I did it : bias mod in my 50/50

[crane]

Wow ! (no, not the game..)
Incredible. I've pluged a quartet of =C= 6L6GC inside. Ususally I'll do nothing, just play.
But this time there is a bias pot inside, and an external home made device for the measures
Ok, 17mV (=17mA, 1ohm resistor), it's a bit.... super cold ! about 25% of the max power. Then I turned the pot until it reach 50mV, about 75% of the max power.
I was playing for only 10 seconds when a big smile cross all my face
I own this amp for ten years, and it has never sounded so good ! Lot of punch, huge headroom, rich harmonics....
Do this mod, it's like day and night !

 

[talltxguy]

Crane...I'm actually taking my 50/50 into a tech this weekend. I certainly appreciate the post! I'm gonna ask him about this.

What kind of tubes are you running in your amp?

 

[crane]

I run a quartet of Svetlana =C= 6L6GC.
Don't hesitate to ask for the mod, it's a must !

 

[RonS]

Hi, did you modify the 50/50 yourself or did a tec did the mod? I have two 50/50's, one has the mod and the other doesn't. Indeed, the amp sounds much, much better with the mod. I want to upgrade the other 50/50 too and would do it myself if provided with a DIY.

So, if you did it yourself, can and will you inform me how you did it?

regards and thanks,
Ron

 

[crane]

I did it myself, quite easy if you know how to solder. But it's dangerous, see my post about it :

http://forum.grailtone.com/viewtopic.php?f=5&t=32130