Featuring new monochromatic chassis styling derived from the REF250 and REF150, the ‘750 has a slightly wider, close-fitting anodized front panel with new silver side panels. Aluminum buttons and twin analog meters have replaced the knobs and fluorescent display of the 610T – one for output bias adjustment and monitoring power output, the second for line voltage.
The appearance is more refined and attractive, but is clearly a statement piece from Audio Research. A new, optional 12V fan-cooled silver top cover is available at additional cost. Using the now-standard KT120 output tubes (8 matched pairs, driven by another matched pair) in the classic Audio Research push-pull Class AB output stage, the input stage has been streamlined, using very low noise jFETs mated to a 6H30 twin triode follower. A 6H30 driver and 6550WE regulator provide regulation of the power supply.
Meanwhile, power-supply energy storage has been increased by 30%, to 1300 joules! A meter for tracking tube hours has been conveniently added to the back panel of the chassis, along with jacks for the optional top cover. Handles are positioned fore and aft for easier lifting and movement during installation. Because all Reference amplifiers are fully balanced from input to output, the input is XLR-only. There are 4-,8-, and 16-ohm output taps. As on other REF amps, there is a 20A IEC connector.
Sonically, the REF750 is simply the most breathtaking power amplifier ever produced by Audio Research. The sense of fluid ease, spectral coherence and unlimited dynamic range is immediately apparent – and the degree of sheer improvement over the previous 610T is enormous. If you are familiar with how much the REF250 advanced beyond the 210 in sonic virtue, you have but a glimpse of what to expect from the REF750. It is an experience you will not soon forget, and one that will plant you in your listening chair whenever the power is engaged. The REF750 is a serious amplification system for the listener who is ultimately serious about the fidelity of music playback. These amplifiers can be described in no other way that will do them justice. They are big, they are heavy, and yes, they are expensive. But they elevate music to a new level of truthfulness and passion, connecting listener and performance.
