Laskyman
Well-known member
Is there any harm in running channel 2 and 3 in 10 watts pretty much all the time?
Multi Watt question...(Mark V specific)
- Thread starter Laskyman
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I doubt that you would cause any harm in doing such, however two of the power tubes will not be in use, They will deteriorate just as much as the two in use since the heaters are not turned off on the tubes that are not used. I would run the amp at full power for the 10W mode in case you have any drift on the ac input. Also if you are not using CH1, leave that in 10W mode as well since there is a dramatic voltage change when switching between channels from (90w/45W) to 10W. You may also want to swap tubes after a while (say a few months or so), exchange the two outer tubes with each other, and the same with the inner tubes. Don't confuse the Rectifier tube as one of the 6L6 tubes, the amp will not work after that type of mistake.
elvis
Well-known member
I think that this is a good approach, but I'd like to offer an alternative opinion on a couple points.
If the heaters are running but the tubes are not biased they will get very little, if any wear. The wear comes from plate current damaging the metal surface. The heater should run a lot longer than the tube life.
While it won't hurt to swap the tubes, at 1/5 the rated power, there won't be a whole lot of wear on the active 10W tubes. It would take a long time before they were worn significantly compared to the idle tubes.
If the heaters are running but the tubes are not biased they will get very little, if any wear. The wear comes from plate current damaging the metal surface. The heater should run a lot longer than the tube life.
While it won't hurt to swap the tubes, at 1/5 the rated power, there won't be a whole lot of wear on the active 10W tubes. It would take a long time before they were worn significantly compared to the idle tubes.
I would agree. My thoughts on the idle tubes off line, they may not be drawing any current and will essentially be off (not operating). However, long tern use of tubes on heaters alone may lead to cathode stripping, that may just be a myth with little or substantial evidence it will occur.
10W mode should be fine. I should use it more often than I do since I believe my hearing has degraded since I got my Mark V, spending too much time in 45W/90W and sitting a few feet away from the cab. :roll:
10W mode should be fine. I should use it more often than I do since I believe my hearing has degraded since I got my Mark V, spending too much time in 45W/90W and sitting a few feet away from the cab. :roll:
10W mode is single ended Class-A (sort of) and uses one inner & one outer powertube in parallel (explained in the manual). This is why Mesa does not recommend running EL34's in the Class-A spots with 6L6's in the other positions of the MKV, but it's fine to do in the MKIV (no 10W mode).shimmilou said:
Dom
Authorized Boogie
Well-known member
10w mode utilizes V8 and V10. I hope this helps!
Authorized Boogie
Well-known member
domct203 said:
We recommend using ALL 6l6's or ALL EL34's - NOT mixing them under any circumstances. Thanks!
Mix tubes in a Mark V????? (I admit I have done this, but tubes of the same family, never considered el34 with 6L6 in the V) I assumed all tubes would be same :shock: I did not consider integrated quad.
I wonder how an integrated quad would sound in the Mark V. Since the bias circuits are different (assumed) for this amp, probably not suitable for EL34/6L6 integration. Otherwise they would not have installed a bias switch for tubes in use.
Yep, V8 and V10 are used in 10W mode, V8 and V9 in 45W mode. If you keep the matched pairs as specified in the manual, V8 and V9 matched, V10 and V11 matched, and if you intend to use 10 W mode all the time, extend the life of tubes by swapping V8 with V10 and swapping V9 with V11. That way the matched pairs remain matched. If you are running an integrated quad with EL34, don't do this. If it is a 6L6GC tube, okay to swap. Voicing for 10W mode should be V8. In all other modes, V8 and V9 will set character. 90W mode parallels V10 with V8, V11 with V9, so the outer tubes will influence tone to some extent, bulk of tone will be supplied by the hotter tubes in the center positions.
I wonder how an integrated quad would sound in the Mark V. Since the bias circuits are different (assumed) for this amp, probably not suitable for EL34/6L6 integration. Otherwise they would not have installed a bias switch for tubes in use.
Yep, V8 and V10 are used in 10W mode, V8 and V9 in 45W mode. If you keep the matched pairs as specified in the manual, V8 and V9 matched, V10 and V11 matched, and if you intend to use 10 W mode all the time, extend the life of tubes by swapping V8 with V10 and swapping V9 with V11. That way the matched pairs remain matched. If you are running an integrated quad with EL34, don't do this. If it is a 6L6GC tube, okay to swap. Voicing for 10W mode should be V8. In all other modes, V8 and V9 will set character. 90W mode parallels V10 with V8, V11 with V9, so the outer tubes will influence tone to some extent, bulk of tone will be supplied by the hotter tubes in the center positions.
One more note, I do this every so many months of use (swap the centers for the outers) if they are all the same.
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