Do I need to rebias my SF Deluxe reevrb.

squeally dan

Member
Messages
6,315
I've been using my Deluxe with a pair of 6L6's instead of 6V6's. I took it to a local tech for rebiasing when I made that change. Today I called him to let hin know that I might go back to the 6V6's and he said there was no need to rebias when doing so because it is silver face. Is this right? Don't I needto rebias it when going from 6L6's back to 6V6's?
 

Top Geezer

Member
Messages
201
I had the same situation on my SF DR. I took mine in for a service and the amp tech told me there was no bias pot on this amp (apparently some of the newer SF's were not made w/ a biasing pot), my amp tech added one so you could rebias the tubes correctly.

Sounds like you need to add one too.
 

Rosewood

Member
Messages
1,859
Boy that's weird unless he just let the 6l6's run with the 6v6 bias, nah, nobody would do that.
 

squeally dan

Member
Messages
6,315
He said that when he put in the 6L6's he rebiased according to the directions I provided. But now he said changing back won't require a rebias. Looks like I need to try someone else.
 

slider313

Gold Supporting Member
Messages
8,708
I had the same situation on my SF DR. I took mine in for a service and the amp tech told me there was no bias pot on this amp (apparently some of the newer SF's were not made w/ a biasing pot), my amp tech added one so you could rebias the tubes correctly.

Sounds like you need to add one too.


It may have had a balance bias, but it still would have some range of adjustment to an extent. If the tech couldn't find the bias pot.............
 

Blue Strat

Member
Messages
30,722
Deluxes never went to "bias balance" pots and every one of the 100s I've seen had a bias pot including late '70s versions, of which I own two.

Even if an amp doesn't have a bias pot, you still have to bias it unless it's "cathode biased".
 

squeally dan

Member
Messages
6,315
Ok. What type of probe woud you recommend? I've never done it but I'm all for learning how. I'm kinda sick of relying on other people to fix my stuff and wondering if they are doing it right? Can I figure out how to do it without watching someone else do it first?

I actuallyly fixed my reverb pan this week by resodering a lose wire. Didn't know how to use one of those but I did it without killing myself. Maybe I can do this also.
 

Blue Strat

Member
Messages
30,722
www.tedweber.com Bias Rite or Google Bias King.

There should be instructions. It's a bit mysterious the first time, but isn't everything? Definintely not rocket science and it will save you a lot of time dragging it to the tech.
 

mcgriff420

Member
Messages
1,547
I just picked up this bias meter from Alessandro, the only concern I could forsee is if you have a tight tube location in a head format you might have to pull the chassis.

biastester.jpg
 

Blue Strat

Member
Messages
30,722
OK, I'm going to give it a a shot.

Is it just as easy on a black face pro reverb?

Yes, and the same for any black or silverface Fender with a bias pot (some Silver Faces have bias balance pots that would need to be converted).

All '60s and '70s Fenders with bias pots are accessible from under or inside the chassis.
 




Trending Topics

Top Bottom