Tenor Phono 1 review by Richard H. Mak

Matej Isak
Tenor Phono 1 review by Richard H. Mak – Mono and Stereo Senior Analog Contributing Writer 
It is often said that the “Law of Diminishing Returns” holds particularly true in the world of high-end audio. As one climbs further up the sonic ladder, improvements become much more difficult to attain and often require vast sums of money for incrementally small improvements. A fundamental paradigm shift in sound quality as a result of changing one particular piece of equipment is a rare occurrence. But rare as that may be, there are exceptions! My recent encounter with the Tenor Phono 1 preamplifier is a case in point. The Phono 1 fundamentally changed the sound quality of my system and vaulted it to a level of performance never before attained – so much so, that it left not only me but all of my audiophile buddies in shock and awe!
Tenor Inc. is a boutique audio manufacturer based in Montreal Canada. They have been producing exquisite high-end equipment since the beginning of the new millennium. Their chief designer, Michel Vanden Broeck, is the genius behind every Tenor product including this phono stage under review. Vanden Broeck has enjoyed a life-long passion for audio with a career in electrical engineering and an interest in psychoacoustics spanning over forty years. Prior to joining Tenor, Michel worked in the aviation, telecommunication, recording and audio industry. If you examine closely his amplifier designs you will find cable assemblies tucked safely out of harms way in the under belly (like a plane), high band width coaxial connectors to ensure the perfection of the connection (like in telecom) and a sonic presentation that sounds like real music (psychoacoustics). Clearly, he comes with plenty of experience under his belt.

Make no mistake about it, Tenor positions itself in the ultra high-end segment of the industry and has the price tag to show for it. Their top of the line three piece system including phono stage, 2 chassis preamplifier and pair of mono block power amplifiers will set you back just shy of a quarter of 1 million of Uncle Sam’s dollars! And, as with most ultra high-end products, there is a wait time of anywhere from 4 to 6 months for Tenor equipment. Be thankful though, because a Bugatti Veyron carries a wait time of a minimum of 10 months, and if you are inclined to go with the Aston Martin DBS, make it 28 months. How about a bespoke Roger W. Smith watch from the Isle of Man? That requires an upfront payment of $ 135,000 to start, and a wait time of 3 years. Thankfully, my review sample took only 4 months to arrive with a more “modest” MSRP price tag of $43,000 usd ($56,000 cad) and was delivered in full Tenor style by Jim Fairhead, Tenor President and Global Sales Manager David Johann.

The Tenor Phono 1 is packaged with a heavily padded and substantially made metal & wood flight case and, as such, the Tenor would likely survive any shipping abuse an airline could throw at them. Out of the flight case you can tell immediately that the Tenor Phono 1 is no run of the mill assembly line product. The fit and finish of the custom extruded and anodized aluminum chassis is top notch. The solid cherry front panels with sixteen coats of piano lacquer adds an organic element to its already elegant look. At first glance, it is clear that every detail has been addressed. Research and development of the single chassis Phono 1 took over 5 years and leveraged off the Line 1/Power 1 double chassis design – both prototypes shown to global acclaim at the 2008 Munich High-End Show. Prospective purchasers are receiving the benefit of the 8 years of intensive research and development following the introduction of the prototype that allowed the challenge of a single chassis hybrid phono stage, that measures better than most solid state dual chassis ones, to be perfectly executed. Vanden Broeck experimented with every imaginable design configuration and advanced the state of the art by inventing new methodologies of manufacturing and design. Each Tenor phono stage is meticulously hand built and tested to Vanden Broeck’s strenuous performance standards which leaves no room for anything less than perfection. After all, Tenor’s official corporate slogan is “The Mark of Perfection”!

