Newbie here - How to add digital out (Coax preferred) to NAD 522?

[Jonathan M]

SSIA really.

I have a NAD 522 that I'd like to add a digital output too.

I understand that I need to tap the output from the decoder chip (or the input to the DAC chip).

What does one need to do to convert this or whatever to be output via a coax (or optical) connection?

Any help/suggestions on where to read up on this would be greatly appreciated.

Oh, and schematics of the NAD 522 (and/or similar units) would be a plus.

Thanks in advance,
Jonathan

[A 8]

Dont know the nad specifically but typically you will find a digital out on one of the chips, just get a 74HC04 and paralell 3 or 4 gates, add a transformer or a cap and a 75 ohm series resistance before the output terminal and you should be ok.

I would suggest getting the schematics before doing anything.

[Jonathan M]

Found this schematic on the web:

[A 8]

Cant open it, what is it?

I meant the schematics of the NAD so that you can find spdif out.

[jwb]

I don't have this player, but it is unlikely that an SPDIF signal is present anywhere inside it. The signal from the transport to the DAC is probably in I²S or right- or left-justified serial digital format. To add a digital output, I would find the termation of this signal, probably at a DAC chip, and add a SPDIF transmitter mounted on a tiny circuit board, right on top of the DAC. You could use CS84xx series chips for the transmitter.

[A 8]

I disagree with jwb, it is more likely then unlikely that you will find it inside the nad.
Manufacturers typically design with similar or the same curcuits for different price levels, not true for dac chips but true for decoders etc.
Either way the first step is to get the schematics of the nad to decide if you need a CS84XX or not.

[maczrool]

Here's a readymade circuit board if all you need is I2S compatibility.

[A 8]

What is nad522? CD player?

[Jonathan M]

Hi all,

Thanks for all the responses. I appreciate all of them.

I have a lot of work on at the moment that came up quite unexpectantly (As it does) so I won't be able to have too much of a play until next weekend probably.

The NAD 522 is the player featured in the movie "High Fidelity". It is the pre-cursor to the C521i that did have digital outs (As did the 542 and 562 in the NAD range at the same time as the 522.)

Once I get a chance to pop it open and see what it's got, I'm sure we'll be able to track down the likelihood of simple modifications.

I'll post again once I get some more info.

Cheers,
Jonathan