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Positive Feedback ISSUE 29
january/february 2007


Phono Stage Hoedown - Walker Audio AHT, Lamm LP2 Deluxe, ASR Basis Exclusive, Oracle Temple PH 1000, and the ART Audio Vinyl Reference
by Marshall Nack


AHT/Walker Phono Stage

I'm listening to Zubin Mehta and the LA Phil doing Ravel (London CS 6698) on my reference American Hybrid Technology Non-Signature phono stage. AHT is no more, but in its time (about seven years ago) this unit was on most people's A list. Mine is an original with mods by the current patent holder, Walker Audio. For an infusion of $400-500 USD, Lloyd Walker brought it up to a little below his discontinued low-end Walker Signature. (He only makes the $14,000 Reference now.)

Over the years, I have tricked out the AHT/Walker with roughly $1500 worth of tweaks. These include Harmonix TU-66ZX footers under the separate and very heavy power supply, and Mapleshade brass Heavyfoot cones glued to the bottom of the control unit, whose conepoints rest on Harmonix RF-900 spike bases. Lead-filled Walker Tuning Discs sit on top of both chassis. (By the way, sometimes the TAOC TITE-35S component footers placed on top work even better). A Ground Block from the defunct Versa Labs is on the tonearm ground wire. As you can see, the tweaks have accumulated over time.

Ma Mère L'Oye sounds somewhat dynamically restrained, a bit grey. Only at the final crescendo, does the piece open up and come alive. When I flipped the LP over to Daphnis and Chloë, with only 16:20 minutes vs. the 28:35 of programming on the verso, now there is dynamic noodling and micro-events afoot. Then Wham! What was that? Full orchestra and chorus combine for an ecstatic moment, with nary a hint of overload. (There's a huge quality difference between 16 and 28 minutes a side for an LP manufactured in 1971.) This is a sinewy, taut sound, packed with information. Notable for its lack of artifact—actually its lack of anything extra added to the sound—it might go a little too far in this direction. Its extended range on top is a little lean, a little dry, a little too clean. It is a speed demon and likes to play staccato: reverb trails are slightly shortened. The stable image placement on the soundstage is pretty convincing for a traditional orchestral layout, but it could learn to dance better—the stage is a little stiff. In other words, micro-dynamics are not its strong suit. String tone is very good, if not the utmost in grace and subtlety. Nonetheless, you won't have trouble distinguishing among instruments for timbral cues are well served. Mind you, I'm listening with an all solid-state food chain from phono stage down to amp binding posts. No grain, no edginess—this is solid-state done right.

I like the AHT/Walker for its neutrality, soundstaging, dynamics, and its freedom from artifacts—it's a clean, yet musical sound. The tonal balance is a bit lighter than I like (that's why I pile on the Walker Tuning Discs or the TAOC, to mass load it and bring it down), but the treble is handled nicely. However, it could use more low-end thrust and midrange richness.

I generally use TARA Labs The One PC coming out of the IDAT conditioner, and TARAs' The 0.8 with ISM Onboard interconnect with the AHT/Walker. Sometimes you'll find a Harmonix Studio Master PC there.


the Lamm takes over

Next up is the Lamm LP2 Deluxe, with its five tubes and $6990 MSRP. My sample had recently been re-tubed and factory serviced. I situated it on my TAOC rack with a set of their TITE-35S under foot. The Lamm's tonal balance is a lot darker. You will notice its abundant bass is more organic and integrated, less prominent (keywords that can also be read as warmer and softer). The treble is sweet and a bit rolled off. The midrange is clear and accurate. The top and bottom have moderate "tubey" qualities; the middle has a cool clarity. The Lamm LP2 profile has a family resemblance to their L2 Reference line stage. Flutes have more breath and less treble, and are more lush and midrangy. I had to remove a set of Harmonix footers from under the Linn Lingo turntable speed controller to reduce the "humidity". (The Harmonix devices were there to warm up the chill of my AHT/Walker.)

