Analog Corner #286: StillPoints Aperture II, VPI Voyager, Bespoke Passive Preamplifier

VPI Industries Voyager phono preamplifier
Following my auditioning of Channel D's Lino 2C current-mode phono preamplifier, back in the world of voltage amplification, here's another phono preamp from another company based, like Channel D, in New Jersey. Probably not since Dynaco manufactured its electronics in Pennsauken has the Garden State enjoyed such riches of analog electronics!

A few years ago, turntable manufacturer VPI Industries (footnote 1) hired the talented electronics designer Mike Bettinger to be their director of electrical engineering. Bettinger first came to my attention as the designer of Luminous Audio's superb-sounding Arion phono preamplifier ($6395), which I reviewed for AnalogPlanet in August 2015. VPI's Voyager, a versatile moving-magnet/moving-coil phono preamplifier costing $2499—less than half the Arion's price—is clearly aimed not at buyers of VPI's costly Avenger and Titan turntables but at those who go for the bread-and-butter models that probably account for most of the company's sales. The Voyager includes such useful convenience features as two independently configurable inputs, selected with a pushbutton on the front panel. Each input can be set for an MM or MC cartridge, and for capacitive (MM) or resistive (MC) loading, each of the latter limited to three well-chosen values—respectively, 100, 500, and 1k ohms and 100, 200, and 270pF—all selectable via the front panel.

The Voyager is a two-stage design. The input stage uses a Linear Systems JFET/bipolar discrete op-amp for gain, and provides 75µs passive deemphasis. The second stage uses differential JFETs for additional gain and active equalization. The symmetrical, single-ended design is purposeful, with low-noise servos to maintain circuit balance. The power supply is a unity-gain, voltage-stabilized design.

The Voyager is made in the US using all US-sourced parts, and its four-layer printed-circuit board is populated with 1% metal-film resistors and polypropylene film capacitors. Equalization components are pre-screened for tight tolerances. Its specified MM gain is 42dB, its MC gain 62dB.

Bettinger has designed into the Voyager many operating touches usually found on more costly phono preamps—such as reducing switching transients to a minor pop via an auto-muting circuit, which also mutes the output to reduce or eliminate pops from static discharge or an accidentally dropped stylus (who, me?).

I first used the Voyager with Rega Research's Ania MC cartridge ($795), mounted on Rega's new Planar 8 turntable, which I reviewed for AnalogPlanet in March 2019. The Ania outputs 0.35mV and has a nominal impedance of 10 ohms. I also used Goldring's new Ethos cartridge ($1495). Both cartridges well matched the Voyager's clean, open, quiet sound, and the Voyager let each express its unique personality: the Ania is somewhat cool and analytical, the Ethos pleasingly warm and well detailed.

Humans aren't supposed to have good aural memory, but on first hearing the Voyager, I immediately took the Wayback Machine to my PS Audio 4.5 preamplifier with built-in MM/MC phono stage—though without all of the RF the 4.5 picked up. Like the old PS, the new Voyager sounded wide open on top, clean and transparent in the midrange, and reasonably well extended and nimble on the bottom. Best of all, its transparency extended from top to bottom of the audio band, with no obvious "there" there—which is good!

On the other hand, if you prefer a rich, warm sound, the Voyager didn't provide it. From what I remember of its sound, you'll get that from the Kiseki Purple Heart, which happens to be a favorite of VPI's founder, Harry Weisfeld. Combine the Kiseki or any warmish-sounding cartridge with the Voyager and for $5000 and change you'll probably have a very nice combo.

However, the low-internal-impedance, low-output Ortofon A95 was not a good match for the Voyager, compared to how it sounded through Channel D's Lino C 2.0. The A95 needs to be loaded with closer to 30 ohms, but beyond that, the Voyager couldn't begin to match the Lino C 2.0's transparency, image specificity, freedom from additive artifacts, and especially its vivid three-dimensionality, which variously put me in London's AIR Studios with Eleanor McEvoy, and wherever in France the Bassano disc was recorded.

That's not to say that the VPI Voyager isn't a very versatile, fine performer at its price. Rather, with the right cartridges, both can be great: but with the wrong ones, not so much. That said, with a low-internal-impedance, low-output cartridge like the Ortofon A95, the Lino C 2.0 was stupid-great for the money and beyond. I just wonder how many buyers of $6500 cartridges will consider a $2499 phono preamp. If they don't, that's a mistake.

