I put the DAC in a box tonight, so it would be safer to handle with the crowd on hand. I ran into a little problem though, maybe somebody can help...
I designed a simple power supply to feed the local regulators on the DAC. I used a Hammond 5V center tapped transformer, #166L5, using the outer taps, not using the center tap. I made a full wave bridge rectifier with fast diodes, filtered it with a 4700uF Nichicon 16V cap and a 5k bleeder resistor. Blimey to hell I am getting 7.4 volts out of it.
My wall voltage is 123V as always. Tranny is rated 115, so there wil be a bit of a bump from that, but not 3 volts! I double checked the wiring, looks good. Duncans power supply simulator predicts 5.6VDC with 30mV ripple with this power supply, which is adequate for the regulators I am using.
I measured 6.4VAC where the secondary connects to the bridge, so might it be a mislabelled transformer, or must I measure it without the bridge connected?
The part that really has me baffled, is why am I not getting the .7 voltage drop through the rectifier? Crazy!
I rigged up a power inlet to I can use the DAC with the 5V external regulated power supply that I have been using since I first ran the DAC, have it playing now. I can also use the external power supply to power the TT, with a different plug making 12V. I do need to label them so the 12V doesn't go into the DAC.
Rich