The LP2's stage is diffuse and blended, or more holistic and forgiving if you will. It is not as deep and dimensional as the AHT/Walker, nor is the dynamic range as wide, but its ascent to crescendo is stepless, and its transients are a model of naturalism.

Now let's slip on William Boyce, the twelve overtures, a Chandos Super Analog LP box set (DBR 2002). Hey, what happened here? We just did a 180, with the Lamm assuming many of the qualities I used to describe the AHT/Walker—focused, reasonably hard-edged, full-range, forward, clear, and a little resolute. By any standard, the sound of this LP is not noticeably lush or tubey.

And how about the Brahms Violin Concerto, with Heifetz and Reiner leading the Chicago Symphony Orchestra, a renowned RCA shaded dog from 1963 (LSC 1903). Now we're back to the tubey qualities in the foreground. I can hear every note in the Iceman's first movement cadenza, and the rapturous oboe solo introducing the second movement… way to go, Ray Still! (He was the Chicago principal for many years and one of the greatest oboists of the twentieth century). This is tone with a capital T: uncommonly well realized and credible, and SOOOO satisfying. I note the tubey halo around instruments has made its appearance.

Let's hear the same Brahms violin concerto on a vintage Colombia "six eye" first pressing (MS 6153), with Isaac Stern, Eugene Ormandy and the Philadelphia Orchestra. Tonally, there's no comparison. The Colombia LP is much lighter and lacking body, plus the hall ambience lacks integrity, compared to the RCA Shaded Dog of the same era. However, Stern's tone is sweet and warm, less sharp than Mr. Heifetz's. However, the orchestra under Ormandy is not playing as well. The third movement begins wonderfully, the shock of forté coming out of nowhere. Stern rises above the orchestra, and then his sweet tone succumbs to tape overload or inner groove distortion. Ah, well, the illusion is shattered, never to be recovered.

Back to Ma Mère L'Oye. It sounds luxuriant and rich after the AHT/Walker. Now I don't mind that most of the piece is scored in the midrange and piano—the inner life and vitality are stunning. The Lamm has reasonable macro dynamics and never shows strain. But it is truly superlative at micro-dynamics, at bringing animation to steady-state events.

Summing up, so far

The Lamm and the AHT/Walker have excellent evenness of response, few artifacts, sufficient gain with MC, and very low noise. Both unfailingly made music, with resolution that eliminated much of the guesswork on my part. They both took me out to an evening at the concert hall, never reproducing sounds that you wouldn't hear there. Most surprising was how similar they were, to the tune of say 90%. While the Lamm's tubes were, of course, audible, this aspect was not excessive. And some Harmonix tweaks remedied the AHT/Walker's solid-state chill.

I like 'em both. Ultimately, though, something was missing along the lines of involvement, of connection to the performance, with the Lamm LP2. All things considered, I'd give the nod to the AHT/Walker for its clarity, neutrality and dynamic drama. At this point in the survey, it is staying put as my reference.

Noto bené: These comparisons were done with my reference Linn LP12 rig, a fixed commodity, which hasn't changed much over the course of half-a-dozen years of ownership. No need to: with a little help (see the sidebar below on Ultimate Tweaks for the LP12), this top model LP12 just keeps performing. That's not to say there aren't better tables out there, just that so far it hasn't hinted at being the weak link in my rig— not yet, anyway. Likewise, I've had this version of the AHT/Walker for almost half-a-dozen years—another fixed quantity. The AHT/Walker's gain is set to 60 dB with loading at 1000 ohms for the Linn Arkiv II MC. Over time, these two components have been optimized together.

The Lamm LP2 has no load or impedance adjustments: it is fixed at forty ohms—your only choices are between MM and MC, period. This may well be too damped for the Linn Arkiv II cartridge, and may account for its underwhelming performance.

ASR Basis Exclusive

The Information is Accounted for

Now it's the ASR Basis Exclusives' turn at bat, a German import that sells for $7000 USD.

The Brahms Violin Concerto with Heifetz is not far tonally from the Lamm. The ASR is similarly slightly dark, sweet on top, sophisticated, with LOTS of weight. But the Iceman emerges with a cleaner, more extended and more defined top-end from approximately the same center-left and forward position. The solid-state ASR renders images with satisfying timbre and very full bodies.

