I finally got the Aikido preamp finished (at least to the point where I can connect it to source, power-amp and speakers). So I used a walkman CD-player, cheap power-amp and cheap speakers.
The Aikido worked, and there was very little HUM.
When I connected it to my main system, I got a LOAD OF HUM.
Now, as I remember, the signal GND in my power-amp is isolated from chassis (at least at the RCA's).
I also did not connect from the Aikido circuit-board GND to the chassis/Earth bolt. This obviously has resulted in floating PSU and signal circuitry.
However, I subsequently did jumper the circuit/board GND to the chassis, via one of the board's mounting screws, although it may not have formed a good ground.
So what might I try first:
1. Connecting board/PSU/signal from the board GND to the "star" earth at the chassis GND/Earth bolt?
2. Morgan Jones recommends tying the center-tap of the AC heater transformer to 0V DC GND?
3. Maybe I also need to do that with the center-tap of my HT transformer also?
4. What about grounding the RCA's to the chassis?
Any ideas?
Thanks,
Charlie
