Tuesday, May 23, 2017

Master 7 Triumphant!

The Audio GD Master 7 Singularity arrived on Monday morning, 5 days after being shipped by the factory in China.  It immediately vanquished all my fears and doubts.  Packed perfectly, handled perfectly, and smell free in every level of wrapping.  I didn't recall selecting Air Freight but if that was what this was, I'd do it again.

I let it rest for a few hours in the living room, then unpacked and set it up, then warm up with the power amp unpowered.  Upon unwrapping I immediately had to place it in it's designated location atop the marble slab (where the Audio GD Dac 19 Anniversary Edition had been until minutes before) because there's no other free space large enough in my home to rest it on except the dirty carpet.  When you get the Grand Piano, you have to live around it.  This impressive looking unit is as large as I imagined, but not quite as heavy as I imagined, though certainly no lightweight.  It's large because doing things the right way from end to end takes a lot of well engineered circuits and parts.  To get tiny, you need to make compromises.

Also immediately, it was clear that this was not the kind of problem unit I had feared.  The hoped-for combination of greater sweetness with greater transparency was obvious, though to appreciate it fully took a few hours, listening to many things I couldn't listen to for years, now revealed with such clarity and sweetness it became possible again.  There was never a sense of needing to "turn it off" even playing the unplayable, at very loud levels, and the often more challenging very soft levels.

My audio perfectionist friend agreed that having the voltage set to exactly what's required to drive the power amp to peak power is best, and not waste resolution on useless voltages.  And it seems that Audio GD did exactly as I had ordered, to achieve the optimal spectral balance I needed to raise the subwoofers and super tweeters by 1.5dB, the change from 2.5V max of the old unit to the 3.0V of the new unit.

The slightly astringent quality of the old system with the cheaper DAC is now gone, replaced by endless depth and richness.  What I wasn't expecting was how all the imaging became MUCH more solid and correctly located between and behind the speakers.  That's the virtue of dual mono construction and fully balanced operation and connection!

I haven't done any technical tests, not even measuring the voltage, but I don't think I have to.  It couldn't be THIS good without having nearly unmeasurable distortion, state of the art resolution, and so on.  And it wouldn't have this level of transparency if they had slipped me the NOS version by accident.

Truth be told I don't know how much of the improvement comes simply from using balanced inputs on the Krell, in my system especially.  The Krell isn't powered through the same conditioner as everything else, and though I've never noticed a ground loop, at some level there must be current flow through shield grounds, and the effect of that is virtually eliminated by balanced connections, among their many other advantages.  Mind you, with some equipment in some configurations it is unnecessary and perhaps even suboptimal, but in my system, balanced drive of the power amplifier was a too long overlooked requirement.  (Actually, I tried balanced operation many years ago when it was being power by Behringer DCX crossover, but I feared probably erroneously that it was leading to the excess heating in one channel--the problem that was ultimately fixed by getting the full Capacitor Service from Krell.)

But I also know now that 1704's aren't being used correctly except in differential mode, and better yet parallel differential, as all the big name DAC's from Levinson and others did back in the day they were still being built with the best PCM chip ever.  The potential of this chip is lost without differential operation.

So now, everything is being done right, and it sounds that way.

Sadly for the rest of you, this unit is part of a very limited production using the very last unused Burr Brown 1704's which Audio GD scoured the world for (becoming, ultimately, the biggest name in audio to rely on them, after Lite Audio bailed a few years earlier on making 1704 balanced units).  In future, and for replacements, it looks like 1704 lovers will be scavenging other old salvage units for the super special unobtanium parts.  Eventually, possibly, even better hybrid R2R technology (such as used by MSB) will trickle down to non-stratospheric prices.  Audio GD is trying their hand in that game, but it might be awhile before they can reach the same levels as they had with 1704's, let alone MSB.  Then again, I don't really know if even an MSB Platinum or whatever would sound better than the dual differential 1704's in my Master 7.

Anyway, it's hard to imagine something being even better than this, but that's what I thought about the Audio GD Dac 19.  But I've got what I need for now, I think.  (This was a kind of record setting audiophile purchase for me, I believe the most expensive audio component I've ever purchased brand new, and among things not so qualified only the Krell amplifier cost more.  So I hope it's enough for awhile, the forseeable future.)

