Melco dedicated media library improves S/N ratio of DAC vs Mac

This goes back to last month and the review done by Hi-fi News for the N1A (August publication - current one is September).

A very interesting aspect came out from the review, while its use as a network player as far as the reviewer was concerned did not improve on their current setup, it was a different story when used specifically as a USB storage-push device into a traditional USB DAC with the reviewer mentioning the improvement for sound quality was notable when compared to an Apple Mac setup.
The reviewer in the USB setup used a Naim DAC, and then Marantz HD-DAC1,Pioneer U-05, and Denon PMA-50 (digital integrated DAC).
Now what is interesting is that Paul Miller noticed the same and looking at measurements it was noted switching from a dedicated PC/Mac setup for audio to the Melco improved the noise floor of the DACs (specifically using USB).
He tested and measured the Melco used with Chord Hugo and also the Oppo HA-2 as these can run in battery mode and isolated from mains.

The A-weighted S/N ratio results using USB between DAC and PC or Melco were as follows;
Chord Hugo with PC 91.5dB, with Melco 105dB
Oppo HA-2 with PC 96.6dB, with Melco 106.9dB
Jitter improved in both cases, but it was pretty exceptional anyway for the Chord to begin with and Oppo was incredibly good anyway but improved from 97psec to 60psec.

To me this is interesting as it shows how noise from a PC/Mac can possibly be picked up by the listener due to the influence it has on the DAC, even when talking about measurements where it is exceptionally low.
It would be interesting to see the results with a product designed to have greater isolation, but the reviewer did use the Naim NDS player that is pretty good.

So if using USB with a PC/Mac, might be worth considering a highly specific-focused product such as Melco/Auralic/etc instead.
It is worth pointing out that while the Melco did not improve the reviewers network SQ setup, this is due to it being very dedicated using fibre optic cabling and excellent switches but he did feel there was a subtle improvement if the environment was more like a general home setup using the router-hub and not fibre-optic cabling/quality switches/etc.

Anyway no-one should assume USB is immune to influencing DACs, especially noise generated by the actual PC/Mac.
Cheers
Orb

amirm said:

Fascinating. In my HDMI testing I could see laptop noise bleeding into the DAC but nowhere near these values.

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Yeah,
would be great if they followed this up with an investigation, although the subjective possibly correlates to these improvements.
With their S/N they measure throughout the whole 20khz, has quite a lot of measuring points so would be nice to know a bit more about that noise structure.
Also it is probably fair to say using battery DAC for the measurement has created the optimum environment to measure influence of noise on the DAC S/N Ratio caused by a PC/Mac.

But I tend to accept the review because they do not know the measurements and also his conclusion was using it as a network player brought marginal improvements that could be done with cheaper alternative solutions but where improvements happens is with USB.
His review conclusion on network use correlated with the measurements by Paul Miller where improvements were negligible to marginal.
Cheers
Orb

dallasjustice said:

I've used different servers and softwares and even highend external power supplies with my Lynx Hilo and they all measure the same using RMAA. If there are differences that large, then the DAC is probably defective or there's something else wrong with the setup.

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Dallas, you might not be aware but Paul Miller is the creator of the Miller Audio measuring suite (similar to the Audio Precision products in many ways) and has a good background in science-engineering for this purpose.
It goes beyond a faulty DAC or setup because they used multiple DACs, including those that can be isolated from mains using battery.
This was also replicated by Paul Miller who was not the reviewer but does all measurements separate to the review; so different environments and PC/Mac.
Please appreciate they measure at many points through the whole 20hz-20khz range at DAC output.
Just curious when you measured PC-USB-DAC, how did you do this yourself including software test generator from the PC-Mac and what was your baseline such as equivalent to Melco?
I do not think it is advisable (not suggesting you did this but some might consider trying) to compare performance results of a DAC's measurements between SPDIF and USB due to different chipsets/circuitry/protocols-framing-timing-etc involved.
Edit:
Just to emphasise, I am not saying this issue is equal for all USB DAC designs but something that is well worth considering in the context of achieving 'WhatsBest'.
Cheers
Orb

