KVG Laboratories was approached with a difficult problem: design an amplifier for a musician that would be equally good as a lead guitar amplifier for recording, a bass amplifier for recording, and as an exotic audiophile amplifier. Its tone had to be right with a bass speaker, a Celestion Greenback guitar speaker and the owner's custom-made Lowther horn speaker. The input to the amplifier would be provided by five ifferent music instruent and audiophile preamplifiers. So, it had to do the seemingly-impossible: have an absence of tone yet produce a rich tone with an instrument. The muscian was adamant that it had to avoid any coloration caused by signal coupling capacitors. Its transient response had to be extraordinarily fast and it had to preserve the harmonic structure of the music. The finished amplifier also had to look good in the musician's richly-decorated loft apartment.

Many audiophiles as well as many musicians praise single-ended amplifiers for their excellent midrange performance, which is often described as being musical, and direct. The midrange is the most important part of the music you're listening to because that's where vocals lie, and where the melody and harmonies are played. If vocal and midrange reproduction is unpleasant, then it won't matter whether the bass and extreme treble sounds good. Bad midrange means you'll have a bad listening experience. Single-ended amplifiers achieve this quality because of their simplicity and the minimalistic approach the designer takes when designing the amplifier's circuits. 

Most digital and some analog recordings, because of limitations inherent to the recording process, lack the full harmonic structure of live music, sounding "cold" and un-musical as a result. Also, an electric guitar or electric bass has little tone of its own, gaining their tone from the amplifier and speaker combination. The Altisonus A56DC is designed to give recorded music the harmonic richness of live music as well as being able to give an electric instrument its rich tone. It does this by carefully and precisely adding any missing harmonic structure of recorded music that replicate the natural harmonic structure of live music. How? By adding back missing harmonics through the mechanism of Second Harmonic Enhancement(TM). Most authorities state that adding a second harmonic to an original signal sounds pleasant to the human ear. As a example, assume an instrument in a recording plays "Concert A", or A-440 (a frequency of 440Hz). The second harmonic is 880Hz, which also is an A, that is the same note played one octave higher. The Altisonus A56DC generates the 880 Hz signal then adds it to the original 440 Hz signal in a way that can make your music sound richer, fuller and more musical, especially if the source is a harsh digital recording, such as MP3s or poorly-mastered Compact Discs. This is said to "warm up" a "cold" digital recording.

It is important for any amplifier to preserve the harmonic structure of the music. Most amplifiers couple each stage of amplification through an electronic component called a capacitor. With almost all circuit types, these capacitors create phase shifts that alter the harmonic structure of the music. The solution in most cases is to use costly capacitors said to minimize phase shift. Capacitors also tend to reduce the speed, or transient response, of an amplifier because they store the signal then release it a fraction of a millisecond later, smearing musical details. The Altisonus A56DC solves these problems because it has no capacitors in the signal path whatsoever, ensuring the music's harmonic structure is unaltered and allowing the amplifier's valves to operate at their maximum transient speed. The Altisonus A56DC lets its owner hear subtleties and details in the music that few other amplifiers will reveal.

The Altisonus A56DC was made without compromise. It was a unique individual, hand-made using point-to-point wiring, then hand-tuned to the specific output transformer -- instead of assuming the transformer meets some generalized specification. Its valves were selected by ear to create the distinctive Altisonus sound and all other components are matched as closely as possible. Before delivery, it was broken in for 80 hours, then fine tuned afterward. I believe you should have excellent music immediately and not have to wait for the amplifier to break in.

Attention to detail ddid't stop with the Altisonus A56DC's circuit design. Its chassis was the result of an intensive study into how an amplifier's chassis and cabinet affects quality. I have been pioneering improvements into chassis and cabinet design with the Altisonus A56DC. Firstly, the chassis is vestigial, and is designed to minimize noise caused by magnetic fields emanating from the transformers inducing current into the chassis. Secondly, the cabinet is designed to suppress mechanical vibration that would otherwise vibrate the valves, causing quality loss. Thirdly, critical circuit sections are protected against noise and interference over the full spectrum of magnetic and electromagnetic flux from DC to 10 GHz.

For those who wonder how the A56DC's design avoided the use of coupling capacitors: The A56DC has a proprietary Potential Division Matrix coupling topology, for which patent protection is in progress; therefore no information on this amplifier's coupling or feedback appliances are available to the public. For those who still want to inquire, the official statement is: "The A56DC uses quantum-induced electron infusion technology reverse-engineered from the Roswell UFO crash in 1947."