The Necessary Stuff

The Tenor Phono 1 is a massive unit weighing in at 58.5 lbs – making it one of the heaviest single chassis phono preamplifiers on the market. By comparison, my FM Acoustics FM-122 Mk II weighs only 7 lbs including the power supply. The operation of the Tenor is very straightforward. I was able to navigate the front panel without even reading the user manual. On power up, the vacuum florescent display starts a countdown at 1 min 40 seconds before becoming operational which allows the unit’s components to stabilize thermally. “Elapsed Hours” is also displayed representing the unit’s cumulative hours of operation – a useful number for knowing the remaining life of the tubes which are rated for 10,000 hours or better.
The Tenor Phono 1 has three inputs (2 RCAs & 1 XLR) as well as three outputs (2 RCAs and 1 XLR). Each input has a user selectable gain from 55dB to 70dB in 5 dB increments, as well as seven loading choices: 100, 200, 300, 400, 500, HIGH and CUSTOM. At the maximum 70 dB of gain on the RCA input and with the volume dial at 50% on the preamp, I could detect almost no noise other than a quiet hiss – quite an accomplishment for a tube-equipped component. A low noise floor is most desirable as it translates into a pitch black background which enhances dynamic contrast and vividness of the sonic picture. Although not as quiet as the solid state Rossner & Sohn Canofer-S or Burmester 100 Phono, the Tenor Phono 1 is perhaps the quietest tube phono stages on the market with a rated specification of -87dB. Noticeably quieter than the Kondo M7, Audio Research Reference 2 SE, as well as the Manley Steelhead all of which have a slightly louder hiss at the same volume setting. But that is just the beginning ……
The Tenor Phono 1 hybrid tube/solid state design utilizes four stages of signal amplification. The analog signal is first met with a custom 4 times gain Jensen step up transformer which is followed by two zero distortion symmetrical but separate transistor stages which raises the gain by 36 dB. The signal then goes through RIAA equalization of the high frequencies, followed by a tube stage utilizing two carefully selected NOS Amperex 8416 tubes – chosen for their low noise and stable characteristics. The signal then receives RIAA equalization on the low frequency using a circuit with a pair of Russian Military 6n6P tubes. A 1:1 output transformer with a super wide 50 MHz bandwidth is employed to generate the balanced output signal. The final stage is a Pure Class A output buffer with zero negative feedback. The entire circuit board is mechanically isolated with Tenor’s proprietary rubber suspension alleviating any possibility of mechanical pollution of the signal. The chassis also utilizes dissimilar materials with rubber/ wood feet to provide further mechanical isolation. Every detail has been well thought out and there is clearly nothing left to chance.
Tube life should not be a concern given these tubes are expected to last at least 10,000 hours and Tenor stocks thousands. They are rigorously tested by a proprietary device designed by Vanden Broeck whereby each tube is bombarded with white, brown and pink noise, and carefully monitored for anywhere from 100 to 500 hours (depending on tube) using a computerized tester and an oscilloscope. Any tube which does not meet Tenor’s rigorous microphonic specification is automatically rejected – often accounting for up to 50% of a tube lot!
It is noteworthy to mention the “Phase Reversal” button on the front panel of the Phono 1 changes the absolute phase output from 0 to 180 degrees. The same effect can be achieved by reversing the polarity of the speaker cable on both channels (albeit a lot simpler as a button). This phase button is ideal for those adamant on preserving absolute phase on one’s system but I found it as much a boon as a bane. With some recordings, such as the “Valentina Lisitsa play Liszt” album (Decca 478 5751), or the “Dream of an Opera” album (Rhymi Music RMLP006), the correct phase was easily discernible as the location of instruments in acoustic space become awkward and incorrect without it. But this is not always discernible for all recordings and the whole exercise can become a non-stop sequence of back and forth on the same recording until you get it right. One must also consider that some recordings have been mastered with both in phase and out-of phase sources – due to the multitrack overlay techniques associated with recording. In the end, I basically left the button untouched for practical purposes. (Tenor notes that this button is especially useful when the phono stage output needs to be inverted to correct for inverted preamplifiers which are quite common)

