Cleaning Up A Mark IIB

[StevieB]

I'm own a Mark IIB that I purchased new back when they were first introduced in (1978?),

I've never really played this amp much as I was never able to get it to sound clean enough (even on the clean channel).

I've recently read some posts on this forum where some folks are talking about how "clean" the sound is from their Mark II's. So my question is:

How can I make it sound the cleanest? Are there some output tubes that are better/cleaner than others? Are there some pre-amp tubes that are cleaner/better than others? Any other parts or settings info would be appreciated as well.

Thanks in advance for any input.

 

[acorkos]

for starters, 100 watt setting (if you've got it) will get you the cleanest sound possible. my IIB in 60 watt setting runs out of headroom pretty early on the volume control dial.

fresh tubes will help, too.

what speaker(s) are you runnng through? that can be significant

turning down volume I and raising the master volume is important.

low output pickups on your guitar, or maybe rolling off your guitar volume slightly and have a treble-bleed mod installed on your guitar volume pot.

finally, i would measure the power tube bias and make sure it's not running too hot...that could rob you of cleans as well.

 

[gonzo]

you could also try a AT7 instead of AX7 in the V1 position....

 

[Tommy]

You can put 12at7 instead of 12ax7 in V5 (phase inverter) for more headroom.

 

[glawk]

use at7 and also get either a k120 or altec speaker in there...