Oh yeah! The Mod50 came today.

[ringemaster]

Wow.......I am soooo pumped about this thing. Spent some time, unwrapped the tubes, put 'em in, and let her rip.....uh at least a bedroom volume. I can't wait for practice tomorrow where I can really let her fly. I'm also waiting on my Bman module to come in about a week or so (I've currently got the Vox and Twin modules in). I like the Vox on low gain and the Twin I have a hard time not getting a good sound.

Anyway...I actually have a question. I see that there's only one 'BIAS ADJUST' on the back (even though there are two different test points'. How can I adjust the bias of one tube without changing the bias of the other. I was able to get them about 2-3 mV within each other, which is OK, but is there anyway to get them closer?

Thanks,

Dave

 

[Chad]

Congrats on the amp!

As far as the bias, you'll wanna find a compromise that is still within the recommended settings. Having well matched tubes helps with this.....sounds like you're doing pretty good if you got them within 2-3 mV. With time, the tubes that came with my RM50B had drifted 7 mV apart, so I ordered some new tubes from Doug's Tubes. They are almost a perfect match!

 

[3 Mile Stone]

Congratulations! It's a great day when you pull out that beautiful black and tan box and go ... WOW ... that's MINE!

Some sets of tubes and some brands bias closer than others. My JJ 6V6 are right on the money, same goes for the Tung Sol 5881. My Mullard EL34 set is way off. Just do the best you can without going over the high end of the range.

 

[maximus1]

if you use a multimeter just keep adjusting until they are the same . mine usually stay within 1 or 2 even as much as i hall it around but definatly get macthed duets . also experiment with different tubes

 

[Chad]

if you use a multimeter just keep adjusting until they are the same . mine usually stay within 1 or 2 even as much as i hall it around but definatly get macthed duets . also experiment with different tubes

Not on the amps with two power tubes....they only have one bias adjustment pot.

 

[mctallica1]

I have found on the MOD50 that it really helps to get your tubes from someone who tests them and can provide matched sets. Lots of folks who advertise their tubes as matched, in my experience, really aren't selling matched sets.

My personal favorite supplier for this (and all my tubes) is Dougstubes.com

He tests every tube he sells (power and pre) and stands behind them.

 

[ringemaster]

Thanks! That last comment helps out a bunch. I was a little worried that I couldn't adjust them to be the same, but I'm not worried anymore. I'm also excited about trying different tubes.