November 2010

World Premiere!
Virtue Audio's Dodd Modified Sensation M451 Integrated Amplifier
Hearing Is Believing
Review By Ron Nagle

  The Virtue Audio story should not be told outside the framework of one other company, and that is Tripath Technology Inc. located in San Jose California. Founded in 1995 by Adya S. Tripathi, Tripath Technology is a semiconductor company that develops designs and markets integrated circuit devices. Tripath markets their IC chips, or chipsets for use in products made by other companies. The Tripath chip is referred to as a "Class T" amplifier; it is a variant implementation of a "Class D" Digital Amplifier. The Tripath Company redesigned the IC digital control functions to increase efficiency and improve the quality of audio amplification. One of their amplifiers, the TA 2020 was named one of the twenty five chips that shook the world by the IEEE Spectrum Magazine. "Class T" is a registered trademark of Tripath Technology Inc.

Virtue Audio was founded in 2005 by Seth Krinsky. Mr. Krinsky knew that Tripath the digital chipmaker was in the process of filing for reorganization under chapter 11. The Bankruptcy filing became a reality on February 8, 2007. The visionary Mr. Krinsky subsequently purchased a large inventory of Tripath Chips even though at that time he did not have an amplifier that could use them. As of now Mr. Krinsky owns approximately 50,000 Tripath chipsets. Finally, as reported by Bloomberg Business Week, on April 22, 2008 Etelos Inc. an IP provider acquired Tripath Technology in a reverse merger transaction. Subsequently Cirrus logic purchased the Tripath intellectual Property from Etelos in an auction for about $3 Million Dollars but did not produce a high power chipset.

Debut
Virtue Audio made their first public appearance at the Rocky Mountain Audio Fest in Denver, which was October 10, 2008. I remember seeing their colorful amplifier the Virtue 1, base price $249 in room 2032 at the Marriott Tech Center. The Virtue 1 used the Tripath TC2000 and TP2051 chipsets in a dual mono configuration. The following year, January 2009 they exhibited the Virtue 1 and the up scaled Virtue 2 at The Home Entertainment Show in Las Vegas. I visited them that year in Las Vegas; they were at the Alexis Park Hotel in two rooms, 1703 and 1510. It was in room 1510 that I heard these diminutive amplifiers driving the $21,000 Clairaudient line source speakers.

Empirically
On a personal note, about two and a half years ago I attended a Rave Meeting of the AudioCircles.com, the New York City audiophile group. At this meeting, they conducted a "digital shoot out" of equipment that members owned and brought to the meeting. That day the Rave audiophile attendees auditioned and quickly dismissed a new and popular ICE powered line amplifier that I had brought with me to the meeting. What was most noteworthy at this meeting was the apparent differences between the Class D ICE implemented digital technology developed by Bang and Olufsen and some of the Tripath based components. Most of the Tripath based amplifiers brought to that meeting sounded far more natural at the treble frequencies and exhibited fewer digital artifacts.

My position regarding digital amplifiers is that there should be made a broader classification of amplified sound. It would not just include classic tube or solid state sound qualities but a third very characteristic digital depiction of music.

The New Sensation
This article is the first formal Web Magazine review of the modified Virtue Audio Sensation M451 amplifier equipped with the new Dodd Audio Tube Buffer. The original Sensation amplifier has been around since early 2010. Engineer Micheal Mardis did the initial design work. Virtue Audio along with the talented Gary Dodd has never stopped working to improve their amplifiers. What really grabs my attention is the esthetic choices of wood grain covers (the review sample has a zebra wood veneer top) and the room matching mix of red, blue, yellow and green side panels and button colors. The basic Sensation amplifier has a $799 list price.

The Virtue Audio web site is a testament to the meaning of the word innovation. I will not even attempt to detail all of the possible circuit upgrade options and interactive design it your self color combinations available on this website. You really should visit this audio freaks fantasy fun Web site and see it for yourself. Additionally the Dodd Audio tube buffer may be purchased separately as a kit upgrade. It is possible to purchase the basic no frills Sensation amplifier and latter on add improvements when you can afford them.

