McGary Audio

Thursday, August 15, 2013

Audiophile Review!
Parasound Zdac 24/192
Digital-to-Analog Converter


Review Update 4/15/15: See Review of New zdac v.2


Brevis...
Price: $475
Likes: low price, hi-fidelity
Dislikes: no 192 decocde via USB
More info: Parasound Zdac

by John Gatski

  Audio D/A converters pervade the hi-fi aftermarket landscape these days — with a lot of press going to the $1,000+ DACs. But you don’t have to spend four figures to get audible improvements over the garden variety DACS built into many of the digital media players and computers. Or maybe you just want to replace that old DAC that was once the cream of the crop, but do not want to spend a lot of money. The Zdac from Parasound, priced at under $500, fits that criteria nicely.
  I have used Parasound products for nearly 20 years; amps, preamps, phono preamps, and universal players. They always offer fantastic audio bang for the buck; the Z-dac D/A fits right in.

Features
  The $475 Zdac sports just enough bells and whistles to make it useful for most applications, including computer listening, audiophile racks, and even home recording stereo monitoring tasks. Its connection list includes the usual SPDIF inputs (TOSlink and Coax), as well as USB; analog output consists of separate balanced and unbalanced outputs, plus an 1/8th-inch headphone jack.
  The front panel features an input selection switch, headphone jack and volume, and power switch. For this price range, you do not get any sample rate or word length indicators, just the input indicator. Keep it simple, keep the cost down.
  The Zdac’s good fidelity comes courtesy of the Analog Devices AD1853 24-bit/192 kHz digital to analog converter chip, the same chip used in the Benchmark DAC1 series. All digital input signals are re-clocked and up-sampled to 422 kHz for improved sonics and improved jitter reduction. The Analog Devices AD1895 sample rate converter chip is used for the upconversion.

The Parasound Zdac is a best buy D/A converter that offers surprisingly good audio via its line outputs, considering its price. As a result, it gets an Everything Audio Network Stellar Sound Award.

  The Zdac is compatible with almost any computer audio PCM format, but is limited to 96 kHz/24-bit because of its driverless USB 1 implementation. No 192 kHz PCM, as well as DSD/DoP playback.
  Regarding computer utility, the Parasound seems a bit more Windows friendly — with its PC software variable volume mode that enables direct connection to a power amp (perhaps a Parasound?). The Zdac works fine with a Mac, but the computer line-out volume is fixed at max when using the Zdac, thus, you will have to use the playback program's volume control to adjust the level — if you connect the DAC straight to an amp.
  The Zdac’s high current headphone amp is claimed to drive virtually any headphones from 32 to 600 ohms. Some of the initial Z-dacs did not like high-impedance phones, but later units were re-designed to handle such a load.
  Parasound is proud of the fact that the Zdac uses a high-quality, toroidal transformer, which maintains an air of hi-fi pedigree for a DAC in the under $500 class.


Parasound offers balanced and unbalanced outputs


  The Zdac’s factory specs are quite good with a 110-dB signal-to-noise ratio, and low distortion throughout the audio band of the various sample rates. The analog outputs, via unbalanced or balanced, have plenty of oomph — with 2.1 volts and 4.2 volts respectively. No jitter reduction numbers are listed in the specs.
  The Zdac is of typical half rack proportions and weighs in at about 5 pounds. It is available in silver and black. In my opinion, the silver is much more attractive. The unit is manufactured in Taiwan.

The set up
  When the Zdac arrived, I had numerous tester DACs and my own reference DACs to make comparisons, as well as a number of standalone high-end players of various vintages. The other DACs were in higher priced categories: Benchmark DAC2 HGC/DAC2 D/DAC1 Pre, Mytek Stereo192-DSD, and TEAC UD501. If the Zdac was 80 percent as good as the $1,500 DACS, it would still be a sweet deal. (It ended up being better than that.) 
  I monitored the DAC’s line outs via a high-end headphone amp (Bryston BHA-1), as well as through my hi-fi rack system, which consisted of MartinLogan Montis speakers, Pass Labs X350.5 MOSFET amplifier, and Coda solid state preamp. All interconnects (digital and analog) were courtesy of WireWorld. The power cables and strip were Essential Sound Products Essence II.

The audition
  Via the rack system, I immediately noticed how similar the Zdac's sonic signature was to the Benchmark DAC1, which makes sense since they use the same chip. The sound of the 24/96 copy of the DMP label’s Warren Bernhardt So Real SACD, had that slightly cool, crisp, slightly forward character of the DAC1. Via headphones, I could sometimes hear subtle differences between Zdac and DAC1, but not always.
  On some percussion heavy music, the DAC1 audio had a teeny bit more width and depth on ultra treble detailed jazz, and it was a tad smoother on brass, but the difference on most music was not that great — especially with speakers. The MartinLogans relayed the Zdac’s detail with a finely focused top-end and tight bass. This is a $475 DAC, eh? Hmm.

