So I made this AA1164 Princeton Reverb, but it makes pretty bad hum.
I'm almost certain it has something to do with my sketchy grounding layout.
Some explanations how the hum behaves:
- Reverb level pot adds very much hum, when you increase it.
- Volume pot reduces hum somewhat, when you increase it. It also makes a tiny click around 2 o'clock
- When every pot is at 0 and volume at max, there is hum, but much much less. I don't consider it acceptable though.
I've placed 1 ohm resistors between cathode and the ground, on a jack where the ground pot should be - so I could read the current of the tubes without removing it from the cab, for easier bias.
Here is a grounding layout that I used. I would appreciate if somebody could correct it.
http://oi68.tinypic.com/2ztlngw.jpg
http://oi64.tinypic.com/s2tz52.jpg
http://oi64.tinypic.com/mtqy6w.jpg
I'm almost certain it has something to do with my sketchy grounding layout.
Some explanations how the hum behaves:
- Reverb level pot adds very much hum, when you increase it.
- Volume pot reduces hum somewhat, when you increase it. It also makes a tiny click around 2 o'clock
- When every pot is at 0 and volume at max, there is hum, but much much less. I don't consider it acceptable though.
I've placed 1 ohm resistors between cathode and the ground, on a jack where the ground pot should be - so I could read the current of the tubes without removing it from the cab, for easier bias.
Here is a grounding layout that I used. I would appreciate if somebody could correct it.
http://oi68.tinypic.com/2ztlngw.jpg
http://oi64.tinypic.com/s2tz52.jpg
http://oi64.tinypic.com/mtqy6w.jpg