Hiwatt DR103 1M Bias Pot (It works)
Posted: Tue Apr 17, 2012 5:00 pm
From another post on this forum, i decided to try out a suggestion to add a simple 1Meg linear pot to my '72 DR103 to allow for bias adjustment. All other suggestions showed multiple desolders and component additions. I wasn't comfortable with that since this is a vintage amplifier. But I stumbled upon the post simply telling me to put a 1M linear pot in between the 47K resistor to ground. No components removed, and only one solder joint decoupled. Extremely low impact. Well, I was sceptical because it was SO simple...
...well, it WORKS. VERY well in fact. Before my RFT tubes were hovering around 58mA. I NOW have a great 35-58mA range to work with. Its a life savor if any of you plan on gigging with these amps!
I drew up an illustration of what it looks like to help future do-it-your-selfers:
...well, it WORKS. VERY well in fact. Before my RFT tubes were hovering around 58mA. I NOW have a great 35-58mA range to work with. Its a life savor if any of you plan on gigging with these amps!
I drew up an illustration of what it looks like to help future do-it-your-selfers: