EL34 w/ Silicon Diode Rectifier

[Platypus]

Why does Mesa recommend not using the diode with these tubes?

Any problem in doing this in a dual rectifier?

 

[jbird]

1st of all, being the Dual Rectifier is a Mesa, I think yes there may be a problem! 2nd, I'm not sure of the quazi moto affects on it, but you can reference Eurotubes for an explanation of different current draws and voltages with the different tubes. I would be curious where you got this info? I never saw it in the manuals! Hence, I used to run my EL34's in the diode mode! It was'nt until I spoke with Bob at Eurotubes that I learned of it being a no-no! BTW, I purchased a set of GZ34's as my Rectifiers, which are'nt as mushy as the stock 5U4's! Nice!

 

[cnumb44]

This sounds like it might be specific to the Recto amps. I have a Lone Star Classic and it has a switch to change from 6L6 to EL34 and there is nothing in the documentation on what type of rectifier to use.

 

[xnfx]

In most of the Mesa manuals I've seen (stiletto, nomads, road kings, rectos) there are sample settings that have you using both.

Jbird,
What did Bob from Eurotubes say about it being a no no?

 

[Platypus]

It says in bold letters under the actual tube/diode dipswitch that it is best to run the tube rectifier with EL34s..


jbird: what do you mean 'being the dual rectifier is a mesa, I think yes there may be a problem?'

 

[jbird]

jbird: what do you mean 'being the dual rectifier is a mesa, I think yes there may be a problem?'

Re-read your 1st post!
Maybe I should ask what amp you are dealing with? My two channel Dual Rec says nothing under the rectifier select switch!

 

[jbird]

In most of the Mesa manuals I've seen (stiletto, nomads, road kings, rectos) there are sample settings that have you using both.

Jbird,
What did Bob from Eurotubes say about it being a no no?

He did'nt go into specifics, just sort-of noted that Mesa should make it clear not to use the diodes when in the EL34 bias select. It's not in the manuals! Nor have I seen it on the rear of my amp!

 

[Platypus]

jbird: what do you mean 'being the dual rectifier is a mesa, I think yes there may be a problem?'

Re-read your 1st post!
Maybe I should ask what amp you are dealing with? My two channel Dual Rec says nothing under the rectifier select switch!

3 Channel Dual Rec Solo head, says in white letters right below the switch.


Just curious, I like the tightness of the diode and I was surprised they said not to.

 

[Platypus]

This is printed on the back just for clarity.


Also jbird if you wouldn't mind posting that link to bob's words on that I'd appreciate it.

I know the recommend against this but will it actually hurt my amp or tubes to play in this setting? It seems weird they cannot use the diode to me.

 

[jbird]

Try www.eurotubes.com :arrow: The info does'nt necessarily imply against the use of EL34's w/diodes, it just states the different ratings. I was told over the phone by Bob at Eurotubes, my '00 two channel Dual Rec says nothing against it! I would'nt know why you can't, maybe shorter tube life, warranty issues, etc. If you like that tighter sound w/EL34's, try the GZ34's as your Rectifiers :idea:

 

[xnfx]

This must be just for certain amps? Some amps, like the stiletto are only used with EL34's, and have both the diode and tube rectification, and also come with sample settings that use either or in the manual. This is real weird though. I'm guessing it's something to do with the smaller tubes (El34's compared to the 6l6's) being under more strain?

 

[Platypus]

Try www.eurotubes.com :arrow: The info does'nt necessarily imply against the use of EL34's w/diodes, it just states the different ratings. I was told over the phone by Bob at Eurotubes, my '00 two channel Dual Rec says nothing against it! I would'nt know why you can't, maybe shorter tube life, warranty issues, etc. If you like that tighter sound w/EL34's, try the GZ34's as your Rectifiers :idea:

Do you lose any of the 'sag' you get with the 5U4's by switching to GZ34's? What specifically do you notice tone wise between the two tubes?

I couldn't find anything on his site either that said DONT DO THAT.. I wonder if it does anything but shorten tube life..

 

[Jaroslav]

Most probably not. The tubes are quite cold biased, so it should not matter much. Maybe some of the cheaper EL34 cannot withstand the higher voltage in the silicone rectifier mode. This is NOT the case for JJ tubes though...

 

[Platypus]

Most probably not. The tubes are quite cold biased, so it should not matter much. Maybe some of the cheaper EL34 cannot withstand the higher voltage in the silicone rectifier mode. This is NOT the case for JJ tubes though...

This is more along the lines of what I was thinking.. however I am using the JJ EL34L tube which draws more current than the standard EL34.. is this still alright?

 

[Guitarzan]

My Two Channel Rec's don't have that screened on the chassis. I've used the 34's with the diodes and it works fine...

 

[Platypus]

I emailed Bob, he had this to say:

Hi Drew:

Sorry for the late response but I was at the NAMM show since last Thursday
eve and I'm playing a MAJOR game of catch-up.

Mesa says this because they actually got the bias up where is should be in
the EL34 mode but if you use the cheap Mesa EL34's they burn out quickly.
Not to worry though the JJ's are right at home so poke that thing into SD
mode and go!

Thanks

Bob

So looks like tomorrow I'll be busting that out for sure.

 

[jbird]

Aha! I figured tube life would factor in! I too used the SS Diodes with stock Mesa EL34's for a long time, with no issues! I liked the tighter, more focused sound but still missed the tube rectifier warmth. Bob turned me on to the GZ34 rectifiers as they fell right between the 5U4's warm sag, and the tighter SS Diode. Is it the JJEL34's your running or the JJE34L? Can you give a tone report as compared to the stock Mesa STR442 EL34's? Thanx Platypus. :wink:

 

[Platypus]

I haven't used the mesa EL34's though I have used them in a stiletto. I really like the sound of the JJ's, I am using JJEL34L's btw.

I might have to get a pair of those recto tubes, they sound intriguing.

But as far as the tube itself, I love the JJEL34L. It's made my tone sound lightyears better to me. Awesome tight crunch and sizzle and midrange punch and a tight bass without being boomy.

 

[Platypus]

Got the chance to test out the SD mode today with these tubes and all I have to say is wow.

I'll be in the spongy power/silicon diode mode from now on!