The Fet Valve R series of amplifiers represent our highest expression of hybrid design, blending the best of vacuum tube and solid state technologies.
Like its more powerful sibling, the Fet Valve 400R is the result of many years of refinements to our patented Transimpedance amplifier. With our innovations we have distilled these designs to remove the last bit of electronic sound from the music and present you with emotionally rewarding performance free of grain and glare.
All of the basic design concepts are uniquely ours with sixteen allowed patent claims. We design and build these lush, wonderfully transparent, and outrageously dynamic amplifiers to satisfy those who have never been satisfied with solid state alone. The sound stage is life sized and the performers are real.
The Fet Valve 400R amplifier is clear, pure, transparent, with even wider musical range and dynamics than the Synergy series, with the addition of the ability to capture the spirit and emotions of the music like nothing else, and weed out the nastiness at the same time. It appears that there really is something that a vacuum tube can do, when used properly, that makes all the work worthwhile.
For anyone loving real acoustic live music, our hybrid vacuum tube designs are the best possible choice. They can only be compared with live, and unless the live is very good (and performed without electronic sound reinforcement) our patented Fet Valve designs will actually give you better sound at home than you hear at the performance.
You will love them, satisfaction guaranteed, in writing!
Standard configuration includes gold plated machined RCA input jacks, 5-way gold plated speaker jacks, and external speaker fuses.
The faceplate is our silver 1/4" thick sculpted aluminum faceplate. A cost-saving 1/10" aluminum black faceplate with a rocker power switch is also available. Both faceplates feature our incredibly durable double anodized finish. Shipping weight 42 pounds.
Our single ended mos-fet/hybrid vacuum tube design used in the Fet Valve 400R sounds so real because it lets the audio gain parts each work in optimum environments. Vacuum tubes are great at manipulating voltages -- you can play with 200+ volt signals where transistors would go up in smoke and flames. So, we use vacuum tubes for all voltage manipulations; however, vacuum tubes cannot drive difficult loads. They have very limited output current and get in big trouble trying to drive feedback loops, stray internal capacitance, and connection cables, so, we don't let our tubes see any loads at all. They operate in an idealized mode amplifying voltages only, and do it perfectly.
Power mos-fets are super current amplifiers. They control great gobs of current without stress, and when properly selected and used, they perform without needing external compensation, thermal tracking circuits, or VI limiting and protect circuits. So we use all power mos-fets for current amplification duties. There is simply no roughness or compression in Fet Valve amplifiers.
The tubes are run under their maximum rating so that they provide long life and reliability. The output transistors are double-die lateral mos-fets that are extremely reliable and rugged. The lateral mos-fet transistors have a very fast slew rate, low distortion, and very high bandwidth that actually extends way beyond human hearing. The mos-fet transistors are not susceptible to thermal runaway, a significant issue plaguing bipolar transistor power amplifiers.
The Fet Valve 400R produces 200 watts per channel, 20 to 20 kHz into 8 ohms at less than 0.01% THD. Eight double-die output transistors, standard on the Fet Valve 400R, handle challenging speaker loads (2 Ohm loads and up).
Power Supply Circuits
By far the most important innovation is our capability now to offer high powered audio amplifiers with pure analog, high current, high power, high speed regulated output circuit power supplies. The Fet Valve amplifiers output power supply rails sit solid as a rock, unvarying at all between idle and clipping under all musical demands.
Now when the music signal says "do it" you can hear an amplifier that actually "does it" rather than one that "almost" does it as the supply rails sag and vary under load. The rubber is gone, the dynamics and transients are astonishing, and the clarity, without edge or grain or glare, is pure. For good reason "R" stands for regulated output supplies, for reality, and right too.
Not only do the output circuits have regulated power supplies, each 12AT7 tube has three independent regulated power supplies, one for each plate, and a third for the filament/heater. The high power, high current power mos-fet in the output driver patented transimpedance amplifier also has a separate regulated power supply. There are ten regulated power supplies in all, five for each channel. You have never experienced an amplifier with these capabilities before, and when you do, nothing else will suffice.
Our power supply features a high current shielded toroid power transformer capable of providing ample power for all the regulators. The amps are dead quiet and play music from a deep black background.
The Fet Valve 400R operates with standard 120 Volt power, has an IEC power jack, and includes a polarized 120V power cord. For international use a 240 Volt (50-60 Hz.) option is available at additional cost.
Dimensions: 17" wide, 13" deep, 7" high. Shipping weight is 38 pounds.