ok to mix tube types in the outer/"class a" socket on a SC?

[boogiemon]

A while back i noticed that an el34's in one of the outer sockets of my SC Mark had died completely (was dark/cold) but the amp was still working just fine in SC mode. Given that that pair of sockets is not running in "push/pull" mode, does anyone know if it's possible to run w/a 6L6 in one and an EL34 in the other? (w/the inner pair running 6L6s of course)


tia

 

[JOEY B.]

Given that that pair of sockets is not running in "push/pull" mode

Where did you come about this info about a Mark III? The answer is that it IS possible, but NOT optimal.

 

[boogiemon]

Well, i've learned a lot reading the post on this board, but i'm no electronics tech so i'm not sure about the push pull thing, but my understanding is that class AB amps operate in push pull and since the outer sockets are supposed be class A, i assumed they are not in a push/pull config.

As for putting one 6L6 and one EL34 in the outer sockets, could you elaborate a little? Mainly i'm concerned about whether i'll fry something if i try, but any info is welcome.

Also, is it correct to assume that having a matched pair in the outside sockets is not going to make an audible difference?

thnx.

Given that that pair of sockets is not running in "push/pull" mode

Where did you come about this info about a Mark III? The answer is that it IS possible, but NOT optimal.

 

[JOEY B.]

The outer sockets of the Simulclass amps are not single-ended class-A. It is still a push-pull type circuit, so a matched pair of tubes will be optimal. One 6L6 and one EL-34 would most likely have a severe current draw mismatch.

 

[boogiemon]

ok thnx.

i just got one of the amp-head bias testers & have been measuring the current draw of all my tubes. Given that i have a pretty good mix of old-new in various color groups (mesa tubes), if i find an el34 & a 6L6 w/in a few mV of each other could they be considered a matched pair & be used in the outside sockets?

The outer sockets of the Simulclass amps are not single-ended class-A. It is still a push-pull type circuit, so a matched pair of tubes will be optimal. One 6L6 and one EL-34 would most likely have a severe current draw mismatch.

 

[JOEY B.]

ok thnx.

i just got one of the amp-head bias testers & have been measuring the current draw of all my tubes. Given that i have a pretty good mix of old-new in various color groups (mesa tubes), if i find an el34 & a 6L6 w/in a few mV of each other could they be considered a matched pair & be used in the outside sockets?

I would say NO, because they are different tube types with different capacity(in wattage).