Hoping you guys can save me a couple of hundred notes on a DAC.

[antcollinet]

Hi All.

I've been researching DACs to replace the Soundblaster Omni 5.1 I'm currently using (because I have it), which got very poor measurements (SINAD 90 amongst others). I've been looking at Modi 3+, Topping E30 and Topping D50S. Dac to be paired with a just ordered Rega Brio, and Dali Oberon 5's.

Main source for the dac is losslessly ripped CD's from Mac.

Then yestereday I read this thread:
https://www.audiosciencereview.com/...-a-good-dac-pairing-for-the-2-0-stereo.15004/

And in particular, this post from Rja4000

What he means by "insignificant" is that you won't hear (ever) any sound degradation due to the DAC.
That means it will perfectly do the job.

You may find your amp's specs here:
http://www.rega.co.uk/brio-2017.html#panel2

Input 2-5 (line) input sensitivity = 210mV at 47kΩ
Maximum input 2-5 (line) input level = 10.25V

You also may find some measurements here:
https://www.stereophile.com/content/rega-research-brio-integrated-amplifier-measurements

As you can see, the Amp distortion and noise is setting between 0.02% and 0.05%
With 112dB SINAD, the DAC THD+N is <0,00025%
That's around 1/100, so the DAC-induced degradation is meaningless.

So the sound blaster with 90DB SINAD is still going to be THD+N <0.0032%, so still swamped by the amp distortion - albeit perhaps only 1:70 rather than 1:100 - such that I'm unlikely to hear any improvement with a better DAC?

So based on that - should I stick with the sound-blaster now, and, perhaps put the £120 to £250 towards a MiniDSP (EG DDRC-24) with Direc later?

Thoughts appreciated.
Thanks.

 

[AnalogSteph]

So the sound blaster with 90DB SINAD is still going to be THD+N <0.0032%, so still swamped by the amp distortion.

So based on that - should I stick with the soundblaster now, and, perhaps put the £120 to £250 towards a MiniDSP (EG DDRC-24) with Direc later?

Sounds like a plan.

As a pure line-level source, you don't need anything fancy. Amir's results also were on the pessimistic side because his output would get truncated at 16 bits, a software issue (not the last time this has happened either). You being on the Mac, you can probably ignore that, assuming you have set up the audio device correctly (I would choose 24/96 and potentially go with software resampling where deemed critical). The iXBT guys got a dynamic range of 99.4 dB(A) in loopback out of the Omni, which is about in line with the converters used - I won't be too surprised if the input can take a full 2 Vrms (as usual for Creative devices) which the output cannot reach, so another ~2 dB may be getting lost due to this slight level misalignment. About 100.5 dB(A) is what you could have hoped for under ideal conditions (note that the CS4361 DAC is in fact spec'd at 103 dB(A), not 105 as they write).

As you note, the Omni may not be a world-beater but it looks like the Brio is substantially less so indeed. Since all the line-level inputs can take >10 Vrms I'll assume they're going pretty much straight to the volume pot, making a 1 W SNR of 72.2 dB(A) appear pretty mediocre - that's a full power SNR of 89 dB(A) and change only (or ~700 µV(A)), in line with some other small Class D amps but hardly worthy of a device that costs as much as it does. That would be seriously noisy by hi-fi standards. Here someone writes about a hiss appearing on input 1 at elevated volume, so I guess my assumption may have been wrong... the most common complaint about unwanted noises is related to mechanical transformer buzz, which toroids are susceptible to in the face of (effective) DC in the mains, especially if they are not vacuum-impregnated which the one used does not seem to be.

It appears the entire chassis is being used as a heatsink, so I'm not surprised it gets toasty when stressed. A 50 wpc amp probably is about as much as you'd want to cram in there, too. In light of limited cooling they're not likely to run super high idle current either, which would help explain why distortion performance isn't all that great. Dominant 2nd... makes you wonder whether there's a quasicomp output stage at work there, Naim style. Wire routing looks a bit peculiar... and it's the second amplifier I've seen where secondaries are tied but not twisted (not Douglas Self approved).

 

[antcollinet]

I've had the amp for a 1 week home demo - I'm not worried about its performance. Certainly knocks the spots of the aging Sony AVR it will be replacing.

I would be interested in seeing it measured here though.

 

[abdo123]

I approve the plans to include Dirac in the future.