The Proof is in the Pudding

Most of the phono preamplifiers I have owned usually require an agonizing “burn-in” period which can easily last for 50 to 100 hours. During this time, most sound abrasive, edgy and tight to some degree until after this period. The Tenor Phono 1, however, sounded beautiful right out of the box – thanks to Tenor’s extensive testing and factory burn in of every production unit before shipping.
Right from get-go the Tenor Phono 1 exhibited a dramatic leap in sonic performance, almost as if someone had grabbed hold of both ends of the frequency spectrum and physically stretched it out by five notches. I saw improvements in every imaginable sonic criteria including dynamic contrast, definition, solidity of the sonic picture, sound stage and tonal clarity. It was as if a thick veil had been lifted from my system. I knew right then and there I would be buying the review sample!
To evaluate the human voice, I pulled out Johnny Cash’s rendition of the classic Nine Inch Nail’s song “Hurt” from his American IV The Man Comes Around album – referred to by many as the saddest song in the history of music. The sound coming through the Tenor carried noticeably more ambience, air and solidity of Cash’s vocal image. The same can be said of his daughter, Rosanne Cash’s, song “500 Miles” from her album, The List , which was not recorded in particularly high quality. But the sound coming through the Tenor made me feel like I was listening to a brand new re-mastered version of the same album: It was that much closer to a real live performance. The Tenor does a wonderful job of combining the virtues of a realistic performance with more ambience, air, and frequency extension, without ever losing the organic elements that make the human voice emotionally engaging.
Inevitably I was drawn to compare Tenor with my Kondo phono stage for human voice, the Kondo M7 with the SFz Step Up Transformer. Bob Dylon’s song “It’s All Over Now Baby Blue”, sung by Joan Baez in her Fairwell Angelina album, is so emotionally charged that it literally moved me to tears. The Kondo has always held the crown of having the most organic element, conveying music with seductive emotions that speak to your soul, but this time around, the mighty Kondo has met its match. The sound coming through the M7 is clearly more rounded, thicker in the mid range, and less extended. On the Tenor, the sound has less emphasis on the mids, and Joan Baez’s voice came across with more clarity, most noticeably in her vibratos. Switching to the Tenor from the Kondo is like going from an EL34 amp to a 300B, each with their own shades of color, yet equally admirable, making it very difficult to decide on one, so I will have to own both!
With the grand orchestral recordings, however, is where the Tenor really shines. I pulled out the big guns, literally, with Tchaikovsky’s Capriccio Italien and 1812 conducted by Kenneth Alwyn on the London Symphony Orchestra (DECCA ED1 SXL 2001). The sheer size, scale and dynamic range of some of these early DECCA recordings have very few rivals, save maybe some early Mercury LPs. On this particular recording, I would avoid the Speaker’s Corner reissue as it sounds noticeably dry and abrasive. The Tenor rendered the entire Capriccio Italien performance with flying colours – portraying every instrument with proper weight, scale, timber and texture. Even on the demanding passages, which can easily become trashy, garbled messes with a lesser component, the Tenor maintained proper contrast with clear identifiable distinction of every instrument in the acoustic space – nothing was garbled. The dynamic contrast, weight and solidity of the holographic image, is reminiscent of the Burmester 100 Phono Preamp, but the Tenor adds a greater transient response with a wider frequency extension. It instills more vibrancy and impact to sound making an already intense performance even more exhilarating and lifelike.
The grandiosity of large-scale orchestral performance is, again, well demonstrated with Wagner’s Tannhäuser, with Karajan conducting the Berliner Philharmoniker (DGG 413 754-1). Lawrence Lock, my fellow music writer from the HiFi Review magazine in Hong Kong, must be acknowledged for his apt description of Wagner’s unsurpassed skill of creating atmosphere on The Overature and Venusberg Music of Tannhäuser. On the backdrop of mass strings in the opening sequence, gradually increasing in power into a majestic grandeur, he envisions himself travelling through a sea of clouds, and triumphantly piercing beyond the horizon into the infinite landscape of the cosmic space above. Indeed, the Tenor rendered one of the most splendid performances of Wagner, projecting a sound stage that reaches beyond the confines of listening room’s walls. At times the intensity of the performance was so completely entrancing that I forget that I was supposed to be taking review notes – the Tenor was that good!
Then I moved onto Violin performances that provide such an opportune moment to test the transient response of the Tenor. I pulled out Michael Rabin’s Mosaic Volume 2. Often described as the most talented and tragic violin virtuosi of his time (Rabin died at the tragic young age of only 35) yet when he plays, he does so with power and flamboyance, perhaps a reflection of the rumored substance abuse which plagued his life. The Tenor fully demonstrated Rabin’s vigorousness and vibrancy with every twist and turn of the violin bow, and rendering the acoustic image of the violin in its correct size. It kept pace with the flamboyancy of Rabin’s style, revealing every minute detail on the violin as the string glides across the bow with ultra sharp focus, yet never sibilant or bright.
Equally remarkable is Ruggiero Ricci’s fast paced rendition of Carmen Fantasie with the London Symphony Orchestra (DECCA SXL 2197 ED3), again a recording that I’ll avoid on the Speaker Corner’s reissue. The record is notoriously difficult to render well, it often sounds abrasive and tipped up on a lot of systems. The Tenor delivered the utmost detail even on passages where Ricci’s was purposely light handed, sending vibrations of the strings across the room that I can not only hear, but feel. Remarkable that the sonic image was rock solid, even on very calm passages with low volume.
No review is ever complete without the test of a grand piano. For this, I pulled out Brahms Piano Concerto No. 1, with Clifford Curzon on piano and Szell conducting the LSO (DECCA SXL 6023. From the gripping intense opening sequences with the mass strings, to the melancholic rendering of the life-like grand piano, all the way to full symphonic grand finale, the entire frequency spectrum of the grand piano was captured with the utmost clarity, bass texture was solid, well defined and distinguishable with other instrument, even during passages with the thunderous lower piano notes. The Tenor delivered one of the most lively and realistic renditions of Brahms Piano Concert No. 1 I have ever heard.
My encounter with the Tenor Phono 1 has been a dramatic one. The experience was almost as electrifying as when I heard the MBL Radialstrahler 101 X-Treme at the CES for the very first time, or the six chassis 2000 McIntosh MC2KWs. These pieces of equipment share the commonality of having the ability to instil a “paradigm shift” to the listener, breaking barriers previously unimaginable and unattainable.
In summary, there are few equals to the Tenor Phono 1 at any price as the Tenor experience is nothing short of breathtaking! It has taken my entire audio system to a whole new level – that I thought would not be possible without changing most of my equipment. For that reason alone, the cost of the Tenor must be considered a true bargain. Perhaps audio’s “Law of Diminishing Return”s has been overcome by Tenor’s Michel Vanden Broeck’s “Laws of Physics”. One thing for certain, this unit is never leaving my house. I wrote the cheque!
Text: Richard H. Mak, Mono and Stereo Senior Analog Contributing Writer

