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Purity One

Review #1

Brief Synopsis About the Reviewer:  Who am I?  I am a Physician specializing in Orthopedic Medicine and Sports Medicine.  I was permanently “spoiled” when my Dad brought me into a high-end audio store at the end of my 2nd year in Medical School around 1985.  Suddenly, my Sansui Integrated amp, B & O turntable, and Boston Acoustics speakers just didn’t satisfy me anymore (anybody else been there?).  I got into audio then big-time, but then realized after visiting many dealers and starting to attend shows while listening very critically that no speaker I had heard did everything well.  I first met Speaker Designer Albert Von Schweikert in 1986 as I had bought one of his Vortex Screens and very much admired their sound.  Two years later (1988), I told him my dream to build one of the best, if not the best, speaker system in the world.  Our project took 5 years at which time we explored every speaker technology available from plasma drivers, to planars/ribbons, to electrostatic, to conventional cone driver technology.  I listened intently to every cable, speaker driver, major audiophile capacitors, inductors, and resistors that I could find to make sure that we were using the best materials in every way.  The speaker was 4 towers and weighed about 1-ton.  The subwoofer tower was one solid cabinet housing an 18 inch custom professional woofer driver with transmission line loading and was about the size of a phone booth except only about 2/3rds as deep.  The “satellite” towers were subdivided into 3 cabinets.  The upper and lower cabinets each contained (2) 11-inch Focal woofers for the mid and upper bass.  The center tower housed a ribbon super-tweeter, Accuton ceramic tweeter, and (2) 4 ˝ inch Focal mid-range drivers.  The cabinets had 4 layers of materials with different densities and with special absorbing adhesive between all 4 layers (constrained layering arrangement) to entirely cancel any possible cabinet resonance that might interfere with the driver’s output and to avoid any possible cabinet colorations.  Internal wiring was done with Siltech.  Frequency response was 8 Hz to 100 kHz.  Retail price was set at $65,000.00 for the above speaker system.  After 5 years of hard work (1988 to 1992), it was debuted at the January 2003 Las Vegas, NV CES and acknowledged verbally to me by every well-known High-End Reviewer of that day as the best speaker in the world.  However, as I hadn’t “paid my dues” yet, they were not free to write the same, but Guy Lemcoe did declare it the Best Sound of the Show.  Due to the financing only with my own means and a severe recession in 1992, I decided to close the company.  However, I gave all the rights to use the technology developed to Albert Von Schweikert which he used in various forms in his subsequent models and the Armageddon was eventually developed into the current VR-11 Von Schweikert Audio model.

I stayed in the back scene for some time, attending all major shows and every CES in Las Vegas ever since.  About 1 ˝ years ago, I approached Albert again to try and bring my custom speaker he and I had also designed to be my personal speaker in 1995 that was much smaller and simpler and bring the most current technology, crossover design, and especially the best sounding and cost no object passive components to place in the crossover.  We are nearing the end of this project and are looking forward to marketing the product sometime in 2010.  I would like to add that I am a music lover first and audiophile 2nd.  If a system doesn’t draw me into the music and performance, then it just doesn’t hold my interest long-term.  I enjoy attending live performances and I also play 3 instruments—the trumpet, piano, and guitar.

Search for the “Perfect” Preamplifier:  As a result of the most current speaker project, I have been on a serious preamplifier quest to help voice my speaker prototype as I consider the preamp to be critical to the heart of a reference audio system and have been diligently searching for over the last year.  In fact, I have listened over the last year to many of the most highly regarded tube preamp systems most of which are listed below.  I will remark up front that I far prefer tube preamps to solid state ones in nearly all cases.  I enjoy and have used both tube, hybrid, and solid state amplifiers, but overall prefer a tube preamp mated to a very good solid state amp in order to gain advantages that both technologies and sounds offer.

