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Zesto Audio Andros PS1 Phono Preamplifier Review

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Zesto Andros PS1 Tube PreamplifierIntroduction

This past summer at the 2nd (2011) California Audio Show by Dagogo in San Francisco, I had the great fortune of providing the coverage of the Zesto Audio/Fritz/Wywires Room.

Mr. George Counnas, designer of the Zesto Audio Andros PS1 phono stage, was spinning some vinyl, and his gracious wife and business manager, Carolyn Counnas was managing the crowd. At the time, I thought the system as a whole was sounding pleasant enough. However, it being an audio show, and an entire system and room that were unfamiliar to me, I made a note to come back, and continued on. Later during the show, I happened on the JIB/One World Audio room where once again, the Zesto Audio Andros PS1 was making some truly great analog sound paired with a Lyra cartridge, Graham tonearm, and a vintage Luxman turntable. I didn’t waste any time and went immediately back to the Zesto Audio Room and arranged with Carolyn and George Counnas for a review sample of the Zesto Audio Andros PS1 (which I received this past August).

The Andros PS1 is the debut product from Zesto Audio. George Counnas, as it turns out, is a music lover, vinylphile, and an audiophile who happens to have a passion for vacuum tubes. With a lengthy career under his belt working for Decca Navigation developing navigational systems for the Royal Air Force, he is armed with the tools to tackle such an endeavor. This background has certainly come in handy as he blended the old and the new in developing a fully modern, Computer-Aided-designed, and ear-tuned phono stage. In George Counnas’ own words, his Andros PS1 is an uncompromising design that was achieved through rigorous testing, auditioning, and 71 circuit changes (72, as of this writing), along the way.

Getting Started

The Zesto Audio PS1 arrived at a very interesting time. I had just received the Merrill Williams clamping system to complete the R.E.A.L. 101 and had had the pleasure of listening to the table/arm/cartridge combination for nearly the entire summer. So at the time of the Andros PS1’s arrival, my reference system was locked in with the Martin Logan CLS 2z 20th anniversary, Martin Logan Depth (2) subwoofers, Pass labs XP10 linestage preamplifier, Pass Labs X350.5 power amplifier, ASR Mini Basis exclusive phono stage, and the Merrill Williams R.E.A.L. 101 turntable/Ortofon TA-110 tonearm/Accuphase AC-3 playback combo to round out the front end. The cabling was set as Aural Symphonics MagicGem v2t power cords, TRS Audio Pure Note Designer’s Edition interconnects and speaker cables. I was already quite familiar and accustomed to the analog front-end’s sound and capabilities within the context of my main system. According to George Counnas, the Zesto Audio Andros PS1 is delivered with a good 50 hours of burn-in time on it. Since they are all hand-built and ear-tested, that makes a lot of sense. Certainly, the care and attention to detail that are embodied in this product came through in every way, but I’m getting ahead of myself.

The Zesto Audio PS1 is packed with features and is built like the proverbial tank. First of all, it is a dual mono design that shares a single power supply and is all contained in a single, very solidly built twenty-pound steel chassis. The rear panel is configured with totally separate settings, inputs and outputs, for each channel. Each channel has separate moving magnet and moving coil switching, which is a little different from what I have seen in other phono stages with which I am familiar. In fact, all configurations are “dual mono, including resistance loading options for MC cartridges (20-30-40-50-100-200-400-1000), high and low MC gain settings, MC balanced inputs, MC single-ended inputs, MM single-ended inputs, and even separate ground per channel. It is important to note that the outputs are strictly single-ended and not balanced.

Just in case you were not keeping track, the Andros PS1 is one very feature-packed phono stage. You can have two fully configured tonearm/cartridge combinations attached, though balanced connections are limited to the MC input only. I would usually much prefer having all settings readily accessible on the front of the phono stage, but the rear layout on the Andros PS1 is so clean and clearly marked that it makes on-the-fly changes a bit less painful than the usual rear setups I have seen. While my current ASR Mini Basis Exclusive lacks any front-facing settings at all and in fact, the resistance and output settings are internal, which is truly a pain, I longingly look back to my days with the vacuum tube Melos Reference phono stage as it had the resistance settings for each channel on two rotary switches on the front panel. I miss that kind of accessibility. Although I guess in today’s dollars, that dual-chassis unit would probably have an MSRP into the 5 figures! That said, this is about the time I should mention that the Zesto Audio Andros PS1 retails for $3,900. Just from the standpoint of features alone, this seems to be quite a breakthrough price for all that is offered here.