The Bespoke Audio Company passive preamplifier
Each May since 2013, I've lingered at The Bespoke Audio Company's booth at the annual High End show in Munich (footnote 2), ogling the jewel-like beauty of their passive, transformer-based line preamplifier. Inside and out, this hand-built component is not merely among the most beautiful of high-end products—it is, to my eyes, the most beautiful. Each year, Bespoke cofounder Harry O'Sullivan asks if I'd like to review it. Each year, I say something like, "at some point . . . ," mostly because I was concerned I wouldn't like a passive design. I need more action.

Then, in his October 2015 "Listening," Art Dudley beat me to it—although, as he explained then, he did so with the same hesitancy and for the same reason. I paraphrase: what you gain in transparency and purity you somewhat lose in drive.

At High End 2016, although Stereophile had already reviewed his preamp, O'Sullivan again asked if I'd like to listen to it at home. It took me another year or two, but at last I succumbed, and was sent a sample with all-silver transformer windings and connecting wires. A few improvements made since its arrival include a Bent Audio remote-control handset engraved with round TBAC logo (my sample had originally come with a last-generation Apple TV remote while TBAC worked out the details) and a few cosmetic upgrades. Also, the Furutech rhodium XLR input and output sockets that were extra-cost options on my review sample are now standard equipment. The supplied unit included a French-polished top plate of Burr Veneer. The look is low-key and elegant.

Inside are 442 parts, almost a mile's worth of winding wire, and 180' feet of connecting wire. More of the story can be read on Bespoke's website. The version reviewed costs $23,235, the price varying with the options chosen (see website).

My review sample had three balanced (XLR) and three single-ended (RCA) inputs, balanced and single-ended outputs, and that's it—though you can specify any combination of RCA and XLR inputs. On the front panel are two knobs: a stepped } attenuator—as with any passive pre, it maxes out at 0dB—and a source selector. The transformer design can convert single-ended signals to balanced, and vice versa.

I ran the Bespoke balanced into a pair of CH Precision M1 monoblock power amps, and later, for comparison, played the same high-resolution tracks with my dCS Vivaldi One's balanced outputs plugged directly into the amps. A comparison doesn't get more direct than that; I'm glad I waited until I had the dCS. I also played a lot of LPs.

There was enough gain from all sources to effectively run a passive preamp—I never needed to notch it up to 0dB. The audible differences between the direct connection and through the Bespoke passive preamp were minor though not subtle, and surprisingly not mostly about drive; I felt little was lost in that regard. Rather, the Bespoke pleasantly smoothed out a slight digital edge to create a buttery-rich (but not too rich) sound that was particularly pleasing in the midrange and top-to-bottom coherent—rich but not thick, and not at all sluggish even with heavily rhythmic rock and jazz. All music was set against "black" backgrounds without, obviously, electronic effluvia or noise. I never felt that attacks were too smoothed or that air was squelched, though the Bespoke did a tiny bit of both.

I streamed all of Joni 75: A Birthday Celebration, a concert in tribute to Joni Mitchell (Decca/MQA). Particular standouts were Norah Jones's cover of "Court and Spark" and Rufus Wainwright's of "All I Want." From my library I enjoyed the Anthony Wilson Trio playing "Theme from Chinatown," and "Part VIII" of Keith Jarrett's Testament: Paris/London (3 CDs, ECM 2130/32), and never felt that any of it was slowed down or thickened by Bespoke's passive preamp. In fact, the same tracks played a second time directly from the dCS Vivaldi One sounded somewhat less coherent and more aggressive, though whether that was in the recordings or added elsewhere is difficult to ascertain.

I'm out of space, so please read Art's review. I really enjoyed The Bespoke Audio Company's passive preamplifier. If I had the money to keep one around for special times, I'd buy it. But I don't.

Stillpoints Aperture II
In their quasi-religious pursuit of sonic purity, some audio enthusiasts are obsessed with keeping things simple: single-tube, single-ended-triode amplifiers; single-driver, crossoverless speakers; even DACs fitted with "vintage" Philips TDA1541A Crown non-oversampling chips, and some without anti-aliasing filters—never mind such products' serious shortcomings, sonic and otherwise.