Tube preamplifiers I have extensively auditioned in the last year:

1) Shindo Monbrison, Masseto, and Vosne-Romanee Models.
2) Audio Research Reference 3 and 5 Models.
3) Balanced Audio Technology REX Model.
4) Conrad Johnson ACT-II.  (Awaiting an Audition of the Conrad Johnson GAT Linestage Soon).
5) Audio Valve Eklipse and Conductor Models.
6) Allnic L4000 Linestage Model.
7) First Sound Linestage (Presence Deluxe 4.0 Mk II with Paramount Plus Upgrade)
8) Lamm LL1 Signature Monaural Line Level Preamp and LL2.1 Line Level Stereo Preamplifier Models.
9) EAR 868 and 912 Preamplifier Models.
10) Purity One Tube Linestage Model with V-Cap Upgrade

The focus of this review will be #10 above—The Purity One Linestage with TFTF V-cap upgrade.  Before I start this review, I would like to congratulate all of the above tube preamp models and manufactures as every piece is a jewel in its own right with no major flaws, but each with various amazing strengths and different “flavors” depending on the listeners preferences.  The Purity One is most deserving to be in the company of the above august list which I believe to be some of the finest tube preamplifiers in the world.

Introduction: The Purity One is the brainchild of Designer Bill Baker, owner of Response Audio and Bella Extremme.  There is one higher model featuring some balanced inputs and outputs called the Purity One Reference.  The retail price of the Purity One with V-cap upgrade at the time of the review was --------.

Associated Equipment for Testing:  Amplifiers used to audition the BellaMax Linestage included:  1) McIntosh 402 Stereo Amplifier (400-Watts into 8-Ohms), 2) Nelson Pass Aleph-2 Single Ended Class-A Monoblock Amplifiers (100-Watts into 8-Ohms), 3) Vincent SP331 Hybrid Stereo Amplifier (150 Watts into 8-Ohms), and 4) Triode Corporation Ltd of Japan TRV-845SE Model (Integrated Amp with Preamplifier Input Option, 20 Watts Class-A into 8-Ohms, and Featuring High-End Carbon Resistors and Mundorf Capacitors).   Speakers used:  1) An Earlier Custom Prototype.  2) B&W XT2 Mini-Monitor Monocoque Body with JL-Audio Fathom f113.  3) Vienna Acoustics Mozart.  4) Von Scheikert Unifield 2’s.  Sources included: Fanfare FM/AM Tuner (FTA 100 Model), an Upgrade Company Signature Upgraded McIntosh MCD-500 CD Player (With Analog Volume Control and Digital Input), MacBook Pro with Belkin Gold USB Cable into a Music Streamer Plus Passive DAC Unit for Internet Radio Streaming and Lossless Ripped CD’s.  Sadly, I am without an Analog Rig—a problem I hope to remedy in the next year.  Interconnect Cables included DNM, Crimson, Synergistic Research (Precision Reference), Zonotone of Japan (Retail Price of $1,850.00), and My Own Design (MOD).  Speaker Cables included DNM, Crimson, TARA RSC-1, Zonotone of Japan ($4,400 a pair), and My Own Design (MOD).  All powercords are “MOD” and typically nearly double the resolution of any component they are plugged into and to date have never been surpassed by any commercial cable I have tried against them.

