A couple of questions

[screamingdaisy]

Two quick questions;

1) Can someone confirm if I can drop a pair of EL34s in the outside sockets with 6L6s in the inside?

2) If I can, does the amp need to be on EL34 or 6L6 mode?

 

[eudaimonia02912]

1. No, you can't.

 

[screamingdaisy]

1. No, you can't.

1) I already know the answer, it was meant as a lead in to question 2.

2) The answer should be 6L6 mode because the outer pair is cathode biased thus only the inner pair requires a bias resistor.

However, I'd like to double check with someone before I swap the tubes out.

 

[phyrexia]

EL34s in inner pair 6L6s in outer pair 6L6 bias mode. cold biassed el34s in this setup

 

[screamingdaisy]

Which pair shuts off in 45w mode?

 

[eudaimonia02912]

So I'm misinformed and you can do this?

How does it sound?

 

[phyrexia]

all 4 tubes active in 90w
inner tubes active in 45w
two power tubes closest to power cable active in 10w

you can run the mixture in 10w mode for at least a short while without damaging anything (i have done so)

but i like 6L6s in the outer pair, 6V6s in the inner pair, 6L6 bias mode, tweed power. or you could swap their positions and have a more authoritative 45w mode.

 

[screamingdaisy]

Cool. I'll give it a shot. I generally prefer 6L6s for clean and EL34s for dirt, but I'll mess about for a bit and see what sounds best.

 

[screamingdaisy]

Dropped a set of EL34s in the outside sockets. Left the amp on 6L6 mode.

Sounds great.

Clean channel in 45w mode has nothing but 6L6 tone.

The two dirt channels in 90w modes have a bit more mids and compression.

Overall, I like it.

 

[phyrexia]

that is not the proper way to do it.

EL34s in inner pair 6L6s in outer pair 6L6 bias mode. cold biassed el34s in this setup

when you have el34s in the outer sockets, they're biassed so cold as to barely do anything. if you mix them, the EL34s need to be in the inside pair.

there was a thread about this many months ago. some forumites took real measurements of the voltages in the amp. joey b. and lesterpaul helped.

 

[screamingdaisy]

that is not the proper way to do it.

Sounds good. Doesn't care. 5-year warranty, and page 6 in the manual to back up my claim.

when you have el34s in the outer sockets, they're biassed so cold as to barely do anything. if you mix them, the EL34s need to be in the inside pair.

there was a thread about this many months ago. some forumites took real measurements of the voltages in the amp. joey b. and lesterpaul helped.

I found one thread that said the inside pair was the cold pair. I haven't happened into the thread you're referring to. Any chance for a link?

 

[pathos45]

it says in the manual NOT to do this. Only to use one set of quad or the other. And if your mess your amp up they can tell and you void your warranty

 

[MrMarkIII]

It sure seems like a lot of folks are determined to fit the square peg into the round hole by insisting the Mark V act like a "true" Simul-Class amp (meaning "old Simul-Class amp"), instead of settling for the truth, which is the Mark V simply wasn't designed for a mixture of EL-34s and 6L6s.
By the way, has anyone actually blown up a Mark V during one of these tube-rolling experiments? Anybody made a warranty claim?

 

[screamingdaisy]

it says in the manual NOT to do this. Only to use one set of quad or the other. And if your mess your amp up they can tell and you void your warranty

You can run EL34's in just the outside pair or all 4 power tube spots"

- Mark V manual, page 6

And how would I void my warranty by following the manual?

It sure seems like a lot of folks are determined to fit the square peg into the round hole by insisting the Mark V act like a "true" Simul-Class amp (meaning "old Simul-Class amp"), instead of settling for the truth, which is the Mark V simply wasn't designed for a mixture of EL-34s and 6L6s.

I blame Boogie for including the idea in the manual.

 

[domct203]

And what's the question about speakers?

Dom

 

[screamingdaisy]

And what's the question about speakers?

Dom

I edited it out and moved it to another thread.

 

[JOEY B.]

Scroll about halfway down the page. http://forum.grailtone.com/viewtopic.php?f=33&t=38013&start=30

 

[pathos45]

Finally a BIAS SELECT switch is included that allows you to run EL34 power tubes in place of the stock compliment of 6L6’s. The EL34 style tubes will produce a brighter, skinnier sound that will clip with a whole different harmonic content that can be nice, especially for recording where you may not need the Channel switching performance of all 3 Channels and can dedicate the amplifier to one specific sound. The 6L6’S will most likely perform better for a wide range of sounds and certainly sound fatter and richer on most all the sounds and produce the greatest clean headroom. Whichever tubes you prefer, MAKE SURE THE SETTING OF THE BIAS SWITCH MATCHES THE TUBES IN USE!


where there does it say you can use both at the same time?

 

[screamingdaisy]

Scroll about halfway down the page. http://forum.grailtone.com/viewtopic.php?f=33&t=38013&start=30

Man... there's a lot of deleted posts in that thread.... bitch fight break out or something?

Anyway, long story short is that the middle pair are the 'class A' pair so the EL34s should be on the inside.

And don't use 10w mode.

 

[screamingdaisy]

Finally a BIAS SELECT switch is included that allows you to run EL34 power tubes in place of the stock compliment of 6L6’s. You can run EL34's in just the outside pair or all 4 power tube spots. The EL34 style tubes will produce a brighter, skinnier sound that will clip with a whole different harmonic content that can be nice, especially for recording where you may not need the Channel switching performance of all 3 Channels and can dedicate the amplifier to one specific sound. The 6L6’S will most likely perform better for a wide range of sounds and certainly sound fatter and richer on most all the sounds and produce the greatest clean headroom. Whichever tubes you prefer, MAKE SURE THE SETTING OF THE BIAS SWITCH MATCHES THE TUBES IN USE!


where there does it say you can use both at the same time?

See red above. I have the original manual. After downloading the newest one off their website it looks like they've edited it out.