M 451 Nomenclature
My review sample is finished in basic black anodized aluminum. This is also true for the large motor driven Alps volume control knob, positioned dead center of the front panel. To the right of that is a cool input push button, each actuation of this button steps/selects one of the  three line level input's. The selected input is shown by one of three front panel blue LED's. The left side panel has another intuitive multifunction power switch. This push button power switch is labeled, Protect, Standby and On/Off, again one of three blue LEDs will tell you which function is active. This amplifier comes equipped with a remote control. The rear panel has a small on/off rocker switch; this will switch power into the control amplifier from a separate outboard power supply. The power supply connects to the amplifier with an umbilical cord and a four pin DIN style plug. There is a selection of power supplies you could use with the M451 amplifier. The basic switching power supply that comes with the amplifier is rated at 24 volts and 65 watts. At additional cost, there is the 30 Volts at 90 watts power supply. And the next largest separate linear power supply is specified at 30 volts and 130 watts and costs $149.

My test sample came with the JT 130 watt transformer power supply capable of delivering 100 amperes. The JT 130 power supply option will add $249 Dollars to the price. The last optional power supply is pure DC and sourced from a rechargeable battery. This battery supply is made by Dodd Audio and the price is $149, you can find it on the Virtue web site. The stock Sensation M 451 power amplifier is rated at 87 watts per channel and can deliver a maximum of 7 Amperes under load. Respectable specs even so it will not adequately drive a few of the more inefficient speakers made for the high-end market.

The back of the amplifier has nine RCA female jacks. Three pairs of jacks are inputs for the three line level sources. Two are left and right Pre-out and the last RCA connection is for a center channel mono subwoofer. I did not use the subwoofer out for this two channel review. A very nice feature is the Propeller style speaker binding posts. These Propeller binding posts make it very easy to secure your speaker cables.

The Best Is Last
My sample M 451 came supplied with the Dodd Audio tube buffer and a JJ branded ECC 803S/12AX7 tube. There is much more audiophile fun and madness in store when you start tube rolling the Buffer circuit. The tube filament / heater supply is 12 Volts so you may substitute most any dual triode 9 pin tube that uses a 12 Volt heater. The top of the amplifier can slide open giving you access to a switch that will remove the Buffer from the amplifier circuits. And because of this It is possible to do a quick A/B comparison with the tube switched in or out. If you do swap tubes, the amplifiers sound will change and take on the characteristics of the tube you substitute into the Buffer circuit. This feature is a tube tweakers dream. Additionally the Tube Buffer circuit may be added post purchase to the M 451 as a $300 upgrade. The Owner's Manual contains a long list of substitutable tube types.

Hearing Is Believing
Like most amplifiers (albeit very quickly) when first turned on it takes an interval of playing time for a burned in M 451 to properly hum a tune. The manufacturer advises running the amplifier for a hundred hours to fully burn it in. Under normal operating conditions the Sensation runs unusually warm for a digital amplifier. Having said that, I'll have to describe the amplifiers sound two ways: tube in and tube out. The easiest thing to do is tell you that with the tube buffer switched out it is one of the best digital amplifiers I have ever heard. It is fast, clean, and free of the cold grainy treble and the characteristically elevated bass response of other digital amplifiers.

With The Tube Switched Out
Listening to the Clarity Cable CD track 14, Take The Long Way Home by Supertramp. This is a multi track cut with a ton of studio reverb that is fast punchy and full of rock and roll excitement. This style of Rock and Roll is a good match for the Sensations digital sound. With long term listening you will find there is vanishing digital grain riding on the musical fundamentals. Bottom line, if you know what a classic transistor-based Class A/B amplifier sounds like, than you know ninety five percent of the Sensation M451 Triamp sound.

