Mesa Mods

FATTY · Post by **FATTY** » Tue Jan 29, 2008 2:48 pm

Has anyone ever heard of moding a Rectifier ? I'm happy with my sound but, I was just wondering because someone told be you can mod the bias. I know that mesa has a bias that never needs adjusted but what could you do? Also what brand tube are Top Notch ( High Gain) ?

lonewolf · Post by **lonewolf** » Tue Jan 29, 2008 5:07 pm

I can't imagine what you could do with a rectifier, except maybe change some capacitor values to allow more upper harmonics thru the preamp stages.

You only want to change the bias when you change to a different tube type or to balance mis-matched tubes. As you probably know, the Rectifiers have a bias switch to allow auto-biasing of both 6L6 and EL34 tubes. That is a nice feature that I wouldn't mess with.

I suppose you could change some resistor values to get a higher or lower bias voltage, but the effect would be audibly negligible (except at extremes) and you could end up with big problems prematurely using up tubes.

A good amp for doing bias tricks is the THD Flexi-50. I am currently scouring eBay for a used one:

http://www.thdelectronics.com/product_page_flexi50.html

The Shadow · Post by **The Shadow** » Tue Jan 29, 2008 5:54 pm

Trace at Voodoo Amps offers mods for this as well as other amps.

http://www.voodooamps.com/home/

old Skool · Post by **old Skool** » Tue Jan 29, 2008 5:57 pm

Yep I was just going to post about voodoo amps. I've read nothing but good things about their work. I have an ADA MP-1 that hopefully will be on it's way there before too long.