Focus Audio Liszt Sonata Integrated amplifier

Life is beautiful, I must confess!

In the past 12 months, I’ve been blessed with the opportunity to review top high-end audio gear from the very best. Tube magic can be very addictive and compelling when heard through such products as Audio Note Kondo and Thrax. Unfortunately, they come with a price tag that only few precious souls can afford.

My next quest, upon my descent back to earth, was to review a product more reasonably priced and that also sounds great. One product which came to my mind was the Focus Audio Liszt Sonata integrated amplifier. Why? About two years ago, when I was reviewing the Audio Note Kondo Overture Integrated amplifier, I was informed by Kam Leung of Focus Audio that he was working on his own tube amplifier employing EL34/6CA7 output tubes. Last winter I contacted Leung for a review sample and fortunately he was able to send me the Liszt Sonata Integrated amplifier.

Focus Audio, not just speakers…

Focus Audio is a renowned high performance loudspeaker manufacturer from Toronto Canada and has been producing speakers since 1993. Kam Leung is the technical director and designer of Focus Audio. As a teenager he developed his passion for electronics and stereo systems. After graduating from the University of Hong Kong he was involved in multi-discipline engineering construction projects and production in the private sector and for the government. In 1993 he immigrated to Canada and Focus Audio was born in Markham, Ontario, a high-tech town north of Toronto. Since then Leung has pursued his dream of designing and manufacturing high-end loudspeakers.

After years of listening to different brands of amplifiers for his research and development, and showcasing his speakers in various high-end audio trade shows, Leung decided it was a time to produce his own amplifiers exclusively optimized for his loudspeakers. With high praise and critical acclaim, he launched his first electronics: the Liszt Sonata integrated tube amplifier. Leung chose the EL34/6CA7 as output tubes because “they exemplify the best of both worlds; the elegant sound of Single Ended Triode tubes such as 300B, and the ample power and dynamics of the high power pentodes like the KT88 and more.”

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The Liszt Sonata is an integrated amplifier based on the EL34/6CA7. It’s a push-pull class- AB design with deep class-A bias to get the sonic benefits of class-A operation, producing 35-watts per channel. The driver circuit is a cathode coupled voltage gain and phase-splitter design. It’s simple and good sounding circuit topology was implemented in many highly successful tube amplifier designs through the 1940s, 50s, and 60s. Leung states that “our goal is not to reinvent but to leverage the fruits left by these brilliant designers.” The driver stage utilizes two 12AU7s and one 12AX7. All tubes are from Electro-Harmonix. Auto-biasing is employed to give best stable operation without the need for frequent bias adjustment. The power supply is the heart and soul of the amplifier and Kam Leung is very serious about his power supply design. Liszt Sonata’s power supply is well designed and has a massive power transformer. Its power transformer is essential for the delivery of unrestrained current supply to the amplifier. The power transformer weighs 17.5 lbs and it is designed to supply about 300% of the required current the amplifier needs. This extra current capability is responsible for the flat 20Hz response at the rated output. Leung says, “The transformer uses the top grade grain oriented silicon steel lamination to ensure cool stable operation.” Instead of using the traditional large value-capacitors design, Focus Audio’s approach is to use a fairly small value 30uf film capacitor from the German manufacturer, Mundorf. Leung explains that this small capacitor provides a wide charging window for the rectifier and the current waveform is very close to sinusoidal with no spike. It also uses high speed rectifiers with fast switching recovery times to minimize the rectifier switching noise. This, together with the 30uf Mundorf film input capacitor which has very low impedance at high frequencies, (about 0.0095 Ohm at 57 kHz) enables it to filter out most of the noise components from the AC line and the rectifier. This allows us to hear the low signal with less noise.

The Focus engineering team has spent many months designing and building many prototypes of output transformers. The Liszt Sonata utilizes custom designed double C-core output transformers which have excellent magnetic properties and that enables them to use fewer primary turns to achieve the same inductance and hence the leakage inductance is lower. The lower leakage inductance is purported to give better high frequency performance. All parts are carefully chosen after many hours of listening tests. The ultimate performance Mundorf silver gold oil capacitors is used. Leung hand-solders the 24-step, relay-controlled, ladder volume attenuator, using high-quality tantalum resistors for volume control shunt resistors. This process is extremely labor-intensive to assemble and makes it very costly to build. Custom made Cardas ultrafine copper wire is used for the lead out wire of the output transformer.

The Liszt Sonata is single-box, made with a low key, well-built, and a high-quality finish in a silver-anodized aluminum. The layout of the front panel is elegant and simple. It employs only two rotary knobs. On the left is a function selector knob; on the right is a volume knob, and in the center is a minimalist digital display. The rear of the Liszt Sonata reveals three high quality RCA inputs and one XLR input, an RCA and an XLR direct input that can bypass the preamp section. You can use the Liszt Sonata as a power amplifier – I’ve used several reference preamplifiers to see the full potential of the amplifier section – and, as always, it sounded superb. The power switch is a rocker at right rear and features a set of very high-quality binding posts for 4 and 8 Ohm taps. The chassis is well ventilated on the front top cover.

