Those connections look correct. I would start by making sure the firmware is up to date on the Amanero. It's possible the Amanero module has an issue.

There is only one version of the Sidecar in the wild, and your S/PDIF implementation should not have any impact.

How do you have the MUX module connected to the Sidecar?

What you need to do is verify that the Sidecar is switching, and that all I2S input connections are making it to the outputs. This should be straight forward continuity testing.

We'll start there.

Okay, that clears up part of my confusion. The board you are referring to as a MUX is not a MUX, but instead a four-channel level converter (muxing is done inside the ES9018 chip).

Ribbon cable and routing might be part of the problem...

After confirming the Sidecar function, it would be good to test first with just one DAC and a straight, unfolded ribbon.

Edited by user Tuesday, March 31, 2015 8:27:21 PM(UTC)  | Reason: Not specified

I have made some measurements on the Sidecar and would like to report them. It appears to me (please correct me if I'm wrong) that the sidecar is not switching between the S/PDIF and I2S inputs.

First, I measured the voltage at the LED for the USB input, which is used as the trigger voltage for the Sidecar relays. It was 3.293 volts.

Second, I measured for continuity between the I2S inputs (on left side of board) and the same outputs to the Buffalo 3 board (header on bottom side of board). Hopefully, I'm reading the schematic correctly. I got the following results:

BCK ----> BCK = open

D1/LRCK ----> D1 = 342.6 mR

D2/DATA ----> D2 = 445.7 mR

GND ----> GND = continuity for all ground as they are tied together and not switched.

Finally, I got a schematic for the Omron DPDT relays used on the Sidecar and checked the resistance (all three relays measured the same):

Pins 1 + 8 are the coil and the resistance was 1.754 R

Pins 3 and 6 are the common pins for their respective sides of the switch. They switch between pins 2 and 4 on one side and 5 and 7 on the other side, with contact between pins 2 + 3 and 6 + 7 in the unenergized state.

Pins 2 + 3 and Pins 6 + 7 = 0.2 R

Pins 3 + 4 and Pins 5 + 6 = open

It seems that the relays measure as expected when they are not energized. I will try to energize them and take additional measurements to see if I can determine if switching is occurring.

Please feel free to offer any suggestions. All input is greatly appreciated.

What value resistor do you have installed on the Sidecar?

You should try switching the Sidecar directly, but connecting VD to B with a jumper wire. If you hear the relays click, then check continuity again.

Assume all of that works, we can look at how you have the B terminal wired to the switch board.

What voltage is VD?

If supply 5V to VD and B you should definitely get a relay click.

UPDATE

Suspecting that the transistor was bad, I removed it from the circuit board and tested it. The transistor is indeed bad, but I also wondered about the integrity of relays. I removed power entirely from the power header on the sidecar and instead powered each relay directly from a Placid HD set to 5 V. (The coils of the relays are rated at a maximum of 24 V.) For each relay, there was no click when the coil had 5 V. applied and in addition, continuity didn't switch to the opposite poles as would be expected.

I'm speculating that the transistor failed and probably took the relays with it, but this is only speculation.

I've ordered a replacement transistor and relays. After they have been installed, I'll update this thread.

Thanks, Brian. I look forward to receiving the correct relays. Would you please also send a BC639 transistor? As noted above, the one I have tested bad. I'll be glad to pay for it - just let me know the cost.