And there are similarities to the AHT/Walker as well. In many respects, these three are more alike than they are different. None strives to paint an overly pretty picture. None sound like old-fashioned tubes. For that matter, none sound like solid-state. Rather, they all want to sound like some version of neutral and realistic.

But here's where the ASR is different. It imbues the stage with a sculptural perfection upon which everything is distinctly and unwaveringly sited. Images are large and have a massive, dense solidity. Their size varies proportionally. The ASR stage is not the jewel-like sharp and hard edges of a cool, polished diamond; rather, it's more like a purposefully worked hunk of bronze: massive. You will have no doubt determining who is sitting where and playing what instrument—the musicians don't get up and move around in a game of musical chairs.

While it has no apparent grain or artifacts, the perfection of this sculpture is mainly attributable to the ASR's expertise at vacuuming, or stage cleaning. It features not just the lowest "noise floor" I've ever heard with vinyl; it also purges all distracting, non-musical sounds that have been riding along unnoticed with, and masquerading as part of, the signal—stray mechanical noises that I didn't even know were there because they've always been present.

How does it do this? Is there some form of noise reduction in the ASR's built-in conditioning? Is it due to the battery power supply? I dunno—the manual gives no clue. However it is accomplished, one thing is for sure: the ASR isn't dropping info in the process. Au contraire, events pop out everywhere. Its retrieval and articulation, along with its purity (largely from the vacuuming operation), set new benchmarks. You will not know what to pay attention to first: if you're the sensitive type, you may even find it overwhelming to the point where it inhibits relaxation. The ASR is exciting to listen to for the vast dimensional panorama it lays before you and the staggering wealth of information upon it. But don't get the impression that it's thin and dry, which usually goes hand-in-hand with resolving over-achievers. The temperature is definitely not chilly, but kind of temperate, warmer than the others, and there is ample flesh on the bones.

There's no longer the distortion on the big crescendos, which occurred at spots with the AHT/Walker, especially as we got closer to the center spindle. You can hear into the peaks. The ASR stays clean right up until the last notes.

Speaking of crescendos, the ASR is most impressive when you throw a full orchestra its way. It can re-create the mammoth plentitude of ninety or so heads playing simultaneously better than any device I've heard so far, including digital sources, and do it without strain or shrinking the sound. It expands effortlessly, and can unleash quite a low-end wallop. Macro dynamics are super and quality is unvarying as the signal cascades upward. And remember, it runs off a battery pack. (But what a battery pack! The thing dwarfs the separate control section, and is about twice the size and three times the weight.)

However, you won't experience its power capabilities unless the source calls for it. Most of the time the ASR coasts along in a smooth, sophisticated, extremely articulate low-key guise. It is more tubey sounding than the AHT/Walker, and warmer than the Lamm. And yet, it's best described as neutralOK, let's make that warmish-neutral.

The ASR Basis Exclusive is the modern sound of analog. You won't recognize the familiar analog we grew up with and love. It starts with analog's well-known virtues: transient credibility; textural fidelity; smooth and continuousness tonal gradations; supple dynamics; truthful articulation. Then absent the well-worn family of artifacts that we've come to accept with this medium over the years, like stylus-in-groove distortions and that noise the ASR mysteriously vacuums up. Now add to the mix: extreme channel separation; extreme signal to noise ratio; vanishing noise floor; something best described as digital-type bass (a very deep and taut low-end wallop that I've only heard from digital front-ends). Marinate these ingredients overnight and voilà, you have a new breed of analog, incorporating the potent strengths we've gleaned from the experiment with digital media. We're learning how to make vinyl stronger—this is it.

Resolution that can be Resolute

The lack of artifact, the resolution, the noise reduction… the recipe can be resolute if you don't watch out. Its determined neutrality means there will be less thrills of the cinemascope variety. It can be less involving to those used to the wide screen effect. Dress it with musical wires, like Kubala-Sosna or Kharma. You don't want to exacerbate this tendency.

