Multiple DAC Inputs

[Lee S]

This may appear a silly question to those in the know, but I have just built a DIY DAC and was just wondering if it was possible to have a number (2 or 3) of co-axial SPDIF sockets on the case and simply switch between sources (SB, CDP, PVR) using a rotary switch?

There is an input transformer and blocking/filtering caps and 75R matching resistor on the PCB itself before it enters the first IC, so is it as easy as just switching some input sockets or is there more to it?

Other multi-input DACs I have seen, have a set of transformers, caps, resistors, etc for each input and switch AFTER that. Why is this? Does it matter?

Yours confusedly,

[Andrew]

That should work.

[al newall]

It did work on one version of my DAC. Shouldn't be any problem.

[pre65]

How about the multi input single socket self select option ?

[Lee S]

How about the multi input single socket self select option ?

I am afraid the selector gets worn out very quickly in this setup Phil.

Thanks for the info chaps. I did wonder if it would be that simple, but other circuits seem to over-complicate this by using multiple transformers, and even ICs and I wondered why all this, what can only be described as, over-engineering, if it can be simply be done before all the circuitry. I thought it may be something to do with the fact it is meant to be co-axial right up to the IC, but I didn't think an inch or two of extra cable within the casing would matter too much.

Cheers for that.

PS: Al - this is that DAC board you donated. It sounds rather good ackcherly. It has taken me this long to get it finished though. Not even bothered with valves or NOS yet. It's actually running in OS and with some op-amps. Still sounds good to me though. Many thanks. Do you want your old CD50 back? It's here if you do. I canibalised another old one I had for the tda1541/saa7220, so yours is still here and in one piece if you ever need it. Cheers.

[al newall]

Good stuff Lee.
Do what you want with the CD50, i don't need it.