Parasound Zdac Page 2

My initial taste of the Zdac came not from a headphone setup but rather my speaker rig. I fed it via USB from a laptop running Foobar2000, and used my highly transparent Analog Design Labs Svetlana 2 as a preamp. Amplification was handled by a Parasound Halo A23, driving Salk WOW1 monitors on Sanus NF30 stands. Yikes! This setup sounded killer. The Zdac replaced a more expensive Bladelius DAC and the system sounded noticeably better with the Parasound in place. I have to agree with Michael Lavorgna when he called the Bladelius unit somewhat lean---the Zdac seemed to add a good dose of oomph and gusto where prior there had been very little. I casually used this configuration for a while and repeatedly thought to myself: there's just not much more to be had here. At that point the room seemed a more significant limitation than any of the individual components. This speaks to the quality of the Zdac as it was by far the least expensive component in the chain, yet was able to avoid being a weak link.

Next, I got "serious" and moved the Zdac into my headphone setup. It ended up sitting on a rack along side several other units costing twice, thrice, up to ten times as much. Interestingly, the most expensive unit wasn't my favorite, and the least expensive (the Zdac) didn't fall to the back of the bunch. Apparently "you get what you pay for" is not a universal truth after all. I initially used it as a DAC only, paired with the Icon Audio HP8 MkII which powered a Beyerdynamic T1. I started by feeding it via coaxial SPDIF from a Cambridge Audio 840C spinning a few CDs - Unity by Ernie Watts (XRCD), some Gap Band, the new Norah Jones release, some Damien Rice. Again I noticed a distinct lack of any weaknesses. Not merely for a "budget" DAC but just in general. I've become somewhat of a snob recently, due to consistently using higher priced DACs, and yet the Zdac was not letting me down one bit. It might not have the complete transparency of my Resonessence Labs Invicta ($3999) but it didn't stand out as being hazy, harsh, or overly "digital" in the least. The sound was engaging and full, with a nice tonal balance that didn't leave me wanting for much more.

I don't normally spin CDs very often, so I switched to my Auraliti PK90 music server. Moment of truth - will the Zdac be compatible? Yes! Linux users rejoice! It's always a bit of a gamble when trying a new DAC with the Auraliti - some work just fine, some refuse to work at all, and I've even had one unit that worked with certain sample rates but not others. Weird.

My headphone system is more resolving than my speaker setup and I could get a better sense of how capable the Zdac really was. A few things became apparent - first, this is not an ultra-analytical sounding DAC. People who gravitate towards gear like the Bladelius DAC as the definition of neutral would probably find the Zdac a bit "overly ripe" for their taste. It's got a full, organic sound that to my ears sounds an awful lot like real music. This is a trait it shares with most of my higher priced DACs, though I fully admit that expensive counterparts of the leaner variety also exist. Don't let me scare you away though---this isn't some lush sounding tube DAC or rolled-off NOS design. On the whole it seems well balanced and should work well in most systems.

To test that theory, I swapped some components in the system, keeping only the PK90 as source. This time around the Zdac fed a Violectric V200 headphone amp via XLR, which then powered an alternating selection of JH Audio JH13 (FreqPhase version) and Audeze LCD-2 (latest model). This was a deliberate contrast between the LCD-2 with its somewhat relaxed top end, and the JH13 with its more energetic presentation. The system worked well with both meaning the Zdac was neither too bright nor too dark. Theory confirmed.

Bob MacDonald, an engineer from Parasound, advised me that given the same source material, all three inputs should sound the same. I found that to be true in a broader sense where they all had the same general character. But when push came to shove I thought the USB input had the edge in terms of detail retrieval and overall realism. This probably reflects my transport situation as much as it does the Zdac itself so I wouldn't make a big deal out of it.

This is a little awkward because recently, on this very website, Steve Guttenberg offered his opinion on the Emotiva XPA-2 and Schiit Bifrost units as being superior to the Zdac. In a great example of "we all hear things differently", I came away from the comparison with a contrary result. I felt the Zdac was by far the better DAC, with the Bifrost and XDA-2 taking 2nd and 3rd respectively. The Bifrost makes a great "gatekeeper" DAC---anything better is something I'd be interested in hearing, while anything falling behind is merely an "also ran". I thought the Zdac had better imaging, a more realistic soundstage, and deeper, more lively bass. It made the Bifrost seem comparably flat and 2-dimensional, and not very engaging. Both came from the same school in terms of having a somewhat musical sound signature, but the Zdac was a mature senior while the Bifrost was a lowly sophomore at best. Considering their respective sound and feature sets, the Zdac seemed to me like the obvious choice.

Lest we forget, the Zdac also has an integrated headphone section. Far from being merely a throwaway feature added to garnish a check mark on a feature list, the headphone amp is actually rather nice. It does have some limitations---the 10 ohm output impedance means it isn't really ideal for low impedance headphones. And there's a "pop" when powering on or inserting headphones, which is mildly annoying---especially since Parasound makes a point to mention how they use relays on the RCA and XLR outputs to avoid this very thing. As long as I'm complaining, it looks like they could fit a 1/4" jack on there, so I'm not sure why a 1/8" jack was chosen.

