Audio-gd Reference 7.1 DAC review (8 x PCM1704)

“Carlsberg: probably the best beer in the world“.  Saatchi and Saatchi’s tagline dominated British media in the 1980s.  Carlsberg advertising was everywhere.  And who was anyone to say that it wasn’t the best beer in the world.  Taste in beer – like taste in music – is so utterly subjective.  But you had to admire their advertising chutzpah.  People are obsessed with the notion of “best”.  They want the best.  They demand the best.  They deserve the BEST.

I was recently asked: “John, who makes the perfect and/or best DAC?”.  My curt reply: “No-one does, buddy”.  There is no such thing as the perfect hifi product.  As audiophiles, we might like to kid ourselves that we are striving for perfection, but in reality we are striving to minimise compromises.  Similarly, best is so utterly subjective…which led to a thought that constantly pulls on the back of my skull:  writing about sound is so utterly ridiculous.  Writing about something so intangible AND so subjective – how silly.

The personality quirks and behavioural oddities of DACs that sell for less than a grand can be more easily tolerated.  As the sticker price rises, so diminishes our compassion for flaws.  Some Sabre-based DACs offer tremendous detail without the ’emotional detachment’, but even they have very small quirks (over-exuberance, excitability). Some have complained of glare and/or sibilance. These are ‘features’ that I am happy to ignore at less than a grand, but not at the $2k mark. Product evaluation – and its consequent star rating – is all about price context and the (nearest) competitor’s talents.

I’ll confess to a personal penchant for NOS DACs.  The small change-robbing TeraDak Chameleon (AU$500) has been my DAC of choice for some months now.  Despite brief flings with other review products, the Chameleon is what I always come home to.  The Lite DAC-83 was clearly a tonally richer, better-resolving device (and I almost sprang for it).  Sat next to the Lite DAC-83, the Chameleon lacked dynamics and top-end extension…but…but…there’s a homeliness – an *ease* – to the two-box TeraDak that’s hard to go past.

What both the Lite and TeraDak have in common is the separately-boxed PSU.  Coincidence?  Nope.  A DAC’s power-supply implementation is critical to its sonic presentation.  “Like, duuuuuh”, tuts young Kingwa – the Audio-gd troop leader knows this upside down and inside out:

“The power supply is most important. Even applying the best DA chip and the best amp, if matched to a normal power supply, the total sound may still be average or sound musical, but can’t be neutral and detailed. That is why it is easy to find hi-end grade gears maybe without the best chips or amp stages, but with plenteous dedicated DC supply circuits.”

Having heard this theory in action in the Audio-gd NFB-2, I hit up Kingwa for his top flight model:  the Reference 7.1 (a dot point upgrade of the Reference 7, ready for 2011).  At US$1900, expectations were much higher and tolerance of quirks considerably lower.

The Reference 7.1’s entrance was dramatic.  Whichever way you consider its physicality (size, weight, component count), value for money corners you at every turn.  There is no way of escaping the amount of engineering skill that Kingwa has poured into his flagship DAC.  If 47Labs minimalism connotes Jonathan Livingstone Seagull, then the Audio-gd Reference 7.1 is Ulysses.  It’s easily the largest component to grace the Darko household: at 47cm deep it will challenge even the largest of display racks.  The brushed alumunium casework is solid but functional and the source selection knob sweeps gracefully.

Removing the lid for a peak inside isn’t as simple as one might think.  Some lid screws ‘go nowhere’.  Only by tackling them all were the imposters revealed.  (You only need bother with the four corner screws and the two smaller, Phillips-headed screws closest to the rear of the unit).  Once inside, we note three R-core transformers riding up front: one for each channel’s (analogue) output stage and one for the digital input stage.  Separation of power supply is fundamental to Kingwa’s design philosophy.  He’s a believer in the power supply being as (if not) more important than the choice of DAC chip. In the case of the Reference 7.1, the chip choice remains generous and strictly old-school.  No delta-sigma here.  Instead, four Texas Instruments, R-2R ladder PCM1704U-K are deployed per channel.  Eight in total.  The receiver chip is the well-regarded DIR9001.

