MK V User Manual Revisions

[Chester]

I see Mesa released a revised the MK V manual in Sept. Anyone know what the revisions are, or done a comparison with the previous version?

Just interested ..

 

[screamingdaisy]

I have the original manual, which includes a suggestion to try running EL34s in the inner pair with 6L6s in the outer... Which they quickly removed shortly after the amps release.

My understanding is that running the amp in 10w mode with mismatched tubes will damage the amp.

Not sure what other changes have been made.

 

[barryswanson]

So it's ok to do this on 45 and 90 watt modes? If so what are the characteristics of the amp with this tube set up?

 

[screamingdaisy]

I suspect that it'll void your warranty.

Previous Simul-Class Marks were designed to run with both EL34s and 6L6s in the power section. I don't think the Mark V was designed to run this way. One dude on the board tested it anyway and said the EL34s were running really cold. I suspect that they sacrificed the ability to run a mix of tubes in favour of adding the 10w mode.

 

[littleguitar]

Mine is runnig that way since the beginning ! Always in 90 w mode...and have no issue

 

[barryswanson]

What does it sound like?

 

[littleguitar]

to my ears, best of both world between el 34 and 6 l 6 !
clean doesn't suffer to much with 2 el 34 and the bottom end to !
It bring some kind of "bite" in the sound with a touch of british flavour.

 

[Authorized Boogie]

The Mark V should NOT be used mixing EL34's and 6L6's!! The amp can be run with EITHER EL34's or 6L6's - and we've found the best tone and stability to be with 6L6's. Thanks!

 

[ryjan]

The Mark V is NOT a Simul-class design and should NOT be used mixing EL34's and 6L6's!! The amp can be run with EITHER EL34's or 6L6's - and we've found the best tone and stability to be with 6L6's. Thanks!

It does say "Simul-Class" under the slave level knob on the back. :?:

 

[Authorized Boogie]

Sorry about that, early morning (now edited) post :wink: . The amp IS Simul-Class in the 90watt mode - mixing Class A and Class A/B. However, its not meant to mix tube types, as in the earlier Mark Series amps.

 

[ryjan]

Gotcha. That makes sense but it's too bad we can't run both still. That was one of my favorite features on my old Mark IV.
Can't please all of us all the time though. :wink:

 

[littleguitar]

Sorry about that, early morning (now edited) post :wink: . The amp IS Simul-Class in the 90watt mode - mixing Class A and Class A/B. However, its not meant to mix tube types, as in the earlier Mark Series amps.

I play something like 2 or 3 hours/day since 3 years now and never had any kind of problem in 90 w mode !!! :mrgreen:

Power tubes are still stock.....and still sound great !

 

[barryswanson]

In what position do you run the bias switch?

 

[bandit2013]

I would not run the amp with integrated quad of el34 and 6L6. The simul-class circuit is not the same as the older mark series amps.

I have run all EL34 and have no issues with clean channel (actually sounds really good). There is more compression on CH3 with the EL34 but that is not at all bad in any way. I actually prefer the sound of EL34 in the Mark V over 6L6.

 

[screamingdaisy]

FWIW....

Bias Rite readings:

Plate Voltage: 450-full power , 370-Variac Power

Current Draw:

all STR-440's 6L6 - Outer sockets 30-32mA
Inner sockets 36mA

with 6L6 and EL-34 blend and 6L6 bias setting -

Outer sockets 30-32 mA
Inner sockets 10 mA

with all STR-450 EL-34's , EL-34 bias setting

Outer sockets 43 mA
Inner sockets 53 mA

- http://forum.grailtone.com/viewtopic.php?p=280385#p280385

 

[littleguitar]

In what position do you run the bias switch?

6 L 6 position !

 

[littleguitar]

FWIW....

Bias Rite readings:

Plate Voltage: 450-full power , 370-Variac Power

Current Draw:

all STR-440's 6L6 - Outer sockets 30-32mA
Inner sockets 36mA

with 6L6 and EL-34 blend and 6L6 bias setting -

Outer sockets 30-32 mA
Inner sockets 10 mA



with all STR-450 EL-34's , EL-34 bias setting

Outer sockets 43 mA
Inner sockets 53 mA

- http://forum.grailtone.com/viewtopic.php?p=280385#p280385

sorry this is Chinese for me, I trust my ears just as you sugest