The ASR went straight into the wall using the manufacturer's provided power cords. I used it on battery power all the time. You can use it on AC, but you'd be wasting your money. Brief audition of the wall vs. the battery sounded grainy, cooler and less liquid. So you save on a separate conditioner and aftermarket PC. You'll have to find space for the battery pack though. I left it on the floor, while the control section went onto a TAOC shelf. No tweaking was required.

ART Audio Vinyl Reference

Now we come to a tube hybrid unit, the ART Audio Vinyl Reference. I have the hot-rodded version with V-Caps, a $500 upgrade to the basic unit, bringing the cost to $5000. Let's begin with a fabulous DECCA purple label second pressing of Gilbert and Sullivan's The Yeomen of the Guard, with Malcolm Sargent leading the Royal Philharmonic Orchestra and the D'Oyly Carte Opera Company (SKL 4624).

The VR immediately revived memories of vinyl glory days past, with palpable voices suspended in space before you, and a presence and sparkle only valves (and only old valve sound at that) seem to muster. Surprisingly low noise and few irritating artifacts, like the AHT/Walker or the Lamm (but not as low as the ASR), although with less separation and detail—more confusion—on the big stuff than these others. Woodwinds have oodles of bloom. English oboes sound like foghorns once again. What this machine does with timbral realism, the way it projects instruments into space, the way it handles balance among instruments, that is, the loudness of the trumpets and the perceived distance between them and the violins and the singers, makes for a decidedly satisfying musical session. You will not confuse analog playback through the VR with quality digital replay—these two are traveling on different paths.

First impressions were misleading. Initially I thought there was a slight sharpness to the transient edge, but this went away after the unit had around 50 hours. I thought the decay might be a little foreshortened, but this too melted away with burn-in. And I found stage width a little constricted and compact… until I put on the Boston Pops Light Classics (LSC-2547 shaded dog) and the boundaries of the room stretched, with uncanny sounds far outside the speaker position, impressive more for the extraordinary width than the so-so depth. At times, I heard distortion that I didn't recall with the other stages. But I know from other LPs that the can VR handle wide dynamics without breakup.

Now I think the VR is passing a fair replica of the source, in that it produced a variety of sounds from record to record.

Of course, the VR engaged in a covert cover-up of some source unpleasantness, the way tube components voiced this way usually do. It doesn't give images a razor-like sharpness—they tend to be a little blurry on the edges and blend amongst themselves—one image runs into the next without a "deep silence" imposed between them. It doesn't have staggering macro dynamics, or the tightest bottom, or the most dimensional soundstaging, or the fastest transient attack. Likewise for the just average resolving acumen. (Don't worry. All are satisfyingly well done: you won't be left having to make excuses on these accounts.) The VR is not designed to achieve stardom here.

It's the inner life and enhanced presence, palpability and emotional connection of what it does report on that may turn your head. This was the designers' top priority. One review of the Vinyl Ref called it the SET of phono preamps. Yes, that's true: the VR reports on fewer events, but they come packaged in a SET-like envelope. It has the excellent coherency and integration of those devices, plus frequency extremes are well represented, and dynamics and transient speed are good.

Its bottom is abundant and forceful without being overly warm or plummy. While not as big and dynamic as the ASR or the Oracle Temple (coming up next), it doesn't wimp out on the bottom. Yet, it doesn't pummel or attack you; rather, it tends to caress you. The sound is far from even approaching grating or irritating.

Tonal balance among the VR, ASR, and the Lamm is close.

The VR would be my top choice for fare employing small-scale forces: soloists, duets, especially vocals, and maybe chamber ensembles, where intimacy is desired. It would be my first choice for a five-part Motet, even though it might not separate out the parts as well. But the tables would be turned if I wanted to listen to a symphonic work by Mahler. The main thing about the VR is how involving and how much fun it is to listen to.