More copy and paste from the Audio-gd website:

“The Reference-7.1 had total 21 PSU groups are applied. Uses 19 groups of high-quality class A parallel connection PSU with dedicated DC supply double-stage PSU, which can offer very clear DC power for the DAC, producing a very black background and neutral sound characteristic. The double-stage PSU is very important for digital parts. Some designs may have very low jitter in theory, but if the power is supplied by a dirty or low-speed power supply, it will increase the jitter and pollute the data, and degrade the sound quality obviously.”

“The class A parallel connection PSU has very high input impedance to avoid pulse through the PSU from affecting the DAC and low output impedance with very fast speed and high linearity, so it is a very clean power supply. In my experience, its sound is better than battery power supply, better human sound and neutral.”

As such, the Ref 7.1 is a truly balanced implementation with an ACSS-focussed topology that even benefits those connecting via the single-ended, RCA connectors.  As the Audio-gd website explains, “(The Ref 7.1) applies ACSS technology, even though maybe you only connect to XLR or RCA output, Reference-7.1 will always operate in ACSS technology, and benefit from ACSS technology. Therefore, XLR and RCA output will also definitely bring about improvement in sound quality. Even through RCA output, the 8X PCM1704UK DA chips will perform fully.”

The more limited array of input options is where this Audio-gd box falls short of that offered by the Lite DAC-83.  There’s no USB or I2S on offer here.  The omission of USB might well be a sign of the times: the trend toward separate digital interfaces.  I use a John Kenny battery-modded Hiface that extracts USB from a Mac Mini and spits out via BNC.  The Squeezebox Touch is connected via coaxial.  Optical and AES/EBU are also present.  (N.B. The single input version of the Reference 7.1 will save you US$150).

Audio-gd’s ace in the hole is the DSP-1 module that sits proud of centre in the walled-off digital input zone.  You’ll need to pop the lid to configure that DSP module to your preference.  The red and white switching modules (as seen on the DSP-1 specifications page) have recently been substituted for more traditional jumpers.  Anyone who has ever set master/slave jumpers on a computer hard drive will have few issues navigating the settings.  Easy peasy.  The user can set the filtering, dithering and PLL to ON/OFF.  Also user-configurable are the digital filter stopband attenuation (-130db, -90db and -50db) and the oversampling rates (2x, 4x, 8x and NOS).  Yes, NOS.

The PCM1704 decoder chip is a curious beast.  NOS mode realises the theoretical sampling frequency of 768khz.  When enabled, oversampling is calculated off-chip, in this case by the DSP-1.  Kingwa advises the 8x oversampling mode with -130db stopband attenuation to sound best (there’s that word again), with which the user is restricted to a glass ceiling of 96khz sampling frequencies.  Do the maths: 8 x 96khz = 768khz.  (Regular readers will know that I’m fine with “only” 24/96).

First up, let me allay some concerns:  this DAC plays 24/88.2 without issue.  The recent HDTracks hi-res reissue of The Rolling Stones’ Through The Past Darklysounded neatly fettled and exceptionally dynamic.  Soundstaging was notably taller and deeper than my 16/44 version; but that says more about the improvements HDTracks have brought to the table than the DAC at hand.

The Reference 7.1 also brooks no quarrel with 24/192; although I should think downsampling is occurring.  Still, at least the user isn’t left with white noise or silence.  The spice MUST flow!

But hi-res audio fles isn’t where my listening sessions started.  They began with good-old-original Redbook (16/44) and – as with all DAC reviews – a quick A/B session with two identically-cabled Squeezeboxen.  In the red corner:  the TeraDak Chameleon (NOS, 16 x TDA1543).  In the blue corner:  the Audio-gd Reference 7.1.  Usually these punch-ups go the full fifteen rounds and are often decided on points.

