I built a tube OD from a schematic I found online.
It was designed for 120v mains but I have adapted it to 220v operation since I live in a 220v country.
I have eliminated the voltage doubler section and used a full bridge rectifier and a single 33uf 350v cap and I am getting some kind of mains hum, which I believe is due to the filter section being inadequate. I think I need another filter cap, but I'm kind of a newb at this, so I'm pretty sure adding another cap just like this will not solve my problem. any help would be greatly appreciated.
>>1017266
B+ will be closer to 310v than 210v
>>1017279
slight correction
I didn't notice you didn't show the cap - connected to ground.
>>1017281
just tried this. not getting any sound. weird.
>>1017311
If it was actually wired like your schematic it shouldn't have worked the first time.
You have the B+ just dangling with no complete path.
The capacitor will be charged but no path for current flow.
If this is just a mistake on your schematic and the device has the minus on the cap connected to ground, adding the resistor and second filter capacitor should reduce hum.
What is the plate voltage on the tube?
What is the cathode voltage on the tube?
Both measurements should be taken relative to 'common' or 'ground'.
>>1017266
All I see is a fw bridge and a 30 micro reservoir cap. You could use software or an oscilloscope to test your power supply output. I'm sure there's a good deal of ripple. Maybe add more LC (choke) or RC filtering.
