21-11-2020, 04:15 PM
(This post was last modified: 21-11-2020, 04:17 PM by ppppenguin.)
Not sure why you're bothering to change the valve types. The original P series valves add up to just over 12V which is easy to supply. the PC900 is one of those rare 300mA valves where the heater voltage is LESS than 6.3V.
Manual gain control as you describe strikes me as a good temporary solution. 36mA seems a lot of current for a small signal valve circuit but if that's what's needed to give good large signal handling then they had to do it.
Manual gain control as you describe strikes me as a good temporary solution. 36mA seems a lot of current for a small signal valve circuit but if that's what's needed to give good large signal handling then they had to do it.
www.borinsky.co.uk Jeffrey Borinsky www.becg.tv