BTW, if you want to take a trip down memory lane, there's no better transport than to cue up Light Classics (or any of the Boston Pops Shaded Dogs). Through the VR, you will re-live the burnished Golden Age. Be sure to check out the mob scene on Ketelbey's In a Persian Market on side two. The musicians are required to conjure their impression of an outdoor marketplace in Persia—those untrained, raucous voices sound like they're having a good time, no? All right, it's warm and romantic, and in the final analysis, it made performances sound better than through the other stages. But couldn't one make a case that's the way these all-tube, circa 1960 recordings are supposed to sound?

The unit remained largely untreated. The VR started out powered by TARA Labs The One PC coming out of the IDAT, and The 0.8 signal wire. Later I switched to a Kubala-Sosna Emotion power cord. Impedance was set to 300 ohms. If you want to make it sound more powerful, put a set of TAOC footers underneath.

Oracle Temple PH 1000

The final contender in this survey is an import from Canada, the two-box, solid-state Oracle Audio Temple PH1000. This was the mystery guest: the company name is familiar, but I can't say I've heard any of their analog products nor read much about them.

The Temple main chassis is beautiful to look at. Made from hand-brushed, lacquered and air-dried aluminum for a satiny, luxe finish, full functionality is accessible from the front panel via a bank of rotary dials. The separate power supply, on the other hand, is a very ordinary black, folded aluminum box (I guess it was meant to be tucked away in a dark corner, somewhere out of sight). The Temple is the most expensive of the group at $7500.

First, I tried a Harmonix Studio Master PC, thinking it would nicely complement the Temple's neutral palette. This resulted in frequency integration issues—bass, mid and treble bands were heard separately. Take two, after swapping out the Studio Master for the TARA The One PC, along with The 0.8 IC with ISM Onboard. Ah, now I caught a glimpse of the unit's potential. No more frequency slices missing, no more discontinuity. The Temple is very sensitive to cabling. (And footers. My sample had fixed, soft Sorbothane feet. Until recently, the Temple came with metal feet.)

I had thought the AHT/Walker sounded sinewy, but compared to the Temple, it seems almost delicate. The Temple's presentation is the biggest, most dynamic of the group.

On The Yeomen of the Guard, the introductory forté is huge. This guy has headroom that inspires confidence, exhibiting massive dynamic range and power reserves. The stage is bigger and more robust, dimensional in all directions, with nothing loose or vague about it (if not quite the solidity of the ASR). Texture and edge information are well represented: the blattiness on the rim of trumpets is nicely conveyed in stable, large images upon a naturalistic soundstage. The Temple didn't spotlight instruments nor give them sharp boundaries. It had a nice way of varying image size to properly match the instrument. Yet, the Temple handled itself in a civil manner, always maintaining composure, similar to the ASR.

This one speaks straightforwardly with few editorial embellishments, a real neutral player with very high purity. Transient treatment is incredibly even-handed and coherent. It is fast and articulate, fleshy and taut. (And this served to confirm there was indeed some added excitement to the ART Vinyl Reference transient.) It gives no clue to its solid-state topology: no grain, edge, or obvious artifacts.

The Temple's tonal balance is darker than the AHT/Walker, and lighter than the three others. Its low-end doesn't have the bass slam of the ASR and the ART, but TARA wires remedied that.

However, after I got used to its exemplary performance on the Hifi stuff, its determined neutrality sometimes held me at a distance: I missed the emotional connection. Because it is warm, but not timbrally rich (string tone is very good to be sure, but without the silken quality of the ART, and to a lesser extent, the ASR), I placed a Harmonix RF-57 alongside the IEC jack on the power supply. Then the Temple became more tube-like. Throwing a Kharma Enigma IC onto its outputs gave it another push in this direction.

With this setup, the Temple achieved an acoustically and harmonically satisfying presentation that bonded purity and audiophile rigor. This unfailingly produced startle reactions at the beginning of every session. The Temple and the Enigma are a great match! (Something else to evince that reaction—the one-meter Enigma cable costs $7100, fractionally less than the component under review.) The oboe intro on the second movement of the Brahms Violin Concerto with Heifetz was

just lovely, without the glow around the instrument of the ART VR. The grand old Iceman himself sounded warm and approachable, but cooler than through the ART.

