Any 24 bit NOS DACs?

[labjr]

Maybe it's time to ask the question again. I'm wondering if anyone is working on a non-oversampling DAC project which will handle high sampling rates?

The Metrum Octave DAC is getting rave reviews. I guess they are using some industrial DAC chips(whatever those are) which work up to 15 mhz. Judging by the pictures of the inside, it would appear to be a relatively simple circuit. Of course it's probably harder than it looks. Very interesting concept though. Just when you think you've heard it all, something comes along that's better.


http://www.nosminidac.nl/Octave_English.html

http://www.6moons.com/audioreviews/metrum/1.html

[poynton]

For CD -- no point.

They're 16-bit


.

[labjr]

Originally Posted by poynton

For CD -- no point.

They're 16-bit


.

Well who listens to CD anymore? I listen to as much hi-rez material as I can find.

[wwenze]

6moons gives everything rave reviews.

[abraxalito]

Originally Posted by labjr

I guess they are using some industrial DAC chips(whatever those are) which work up to 15 mhz.

My guess, FWIW : Digital to Analog Converter - Precision DAC (=<10MSPS) - DAC8581 - TI.com

From looking at the datasheet (don't know for sure its this part of course, I'm not the designer) if its this chip then it has glitch problems. So low-level performance would tend to suck rather.

Judging by the pictures of the inside, it would appear to be a relatively simple circuit.

They say they've paralleled 4 per channel, so nothing too fancy happening.

Just when you think you've heard it all, something comes along that's better.

Better than what though? Than a DAC designed for audio with low glitch energy at the zero crossings?

[qusp]

you can run sabre ES9018/9012 in NOS mode at 32bit 1.5mhz

[abraxalito]

What does 'NOS mode' mean here? Who has recorded material at 1.5MHz sample rate?

[qusp]

dsd, in which case it would be played from 1bit. actually i'd have to check what the bit depth is at that rate, but the dac usually runs internally at 1.5mhz, normally it is upsampled and oversampled asynchronously, but you can run it without the OS filter ie NON OS in which case it will simply play at the speed of the incoming signal up to 1.5mhz. you need to then either slave it to the incoming clock, or run both transport and the dac from the same master clock

[abraxalito]

Ah I see - but DSD's sample rate is 2.8MHz so presumably this has to be sub-sampled to play at 1.5MHz?

[qusp]

i havent used it in this mode with any commitment, so i'm not clear on the detail, but afaik RayCtech runs his sabre design in this mode. i will revisit it when i start working on my own masterclock setup, as without a realy good clocking scheme you are opening the jitter floodgates using a clock piped in on the signal

i think there is a half speed and double speed DXD as well. i have seen rates from 1.4 up to 5.6mhz. i only mentioned it as the question was asked what chips can use this mode 24bit NOS and as you mentioned, i would much rather run a part designed for audio. the reviewed unit looks interesting enough, but in trying to shun the usual audiophile scenario, they have created their own. i mean do you really need that much smoothing in a dac with decent regulators?