copy/paste from a thread we posted some time ago...
JOEY B. wrote:
The MkV head owned by Mike ( aka "lesterpaul") was run with STR-440's in the outer sockets and STR 450's in the middle sockets today in a test session. NO issues whatsoever in the 90 and 45 watt power settings. In fact, with this tube layout and the bias select in 6L6 mode, we got SCARY close to the original simul/EQ/Rev C+ sound with the MkIV mode of the MkV. The 10 watt power setting is the only thing different with the MkV power section (aside from the inner pair being the ones with the hotter bias, instead of the outers on the older Marks), and if you go there with a "blended" tube setup, you do so AT YOUR OWN RISK.
**** skippy a few el 34 thoughts ...it was nice in the cleans with a Les Paul..which has "fatness"...cant comment on a superstrat (yet...)-more growl with the proper EL-34's ..we tried the 450's,the GT El 34M, and the Sylvania 6CA7's..(****!!)..
the skinny...the EL's had warmer highs,and were THE DEAL in Mk 1mode!!!less bottom end compliments the MK 1 mode, which is TOTALLY BADASS with good 34's in there...we were in MArshall mode a few times, with classic tones bouncin' off the walls...we were able to get a good transition between all 3 channels using fat or tweed on 1/crunch on chan 2/IV mode on 3......IMO, MK 1 mode is a specialized application available with this amp..if you MUST use chan 3 in conjunction with chan 2, you almost have to be in extreme setting, due to the vast diff. in eq...I really dig it(mk1)...as Joey stated , we got scary close blending the tube types...(thats why I bought some tubes from JB before I left...)if you are new to Mk amps, take note of what JB printed in above post regarding tube positions,etc...
bottom line, this is a mark amp-it allows you many different applications with a the swap of a few tubes....we swapped quite a few today in 4 plus hours of aural assault, and got quite a few different results...when she is cranked, the differences in power tubes are very apparent/even between the 34's we played with today
and yes, if you are trying to get more Metallica-fied, I would think el 34's are the way for you
-I have a simul runing a combo and a coli running ALL 6L6's, so the all el 34 V is a nice and no brainer compliment-IF you can get your hands on some old Sylvania glass, however, the V enters a class all by itself(as you would expect
with any MK)