Benchmark DAC1 D/A Converter

Benchmark DAC1 D/A Converter

Several of you have sent emails to me with your comments about my preference for analog sources. These comments range from “Right on, Dude. You got it right!” to “Your reviews are worthless without including digital as a source”. There is quite a wide range of opinion out there in hyperspace. I appreciate all of your feedback, whether supportive, critical, or just informative. I think about what you have to say and then merrily continue on my own way. It’s my ball, after all.

Those who noticed the lack of reviews of digital sources are absolutely correct. I see that the last review of a digital component was way, way back in 1997 of a Sony XA7ES CD player. In the 10 years since then, I have reviewed 16 phono cartridges and 3 turntables, plus 13 phono preamplifiers. And not a single CD player, transport, or D/A converter in all of that time. There is a good reason for this omission, if you will allow me a minute to explain.

I’m not really a writer - as some of you have observed. I far prefer to listen to music than to write about it for the simple reason that listening to music is fun, and writing about it moves down the Fun Scale towards the other end - work. I try to make my reviews reliable, which means that I listen to each component at length before writing about them. And that is precisely why there has been a long absence of reviews of digital gear: listening to it just wasn’t fun. This was not only true because of the relative sonic superiority of vinyl playback, but due to the low level of musical bliss on an absolute scale that digital offered. I have owned about a dozen CD players and D/A converters over the years, but had not been motivated to write about any of them, until now.

Benchmark Media DAC1To start off the new year, I bought a Tascam CDRW900 Pro CD recorder/player with the thought that a recorder would have to have a pretty good drive mechanism to be able to burn a disc and, therefore, should make a good transport if one was needed. On its own, it sounded pretty bad: flat, harsh, lacking in bloom, and very low on the enjoyment scale. Transistor-city. So I added a stock Benchmark DAC1 D/A converter and connected the two with PS Audio Digital Reference cable. The DAC1 reduced the severity of the flaws that the Tascam player has on its own, but the combination still lacked the bloom, harmonic richness, and low level resolution that just about any LP system provides easily. I used this combination to listen to a song on a CD now and then, but rarely. In fact, both the Tascam and stock DAC1 were unplugged and stacked in a corner of my listening room for about 4 months earlier this year.

Several months ago, another Benchmark DAC1 arrived, this one having already received the full upgrade from Parts Connexion which includes “the analog output stage...from the DAC chips to the output connectors...including critical signal path caps, resistors, op amps (these are the most expensive and most critical items in the mod...Burr-Brown OPA627 op amps on dual vertical surface-mount adaptor boards), output wire and output connectors. Plus, we upgrade the sonically critical PS (power supply – Ed.) diodes and resonance damp the chassis.” The unit under review here also has the upgraded balanced outputs. The stock DAC1 lists for $975. The mod adds $495, plus another $80 for upgrades to the balanced outputs. Fully modified units are available, too, in case you don’t already have a DAC1.

I am very familiar with Parts Connexion. I buy parts from them fairly regularly, and have listened to several of their modified components, including the PS Audio GCC-250 integrated “control amplifier” and the PS Audio GCPH phono preamplifier. I have had several cyber-discussions with owner Chris Johnson. As you probably already know, Mr. Johnson was the head of Sonic Frontiers. Even though no longer in production, Sonic Frontiers components continue to command high prices on the resale market because of their excellent long-term value. Their mods have always improved the sound to a significant degree, but I had no idea how significant the modifications to the DAC1 would be.

I connected both DAC1s to different inputs on the preamp and was able to easily switch the input BNC connector between the units. This facilitated almost instantaneous A-B comparisons. There was no comparison. While there are many similarities, they all involve the strengths of the stock DAC1. The weaknesses of the stock unit are more or less the standard laundry list of the reasons why CDs have not been part of my listening-for-enjoyment. Compared to LPs, it sounds harmonically thin and bland, grainy or harsh in the upper midrange and treble, shallow sound stage, loss of resolution as frequency increases, and finally, no freaking soul. That last may be just a little bit extreme since I could enjoy listening to a song or two with the stock DAC-1. So make that “only a teeny-weenie freaking soul”.

The Parts Connexion modification of the DAC1 (“PC DAC1”) reduced the common problems with CD sound to the point where CDs are now as musically involving as a competent LP turntable. (Yes, I said it!) Earlier this year, I had an original 25 year old gold-platter SOTA Sapphire turntable with Denon 103R, Benz LP and ZYX Universe cartridges. On a scale of musical enjoyment – the Zen Test – the PC DAC1 is roughly equivalent to the Sapphire/Denon. In the absence of surface or background noise, the DAC1 (and digital in general) is better. Depending on the condition of the record in my aging LP collection, this may be a significant advantage.

