This thread is to discuss the Benchmark HPA4 Headphone Amp.
From the manufacturer:
Benchmark Media Systems, Inc. and THX, Ltd. have partnered to introduce the Benchmark HPA4 headphone/line amplifier featuring THX Achromatic Audio Amplifier (AAA™) technology.
THX AAA™ reduces harmonic, intermodulation, and crossover distortion by 20 to 40 dB to guarantee a realistic and fatigue-free listening experience. It accomplishes this using a patented feed-forward topology to null conventional distortion and noise mechanisms, resulting in the world’s most linear amplifier. THX AAA allows the amplifier to reach its maximum output power and sound pressure level (SPL) without producing the distortion that normally accompanies increased output levels in traditional amplifiers.
Featuring the flagship THX-888 amplifier design, the revolutionary HPA4 headphone amplifier incorporates the same THX AAAtechnology that Benchmark uses in the AHB2 power amplifier. The HPA4 delivers sonic perfection. Hear the music without any contamination from electronic noise or distortion. The HPA4 delivers power, audio fidelity, speed and accuracy over an utterly silent background.
The Ultimate Line Amplifier
The THX-888 amplifier is driven by a Benchmark line amplifier that features relay gain control, relay input selection, and relay muting. The line amplifier incorporates the finest gold-contact relays available. The gain control has 256 steps in 0.5 dB increments. It also features a balance control. Relay closures are precisely timed to deliver silky-smooth volume changes. No other relay gain control offers this level of precision and performance. The HPA4 includes 4 independent 256-step attenuators: two for the L&R headphone outputs, and two for the L&R line outputs. To make this all happen, the HPA4 includes a total of 64 precision relays.