I occasionally favor this principle of less is more—for instance, less of my room's acoustics interfering with the loudspeakers' output produces more accurate sound from my system, and I'm all for that. However, getting the room out of the sound is never a simple task—and is especially challenging for those whose systems must share a multi-use space with other family members or roommates.

Almost 20 years ago, shortly after moving into this house, I sought the assistance of RPG Diffusor Systems' Dr. Peter D'Antonio. Using his Room Optimizer software, we settled on an assortment of his BAD diffusors and Abffusors—wall- and ledge-mounted devices designed to solve a room's measured problems and manage basic acoustical issues such as the first reflections of soundwaves off of sidewalls (footnote 3). A look at RPG's website today (www.rpgacoustic.com) makes what I installed all those years ago look somewhat primitive, but I find it still efficacious. More recently, Synergistic Research's Ted Denney added his tiny HFT horns. To those who laugh: they work (footnote 4).

A few years ago, Stillpoints (footnote 5) sent me four of their Aperture room-treatment frames ($749 each), for which they've been granted two patents. Each Aperture is an absorber, a diffuser, and a resonator in a single frame—22" square by 3" thick and looking like a picture frame. A stacked pair on the front wall behind the speakers blocked the room's only window, but the dramatic improvement in sound made it worth the loss of light. In my February 2015 column I wrote that the Apertures made room boundaries seem to disappear, "greatly enhancing center-image stability, solidity, and focus—areas where I'd thought no improvements were possible," given the other room treatments already in place.

Recently, Stillpoints announced the Aperture II ($800 each), which, among other things, moves the screen structure forward so that it's flush with the surrounding wooden frame. They claim that this makes it possible for the Aperture II to capture more air movement. It definitely improves the appearance of what already was an attractive acoustical treatment; it's now available in a wider variety of frame finishes and screen fabrics. The Aperture II also feels somewhat lighter, and a new hanging system makes it easier to mount on a wall—or, as I discovered, on other manufacturers' acoustical treatments.

I replaced the stacked pair of original Apertures with two IIs. To catch first reflections, I used a third Aperture II to replace a door-mounted RPG BAD Diffusor panel—its back surface was worn out, and it had been falling off the door. For balance, I added another Aperture II at the right speaker's first-reflection point by hanging it directly on a large BAD Diffusor. I sat the remaining two Aperture IIs on the floor, where I'd originally had a pair of first-generation Apertures that were too heavy to easily hang. This took all of half an hour, after I'd listened to an hour's worth of records and files via Roon and a recently purchased dCS Vivaldi One disc/network player.

As good as the original Apertures were, the IIs were better. Center images set up with greater authority than before against even "blacker" silences. This produced intense center-image layering, even with rock albums I've played a hundred times, such as the Kinks' Lola versus Powerman and the Moneygoround, Part One (LP, Pye NSPL18359). In "Strangers," written and sung by Dave Davies, along with a 3D image of his voice connected to a head was the sensation of being able to hear the walls of the vocal booth behind him, and his words were easier to follow in this somewhat reverb-drenched mix. The illusion of my room's sidewall boundaries disappearing became even more convincing, with no price paid in terms of "dead room" overdamping.

Last night I went back in time, to February 1978, and "watched" Leonard Bernstein conduct the Vienna Philharmonic in Beethoven's Symphony 3, from a superb reissue on vinyl of his final cycle of the symphonies, recorded live in Vienna (9 LPs, Deutsche Grammophon 479 8721). My room dropped away. I was in Vienna's Musikverein. Stillpoints' Aperture II panels made suspending disbelief in time travel and teleportation far easier, and that late-evening excursion affirmed why I got involved in this crazy hobby in the first place. The Stillpoints Aperture IIs are easy-to-recommend producers of nothing. And unlike many of the acoustical treatments used in recording studios, the Aperture II is living-room friendly, available in various combinations of fabrics and woods, or even with artwork you supply.


Footnote 1: VPI Industries, Inc., 77 Cliffwood Avenue, #5D, Cliffwood, NJ 07721. Tel: (732) 583-6895. Web: www.vpiindustries.com.