Setup

I used the Liszt Sonata in my reference system, in place of my Karan Acoustics KSA 450 amplifier and Karan Acoustics Mono Reference MKII preamplifier. In addition to my Consensus Audio Engineering Conspiracy loudspeakers, I also spent some pleasant hours using the Liszt Sonata to drive the Kharma DB9-S loudspeakers (review in works). The Pi Greco Sinfonia CD player was used along with Jorma Design Unity cables throughout the system. Installation was a breeze for the Liszt Sonata as there are fewer boxes and fewer cables compliments of this integrated design. Simply attach your source, speakers, and cables and off you go. Surprisingly, the Liszt Sonata is also remote controlled by way of a smooth operating Apple remote. At the touch of your finger you can change and mute the volume, switch between inputs, and Leung suggests dimming the display improves the sound. Cleverly, when the amp is powered up, the volume automatically defaults to mute (zero).

Sonic impressions

Almost right away, the Liszt Sonata sounded very involving, yet authoritative with excellent soundstage capabilities. In terms of burn-in time, Leung informed me that was needed was about 100 hours. As usual, I gave this product a few weeks to settle into the system. After that, all the Liszt Sonata needed was about 20 minutes of warm-up for the circuit and tubes to come alive.

During its time in my system (about 4 months total), the Liszt Sonata performed flawlessly. In fact, it proved to be a most competent and accommodating companion for my reference Consensus Audio loudspeakers Conspiracy as well as the Kharma DB9-S loudspeakers here under review. The Liszt Sonata’s overly built power supply really shines when it’s pushed and it doesn’t sweat a bit. Surprisingly, it never was at a loss dynamically and never ran out of steam even when I purposely pushed it. I found its bottom-end performance more than satisfying with all genres of music. The bass registers were powerful, had both the depth of expression and richness a good tube can deliver, and plenty of detail and pitch definition. Not quite the equal precision and taut extension of my powerhouse 500-watt Karan solid-state, but impressive nonetheless for any 35-watt tube design. Further, the midranges proved detailed, however it was never overly-analytical. Harmonic textures remained liquid and gracious in the best tube tradition. The upper midranges displayed the requisite amount of sweetness on violin overtones and the treble was smooth and liquid with a nice extension.

I began with a beautiful recording of one of my favorites, Rossini’s Sonate a quattro (HMC 901776) by ensemble Explorations; it was convincing and there was rightness to the string timbres had me listening for hours, appreciating the works of one of my favorite artists. The notes flowed beautifully and the complex mix of tonal nuances proved very engaging. String tones were organic and stringed instruments were demarcated by size and character not merely by the range of pitches they produced. It was clearly tube (in the best of its legendary tradition), by way of its level of color saturation, organic-ness and non-mechanical performance. Remarkably, listening to this wonderful music, I was reminded that Rossini was only twelve years of age when he composed his Sonate a quattro in 1804.

As I have said, the Liszt Sonata sounds far more powerful than its rated 35-watts per channel. It was a good match for my 92 dB efficient Conspiracys but I also wanted to see how the Liszt Sonata would sound driving the less efficient Kharma DB9-S. Rated at 89 dB at 4 Ohms, I was pleasantly surprised how easily the Liszt Sonata drove the DB9-S. Listening to Dvorak’s Cello Concerto for Cello and Orchestra in B Minor, Op.104 (JVC) performed by the master, Gregor Piatigorsky and the maestro, Charles Munch conducting Boston Symphony Orchestra, was beautiful. I was impressed at how persuasively Piatiorsky’s cello and orchestra transported me into this recording’s huge venue. Not quite life-sized, but a remarkable accomplishment nonetheless. The Liszt Sonata was able to scale the dramatics of the full orchestral crescendos without much difficulty. The bass was surprisingly taut and full-bodied and well extended. The spatial performance of Liszt Sonata proved also outstanding. To me tubes have a certain magic, creating a superb three-dimensional soundstage. The Liszt Sonata’s presentation of individual images in space was solid – stretching well outside my speakers physical location and beyond my listening room’s front wall.

In Closing

I really enjoyed my time listening to the Focus Audio Liszt Sonata integrated amplifier. At $13k, the Liszt Sonata is expensive but compared against far more expensive brands, it proved to be a excellent product. Considering the “less is more” approach here: no preamp, along with fewer components, cables and AC cords in the signal path. The Audio Note Kondo Overture integrated amplifier is the best integrated amplifier I’ve heard thus far, but it costs $20k more ($33k). The Liszt Sonata, performance-wise, possesses about 95-percent of the mighty Overtures sonics, yet offers up a far greater price/performance ratio. In the final analysis, I found the Liszt Sonata to be a sonic knockout with an asking price that can honestly qualify as affordable. It’s simply that good and hereby highly recommended!