So it came as quite the shock when the challenger knocked the incumbent champion flat on his feet in the third.  The Audio-gd is quicker on its toes, more nimble with transients and an all-round more engaging experience.  A remaster of New Order’s Low Lifeinstantly shows greater acoustic mass and tonal depth than via the TeraDak.  Its floodlit world revealing greater all round detail and downright down-home clarity.  Like the better LED televisions, there is greater luminescence.  Musical performers are uniformly better (back)lit.

And all of this within the first day or two.  The dreaded burn-in had yet to get going.  The Reference 7.1 remained resident in my main rig for close to three months.  I sat on my hands, refusing to venture near a keyboard lest I be wrong or – worse – a victim of enthusiasm for something new that had yet to reveal its annoyances or behavioural peculiarities.

Summer moved into autumn.  The uncorrected personality traits failed to arrive.  I began taking the odd listening note.  Off came the lid again and the DAC was set to NOS mode with four jumpers (positions 2, 3, 4 and 5).

Non-oversampling mode gives you something a little easier on the ears, slightly less focussed – at times a little muddled – but overall a little cleaner.  Musical momentum travels slightly faster in the NOS lane.  This might suit very few listeners but to grumble about it is to miss the point – with the Ref 7.1 and its associated DSP-1, you (the punter) have options.  You can season the sauce to taste; or leave well alone.  I reset the jumpers back to 8x oversampling mode.  Kingwa was correct – it does sound best.

A morning spent churning through a handful of Redshape EPs revealed the The Ref 7.1 to be not the most bass-intense of DACs.  Control of the lower frequencies is excellent – perhaps tightness is what diminishes intensity?  If you demand the most prominent bass from a DAC, the Wyred 4 Sound DAC-2 is your man.  Techno kick drums have slightly better shape and definition in 8x oversampling mode than in NOS mode.

The Audio-gd isn’t as intimate as, say, the Red Wine Audio Isabellina.  Neither does it display the spacewalk detachment of some delta-sigma implementations.  It’s as dead-on neutral as I’ve heard.  Not a talk-to-the-hand neutral, more of a shoulder-shrug, “I’m easy” neutral.  However, it does render compressed or poorly recorded tracks with little compassion.

Such exposure is mitigated somewhat by its warmer disposition.  The Reference 7.1 doesn’t suffer the occasional tinges of artifice of the WFS DAC-2, but (drawing on audio memory) easily matches it for inner detail excavation – the distinct and separate nature of instruments can be heard from both DACs – but the Audio-gd’s presentation is more dignified, less eager to please.  More coherent.  More regal.

Here is a DAC that transcends the need to talk of tight bass, open midrange or airy top end.  It transcends the need to talk of deep-within detail retrieval.  Or crayon-like tonal density.  Or delicate timbre handling.  It offers all of these things.  What sets the 7.1 apart from the pack is its ability to render elasticity:  the reflexive behaviour of attack, decay, sustain and release.  The piano notes that stab Robyn Hitchcock’s “Cynthia Mask” are conveyed without “plink” – the Reference 7.1 is thorough in communicating the organic decay of a guitar string pluck.

I had been warned about Audio-gd DAC’s oft-agonising break-in times.  Those warnings were not unfounded.  Improvements to the (already impressive) initial performance quotient of the Reference 7.1 didn’t arrive as another out-of-the-blue “Eureka” moment.  Openness, clarity and clearer textural information arrived via the slow train.  Imagine finding vindication in what initially was only creeping suspicion.  That’s how the Reference 7.1 took hold of admiration: enough initial wow factor to venture a longer term commitment, but nothing that would grate of annoy during such extended tenure.

Here was the only digital decoding unit to date that had kept the TeraDak Chameleon relegated to the subs bench.  Ordinarily, I am struck more by the similarity of DAC products than their differences.  It takes time (lots of time) to hack away at the bush to reveal (sometimes) miniscule-but-genuine points of separation.  Not so with Kingwa’s top-of-the-ranger.

The Chameleon chalkier sketches don’t compare too favourably to the Reference 7.1’s deep crayon tonal colouring.  Music from the bigger, more expensive box sounds markedly more alive, more vibrant, more real.  It offers greater in-room presence through taller and deeper soundstaging.

