Any 295 owners try an adjustable bias?

talltxguy · Aug 12, 2010

If you've done the mod, do you recall what the original bias was?

Did the mod make that much of a difference for you?

I think the 295 is the best power amp I've ever owned. I know Mesas typically bias on the cold side. I've been reading about how a strong majority of people are even happier with their Mesas after an adjustable bias. I think I'd like to be in that majority.

Thanks for any insight.

crane · Aug 23, 2010

Hi,

The bias on the 295 is a dual bias, same voltage start but it divides in two circuits, for the 6L6 and for the EL34, so you probably have to do two mods. I've go the bias schem if you're interested.

talltxguy · Aug 23, 2010

Sounds good, Crane. Please send it when you get a chance. I sent you a PM with my email addy.

talltxguy · Nov 19, 2010

My Mesa tech didn't wanna mess with the adjustable bias, so I was gonna sell my 295 and get a 50/50 or 2:50 and have an adj bias put on one of them. Then I find a dude in Austin who says he can put an adjustable bias on it. My Mesa tech didn't want to do any drilling. :?

So yeah, I took down the 295 for sale stuff & took my 295 in to him today. I'll post results when I get it back.

While talking with my Mesa tech today, he informed me that he will be selling quite a bit of his private stock in the near future. I was lucky enough to put dibs on a Soldano SP-77.

talltxguy · Dec 6, 2010

Well the tech called me today and told me a bunch of stuff. Bottom line is that he seconds what the Mesa tech said about how "hairy" it would be to put in an adjustable bias pot.

The plate voltage was 550 volts. He said the 6L6's (reds) were pulling around 10 ma of current, which would explain why it felt stiff while playing. By my calculations, 10 ma of current at 550 plate voltage is 19%. :?

He is gonna see about changing a resistor around to raise the current draw around 35 ma, which would raise the 6L6's up to 65%, which is much better. He's gonna let me check it out and see how I like it at that setting.

talltxguy · Dec 7, 2010

Since reds were in the amp, we opted for a 20 ma bias, which is still quite a bit higher than the original bias. This way I can put in hotter tubes if I want it warmer than 20 ma, which I'm guessing I will. Anyway, I pick the amp up on Saturday. Hope to report back with good news.

talltxguy · Dec 11, 2010

Well I'm happy with the 295, but I encountered a 2X12 Roadster combo with over 4 years warranty @ $1499, so I put some $ down. Not sure about the SP & the 295. It's looking like they're gonna be gone very soon.