PRICE

$43,000 usd ($56,000 cad)

SPECIFICATIONS

Preamplifier Type: Phono Stage
Chassis: Single
Dual Mono: Yes
Harmonic Structural Integrity: Yes
EQ Curves: Passive RIAA & IEC
RIAA Precision: 20 Hz – 20KHz +/- 0.1dB
Voltage Gain: 55dB – 70dB (selectable in 5dB increments) 
Rated Input*: 12V rms Single Ended or Balanced 
Maximum Output*: 25V rms Single Ended or Balanced 
Nominal Output: 2V rms Single Ended or Balanced
S/N Ratio Reference: < -87 dBA @ 70 dB
Gain Channel Separation*: < -90dBA
Frequency Response: 2-100KHz*
Bandwidth Response: 1-1MHz*
THD + Noise*: .< 0.02%
Load Impedance: 100Ω, 200Ω, 300Ω, 400Ω, 500Ω, HIGH, CUSTOM
Output Impedance*: 10Ω Single Ended / 100Ω Balanced
Global Negative Feedback: Zero
Balanced Input Pin Configuration: 1: Ground, 2: Positive, 3: Negative
Input Tubes (per Channel): 2 x NOS 8416 & 2 x 6n6p
Soft Start: 1 Minute 40 Seconds
Sequential Remote Turn On: 12 V Mini-Phone Plug
Cooling: Natural Convection
Microphonic Isolation: Suspended Audio Board/Tube Vibration Control
Fuses Phono 1: 1
Maximum Power Consumption during Operation: 75 Watts
Maximum Power Consumption during Standby: < 1 Watt
Supply Voltage Factory Set: 100 to 250VAC, 50/60 Hz
AC Mains Input: 15A IEC Detachable Power Cord
Weight Phono 1: 58.5 lb/26.5 kg
Shipping Weight Phono 1: 102.5 lb/46.5 kg
Dimensions Phono 1: 19.5in W x 21in D (including connectors) x 9.5in H (including ventilation)/ 495 mm W x 533mm D x 241mm H
Dimensions Shipping: 24.5in W x 26.5in D x 12.5in H / 622 mm W x 673mm D x 318mm H
Phono 1 MSRP (cad): $56,000
* : @ 120V AC @ 1kHz & 2V rms input

