Help biasing my 1987
Posted: Sat Apr 27, 2013 7:40 am
Hi
I finisched to assembly my 1987 Amp Marshall Model following SDM layout : http://home.comcast.net/~jbjdav26/1987r17.jpg" onclick="window.open(this.href);return false;, and larry grounding spec.
The amp is really nice and tone seems to be ok, no hiss or hum.
Nevertheless I have a problem biasing V1 and V2
My B+ value is 444 V DC and I've calculated a bias value of 39mA but It is stop to 27mA with bias pot completely open.
Do you have an idea to help me ?
Many thanks
Massimo
I finisched to assembly my 1987 Amp Marshall Model following SDM layout : http://home.comcast.net/~jbjdav26/1987r17.jpg" onclick="window.open(this.href);return false;, and larry grounding spec.
The amp is really nice and tone seems to be ok, no hiss or hum.
Nevertheless I have a problem biasing V1 and V2
My B+ value is 444 V DC and I've calculated a bias value of 39mA but It is stop to 27mA with bias pot completely open.
Do you have an idea to help me ?
Many thanks
Massimo