Top CD transports vs USB converter shootout


In the past 12 months, I had a chance to do some extensive comparisions between various, traditional CD transports and the USB/SPDIF converter. (For those who, for the past three years have been sitting in a cave and do not know what an USB/SPDIF converter is - this ia a device, a bridge that connects between the DAC and a computer, and allows to play music from the hard drive.)

All the transports I tried, from my dCS Scarlatti to the McIntosh MCD-1000, could easily aspire to the State-of-the-Art status and are top of the range models from the respective manufacturers.

So is the USB/SPDIF converter I used to evaluate the transports - the BADA Alpha USB I've been using, is, to the best of my knowledge, the best USB/SPDIF converter available on the market today. (I base my statement on the extensive tests of some 15+ different USB converters I also conducted in the past 12 months - I can describe the results in a separate thread if anyone is interested).

Anyway, the transports I have tried were:

$33k dCS Scarlatti transport:
Scarlatti image

$20k Accuphase DP-800:
Accuphase image

$9k McIntosh MCD-1000:
McIntosh Iimage

And here is the $1800 BADA Alpha USB (on top of the Metrum Hex DAC):
Bada image

I have also tried some other transports as well, starting with a $700 Stello CDT100, but those were much cheaper, so are not really revelent to this thread.

Stello image

All the transports, including the BADA Alpha USB, were connected to my dCS Scarlatti DAC using the generic BNC cable. I'm a firm believer in BNC cables, as in my experience, even a cheap, $10 generic BNC cable can outperform fancy RCA and AES cables costing hundreds of dollars. The only exception was the McIntosh MCD-1000, which was used with the Stealth Varidig Sextet AES/EBU digital cable, as it lacks the BNC output.

During the tests, I have also tried the matching Accuphase DC-801 and McIntosh MDA-1000 DACs. In the case of dCS and Accuphase DACs, I did not use the available clock link feature (which greatly improves the sonics in all-dCS and all-Accuphase systems) as I was interested in comparing the pure SPDIF performance of all transports, not learning that SPDIF as a standard is flawed, which I have ackowledged a long time ago.

The test was as fascinating, as it was ... short. The BADA Alpha USB turned out to be much better than all of those transports mentioned. There was even no need to switch back and forth as we often do to hear the differencies. The difference was so obvious, that you could hear it in the first 10s of a familiar recording (I recommend a recordings with lots of HF energy, like lots of percussive instruments - triangles, hi-hats etc and a lively acustics; pesonally, when comparing different digital cables, digital transports, USB converters or computers, I always use 'La Spagna' by Atrium Musicæ de Madrid and Gregorio Paniagua published by BIS records - a fabulous recording of XV century music; there is also one by Harmonia Mundi, but I like the BIS one better).

The BADA Alpha USB made the sound smoother, with ZERO artificial edge, grain or digital glare.

There was also much better layering of instruments, and air around the outlines. The instruments sounded not only better separated in space, but also much more 3-dimensional.

The resolution also improved quite a bit. You could hear the sounds that you were not aware are on the recording, the HF decays had much longer trails and hung in space much longer.

The most fascinating thing was that sound had better resolution, but at the same time, was so much smoother and fluid. Usually, it is another way round. Very often we try a new component or a cable and at first are fascinated by improved resolution, only to find out a few days later (after we had X-rayed all our recordings), that the increased resolution brings listener fatigue and makes the listening far less enjoyable.

Not this time. BADA pulls this incredible trick of sounding both more resolute, more transparent, and much smoother at the same time.

The traditional transports sounded grainy and congested at the same time. The whole rendition of space just shrunk, as if someone sucked out all air. Once I have heard the BADA, there was no going back.

One may ask - how it is possible that a $1800 device can outperform a $33k transport ?

For starters, the USB converter much cheaper to manufacture, as it doesn't have an expensive (in case of Scarlatti - EXTREMELY expensive @ $5000) CD drive, fancy box, big PSU with separate legs for the drive, display, servo, control logic and SPDIF out, etc. Since it is so small and has no controls, it can get away whit what looks like a $100 box that can be hidden away.

On performance side, I think it all goes down to the quality of the onboard clocks used (and their respective power supplies). The clock stability has a direct influence on the quality of the SPDIF signal, as the whole SPDIF signal is generated using clock as a reference. So more stable clock = more stable (less jittery) SPDIF signal.

All the transports I mentioned use clocks that were available 7-8 years ago, when those transports were designed. They were probably one of the best avalable at the time, but are rather avg by today's standards - there was a great advancement in clock art (with respect to their phase noise) in the past 3 years.

The latest Ultra Low Phase Noise clocks that are used in BADA Alpha USB (made by Crystek), have the levels of phase noise that rival the ultra expensive Rubidium Clocks. Sure they do not have the long time accuracy of the Rubidium Clocks (the PPM figure), but that doesn't really matter, as what is important in digital audio is the short term clock STABILIY (the level of Phase Noise).

Were does this leaves us ? Well, the dCS owners do not really have to worry, as enabling the clock link feature between the transport and a DAC (during the course of this test I kept the clock link feature disconented to level the playing field) will improve its performance. The Scarlatti clock may not be enough to get past the performance offered by the BADA (the U-Clock shurely wasn't), but the Antelope 10M Rubidium Clock is.

Antelope 10M Rubidium Clock image

Scarlatti transport driven by Antelope 10M clock (and needed Antelope OCX clock divider) still gave me the best sound I have ever heard from my Scarlatti system. Not to mention the fact, that it does SACD as well.

But for the rest of you, who DO mind spending $50k for the transport, clocks and cables, this is a great news. Nowaydays for ~$5000 (BADA Alpha USB + CAPS v3 Lagoon computer + NAS) you can have a State-of-the-Art digital transport, that will rival most super expensive CD spinners.
128x128elberoth2
I am surprised dCS, and other high end CDP owners, have not mounted a campaign against your words of wisdom.

I think that they are aware of this fact. That is why their new Vivaldi DAC has USB input onboard.

Please note, that the Scarlatti transport fed from a top quality standalone master clock (like the Antelope Rubidium 10M I used) will still sound better than any of those USB/SPDIF converters, as this arrangement allows you to get rid of SPDIF interface jitter (something those USB/SPDIF converters will always be - by definition - suspectible to).
Elberoth - if the USB converter outputs I2S, then it is not susceptible to S/PDIF conversions.

Not that I feel these conversions are that significant. With some gear, the conversions might be.

Steve N.
Empirical Audio
Elberoth2,

Thanks for the excellent review! Is the dCS Scarlatti DAC
your favorite DAC?

John
I feel MSB DAC IV Diamond with Femto Clock upgrade is slightly better than Scarlatti. Havent't heard the dCS Vivaldi though.
Elbroth, thanks for the excellent review, can you please tell us your exprience with the metrum Hex Dac?