Description

Tested and working great. Local pickup in nyc available From Audio Research: We call it "Hybrid Drive" because that's how it works. As in the Reference 110, a JFET input (for low noise) feeds a 6922 dual triode gain stage, which in turn feeds a 6H30 dual triode cathode follower which drives the outputs through our proprietary coupling capacitors (first used in our Reference 3 preamp). This vacuum-tube input / driver arrangement sets the stage for superbly musical performance and a nuanced, lifelike character at the front end of the amplifier. The output stage is comprised of twelve Thermal Trak® bipolar output devices per channel, producing 220 WPC into 8 ohms, and nearly 400 WPC into 4 ohms. These new devices have the unique ability to automatically adjust their internal bias in response to operating temperature, thereby assuring extremely consistent output performance no matter how hard the amplifier is pushed. Low-noise fan cooling of the output stage keeps the output devices within their operating range. Power supply regulation is all solid-state to assure stability and consistency under high-current-demand loads, and power supply energy storage is a startling 200,000 mF capacitance for explosive dynamics and rock-solid bass impact and control. One look under the cover tells you that the HD220 is all about performance. In performance, as always, your own ears will be the final judge. But we honestly believe that this unique amplifier represents the highest level of sonic performance we have yet experienced from any solid-state or hybrid design. Its musicality is superb, with a degree of transparency and grain less purity that is nothing short of eerie, thanks in large part to extremely low distortion and a low noise floor. Dynamics and bass control are thunderous and controlled, whether driving dynamic or planar-type loudspeakers, thanks to the Thermal Trak® output stage. In short, the HD220 gives you the finesse and nuance for which tube amps are famous, with the consistency and speaker control under high-current-demand conditions that solid-state amps excel at. This HD220 simply goes and goes and goes.