Brief Physical Description of the Purity One Linestage with V-Cap Upgrade:  The Purity One in possion is surrounded by a wood front, top and both sides, a bottom Aluminum plate, and the back is quarter inch black acrylic material.  On the front are 3 wooden knobs.  The left knob is for the on and off switch, the middle knob which features a discrete resistor array internally controls the volume, and the right knob controls the input selection.  On the back, there were (5) pairs of RCA type single ended input connections and (2) RCA preamplifier output pairs.  There is also a simple 2-way switch on the back for low gain (10-db) and high gain (16-db) to optimize the gain level depending on the source chosen (a marvelous feature also found on the Lamm LL2.1).  Since I am not the world’s expert on identifying various wood types, the following is a description by Bill Baker of the wood components:  “The preamp chassis was made up of Baltic Birch Ply. The front was 3/4" solid Maple and then completely covered in Japanese Tamo Ash real wood veneer with a light custom stain mix.”  The unit has 2 tubes in the driver stage which are both 12AU7’s.  My unit was sent with NOS Mullards which caused an incompatibility with my Vincent Hybrid Amp (its light was in fast-blink mode and would not play).  I tried some current production Electro-Harmonix which fixed the incompatibility, but did not give the most optimal sound.  I then placed Amperex NOS Superline Select, vintage early 60’s, measured and matched by the Tube Master himself, Andy Bouwman from Vintage Tube Services in Michigan and audio nirvana was finally achieved.  I took a quick peak inside and noted only one input transformer and all discrete components.  The circuit is said to be a “0 dB negative feedback” and “pure class-A triode vacuum purest tube-circuit design”.  Even the power supply contains no electrolytic capacitors, but polypropylene with bypasses.  As expected, V-caps were found in abundance in the gain stage. What features were missing from the BellaMax/Purity One?  No balance control, no mute function, no phase inversion switch, and no remote with such features as mute, volume control, and input selection.  I understand the newer version of the Purity One comes with a “fully functional remote control”. 

Sound:  While I will outline in more detail the overall sound of the Purity One Linestage, let me state at the beginning that this is one amazing sounding linestage and one of the best that I have heard.  Because this unit features the V-cap upgrades, I did intermittent listening during about 450 hours of break-in time and then serious listening at the 450 hour mark.  My first impressions that continued upon more extensive listening was of a very fast and dynamic sounding preamp that initially seems to walk a perfect line between a “tube” sound and “solid-state” sound with best bass I have every heard from a tube preamp in terms of pitch depth, power, and control.  The midrange was very palpable with lots of substance and body to performers, vivid, 3-dimensional, with just the right touch of natural sounding midrange warmth.  The highs were very fast, open, transparent, and airy with just a amount of natural sweetness that I hear in live music.  In fact, more extended listening reveals that the unit doesn’t sound “tubey” or “solid-state like”, or even a perfect hybrid of the 2, it just sounds very much like live music.  There was an enormous amount of inner detailing, but the sound was not etched, hyperdetailed, or “analytical” sounding.  Rather, the inner detailing was perfectly integrated and joined, not separated, from the musical experience.  It has been written that one of the wonderful features of the Audio Research Ref 3 Linestage is that it had a “lit from within” quality to each sound and performer.  I am glad to announce that the Purity One also has this wonderful quality in spades!  The soundstage had outstanding depth and width with billows of air surrounding each performer and only limited by the recording (as it should be).  The requisite pace, rhythm, and timing (PRAT) was most certainly there sounding both natural and realistic with the Purity One lending music excellent propulsive drive and excitement.  Very importantly, the Purity One was supremely quiet allowing me to listen far into the soundstage and capture all the subtle inner details, especially appreciated on the more quiet passages of different performances!

There are 4 areas where I find many preamplifiers, even very well-regarded ones, to present the biggest challenge:  1) First is reproducing the fast leading edge, then the body, and then the long and natural decay of each instrument and voice.  2) Second is keeping the soundstages full depth and width to the limit of the recording locked in place and well separated during very complex/dense passages, instead of being reduced to an incomprehensible morass of sound.  3) Third is reproducing both macrodynamics, and, more importantly, microdynamics in a realistic way.  I consider the microdynamics to be the life of the music—its moment to moment breathing/living aspect of live music and sound that when absent, makes music dull, boring, and lifeless.  4) Fourth is being able to produce natural intensity/amplitude uniquely to each individual performer in correct time both individually and then collectively against every other performer at each passage of each performance.