The burn-in period had widened the chasm between the Reference 7.1 and the Chameleon.  As guilty as I feel writing this about my trusty steed, returning to the TeraDak Chameleon now sounds like a considerable step backwards. Its familiar milkiness now contrasted by Kingwa’s engineering as flatter and duller.  The Reference 7.1 presentation is far better detailed – with clearer inter-spacial definition and body – but without the Rumplestiltskin look-at-me petulance of, say, Alex Yeung’s (still superb) EE Minimax.  For over the twice the coin as the EE, the Audio-gd is a more mature listen with greater depth of flavour – a sound aged in oak barrels.  Intoxicating stuff.

Now for some (possible) disappointment:  if you were hoping for a sonic deathmatch between the Lite DAC-83 and the Audio-gd Ref 7.1, I can’t help you.  Timing is everything – some manufacturers lend for a few weeks, some a few months – and the Lite was returned to its owner soon after the completion of its review.  If you don’t wish to rely on this reviewer’s audio memory (who would?) then might I point you in this direction.  I concur.  The Audio-gd’s sound is more emphatic, more definite with tonal flavours that work their way across the taste palette.

Let us pull back for a moment.  This probably isn’t the best sounding DAC ever made – having not heard them all, I couldn’t make that call.  To talk of ‘best’ is a fool’s game.  It smacks of desperation – the gentleman, he doth protest too much.   The Audio-gd’s solid-state nature won’t suit every listener.  There are those that just can’t (won’t!) live without those tiny glass bottles or that NOS liquidity.  The Audio-gd is more spring morning than MHDT Labs’ Balanced Havanahumid afternoon; the former’s separation, low level detail resolution and forward projection seeing it as the better man for a late night, low-level listening job.  The Havana might be best suited to taming brighter systems or fattening up a a more skeletal sound.  If you need I2S connectivity, you’ll need a digital transport/converter.  Failing that, the Lite DAC-83 is more than worthy of your consideration.

Me?  I’m keeping this Reference 7.1.  No, it ain’t my usual NOS DAC preference, but Kingwa’s statement DAC is so much on the money for so little (relative) money.  I’m uncertain as to where, but you could spend more and attain greater levels of resolution, greater mass, superior PRaT – but will your additional spend be commensurate with the associated sonic upgrade?  Come on in, Mr Diminishing returns.  The Audio-gd Ref 7.1 could easily be the most refined and exhilarating sounding DAC on the south side of AU$2000 – it’s a new sweet spot for consumers looking to maximise bang for buck.  It’s a box that sounds so utterly well-resolved from the very first note and then only gets better as burn-in progresses.  It’s a DAC that bests (overall) every model that has preceded it in this reviewer’s system (see the Darko DAC Index).  A DAC that minimises compromise such that it defines a new gold standard at its price point.  A DAC that’s a destination purchase.  From a man-in-the-street perspective, you just can’t ask for more than that.

Kingwa’s Audio-gd Reference 7.1: the best $2000 DAC in the world right now?  Most probably.

Associated Equipment

• Herbie’s Tenderfeet
• Logitech Squeezebox Touch
• Mac Mini + John Kenny modded Hiface MKII
• Teralink X-2
• Weston Acoustics Troubador
• Heed Obelisk Si
• 47 Labs Lens
• Usher S-520
• Hoyt Bedford Type I

Audition Music

• Brian Eno – Small Craft On A Milk Sea (Bonus Disc) (2010)
• New Order – Low Life (Corrected Remaster) (2009)
• Robyn Hitchcock – Eye (1990)
• Robyn Hitchcock – Tromso, Kaptein (2011)
• Talking Heads – Brick (Box Set) [24-96] (2006)
• Marco Carola – Play It Loud (2011)
• The Rolling Stones – Through The Past Darkly [HDTracks 24-88.2] (2011)

Further Information

• Audio-gd / Addicted To Audio