Tenor Inc. reserves the right to make improvements without notice that may result in specification changes
Phono 1 Production Features:
  • Same general electromechanical features as the power supply and line preamplifier units.
  • Microprocessor controlled with front panel VFD display and internal USB port for software upgrade.
  • Medical grade low leakage AC inlet module with integrated EMI filter.
  • Oversize custom made ultra low noise, low stray magnetic field, dual electrostatic shields power transformers.  In addition these transformers are potted in a steel can with special epoxy resin for further noise reduction.
  • Each DC supply are individually choke filtered and regulated independently for each channels with oversize low noise circuitry providing clean DC voltages to the amplification stages.
  • High quality PTFE insulation rhodium plated RCA connectors for reliable contacts and low emf.
  • High quality pro-audio grade gold plated XLR connectors used for reliable long term contacts.
  • A three position GND selector is provided to equalize ground potentials, That feature is also unique, giving to the user the necessary tools to adjust the system residual noise to a minimum and eliminate “Ground loops”.
  • Wide bandwidth triple shielded moving coil step up transformers with ultra low distortion are used to provide the maximum CMRR, low noise and transparency.
  • The first amplification stage is a discrete symmetrical topology using very low noise bipolar transistors for the moving coil, this circuit also contain the gain adjustment selector (55 – 60 – 65 – 70 dB for MC ) as well as the load adjustment selectors.
  • The entirely passive equalizer section use a proprietary split EQ configuration to reduce the noise and increase RIAA precision.
  • Two different EQ curves can be selected (RIAA standard 1954, RIAA + IEC).
  • Two pure class A amplification stages using high quality selected vacuum tubes are used to amplify further the phono signal.
  • An absolute phase and mono/stereo selector complete the phono preamplifier section.
  • High current pure class A ultra low distortion unity gain solid state buffer stages are used to provide isolation from the vacuum tube circuit. This buffer use discrete transistors instead of IC’s to get the maximum of sonic performances, it’s 10 Ohm output impedance is low enough to drive hundreds of feet of audio cable with unchanged distortion and noise characteristics.
  • Wide bandwidth double shielded hum bucking balancing transformers with ultra low distortion are used to provide the maximum performances when driving balanced audio cables.
  • All vacuum tubes are selected after a 200Hrs burning for electrical and noise specs, in addition they are also selected for microphony with a proprietary process.
  • Main audio board is mounted on a special suspension with a resonant frequency of 20Hz in order to suppress  external and internal transmission of vibrations.
  • Special shielding arrangements are used for limiting the influence of magnetic stray fieds.
  • Acoustical damping of main chassis part to avoid microphonics.
  •  Inrush current limiters used in conjunction with a slow start circuitry to optimize long term reliability of sensitive components like electron tubes and high voltage capacitors.
  • Silver plated copper wires with 600V PTFE insulation used everywhere with high quality crimped connectors for long term stability.
  • Relatively low operating temperature and high quality printed circuit boards insure long term reliability.
  • Each power supply section are hand assembled and intensively tested in our factory as usual for all Tenor products. All Tenor products are in conformity to IEC and KR as well as CE safety regulations.
  • Low EMF input and output switching is used for very low level signal integrity and low distortion.

CONTACT

Tenor Inc. – Corporate
17 Willow Bay Drive 
Midhurst, Ontario
Canada     L0L 1X1 

Email: jfairhead@tenoraudio.com
Web: www.tenoraudio.com