CH Precision A1

This is a fantastic sounding amp that has been operating trouble free for me since I bought it a few years ago. It was awarded The Absolute Sound Editor’s Choice, each of years 2015 – 2017. Even the A1.5 that replaced it (and sells used for $30K) is a similar design, just with a bigger chassis, a bit more power and some enhanced capacitors and a few other changes.
The A1 supports more output adjustments than most amps, at the press of a few buttons on the panel. Besides stereo, it can be set for bridged mono operation or for bi-amping, with input level matching over 24DB in .5DB steps. I used reduced input gain to allow my Berkeley Reference 2 DAC and Cardas XLR cables to benefit from higher output levels with less overall noise. There are also settings to adjust the amount of global and local feedback in the circuit. The panel can be set to rapidly and continuously show you the output wattage digitally.
Sonically, the most striking thing about this amp is the clarity and natural sound, especially at all levels up through 100 watts (it can produce spikes at 300 watts just fine as well). It has some of the most seemingly distortion free sound and fine detail I’ve ever heard, even at a fraction of a watt. And the outstanding detail and clarity comes in a relaxed sounding atmosphere, without glare.
The A1 is not often available for sale, with owners hard pressed to improve on it without spending 50-100% more. One A1 recently sold on Audiogon for $15K. You can get an outstanding buy on this specific unit because of a (to me) minor cosmetic faceplate issue. The dealer had dropped or banged the amp, causing a dent on one corner. They chose to get a machinist to create a ½ inch long triangular bevel on both bottom corners, blending in with the design. I purchased from the first owner that the dealer sold to, and have had no electronic or mechanical difficulties from this solid Swiss amp.
Read The Absolute Sound and Positive Feedback reviews (see the ch-precision.com website) for a better idea of this amp’s qualities. The A1 produces *exactly* what the source material is relaying, nothing more or less, including big dynamic swings, bass to 20 hertz and below, etc. From The Absolute Sound, the amp offers “linearity – in the frequency, time, and dynamic domains – and musicality in equal parts. The result is accuracy in the service of music, with plume-like orchestral colors, visceral transients, locked-down rhythms, and dynamics that range from subtle to epic. The amp makes it child’s play to follow musical lines and instrumental interplay.”
Local pickup in North San Diego area is preferred. I will work out shipping details (continental U.S.) for serious buyers. Shipping would be about 120 pounds via palette and lift gate, which could be $800 or more. Thank you!

Specifications
Analog Inputs
Inputs type: Balanced (XLR), one connector per board;  Single-Ended (RCA & BNC), one connector per board
Input impedance: Balanced: 94kΩ; Single-Ended: 47kΩ or 300Ω
Input stage: JFET input stage, Ultra-low noise, discrete fully differential stage, 24dB range adjustable gain in 0.5dB steps
Amplification
Amplification stage: Ultra-low noise full discrete class AB design, 5 pairs of complementary output transistors
Output Power: 2x 100W / 8Ω, 2x 175W / 4Ω, 2x 300W / 2Ω in stereo and bi-amp modes; 1x 175W / 4Ω, 1x 300W / 2Ω, 1x 550W / 1Ω in monaural mode; 1x 350W / 8Ω, 1x 600W / 4Ω, 1x 800W / 2Ω in bridge mode
Bias: Patent-pending bias circuitry for constant bias operation
Feedback: User-adjustable local vs. global feedback ratio, from 0% to 100% with 20% steps 
Bandwidth: DC to 450kHz (-3dB) at 1W into an 8Ω resistive load
Signal to Noise Ratio: Better than 115dB in stereo and bi-amp modes; Better than 118dB in bridge mode
Total Harmonic Distortion + Noise: Less than 0.1% with 0% global feedback; Less than 0.01% with 100% global feedback
Binding posts: Two pairs of Argento binding posts for loudspeakers connection
Analog Outputs
Monitoring: Non-intrusive DSP-based protection of the amplifier
Instantaneous voltage & current values are permanently monitored for each channel
Protections: Short-circuit protected; Disconnected loudspeaker detected; Over-temperature of the heatsink; Over-temperature of the output transistors
Power Supply
Transformer: 1200VA single transformer, oversized for low-noise operation
Power capacitors: 2x 47000uF/63V 4-poles capacitors 
Regulators: Non-regulated symmetrical power supply for the power stages; Eight local regulation stages for input/driver stages; Seven local regulation stages for the logic/display
General
Display: 480×272 pixels, 24bits color, AMOLED
Mains operation: Selectable 100V, 115, 230V AC, 47-63Hz
Fuses value and location: Standby fuse (white holder): 250mA T (230V AC), 500mA T (100V AC, 115V AC); Power fuse (black holder): 10A T (230V AC), 16A T (100V AC, 115V AC)
Power supply consumption: <1W (standby), 1200W max in operation
Dimensions/Weight: 440 x 440 x 133mm (W x D x H), 45kg
Remote control: Ethernet based system control via the Android CH Control App