It seems I get far too little time to actually work on things these days, but I've got a small update - a working PSU
It's the same physical footprint as the preamp case and is properly fused and switched. Safety first! The idea with this setup is to minimise power consumption, so to that end I've rigged up the main PSU transformer (an Avondale EI core) via a relay. The relay is triggered by the Jos Eindhoven attenuator board which is powered by a very tiny 6V supply that's been recycled from an old Nokia phone charger. When the main switch is on at the back and the system has been powered down by the attenuator (via remote control or by holding the knob in for 5 seconds), the relay is unpowered which means the 115V supply for the Avondale trafo is disconnected and the PSU consumes only a few mA.
When the power is switched on using the remote or knob, the relay kicks in and 115V is supplied to the Avondale trafo. This in turn powers the superregs which power the AD815. Powered up in this state it consumes 60mA at +/-15V on top of the attenuator's power requirements.
The really cool thing with this is I've setup a spare relay point with which I'm going to send a slave signal to my monoblocks. This will mean I can power everything on/off from the pre
Here's the PSU as it is just now. I've left room in there for more transformers to power the DAC circuitry that'll be getting added to the preamp later:
Here's the little 5V relay that switches the 115V supply:
Everything's designed with safety in mind. Once I'm finished with it there will be no exposed mains. In fact, the only exposed mains just now is on the side of the transformer, but I'm going to fashion a cover for that.
Power is supplied to the preamp by 2 7-pin locking connectors:
The Jos attenuator comes with its own rectifier/smoothing and expects a 6VAC supply, but I've bypassed that and soldered in the 6VDC supply from the phone charger. The 5V relay output uses the pink/white wires and goes out from the pre and back into the PSU:
Next up: build some power amps!
Carl