Fet Valve Ultra 550 Amplifier

Price: $2199 Circuits: Fet Valve Chassis: AVA Amplifier Options: International Transformer $55

For anyone loving real acoustic alive music, our just upgraded hybrid vacuum tube design is the best possible choice.

We have spent the past two years analyzing amplifier performance and the Fet Valve Ultra 350 and Ultra 550 are the result of our engineering and listening evaluations. 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.

The Fet Valve amplifiers are our highest expression of hybrid design, blending the best of vacuum tube and solid state technologies. All of the basic design concepts are uniquely ours - sixteen patent claims have been allowed. We designed and built 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 size and the performers are real.

Our hybrid vacuum tube design sounds so real because it lets the individual 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. Vacuum tubes, however, cannot drive difficult loads. They have very limited output current and get in big trouble trying to drive feedback loops, stray internal capacitances, 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 MOSFETs are super current amplifiers. They can 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 MOSFETs for current amplification duties. There simply is no roughness or compression in Fet Valve amplifiers.

Our power supply features a shielded toroid power transformer and separate regulated 12 volt heater supplies for each vacuum tube. The tubes see no AC ripple at all and thus have vastly extended service lives. There is a separate six stage power supply for the active circuits with isolated regulated high speed analog supply sections for each tube and hybrid section of each channel.

Unlike other tube-MOSFET hybrids, our tube sections do not have to directly drive MOSFETs connected to real world loads, thus the tubes never load down as they are doubly isolated from the real world. The promise of true hybrid design is realized in your music system, not just on paper.

This stunning amplifier is for those demanding musical reproduction that is not reproduction at all, but is best described as a ticket to the performance. You are going to want to dress up and be handed the program before touching the power switch (it really raises the curtains) and then watch the concertmaster rise and the conductor stride in. Close your eyes and you are there.

Fet Valve Ultra 550 hybrid vacuum tube amplifier. 250 watts per channel 20 to 20 kHz at less than 0.01% THD. 17" wide, 13" deep, 7" high. Shipping weight 38 pounds. All new AVA designed black chassis with black anodized faceplate and high efficiency black anodized extruded rear mounted heat sinks with 12 high current TO-3 case power MOSFET output devices. For 2 ohm loads and up.

	U550-inside	U550-inside
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