Finishing off the substantial list of features, the solidly-designed chassis has a sculpted front design that keeps the four JJ (Tesla) gold pin ECC83S/12AX7 vacuum tubes exposed al fresco out front of the chassis in an artistic and functional design that, for some reason has elicited very polarized comments amongst my friends regarding its esthetics. Of course, the exact same can be said regarding the varying opinions of the Conrad Johnson CT-5 aesthetic design. I guess you either like exposed tubes or you don’t! Personally, I find it to be a refreshing change from the norm on both counts.

To finish things off, the Andros PS1 sits atop a set of Isonode feet.

Set-up and Break-in

Since I was already well into the process of evaluating the Merrill-Williams R.E.A.L. 101 turntable on my existing system, I decided to break-in the Zesto Audio Andros PS1 in my reference front-end consisting of a modified VPI TNT /SDS/ Technics EPA500G/ Accuphase AC2. I noted that the Zesto Audio was sounding a bit polite in the bottom end and image depth was not particularly spectacular, so I decided to match the 50 hours of burn-in that Zesto provides, and play the Andros PS1 using my well-worn break-in record and MC cartridge I keep on hand for this task. A couple of weeks later, I had a serious listen and things had definitely improved. At that time, I also confirmed that isolation was not an issue with this unit. Swapping platform material made little if any difference at all, proving both the integrity of the chassis and the effectiveness of the Isonode footers.

My first serious listening session was with the VPI TNT set-up as described above.

Several things immediately became evident. The Zesto Audio PS1 has superb stereo separation and imaging. This translated to a big, full, open sound on live recordings such as Pat Metheny with Christian McBride and Antonio Sanchez Day Trip/Tokyo Day Trip Live on the Nonesuch label. On a different note, listening to the original Island Records UK pressing of Cat Stevens LP Catch Bull at Four revealed a somewhat glassy quality in Cat’s voice. This is not at all uncommon for this record and indeed, it has come up to some degree on nearly every analog set-up. However, in this case, it initially appeared to be somewhat exacerbated by the introduction of the Andros PS1 in place of the ASR unit. Having previously heard this particular record on the ASR/Merrill-Williams pairing served as confirmation that some of the great strides in midrange clarity, and smoothness in the vocal range had diminished when directly compared to the Zesto Audio / TNT set-up.

History has taught me that Cat’s voice on this album can be strident and can exhibit an irritating glassiness to it if things are not quite right in the end-to-end analog set-up. This came through quite noticeably when directly comparing the Zesto Audio /VPI/ Technics EPA-M /Accuphase set-up to the ASR/Merrill-Williams/Ortofon TA-110/Accuphase set-up. After listening to quite a few LP’s on the VPI/Zesto Audio set-up throughout the week, I came to the conclusion that indeed, the $3,900 Zesto Audio Andros PS1 was a huge improvement in many key areas over the $2,900 ASR Mini Basis Exclusive. First of all, the Andros PS1 was very quiet. In fact, it made the solid state ASR appear to have a bad case of tube rush by comparison. Stereo separation was also quite spectacular on the Zesto Audio Andros PS1. However, the overall presentation, detail, pace, rhythm, and low end authority of this end-to-end set-up were no match to those of the Merrill-Williams set-up from the same vinyl.

It became quite clear that the overall analog playback system with the Merrill-Williams R.E.A.L. 101 was so much better than the VPI-based system, that the only sensible approach in realizing the true measure of the Zesto Audio Andros PS1’s capabilities would be to directly connect it to the clearly higher performing Merrill-Williams R.E.A.L. 101/Ortofon TA-110/Accuphase AC3 set-up, and so I did just that.

Adding a Little Zesto (Audio) to the Family

I mentioned in my review of the Merrill-Williams R.E.A.L. 101, that it took the better part of two months to fully grasp everything that the R.E.A.L. 101 achieves. This was in part due to the ASR Mini Basis Exclusive being a limiting factor in the overall analog front-end. I only discovered this once the ASR was swapped out for the Andros PS1.

As a side note, you are probably wondering why I am not addressing the elephant in the room, i.e.,that there is yet another variable in play in the form of the Ortofon TA-110 vs. my prized and much beloved vintage Radio and Broadcasting Series EPA-500 tonearm. This fact has not escaped me. At this point in time as I write this, I have yet to try the EPA-500 directly on the R.E.A.L 101, but it will happen once wire routing modifications to the tonearm are completed, and I will report back on the outcome.

Playing the Zesto Audio first on the TNT set-up was constructive, but not much fun. Hearing the Zesto Audio Andros PS1 on the Merrill-Williams/Ortofon/Accuphase set-up brought life to the party in most every way. It made full use of the clean, explosive bass performance yielded by the M-W set-up and conveyed it on to the rest of the system with force and authority without a hint of bloat or “toobiness.” This thing is perhaps even more iron-fisted in terms of bass control than my old Melos reference was. In my book, that’s a major achievement. Another very obvious difference is the fact that the slightly better HF extension of the Accuphase AC3 over the AC2 was clearly delivered, and yet the noise floor remained vanishingly low. This has to be the quietest vacuum tube phono stage I have yet heard, regardless of price. In fact, I had the pleasure of an in-home audition a few years back of a well-respected $7,000 phono that had a much higher noise floor. So, at $3,900, the Andros PS1 is quite a standout.

