set. Just plug in the tubes. I bet they are fine. Dont let people get you too tied up in what has to "match". I bet you wont hear the difference. Plug those tubes in and let your ears hear the bias...

 

[LesPaul70]

Why buy a bias tester? In mesa its hard set. Just plug in the tubes. I bet they are fine. Dont let people get you too tied up in what has to "match". I bet you wont hear the difference. Plug those tubes in and let your ears hear the bias...

Sorry, Peter, but I find that one of the least insightful responses I've read on this board. Just because it sounds ok doesn't make it right. Generally, when you are running your power tubes way too hot, that may sound awesome, but your power tubes will fail in a matter of days. Worst comes to worst, they'll also damage your amp in the process.

There's a reason people recommend you run the correct bias. And, since in Mesa amp, you cannot trim the bias - like you say - the only way to achieve that is pick the correct tubes.

 

[domct203]

Why buy a bias tester? In mesa its hard set. Just plug in the tubes. I bet they are fine. Dont let people get you too tied up in what has to "match". I bet you wont hear the difference. Plug those tubes in and let your ears hear the bias...

As long as you're using Mesa branded tubes then yes, plug and play.

However, this topic is about Non-Mesa branded tubes, and with Non-Mesa branded tubes you will need a bias probe to confirm idle plate current (bias), or you will risk damaging the amp.

To simply state "plug those tubes in and hear the bias" is poor advise when discussing unknown rated powertubes.

Dom

 

[KiwiJoe]

Why buy a bias tester? In mesa its hard set. Just plug in the tubes. I bet they are fine. Dont let people get you too tied up in what has to "match". I bet you wont hear the difference. Plug those tubes in and let your ears hear the bias...

Worst. Advice. Ever. Really, if that's what you want to do with your own rig, fine, but refrain from advising other people to follow suit. It's just ignorant rubbish. 1000 faceplams.

 

[peterdenny]

I disagree w regards to mesa amps bc the bias is hard set according to everything Ive ever heard about them. I just swapped all my tubes on my new RK. Plays nicely. My rectoverb I did the same years ago and I have thousands of hours on it. No problems. Maybe I am not understanding the whole test bias thing here as your perspective. My point was that according to what I understand about boogie the bias is hard set on the amp and you just flip the switch for that based on tube. Its worked fine for me and everyone I know who plays boogie. Have not paid to have my bias set since I sold my jcm800. I think its mostly hoodoo to be honest. But whatever. It works fine for me and I stand by the fact I think if he plugs in the tubes that it looks like came as a quartet set from a dealer that they will work fine. Maybe I read into his question wrong but I found a nice write up from Randall himself on it. Maybe this is really what the guy needs...

http://www.mesaboogie.com/US/Smith/biasadjust.html

 

[tele twister]

Quite frankly, when it comes to Mesa's rigorous testing and selection process, I will only use their tubes.
They created my amp and gave it life, therefore they know what makes it happy.
I trust only Mesa. It's called loyalty.

HAIL MESA!

 

[domct203]

I disagree w regards to mesa amps bc the bias is hard set according to everything Ive ever heard about them. I just swapped all my tubes on my new RK. Plays nicely. My rectoverb I did the same years ago and I have thousands of hours on it. No problems. Maybe I am not understanding the whole test bias thing here as your perspective. My point was that according to what I understand about boogie the bias is hard set on the amp and you just flip the switch for that based on tube. Its worked fine for me and everyone I know who plays boogie. Have not paid to have my bias set since I sold my jcm800. I think its mostly hoodoo to be honest. But whatever. It works fine for me and I stand by the fact I think if he plugs in the tubes that it looks like came as a quartet set from a dealer that they will work fine. Maybe I read into his question wrong but I found a nice write up from Randall himself on it. Maybe this is really what the guy needs...

http://www.mesaboogie.com/US/Smith/biasadjust.html

This is all fine as long as you are using Mesa branded tubes, or tubes that were selected to operate properly in Mesa's ranges.

This thread is about unknown tubes. All tubes are not created equal, and their natural plate current draw can vary quite a bit. There is a reason for Mesa's color grouping, as well as Groove Tubes ten (10) different rating groups. Both Mesa and GT throw out many tubes that are outside of this grouping as well.

I still say it is not wise to just throw unknown tubes into the amp and not check the plate current (bias).

If the tubes are dissipating 80% or more at idle you are risking red plating, and with that the possibility of damage to the amp.

It's your amp, do as you wish, as will I.

Dom

 

[KiwiJoe]

This is all fine as long as you are using Mesa branded tubes, or tubes that were selected to operate properly in Mesa's ranges.

This thread is about unknown tubes. All tubes are not created equal, and their natural plate current draw can vary quite a bit. There is a reason for Mesa's color grouping, as well as Groove Tubes ten (10) different rating groups. Both Mesa and GT throw out many tubes that are outside of this grouping as well.

I still say it is not wise to just throw unknown tubes into the amp and not check the plate current (bias).

If the tubes are dissipating 80% or more at idle you are risking red plating, and with that the possibility of damage to the amp.

Dom

^^^^^THIS^^^^^ Thank you.