Compared to DACs in older CD and universal DVD-A players, a perfect upgrade path for the Zdac, the improvements were quite noticeable.

  The Z-dac’s headphone amp was good, but the DAC1 had a more expansive image via my Shure SRH1840 and AKG K702 headphones. Overall, I found that, subjectively, the Zdac’s headphone circuit is not quite as hi-fi as the line outputs. Unlike most DAC headphone amps that I review, it also is not a 1/4-inch-input.
  In direct comparison to the newer $2,000 Benchmark DAC2 and the $1,700 Mytek Stereo 192-DSD, which both use the ESS Sabre32 DAC IC, the Zdac projected its slightly forward lower treble character, with the pricier DACs emoting a more refined smoothness. But the detail quotent was very close. The Zdac presented a broad soundstage with ample depth. Again, I say this DAC ain’t no slouch!
  At the recent DC Capital Audiofest, I had several DACs on demo at the Everything Audio demo room, including the Zdac, Benchmark DAC2 D and Mytek Stereo192, used in this review. With DAC levels matched and connected to a preamp with the capability to switch sources very quickly, a steady stream of audiophiles came in to listen to the DACs.


Nice and tidy inside the Zdac


  During the casual listening sessions, quite a few hi-fi buffs said they were hard pressed to hear significant differences between the Z-dac and other, more costly D/As. Some said they did hear the slightly forward treble, in direct comparison to the Mytek and Benchmark, but also noted that the Z-dac, by itself, sounded like an audiophile DAC, especially for its price class.
  Compared to DACs in older CD and universal DVD-A players, a perfect upgrade path for the Zdac, the improvements were quite noticeable. For example, the smooth factor of the Z-dac vs. the PCM DAC of the Esoteric DV-50 (Circa 2003) was significant. The Parasound was way easier to listen to with highly modulated, 24-bit jazz music with trumpets, saxophone, etc., than the Esoteric. An old Denon CD player from 1993, became relevant again — with the Z-dac as its new decoding engine. My Tuck and Patti — With Love CD sounded aces with substantial width and depth of the finger-picked guitar and vocal nuances of the recording.

The Zdac does offer high-res sonic delivery, especially through its line outputs, that comes close to more expensive DACs. Yes, in A-B comparisons with levels perfectly matched, there are subtle sonic differences, but not as much as you would think.

  Switching to my Mac laptop, the USB input worked perfectly with the iTunes, Peak, Soundtrack, Pure Music and Audirvana software; the 24/96 songs played without any glitching. However, I sorely missed the ability to play 24/192 audio files through the USB. The USB 1 protocol is old school for DACS these days. I guess you can’t have it all for $475. (I was able to play the 192 files from the Mac into the Zdac using a M2Tech HiFace Mac iUSB-to-SPDIF interface and a SPDIF coax cable).
  So the proverbial question is: “can a $475 DAC be satisfying to a discriminating music listener”? The answer is yes. The Zdac does offer high-res sonic delivery, especially through its line outputs, that comes close to more expensive DACs. Yes, in A-B comparisons with levels perfectly matched, there are subtle sonic differences, but not as much as you would think. I had to really focus to notice the differences. If you listen to the Zdac on its own with speakers, the room swallows up most of the subtle difference. The Parasound Zdac presents you with a fairly accurate decoding and playback of most kinds of music. Its slightly forward character could make pop music a little busy. But for classical and jazz and acoustic, it is pretty darn good.
  Overall, I enjoyed the Zdac — especially keeping in mind its under $500 price tag. It never missed a beat, even as it baked in the heat of multiple DACS stacked on it at the 2013 CAF. The headphone amp was not as good as the higher cost units I had on hand, but, by itself, it is not lo-fi by any means. I wish that the Zdac could convert 192 sample rate audio files via the USB, but, alas, something has to give in its price range. Maybe something to strive for in the next version.

The verdict 
  The Parasound Zdac is a best buy D/A converter that offers surprisingly good audio via its line outputs, considering its price. If I had an older player or DAC from ten years ago and wanted to cheaply upgrade my sound, I would certainly put the Zdac on my to-buy list. It sounds good, offers enough utility and won’t max out the credit card. As a result, it gets an Everything Audio Network Stellar Sound Award.

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