Having said all that, the amp sounds very respectable for what it is. It continues in the same vein as the DAC section with a clean, clear, slightly smooth presentation. The TPA6120 is a nice amp chip when done right and I'd say that is definitely the case here. I asked Parasound what headphones they used while voicing the amp and they replied with a list that started with Sennheiser HD600. This makes perfect sense as the HD600 sounded excellent straight from the headphone jack. It had a nice black background, good extension on both ends, and plenty of drive. This would make a great starter system, and the amp section is so good that I wouldn't bother "upgrading" until I could throw at least 3 or 4 hundred dollars at a dedicated unit.

A DAC is far more than merely the sum of its parts. There's no shortage of new releases using all the latest chips and packing all the latest buzzwords. But that doesn't mean they compete with the real deal---there's just no substitute for proper design and implementation. Making purchasing decisions based purely on chips and specs has a good chance of leaving a person disappointed. The Parasound Zdac is a great example of this, it doesn't use a cutting edge DAC chip or USB receiver, yet it manages to transcend the limits of what I expect from the average $500 DAC.

In summary, the Zdac looks, feels, and sounds like it could be a $1000 unit. It certainly didn't feel out of place in my rack with numerous competitors in that range. As a DAC, the Zdac offers exemplary performance with practically zero downside unless we count the lack of support for sample rates above 96kHz. As a headphone amp it could use a few tweaks, but still manages to sound excellent with the right headphones. Do I recommend it? Yes! Rather strongly at that.

Parasound home page and Zdac product page.
Some further impressions from owners at Audiogon.

Parasound Products, Inc.
2250 McKinnon Avenue
San Francisco, CA 94124
(415) 397-7100

EraserXIV's picture

Great review as always. Let's get this all off our chests as it is clearly the big elephant in the room:

How does it compare with the Yulong D100, which is almost identical in terms of features, price, and even specs (D100 using an AD1955 which is a suggested alternative for the AD1853 on the analog devices website)?

John Grandberg's picture

The Yulong D100 MkII is a great DAC as well. The Zdac is roughly similar in overall quality but with a different presentation - warmer and smoother. It sounds more like the Yulong D18 in flavor. 

me1337je's picture

I was wondering the same thing. Which one would you advice in combination with a Senn HD598 and a HE-400?

John Grandberg's picture

It depends on what sound you are going for. The Zdac has the advantage when used as a USB DAC. In terms of amp section, the Zdac would be my choice with HE-400, and the Yulong (with its lower output impedance) would be superior with HD598. 

lithium's picture

Hi John,

enjoyable review and I was going through the specs on the ZDAC priduct page that you have provided a link for. According to this page the output impedance of the headphone amp is 40 ohms on the headphone out. So , is this page wrong or did you get your information from an inaccurate source? also the I second the above question about the yulong.

John Grandberg's picture

See above about the Yulong comparison.

As for output impedance - the original run had a resistor on the headphone stage for a 40 ohm output impedance. I questioned this, as the TPA6120 datasheet recommends 10 ohms. Turns out it was an arbitrary decision made by the factory who assembles the devices. Parasound fixed it, so everything after the very first run should have the lower spec. They are still working on updating the website, manual, and marketing sheets to reflect the lower number.

I don't want to take complete credit for this, and maybe they would have changed it regardless, but I was the one who first pointed it out. 

lithium's picture

I think you should absolutely take the credit for this. This might also explain why Steve Guttenberg felt that the ZDAC was inferior to the emotiva XDA-2(output impedance- 0.1 ohms). He mentioned that the difference was more stark when using headphones and he used 32 ohm M-100 for his comparison. Perhaps he got the ZDAC with a 40 ohm output impedance. As you can see I would like to believe that there is a an objective reason for your listening differences.

aravind's picture

Saw your detailed concero review on headfi..can you comment on how the Zdac compares with concero in sound quality?

John Grandberg's picture

Concero is more neutral overall, with more detail and air to the presentation. Both are fantastic for the money. 

RudeWolf's picture

How it would stack against the old D/AC-1XXX DACs? I'm currently listening to a D/AC-1600HD (HD650 driven by a Dynalo) and save for a few dubious design choices it's a very solid sounding unit.

John Grandberg's picture

Good question. I used to really enjoy those D/AC models but it's been quite a few years since I heard them... so I really couldn't say. 

RudeWolf's picture

If you ever get a chance to try the older D/AC-1XXX units be sure to try bypassing the MOSFET output buffer. It sounds much cleaner that way. I really can't figure out why the buffer is needed in the first place, all it does is emit a ton of heat and add a lot of even order distortion.

lithium's picture

Hi John,

I was wondering looking at the XLR outputs of the zdac whether it is a truely balanced DAC?. There are not a lot of balanced DACs at this pricepoint so just curious.