With The Tube Switched In
The first half second of listening your brain shouts, something is missing!  But rapidly the reasoning hemisphere of your noodle cuts in and you realize you can better relate to what you are hearing. When you switch in the tube buffer with the JJ ECC 803S, the sound you hear is a softening of transient attack. This is most noticeable at higher frequencies but in actuality, it affects all frequencies. However, the trade off, if you can call it that, is a richer harmonic envelope encapsulating all the individual components of the music. This effectively paints everything into a more realistic and dimensional sound space. The next ear test is the Clarity Cable CD, track 2, Peggy Lee singing "Fever". Wonderful song wonderful artist wonderful way too listen to the sound of my primary reference, a human voice.

The gestalt is this, when Peggy pauses to take a breath, so do you, when Peggy's phrasing sounds suggestive, she is really coming on to you. That's the Audiophile way it should be, she's speaking directly to you and drawing you deeper into the performance. The Tube Buffer brings out the human warmth in her voice and now any possible digital graininess is banished. Curiosity compelled me to roll yet another tube; it was a new Sovtek 12AX7WA.

Bottom line, a bit different sound but not a better sound. The Sovtek opened up the top/treble with more extension and speed but at the other end of the spectrum the bass frequencies dried up what reviewer geeks like to call, sustain. With a borrowed supply of tubes from my audiophile friend, Paul Mah, I launched into a tube swapping frenzy. The differing qualities of the tubes are too numerous to include in this report. Suffice it to say most of the differences in the tubes sound are subtle. But still this difference is important to an audiophile seeking the very last ounce of believability. Seven tubes later, I found my favorite dynamic "Class A" KT88 tube amplifier sound was contained within a vintage British Mullard 12AU7.

Bottom Line
The Dodd Audio, Virtue Audio Sensation M 451 is an advance in digital design that finally bridges the gap that existed between digital and tube and solid-state amplifiers. It seems evident to me that no matter what type of music you enjoy be it classical, jazz, or rock you now have options at your fingertips.

However Audiopals be aware that not all Tripath based amplifiers are the same, as there can be vast differences. The Tripath IC is only a building block, a starting point for a circuit design. Therefore, the Sensations M451 performance can only be attributable to Seth Krinsky and his team collaboration with talented designers. A musical component such as this is hardly ever seen with so many options and so many features. Indeed, there is so much going on that it will take time before this perfectionist writer runs out of fun things to try. I'm going to get me a Sensation M 451 even though I already have three amplifiers. All factors in place, the reasonable start up price, the performance the impressively solid construction and a thirty day no fault trial period means the Sensation M451 garners my rare recommendation to buy.

"The true world of the Audiophile is not static it is a constant quest for all the things that reach inside of you and touch your emotions."

As always, Semper Hi-Fi

Reference System
Source Components: Marantz DV8400 Universal CD player, Cambridge Audio Discmagic-1 CD transport, Cambridge S-700 Isomagic HDCD D/A Converter, ART DI/O Up sampling D/A and A/D processor, Magnum Dynalab FT 101a tuner and Dynalab Signal Sleuth.

Speakers: Aurum Cantus SES 2, Fritz Audio Carbon 7 monitors.  

System Connections:

Power Conditioning: Richard Gray 20 ampere Substation, Islatrol Industrial 20amp ac line conditioner, Alpha Core Balanced Transformer Power Supply, Audio Power PE-1 power enhancer, Triad 2-ampere isolation transformer

Accessories: VPI Magic bricks, Argent Room Lens system, Room Tunes Panels, a comfortable chair

Specifications
Type: Stereo amplifier with tube and solid-state options
Power Output: 87 wpc @ 4 Ohms
Inputs: Three stereo via RCA
Output: Stereo preamplifier and subwoofer via RCA
High-current PSU soft-start
Attenuator: High quality by Alps
Remote Control Included
80hz High-pass jumper
Input Caps: SoniCaps
Maximum Input Voltage: 30 Volts
Price: Sensation M451 $799
Tube Buffer circuit adds $300
Battery supply made by Dodd Audio adds $149

Company Information
Virtue Audio
Voice: (877) 847-8968
Website: www.virtueaudio.com