Quote:
Originally Posted by DavGoodlin
I would do it. I have an Air Castle farm set I need to do this for. Find a transformer and rectifier combination to supply a well-regulated source to the tube filaments in particular. Battery tubes use the filament as the cathode and ANY ripple on it will be amplified and objectionable for sure.
My experience with doing this on my Atwater Kent 30 showed that the B supply at 90 volts was easy. The heater supply was impossible to filter adequately so, I ended up getting a rechargeable sealed lead acid battery.
|
If it can't be passively filtered (RLC), then actively filter it! Get a regulator chip like a LM317 (you'll need to feed it a few more VDC than you want to get out) with a filter cap before it and after it, that will drop the hum by orders of magnitude.