I'm connecting the DAC output to the Krell amp with Nordost Baldur audio interconnects I bought awhile back at deep discount, and actually for making the Oppo BDP-95 to Lavry AD10 connection, but I decided I preferred antique Denon players with unbalanced outputs so I haven't needed it since.  The Baldur cables are thin and extremely "fast", which generally means little stored energy.  I don't really care how technically fast the cable is, delaying my experience by a matter of picoseconds is not of any consequence, but that's a good indicator for stored energy because stored energy, as such, is not so easily quantified.  Anyway, these are clearly well made high performance cables that are very transparent sounding, which is what I want.  I'm in no rush to find something better, and they turned out to be exactly the 18 inches required.  Compared to many audiophile cables, they are just good cables, nothing to equalize this way or the other, though you could argue the capacitance is a tad higher than necessary at 20pF / ft.  Belden 1800F does better, at 13 pF/ft.  This is of little consequence for me...you could calculate the low pass for a total of 30pF for my cable vs 20pF for the Belden, into 50k ohm load, with a 10 ohm source impedance.  This will be so high in the Mhz you might think the higher capacitance not such a bad thing at all, but anyway, there's another issue here, and that is simplification.  When they say about interconnects that capacitance is the only thing, they're wrong, it's the only thing that goes seriously wrong in ordinary cables.  In audiophile cables, many other things can go wrong.  But possibly, if nothing is done seriously wrong, additional things be done more right, the things of the highest consequence of all, and that is smearing or not smearing information.  And at that level, dielectric absorption is occurring through complex geometries at every point through the table, and interacting with the complex geometries of magnetic and electric fields.  This may or may not cause excess stored energy at various frequencies.  You could argue...these stored energy effects are at such high frequencies I don't care, I care about capacitance that rolls off at 10kHz.  But, when the capacitance isn't going to cause any rolloff until 5mHz anyway, why not arrange to have it balanced with the electric and magnetic fields not to store energy and therefore smear transients in any way.  Since the smearing can be a nonlinear thing, it can ultimately induce the possibility of something being heard differently, as say some tiny threshold is met either synchronously or not with some other.

The input connection is currently being made through the SPDIF input using two cables and a converter box, the latter being a HOSA which converts AES balanced to SPDIF, and the former being standard Canare and Beldon cables.  This is exactly how I connected the SPDIF input of the Dac 19 which had no AES input.  I've just ordered two appropriate-looking 5 ft AES cables now that I have an AES-input DAC: an Audioquest Cinnamon, and a Geistnote Canare.  The Cinnamon appeals to me because solid core conductors, and everything is silver plated, even the braided shielding.  Silver plating is absolutely what you need to do for best ultrasonic signal transmission, and AES is critically reliant on that.  Professionals may be more interested in the ability to resist stress fatigue of stranded wires.  The Geistnote is a souped up Canare (I got the extra special connectors too) and I like the extra covering which makes the wire run more straightly, which I think is preferable.  I think the Geistnote will be my backup cable, but we'll see.  I looked at all the pro cables and none used silver plating or tinning to protect the copper surfaces.  So, just at that level, I figured universally available Canare basically as good as Gotham, Mogami, or Belden.  As it turns out, I've most often used Canare AES, though my most recent special purchases were Mogami Gold and Geistnote, and I liked the latter the best.  Among the high end cables, Cinnamon is the least expensive with the key features including silver plated solid conductors and shielding.  It's far less expensive than anything else with the key features, and I have seen no other features worth buying.  I trust Cardas construction most of all, and Cardas used to make a 'plain' AES but now only seem to sell the high priced Clear.

AES has gotten a bad rap because of jitter.  Nowadays many will argue even coax spdif is better.  Coax has a peerless ability to transmit high frequencies...hence coax has always been used in radio.  The 110 ohm AES cable is not quite as good as coax.

But, and it's a big but, in a complex system there may be more significant concerns.  Even the tiniest of ground current flows can upset detecting the moment of signal transitions in an unbalanced low voltage signal.  So AES is probably better if you are doing more than just one digital connection.  That was what it was engineered for, and, as it turns out, kinda what I am doing.  AES works well for me with my pro-audio DSP's, sampler and DACs.  And done rightly, the differences in jitter are not going to be a big deal compared to "the ultimate" I2R, which I cannot imagine when I will be using if I ever can.

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