Fortunately, amazingly, and rather uniquely in my experience, the Purity One passes all of the above challenges with ease.  I will follow some specific listening examples:

1) Credo/Grimaud, Salonen, Swedish Radio on Deutsche Grammaphon:  This is a true stereo and preamplifier musical torture test!  The piece selected “Credo” by Arvo Part performed by the Swedish Radio Symphony Orchestra conducted by Esa-Pekka Salonen and with performance by Helene Grimaud.  This selection (track 7) tests all (4) of the above preamplifier challenges (especially #2) and more.  This selection ranges from ppp to ffff and all ranges in  between!  This SACD was loaned to me by a fellow Physician and music lover whose relative had a long career in opera in Vienna, Austria. Only the most top tier preamplifiers/linestages will avoid a crash and burn on this test in that the extreme intensity and density of the score collapse into an utter confusion and cacophony of sound instead of keeping all the separate performers perfectly positioned in space within the soundstage as well as properly rendering the individual and collective amplitudes and timing.  My friend who loaned me this SACD was shocked at how well the Purity One did on this intense and difficult to reproduce score—Bravo!!

2) Usher Audio “Be there” Demonstration Disc:  This is a wonderful disc with every recording sounding detailed, balanced, and natural sounding.  Many of the selections contain different languages from Taiwanese to French to Spanish to Latin.  I especially enjoy the “Royal March from the Soldier’s Tale” on track #11 which contains bass drum and snare drums, clarinets, and all manner of brass from tuba, to trombone, to trumpets.  I listen for the naturalness of each instrument’s timber, which sounded extremely natural and realistic (perfect “blat” of the trombone) with phenomenal microdynamics with the Purity One.  What I noticed the Purity One also really got right probably more than any other preamp I have tried was the initial attack of the bass drum, followed by a powerful pressure wave that I both felt and physically experienced a it slammed against my chest followed by a very natural decay of each struck stroke—absolutely amazing!

3) Mormon Tabernacle Choir “Choose Something Like a Star”.  I love every selection, but especially listen to Track 9 “Say Ye to the Righteous” and Track 12 “Ye Shall Have a Song”.  The Purity One gets the space, hall sound, attack, sustain, and decay of the mass chorus right with superb separation of individual voices in each section as well as outlining each section (there are 8 sections) as good as I have heard. 

4) Paul Simon’s  “Graceland” (Newest Version).  Check out track #13 “Diamonds on the Soles of Her Shoes” which has one of the best electrical bass guitar runs of any recording I have ever heard.  The Purity One gets the speed, fullness, vividness, and drive perfectly and draws me into the music with a stunning rendition.

Conclusion:  The Purity One Linestage is absolutely a top, top tier musical masterpiece!  It sounds as much like a live performance as any preamplifier/linestage I have heard/auditioned to date.  It presents with fast, clean, deep, powerful, and natural bass; a vivid 3-dimensional midrange with full-bodied performances, and huge airy and extended high frequencies with proper soundstage width, depth, and height from the very front the furthest reaches back with soundstage only limited by the recording.  It gets the leading edge, body, and then decay of each note right and doesn’t collapse the soundstage on extremely complex passages (as do many other preamplifiers/linestages).  It allows one to hear the musical intensity (amplitude) of each performer individually and collectively that one hears at live performance.  It also breathes life into the music with its excellent microdynamics.  Its quietness allows low level details to be easily heard and allows one to listen deep into the soundstage.  My only reservation about my review unit was the lack of remote control which appears to be remedied in the new Purity One Model.  Unhesitatingly recommended!!

name withheld

Manufacturer Comments:

Thank you for such an in depth, detailed review of our Purity One tube linestage. The Purity One is the result of many years of research and testing of several design concepts. We are honored to hear that your experience with the Purity One directly reflects or design goals with this unit.

As you so kindly mentioned, the production Purity One linestages will in fact be equipped with a full function remote control offering the user the ability to control volume, mute and source selection from the comfort of their listening position. New units will also come housed in a new chassis design sharing some of the lines and family resemblance of the Purity Reference Balanced linestage.