Ebay parallel PCM1794 DAC any good

[snoopy33]

I've found a more modern approach with -

https://e2e.ti.com/support/audio-gr...9211-hdmi-arc-cable-direct-connection-pin-map

It has the same 50ps jitter as the the WM8805 which appears to be as good as it gets. I'm reading Async USB methods are in the 200ps zone.

 

[snoopy33]

No I've given up on HDMI. I did find the Texas DIR9001 though, same 50ps as the WM8004/5. I'll go with that.

 

[kozard]

I was told that the WM8805 locks on the pre-ample only resulting in superior performance. I wonder how that compares with the DIR9001?

 

[Ian Greenhalgh]

The OPA604 and OPA2604 arrived and have been soldered to adaptors and installed.

The only thing left to do now is to sort of the transformer. The one currently installed is the Arcam original which has two secondaries - 12v and 5v, so I'll either have to replace it or add some circuitry to split the single 12v rail.

The receiver board is a WM8805.

 

[snoopy33]

I was told that the WM8805 locks on the pre-ample only resulting in superior performance. I wonder how that compares with the DIR9001?

Both seem to be doing the same thing and quote 50ps which is all that matters. Texas is easier to find and much cheaper though.

 

[snoopy33]

The OPA604 and OPA2604 arrived and have been soldered to adaptors and installed.

The only thing left to do now is to sort of the transformer. The one currently installed is the Arcam original which has two secondaries - 12v and 5v, so I'll either have to replace it or add some circuitry to split the single 12v rail.

The receiver board is a WM8805.

Although there are some reasonable ideas with the board the cost cutting is too evident. You've resolved the capacitor values I guess but the 5v chip feeding the analog side of the PCM1794A is weak. Replace with LP2985-5.0 for 1/10 the noise.

 

[snoopy33]

Here's my 'final' schematic. I'm building it up and will run it off at jlcpcb. It's just a hobby board so I'll make everything available. Every chip is Texas Instruments. Input spdif, Output balanced. Single 5v supply at about 0.55A. Supply can be noisy, USB based etc.

DIR9001 - 50ps, I don't think USB v2 Async can beat this so it's as good as it gets?

PCM1794A - arguably as good as it gets

TPS61048 - +12v/-12v generator, efficient

LP2985 x2 - very low noise LDO's

NE5534 x12 - or equivalent + 2% panasonic film caps.

ATtiny202-SS - mostly to handle standby. The op-amps are current pigs and I don't want it wasting 2.5W of power when nothing is playing. This shuts down the 12v, -12v and 5v lines a delay after the PCM1794 reports no signal.

 

[Ian Greenhalgh]

You should probably start a new thread for your work rather than detailing it here.

 

[thomas XLR]

Hello

As a curiosity.
"PANA - MERA" DAC in two system version. Op-amp 2 x PCM 1794 AK 4118 (parallel PCM1794) and tube version E88CC / 6N23P.
E-mail link: PANA - MERA

Regards
Thomas_XLR