ac701 power supply build

salomonander said:

hey
i still have about 5 mics lying around that use ac701 tubes. i have no powersupplies im afraid. so id like to build some. does anyone know a source for a pcb that could work with minor tweaking and fit in a "neumann like" case?

cheers
jakob

Click to expand...

musiklab said:

I made a design for this , AC701 is a precious mic tube and must be treated as gently as possible.
Never apply HT  before the filament is hot.
So the AC701PSU  design has a slow turn on function,  first feeding  the filament ,  delaying reulated B+  HT  120V  by  a minute or so , via a digital  counter,  and uses dual  transformers for the filament and HT . 
It  can be set for other  filament and HT voltages  by changing regulator setting resistors.
Very low noise  on both filament and HT voltages.
if there´s any interest,  I could  dust off the design  and make  pcb´s  for sale.

Click to expand...

musiklab said:

if there´s any interest,  I could  dust off the design  and make  pcb´s  for sale.

Click to expand...