Footnote 2: The Bespoke Audio Company, Hastings, England, UK. Tel: (44) (0)1424-756471. Web: www.thebespokeaudiocompany.com.

Footnote 3: I wrote about RPG Diffusor Systems' Room Optimizer in November 1999.

Footnote 4: I wrote about Synergistic Research's HFTs in my February 2015 column.

Footnote 5: Stillpoints, 573 County Road A, Suite 103, Hudson, WI 54016. Tel: (651) 204-0605. Web: www.stillpoints.us.

COMMENTS
Jack L's picture

Hi.

"lose in drive" - drive WHAT ??

Not many audio guys know the pitfalls of audio line transformers when used in many hi-end brandnamed passive linestages:-

(1) phase errors;
(2) low & high frequency roll-off due to limited winding inductance
& inter-winding capacitance respectively.
(3) dynamic range & harmonic distortion compromise due to the use of type of magnetic core;
(4) input/output impedance change with the transformer volume tapping selection;
(5) magnetic noise due to audio signal induction by magnetization of the core.
Etc etc.

Take example of phase error which is UNavoidable as the inherent nature of any magnetic device.
(1) At low volume, say -43dB, flat low bass response; phase shift -
1 degree@10Hz;
(2) At mid volume: -20dB, 0.3dB drop@10Hz, phase shift 9.6 degrees@20Hz;
(3) At full volume: 0dB, 0.5dB drop@10Hz, phase shift 12 degrees@10Hz !!!!

Frequency response of a line transformer drops at both ends depending on the receiving load, e.g. input impedance of the power amp. Ideally, most linear for infinity load !!! Higher the better.
Tube power amp is much better than solid state amps which generally get out 100KR or so - rather too low.

That is one way to explain why Art found the Bespoke passive amp was shy in its "drive" as he apparently used it to drive solid state power amps.

On the contrary, resistive volume attenuator is much more frequency response linear, next to zip phase error & less costly for sure.

That's why I full agreed to what Adrianlau's response to Art Dudley's review of Bespoke passive linestage (only USD12,000) in Sept 2016, recommending resistive attenuator instead considering he was a veteran magnetic volume control users for 15 years or so.

Also, why the Bespoke new model tags for USD23,400 so much more in only 6 years ???? Silver winding transformers, silver inster wiring ?

I am happy in adding a straight-line bypass to my active lines gave by using only silver plated oxygen-free pure copper wires of fast speed computer grade. Straight-line bypass as recommended by J Gordon Holt. Driving my tube paper amps - plenty of DRIVE !!

Jack L.

PeterPani's picture

the bypass is for source devices with integrated volume control (since many devices like DAC, CD-Player, TV-receiver etc. have volume control without the need of a preamp).
Regarding the phase errors with magnets: What is your experience with tubed power amp output transformers? Isn't there a phase shift, too?

Jack L's picture

Hi

Yes, all audio magnetic devices get phase shifts, including output transformers. Thanks goodness, the output transformer is at the final output stage hooked direct to the loudspeakers instead of hookup eventually to the power amp like any audio line transformers.

So any harmonic distortion (due to nonlinear & non-seamless hysteresis curve of magnetization), phase distortion, magnetic noises etc etc) generated by the line transformers will be further magnified by the power amp !!!!!!

We got to understand music signals (made up of high orders of harmonics) do not like to travel miles of inter-wiring (against DC resistance, inductance & capacitance in the miles long wiring) let alone the magnetic devices. What can be better than to travel through a very short "straight-line" wire instead ?

Who wants to line up 2 hours queuing up for a ball game ??

Yes, ideally a tube amp should not have any music bottleneck like output transformers. It is there to act as impedance matching device between tubes (of very high impedance) & loudspeaker (of very low mpedance).

That said, not ALL tube amps NEED output transformers. OTL power amp don't need any such music signal bottlenecks at all. Tenor 75W all-triode power amp is an excellent commercial brandname OTL product which sounded superb to my critical ears at a very affordable price.

If you are not an audio handyman like yours truly, get online to find a no-name passive linestage with volume control for some dirt cheap price & put it on to hear the difference. Not the end of the world, my friend. Take it easy.

Listening is believing

Jack L

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