Nobody on /r/beatmatch said much; "Is there such a thing as a digital-only mixer?"

As in, one like the DJM-900NXS but with only S/PDIF Digital I/O? No analog to digital or digital to analog converters necessary.

I mean something where you plug two CDJs in, it has a ton of controls/everything, and then just puts it out as S/PDIF.

The reasoning being:

Significantly cheaper to produce, as signal quality is no longer a significant issue.

Obviously for performance in any venue whose sound system doesn't have SPDIF (which is common not to have), you'd use your own DAC. The point being you can upgrade your DAC at any time without having to get a whole new mixer, and you could even start with a cheaper DAC (I linked a "good" one, there are many for under $100).

Coaxial SPDIF is more durable than toslink so that's why that's more commonly used for DJ stuff, too.

It would also objectively have better sound quality.

The limitation of having to buy your own DAC aside, why not just a mixer that has all SPDIF in (like the high end Pioneer stuff) and then just the two pairs of balanced analog outs for the booth/master and phones for monitoring? Most decent CDJs have digital outputs now, and it's the obvious transition now that digital audio is everywhere.

You could even sell a small SPDIF phono amp/adc...

Edit Okay, here's my idea for a product;

Four-channel (four stereo channels) mixer, with a fifth channel intended for the the mic (buy your own preamp.)

Mic input would be a singular SPDIF input and route to all channels.
Mic channel would have a 3-band EQ: Hi, Mid, Low. With two extra knobs, one adjusting the border between low and mid and one for between mid and high. It would also have the same "on/off" toggle switch from the DJM series, and a "level" knob for each channel. (The EQ would apply to both mics, but each mic would have it's own level control even though it's fully digital from the mixer's point of view.)

Below the mic stuff on the left side of the mixer, there would be two headphone jacks, each with their own level control, and a "cue/master" dial as on the DJM.

The four actual channels could each have;
SPDIF IN
SPDIF passthrough (clones SPDIF in and has it as a direct output. Super easy for a digital-only mixer, and might occasionally be useful.)

They would all have the same 3-band 5-knob EQ as the mic channel,
an LED level indicator on either side of each strip,
a level/digital gain knob at the top,
a small switch for selecting the sample rate,
a "cue" button,
the slider thing at the bottom,
the A/Thru/B switch.

If said mixer had digital effects, a wet/dry / colour knob would be necessary too!

Below the four channels, there would be the same A/B crossfader as the DJM series.

On the right side the top has a sample rate selector for both the digital "Master Out" and "Booth Out," which also have digital gain knobs, but also a gain knob for the additional two "Analog Master Out" and "Analog Booth Out" which of course are balanced XLR and TRS respectively. (Yes, this mixer would have FOUR stereo outputs!)
There would be another pair of LED strips as a level indicator for the master out.

There would then also be both an SPDIF send/return and a stereo TRS one, and a knob to select one or the other.
(Once more, the SPDIF send and return would both need a sample rate selector.)

Thoughts?