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Hello Pedja, I'm finalising the integration of the USB MKII into my AYA II 2014 dac and saw in the manual that even 7Vac is enough. As I have 9Vac on all transformer outputs, I would implement additional RC filters as I'm doing on all other power lines in the dac (taking +/-3V overhead for the regulators).

What would be the minimum Vdc (ripple on top of that) necessary at the final electolyte cap on both AC1 and AC2 lines?

I saw AC1 has no RC at all and AC2 has already 2 steps => any particular reason its first RC is using such a small C?

Thank you,


Hello Berny,

For both the AC1 and the AC2, a final raw DC voltage must be at least 7 V, so the regulators operate properly. So, when you look at the ripple, it should be all above 7 V. Some headroom will be of course still fine.

When using a DC Voltmeter, I would advise to get as close as possible to 8 V DC. It will ensure proper operation at one, and minimal transistors heating at the other side.

The first RC filter cap value is lower to help lowering the current charging spikes, so the whole RCRC setup operates more smoothly.