biasing method

Gtr_tech · Post by **Gtr_tech** » Wed Mar 16, 2005 2:25 pm

I personally have not tried to do it on an english amp. The problem with it is that the current will flow through both the winding and the meter, not just through the meter like it should. I suppose I could try it and make a note of the difference next time I have a Marshall or Laney on the bench.
At any rate, you will read less current on the meter and end up biasing too hot. The cathode resistor method works best when screen current is figured into the reading.

white room · Post by **white room** » Wed Mar 16, 2005 3:45 pm

[quote="Gtr_tech
At any rate, you will read less current on the meter and end up biasing too hot. [/quote]

That is what I am concerned about. Right now, I have my amp biased at 35mA with a B+ of 470V ( using the shunt method) so I am wondering what my "I" draw really is.

Guest · Post by **Guest** » Sat Mar 19, 2005 8:14 pm

Your bias is 470VDC, not 35mA... that is the amount of current.

Billy Batz · Post by **Billy Batz** » Sat Mar 19, 2005 11:35 pm

Anonymous wrote:Your bias is 470VDC, not 35mA... that is the amount of current.

I dont think Ive ever heard anyone not talk about biasing there amp and be refering to the current reading instead of voltage.

Flames1950 · Post by **Flames1950** » Sat Mar 19, 2005 11:45 pm

And if your bias voltage is really a positive 470 VDC you've got a shitload of trouble.

I'll know where you are from the smoke signals.......

white room · Post by **white room** » Sun Mar 20, 2005 1:15 am

Anonymous wrote:Your bias is 470VDC, not 35mA... that is the amount of current.

My plate voltage is 470VDC and my cathode current is 35mA.

I did not mean to confuse anyone...or am I the one that is confused???