The Temple does most of the things contemporary audiophiles look for. And for those who rate PRAT highly, this could be the one for you. It has the snappiest pace of the group. Between that and its full, lively and very present midrange, the listener easily succumbs.

I set the impedance at switch position four (200 ohms), which was nearly ideal, just a bit too smooth. At position five (330 ohms and less damped), it was very exciting, but the treble got close to sounding harsh. I needed something in between. That's when I discovered the purpose of the Capacitance dial. I moved it up to three (100 PF) with the impedance at 200 ohms and, lo and behold, textured edges came back. You can use this dial to fine-tune just the amount of crispness you want. FYI, most phono stages don't provide adjustable capacitance and are fixed at 100PF.

The Temple has the most gain of the group by far. To level match with the others, I needed to set it to three out of a possible six, but it sounded better at its higher gain settings, even if this necessitated turning the volume of the line stage way down.


The conclusions are readily drawn: for all-around best performance, the ASR takes the gold. With its freedom from analog based or editorially inserted artifacts, its unmatched purity, and its superior performance on the main audio course, it sets a new standard. The ASR Basis Exclusive is a Panglossian "best of" sound. This is a place where traditional analog is fortified with what digital playback has taught us is possible. (Conversely, digital has lately gleaned more than a few things from traditional analog.) If you insist on SOTA grades on the main scorecard, the guy to go with is not in doubt: the ASR Basis Exclusive.

The Oracle Temple has a similar voice and comes up close behind. It too, is pure and free from artifacts and colorations, just not to the same degree. It is super dynamic and fast as a bleep-bleep. In that area, it steals the show. If PRAT, the toe-tapping thing, is high up on your list, you could easily succumb to the Temple's infectious pulse.

The AHT/Walker falls into line at a distance behind the Temple. And the Lamm LP2… well, I suspect it wasn't happy with my Linn Archiv II cartridge.

On the other hand, if you have fond reminiscences of those earlier days when vinyl sounded like vinyl and digital sounded new and different, you might find your cup of tea in the ART Audio Vinyl Reference. The VR produces a distinctly different sound from the others. Where the solid-state units throw a wall of info at you, the VR is adequate. It doesn't attempt to scale new heights of macro-dynamics, soundstaging, etc. Its expertise lies in timbral hue and color, inner life, musical flow, and sheer listener involvement and enjoyment, and at these, it comes out on top.

The ASR, the Oracle and the ART provided wholly satisfying phono playback at levels well beyond my current reference. While none of the five contenders suffer from solid-state symptoms, the AHT/Walker came closest; the ASR and the Temple are warmish solid-state; the ART VR sounds like traditional tubes; the Lamm LP2 has a cool tube sound.

Raise a glass, please, and let's toast the twenty-fifth (or thereabouts) anniversary of the digital winter. Isn't it odd, though, to find ourselves in the midst of a vinyl renaissance?

A little sidebar on Ultimate Tweaks for the LP12

The very best tweak I can recommend for your Linn LP12 is to situate the Lingo speed control on a set of Harmonix TU-303 EX or TU-66 ZX—very expensive, but the biggest bang to be had. Place all four of these large, round wood discs under the Lingo. Next, place one or two Walker Tuning discs on top. Balance the Lingo so it rests securely and is stable. Next best tweak is a large ERAudio board between the LP12 and whatever shelf/rack you're using. I also like the Harmonix TU-800EX LP Matte in place of the standard felt one. Other than that, leave the table alone: various tuning dots and weights for the arm, the armboard, the headshell, the counterweight, etc, all proved to be left turns.

Lamm Industries, Inc
2621 East 24th Street
Brooklyn, NY 11235
TEL: 718. 368. 0181
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ASR Audio Systeme
Friedrich Schäfer
Hohe Straße 700 / 5A
D 35 745 Herborn
TEL: +49 2772 – 4 29 05
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Art Audio USA
34 Briarwood Road, Cranston, Rhode Island 02920
TEL: 401. 826. 8286
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