Biasing my Marshall... biasing by ear

[yngzaklynch]

Dave if you ever have a tech question about Marshalls one person that maybe of help is Marshall engineer and designer of the Vintage Modern and the Hendrix Super 100, Steve Dawson. He can be reached at the Marshall Vintage Modern forum as SteveD.
http://marshallvintagemodern.com/index.php

 

[killertone]

Hey Dave -

I do the exact same thing. Screw the numbers, just use my ears. Once I get it where I like the tone, then I run the numbers just to make sure I am not going to blow shit up.

I find that I almost always like lower dissipation settings, I like the bass response especially in the lower range. Right around 63% is where I usually end up. I'm not sure why but by ear I almost always end up there even on different amps.

 

[Rufus Leaking]

So what are you guys using to bias when you go by ear? I use a Weber Bias Rite but was told to never actually play the amp when the Bias Rite is in the chain, so I set it to a number, then have to pull out the BR, put the tubes back in etc... to see how it sounds. PITA, so I usually just go to 70% and leave it.

 

[RoidRage]

I was moving the pot all over the place and found a spot where it started to sound killer. I was cranking up the volume to almost extreme levels and it flat out ripped. No mush, just tone and compression. I was happy. So I took the time to check where the bias was and I almost flipped. I was at 55.5mA (53mA on the other tube) I thought I was reading the meter wrong. Nope. I was running at 90% dissipation

Dave...

You are perfectly right... It's funny I found the SAME EXACT THING... I LOVE 55ma !!!!

But be advised... These settings *WILL* be hazardous to your amps Health!!!!

With Winged C's I've run 45ma for a while with no problem... But then again, I don't play that loud.

Roid RAGE

 

[killertone]

So what are you guys using to bias when you go by ear? I use a Weber Bias Rite but was told to never actually play the amp when the Bias Rite is in the chain, so I set it to a number, then have to pull out the BR, put the tubes back in etc... to see how it sounds. PITA, so I usually just go to 70% and leave it.

My Fortin has external bias points which are extremely convenient. When I bias my other amps I use the Bias Rite but I turn it off when I play. Seems to work just fine that way.