Wednesday, December 8, 2010

Rega DAC: Bassy sound

If you are like many other audiophiles out there who have ventured into the world of digital hi-res hi-fi, you would still have a CD player (which you use as a transport) and a laptop - either Mac or Windows-based - which you will use to stream music data to the external DAC via iTunes or PC-based music players like WinAmp, J River, Foobar, Media Monkey and others.

The hires 24/96, 24/88.2, 24/176.4 or 24/192 files will be stored either in the laptop’s internal memory or an external hard disk.

With a DAC like the Rega DAC, you will encounter a major problem - how do you stream these hi-res files to the DAC without them being downsampled? This is because the USB input of the Rega DAC, like a few others in its price range, accepts only 16-bit/48kHz files.

And you will have a problem looking for a laptop - Mac or Windows-based - that has Toslink or coax outputs. Most Macs offer digital output via optical, but it is shared with the 3.5mm mini headphone jack and a normal Toslink cable cannot be plugged into it. So, if you own a MacBook, MacBook Pro, recent iMac or Mac Mini, you have to buy either a mini-Toslink adapter or mini-Toslink to Toslink cable to stream data via optical fibre to the DAC. However, the MacBook Air has no optical output.

This was the problem I faced. And I could think of only two solutions - borrow a USB/SPDIF converter like Stello’s U2 24/96 USB Link or Bryston’s BDP-1 digital music player to stream the hi-res files natively to the Rega DAC.

So I telephoned James Tan of AV Designs, the Malaysian Bryston dealer, and he said he would lend me the Bryston BDP-1 and the matching DAC next week.

Thus far, I can report only on how the Rega DAC sounds with 16/44.1 files streamed either from the resident Roksan Caspian CD player used as transport and ripped CD files streamed from a Toshiba laptop with Media Monkey.

I also heard 24/88.2 Studio Master FLAC files of Handel’s Messiah from Linn, but these were downsampled by Rega’s USB input.

I compared the Rega DAC with the Benchmark DAC1 Pre (‘warmed up’ with Furutech fuses and Siltech power cord) which was connected with a QED Toslink cable to the Roksan Caspian CD player. The Rega DAC was connected with an MIT Terminator 3 Coax cable to the 'Roksan.

The resident system comprised the Bryston 4B SST power amp, ATC SCM40 speakers, MIT Shotgun MA interconnects and MIT Shotgun MA biwire speaker cables with the entire system plugged to a Furutech eTP60/20 power distributor. I also used Sennheiser HD600 headphones to detect changes in the digital filter settings.


It is pretty obvious that the Rega DAC has a bassy sonic signature. This was especially so when the filter was set to number one (Rega recommends using Filter 1 - the linear-phase half-band filter -  initially before you experiment with the other four settings when using different components).


The bassy tonal balance was at the expense of mid and treble transparency and treble extension.


The Rega DAC


The Benchmark sounded clearer, more open and transparent from the upper-mids to the highs. Cymbals sounded more realistic and horns, higher notes of the piano and violins had better timbre with the Benchmark. The presentation was also less forward with the Benchmark.


Of all the filter settings, I felt that Filter 5 (minimum phase apodising filter) improved the mid transparency and treble extension the most and I used that setting for the rest of the listening session with 16/44.1 files.


It was when I streamed the 24/88.2 Linn Studio Master files through the USB that the Rega DAC’s weakness showed up glaringly. But to be fair to Rega, this is the same fate suffered by all DACs using a 16/48 USB input. When I tested Stello’s DA 100 Signature DAC (http://hi-fi-avenue.blogspot.com/2010/05/stellos-upsampling-dac.html), it sounded about the same through its 16/48 USB input.


I cannot confirm this, but the Rega DAC probably uses the same USB chip found in the Stello - the Burr-Brown PCM2704 from Texas Instruments which supports 16-bit files with 32, 44.1 and 48kHz sampling rates.


Through the Rega DAC USB input, the 24/88.2 files sounded ‘stressed’ and forward and the soundstage was flattened. Singers who were presented as standing in a curved row behind the speakers by the Benchmark were presented as standing in a line by the Rega DAC.


This flattened perspective pushed the images forward and the sense of spaciousness was much reduced.


With the Benchmark, the 24/88.2 files were decoded in their native resolution and the music sounded richer and relaxed with deep soundstage and great spaciousness.

The Rega DAC USB input is good enough for ripped CD (native 16/44.1) or MP3 files, but if you want to hear hi-res music, you will need to use the other inputs.

As I said earlier, you will have to figure out how to achieve that. In my case, once I get hold of the Bryston BDP-1 digital music player, I will post my observations.


Next post: Rega DAC sounds better through its hi-res inputs. Click http://hi-fi-avenue.blogspot.com/2010/12/rega-dac-sounds-better-through-its.html

11 comments:

  1. Macbooks has Toslink output. Have for ages.

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  2. Was the DAC burned in before being sent to you? Knowing Rega digital gear, 400 hours or so of burn in is required as the sound will change quite a lot.

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  3. ben,

    the dac was used for a while, but definitely not 400 hours. someone brought it back from UK and was used in the asia sound showroom for a while.
    while the sound may settle down after running in, the fact remains that it cannot play HRx 24/176.4 files.

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  4. Hi
    I've got Rega DAC on tests, and I've got my own Stello DA 100 Signature 96/24 (I've changed older version 16/48). In my system(Hegel H-100, Neat motive 1, Harmonix CS-120 sp.cable) Rega isn't more bassy than Stello. More warm, and delicate yes, but Stello has more power and drive.

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  5. Very hard to take this review serious.

    First: Macs have had optical out for years!
    Second: Rega Dac uses Wolfson chips, not Burr Brown.

    Do your homework please. These are two things I knew about, but what else is wrong with your review that I don't know about.

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  6. gabriel,

    1) yes, macs have had optical out for years. but as i mentioned in the review, u hv to buy a toslink adapter before u can plug it to the toslink input of yr dac.

    2) yes, the rega dac uses wolfson chips, but i said the burr brown is probably used for the usb input. if i am not wrong, burr brown is the only company that makes usb chips that accept 16bit 48 kHz.

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  7. lam seng fatt, you are probably correct about the USB using a Burr-Brown chip. I've got my Rega DAC connected via USB to my iMac at the moment and in System Profiler, on the USB Tab it shows the following information:

    USB Audio DAC :
    Product ID: 0x2707
    Vendor ID: 0x08bb (Texas Instruments Japan)
    Version: 1.00
    Speed: Up to 12 Mb/sec
    Manufacturer: Burr-Brown from TI

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  8. i'm thinking of buying a rega mira 3 and an oppo bdp 93 or 95 player with a pair of ascend audio sierra 1 speakers. do i still need a DAC?

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  9. in yr proposed system, i would recommend the oppo bdp 95 as it has the superior sabre dac and dedicated stereo outputs. with the bdp 95, you do not need an external dac as its performance should be good.

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  10. better still just use the mTech hiface with your Rega DAC, hirez sounds very good IMHO

    http://www.6moons.com/audioreviews/m2tech/hiface.html

    ReplyDelete