Are these JJ EL34's safe to use in my Mesa Mark 5?

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tele_jas

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I've seen some threads saying that the hotter EL34 tubes are not safe for the Mark V (and they show some fried caps or screen grid resistors). I bought these before I seen those threads.... Will these be safe to use without causing damage? I'm not sure what the JJ rating system is? Are 4.4 cooler (like 4.4 out of 10) or is it 4.4 out of 5?

JJ_EL34_zpse27d8ab6.jpg
 
Since different suppliers use varying test parameters to grade their tubes, it would probably be best to call them and ask. They should be able to tell you how these compare to Mesa rated tubes, which are "middle of the road", so to speak. This also would be equal to Groove tubes 4, 5 or 6 rating. :)
 
Old BF Shred said:
Since different suppliers use varying test parameters to grade their tubes, it would probably be best to call them and ask. They should be able to tell you how these compare to Mesa rated tubes, which are "middle of the road", so to speak. This also would be equal to Groove tubes 4, 5 or 6 rating. :)

I sent them an email, but it sometimes takes a couple days to hear back from those places. Hoping someone here had gotten JJ's with similar labels?
 
It's really not a "JJ" thing. The distributor is the one who tests and rates them.

If it is of any help, to give you are very rough idea, I am using EH el34's in my Stiletto rated "27", from TubeDepot. They are working fine.
BUT this is based on TubeDepot's rating system which may not be the same as other places.
Hopefully the response to your email will tell you exactly what you need to know.
Good luck! :D
 
Here was my reply...I'm still not sure?:

Yes we are the ones that put those stickers on the boxes. The top number is Plate current, and the bottom is transconductance. As we don't know what voltage any of the other companies use to get their numbers they will not be the same as our ratings. Here is a list of what we rate them at if it helps you.

We use the Maxi Matcher Digital Tube Tester to match power tubes.
This tube tester sets the same operating point (i.e. plate, screen and grid voltages) for each tube under test and measures the DC plate current and transconductance. The numbers on the sticker are the tube's plate current (milli-Amps) and transconductance (milli-mhos).

6L6 400 Plate volts 48 Bias volts

KT88 400 Plate volts 48 Bias volts

6550 400 Plate volts 48 Bias volts

EL34 400 Plate volts 36 Bias volts

6V6 400 Plate volts 36 Bias volts

EL84 325 Plate volts 12 Bias volts

We use the http://www.maximatcher.com/maximatcher.html To do this if you would like to read up on the process.
 
Well that is a bit ambiguous...at least for your purposes.
Still, the best way is to put them in the amp and have a tech check the bias idle current. However, I am not sure what idle current to expect in the Mk 5, especially for the SimulClass sockets. Mesa can answer that with a quick call.

If you have no way to check them, perhaps contact the supplier again and see what range of tube they'd sell as recommended for the Mesa amps.
Most places I have bought tubes from are familiar with the ratings for Mesa.
Good luck!

PS don't forget that Mesa may not honor the warranty if damage is caused by non Mesa tubes. So if your warranty has not expired yet, this may be something to consider.
Food for thought!
 
I'm returning them, not gonna take the chance... I'll get Mesa tubes.

I spoke to a "Tube guru" buddy and he said "DON'T PUT THESE IN YOUR MARK V", and I trust him. He said as much as he dislikes Mesa tubes in other amps, because they're colder, he really likes them best in Mesa amps. Plus, he did mention the warranty as well.

So they are RMA'd today.
 

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