Just to add, this issue will vary in level of influence with different USB DAC products, and there should be products that are near fine.
And we are talking about a S/N Ratio measurement that in theory is better or close to the 16-bit dynamic range limit to begin with.
Cheers
Orb

jkeny said:

Thanks Orb, some of us have been saying this for years.
Although it's interesting that Rob Watts remeasured his Hugo with his newly acquired AP APX555 & found no difference between it's different inputs @ -14.5/115.5dB using a Dell T1650
http://www.head-fi.org/t/702787/chord-hugo/11370#post_11772346

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Thanks will take a look at the thread.
Just to add, it all comes down to how they create the 'real world' environment to measure influence of noise from another electrical audio component - well I see he mentions a Dell laptop with the associated AP software.
Strange though that his measurements do not differ for each interface, never seen a product that has identical S/N for all inputs when it is such a compact size constrained product and very rarely jitter equal on all (Rob's measurements saying there is none, which considering the size and design focus of the Hugo is very strange).
Cheers
Orb

Yeah it is well designed, and from what I have seen so is also the Auralic Aries (no internal hard drive I think but supports USB storage devices that is separate to the USB for the data transmitted to the DAC).
One interesting aspect though, the N1A uses standard HDD and has these improvements.
Regarding Melco I think only the N1A has USB+network while the more expensive N1Z model with SSD is (or was) network only.

But would be nice if they also did a test+measurements with several exceptionally designed DAC (shame the Naim NDS was only used in the review and not part of the USB measurements).
Still it is a route I am considering going, either the Melco or Auralic this year.
While not part of the USB measurements done with the Melco N1A, Paul Miller did also use it with his mono Devialets and found it an improvement again over his MacBook.
As further information Paul Miller was using Chord SilverPlus USB cable.
I would assume some noise bleed is still happening but nowhere as notable as examples where S/N ratio is below 100dB, but possibly still enough to influence SQ performance as subjectively heard with the Devialet/Naim NDS/etc

Cheers
Orb

amirm said:

If it is going to happen, it is much more likely with USB because ethernet has isolation transformers and completely async operation.

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Yeah.
Just felt that it was good to see that the reviewer not sucked in subjectively on the Melco ethernet setup sound quality, would had weakened the value of the review IMO if it had been glowing for both interfaces.
Cheers
Orb

jkeny said:

Orb, any idea what were the measurements for the network connection?

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I would need to check but same situation as the N1Z Hi-Fi News reviewed some time back, so if lucky that may be on the internet somewhere but I think it was not worthy of any comment in terms of differences.
Late here so may have a check tomorrow.
Cheers
Orb

Ok looks like the N1Z does indeed support USB playback to DAC these days.
Cheers
Orb

jkeny said:

Orb, any idea what were the measurements for the network connection?

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Heya Jkenny,
Ok gone through the N1Z review and there is nothing different between the performance of the Melco and a high quality PC/router solution.
Going back to the N1A review Paul says in the measurements for the network:

Hi-fi News said:

The lab tests pitched the performance of the Melco against a high quality PC/router solution using various network attached DACs.
Despite the N1Z's superior engineering there were no observable differences distortion (vs level or frequency), response, output level, linearity, or indeed, A-wtd S/N ratio whether the test DAC was driven via the PC network (and Netgear switch) or directly via the same test files stored on the N1Z.
This same 'lack of difference' was observed with Melco's N1A. Small differences in jitter were recorded (for N1Z), the same was with the N1A in situ.
I'm bound to conclude that subjective differences may well be experienced between noisy/shared NAS drives and the Melco(s) but as the quality of the network/NAS/router or switch improves, the advantage offered by the Melco(s) will shrink.

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This is specific to the network capability-performance, not the USB comparison.
Cheers
Orb