The modified DAC1 has very good low-level detail and harmonic richness that still misses the high standard set by better turntables and cartridges. But, and this is a big “but”, I have heard my SOTA Cosmos/Triplanar VII/Benz LP also sound harmonically thin using certain solid state pre- and power amplifiers or cables. This is a clear indication that system synergy is lacking because the Cosmos-Triplanar-Benz combination has the ability to sweep me away to NeverNever Land in a heartbeat and gently return me to my room twenty minutes later. Put the PC DAC1 in the right company, one tuned to maximize the strengths of the PC DAC1, and we have music. Synergy may be obtained using a high resolution, extended cable and tube electronics. The best results by far will be realized using a balanced connection to your preamplifier, where the performance improves noticeably, as much as 1 LP on the 10 Audio rating scale. For balanced cables, I used Mogami 2534 or 2549. The latter is darker overall and has less resolution in the bass than good old star-quad 2534. (2549 unbalanced is a truly excellent interconnect.)

Benchmark DAC1The bass is detailed and powerful, meeting or exceeding this character in the analog system above. Unlike most phono cartridges I have heard over the years, the PC DAC1 does not change character as the frequency increases. These cartridges include the Lyra Titan, Koetsu Urushi, Transfiguration Temper V, and van den Hul Condor XCM. All of these are outstanding in certain areas, but are not consistent across all areas. The PC DAC1 continues its high resolution far up the frequency scale. Even early on in the Age of Digital, we observed very good bass performance from CDs, but with decreasing resolution as the frequency increased. This is due to the fixed sampling rate of 44.1 kHz. This sampling rate allows the fundamental of a 40 Hz bass note to be sampled over 1000 times. However, a 4000 Hz treble note is only sampled about 10 times. This is why resolution decreases with increasing frequency, and why there is so much interest in higher sampling rates (such as 192 kHz) for digital recordings.

The PC DAC1 seems to fill in the missing holes in higher frequency sounds such that any grain is very hard to detect. The sound just gets a bit less resolved at higher frequencies, but not actively annoying as the stock unit’s presentation can often be. This is noticed the most with the sound of cymbals. One of my favorite tests for high frequency resolution and purity, cymbals should sound like a piece of reverberating metal, clear and open and complex, with a harmonic trail that fades cleanly into silence. Sometimes due to problems in the recording chain, but more often caused by the gear in your room, the sound of cymbals degenerates into white noise which sounds just like static on an AM radio. The PC DAC1 has the ability to keep the sound of cymbals realistically metallic and highly resolved, but only if the recording includes it and the playback system is a synergistic partner. The upper frequencies are not quite “analog-like”, but darn close. Coming from a diehard analog devotee, this is saying a LOT about the musical presentation of the PC DAC1.

Towards the end of the review period (I continue to listen to and enjoy the PC DAC1), I replaced the stock fuses with PS Audio's Critical Link cryogenically treated, gold plated, copper element fuses. The apparent depth of the sound stage increased noticeably, and there was a small increase in the cleanliness and purity of higher frequency sounds. When a chorus was singing, it was easier to differentiate individual singers. I then installed these $29.95 fuses in my Manley Neo-Classic 250 amplifiers, Audio Research LS22 preamplifier, and Manley Steelhead phono preamplifier. Having these fuses throughout the playback chain provided a noticeable increase in upper midrange and treble purity and reduction in background grain (more of a subliminal mist, really) that easily makes them worth their cost. I am still playing with my feet, meaning trying different footer schemes under the PC DAC1 including Black Diamond Racing #3 cones with and without Herbie's small Cone/Spike Grounding Bases, Isodamp feet, Ayre blocks, and other such tweaks. So far, some of the best results have been realized when using simple 1/4" sorbothane-type pads under each stock foot. The new Audience PowerChord 'e' Enhanced power cord provides further increases in dynamics, stage dimensions, and upper frequency tonal purity.

To say that Parts Connexion have surpassed my expectations with their modifications of the DAC1 would be the understatement of the year, or more accurately, of the decade, since that is how long it has been since I have truly enjoyed listening to CDs. In fact, I have purchased several CDs instead of their LP versions since installing the PC DAC1. Run balanced in a system that is realistically full and rich instead of “ruthlessly revealing”, the Parts Connexion-modified Benchmark DAC1 makes music. Please hand me the remote.

Overall Ratings:
Parts Connexion-modified Benchmark DAC1: 8 LPs
Stock Benchmark DAC1: 6.5 LPs

Link to Parts Connexion
Link to Benchmark Media