Getting back to the Cat Stevens album for a moment, I am happy to report that the sound of the entire Catch Bull at Four LP through the final analog playback system, Zesto Audio/Merrill-Williams/Ortofon/Accuphase AC3 was nothing short of spectacular. The Andros PS1 added not only a sense of space and lush sweetness to this recording, but imagery that was almost like an auditory pop-up story book, so pronounced was the layering. Every element in the recording was in a well-defined and delineated space. The previously reported glassiness in Cat’s voice was nearly gone, and the usually overpowering drums in the tune ‘Freezing Steel” were clean, powerful, and highly detailed, but were now placed within the overall image without calling attention to themselves. “Ruins,” a tune from the same album, was life-like, rich in detail, and set against a wonderfully quiet background. Overall, listening to this classic, nearly 40-year-old (has it really been that long??!!) LP proved to be more enjoyable than ever.

Listening to Peter Gabriel’s “Growing Up” from the LP Ovo clearly underlined the Zesto Audio Andros PS1’s superb dynamics, holographic imagery, and ability to cleanly and clearly deliver highly complex passages without losing its composure. However, I did note that when reproducing piano, there was a very slight “sheen” to the sound. It appears that this quality continued to emerge from the Andros PS1, although greatly diminished after proper break-in. In the tune, “Sky Blue” from the same LP, the perspective was one of huge size and scale with layers and layers of information coming through. When the choir begins to sing, it’s like the pop-up book effect I spoke of earlier – like an entire group rising into the established space. The resulting realism is real goose bump material, to be sure. As the song ends, Peter Gabriel rises from the piano stool and it squeals. That too came through so lifelike and was so natural and matter-of-fact that it too became just another detail in the highly believable image that was being portrayed.

On other live-in-the studio LP’s, the Zesto Audio Andros PS1 certainly proved not only to be up to the task, but performed remarkably well. Such as in LA Four’s Going Home, a Direct-to-Disc on the East Winds label, Bud Shank’s Alto Sax comes through cleanly and dynamically. In the cut “Softly as in the Morning Sunrise”, the cymbals are vibrant and real, the drums come through with the low frequency power, control, and dynamics that are the hallmark of the Sennheiser 421 microphones utilized in this recording. Finally in “Things Ain’t What They Used to be,” the overall analog system’s pace, rhythm, and timing come through with great toe-tapping goodness.

Listening to the LP Upstairs at United Volume II, a 45RPM Direct-to-Analog Tape record produced specifically for the annual Record Store Day event, also turned into an unexpected treat. The recording has a wonderfully alive and you-are-there quality that is captured beautifully by the analog playback system and amplified by the Zesto Audio PS1 to full effect. The songs ‘Rosie” and “In the Deep” as performed by Corey Chisel come through as alive and believable, right down to the sense of size of the recorded space itself by capturing the resonant tone of the room.

Summarizing it all

The accumulation of notes and comments describing this analog playback system as a whole is rather extensive. I have done my best to include those comments and observations which spoke to the influence that the Zesto Audio Andros PS1 had on the final result. Clearly, its contribution is quite impressive and added substantially to the overall enjoyable nature of the excellent Merrill-Williams R.E.A.L. 101 / Ortofon TA-110 / Accuphase AC3 record playback system.

Once again, the sweetness and delicate nature of the Zesto Andros PS1’s delivery in the midrange and highs are almost counter-intuitive to its ability to also very competently amplify and deliver the sheer, explosive low frequency energy and dynamics that the record playback system sends to it. That said, the Andros PS1 is actually a tad shy in the lowest reaches in absolute terms, but within the context of the overall analog system, you would never know it. So, too, is the very slight sheen to the midrange that occasionally seems to emerge. In most LP’s I played over the past four months, neither of these two things were material enough to make a difference at all in the overall enjoyment of the sound. In fact, these are very minor quibbles in absolute terms. When taken in the context of the Zesto Audio Andros PS1’s MSRP of $3,900, it is ridiculous to even mention them as factors.

As such, I recommend the Zesto Audio PS1 without reservation and indeed, it has now replaced my ASR, as I have decided to purchase my review sample. Congratulations to George and Carolyn Counnas on a fine entry into the world of high performance analog playback.

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One Response to Zesto Audio Andros PS1 Phono Preamplifier Review

  1. Mark says:

    Hello, I am wondering if you are still enjoying this?

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