Proceed HPA-3 Power Amplifier by Mark Levinson

Madrigal Audio Laboratories Proceed (Mark Levinson companion brand) HPA-3 3-channel Power Amplifier: -Rated for 250W/ch at 8 ohms doubling into 500W/ch at 4 ohms which just hints at its reference level of current delivery. -Built like a tank with massive transformers for each channel resulting in a shipping weight of 115 lbs. There is a lot of conversation/information and praise online on the Proceed line of amplifiers with Mark Levinson heritage. To my ears, they sound most importantly cohesive and natural as well as effortless. Please see the pictures for this well-cared lightly-used unit that comes in its original box and packaging with all original accessories/contents. Please add only 1.4% to the price if you would like to pay via Credit Card or PayPal in light of mutual convenience. I will also be selling the accompanying HPA-2 2-channel power amplifier and the AVP2+6 preamplifier/processor. Thank you for your interest. SPECIAL DESIGN FEATURES: -Triple monaural design: Consistent with the finest amplifiers, each audio channel of your Proceed HPA 3 has its own, dedicated power supply—including a separate 663 VA toroidal transformer for each channel. The resulting reduction in crosstalk between audio channels provides superior imaging and reproduction of acoustic space. Demands placed on one channel have virtually no effect on the performance of the other channel. -Low impedance power supply: A critical factor in the ultimate performance of an amplifier is its “power supply impedance,” which can be loosely thought of as the freedom with which the audio circuitry has access to the power it needs, when it needs it. The design of your Proceed amplifier has addressed this important characteristic in a comprehensive fashion. For example, the power supply capacitors (which act as “reservoirs” of power for the amplifier circuitry) are mounted directly to the printed circuit board rather than using point to point wiring. The layout of the circuitry uses short, thick traces for high current paths. This attention to detail yields an optimal environment in which the amplifier may operate to its maximum potential. -Balanced inputs: Each channel of your amplifier is individually configurable to receive either balanced or single-ended inputs. This approach allows you to take full advantage of the greater immunity from noise, RFI, and EMI which balanced transmission of audio signals offers on any preamp-to-amplifier connection where it is supported. At the same time, any or all channels of the amplifier may be configured for single-ended inputs to maintain compatibility with the majority of preamplifiers available today. The gain structure of the amplifier adjusts automatically when you select different inputs to facilitate this “mix and match” approach. -Robust output stage: Each channel of your Proceed amplifier uses twelve 150 watt power transistors. These transistors are all individually tested and sorted, and are used in matched sets to ensure that no one transistor bears a disproportionate part of the overall load. The combination of an “overbuilt” design specification and extraordinary attention to detail in manufacturing improves performance, reliability, and longevity. -Extensive protection: Your Proceed amplifier will shut itself down if it senses either the presence of either DC (direct current) or a short circuit at the output, or any unsafe operating temperature. In any case, a power relay will cause the amplifier to be disconnected from the AC mains. In addition, the AC input to each transformer is fused to protect against any possibility of component-level failure that could draw dangerous amounts of power. Finally, inrush limiting prevents premature aging of power supply components during power-up. Once the power supply has been charged, this in-rush limiting circuitry effectively defeats itself to allow unfettered power supply access to the AC mains. SPECIFICATIONS: Rated power output: 250 w/ch rms @ 8, all channels driven, 20 Hz–20 kHz with no more than 0.1% THD 500 w/ch into 4 Frequency response: within 0.15 dB from 20 Hz to 20 kHz Signal to Noise ratio (main outputs): better than –80 dB (ref. 1 w) Input impedance: 100k(balanced) 11k(single-ended) Voltage gain: 23 dB (balanced) 29 dB (single-ended) Input sensitivity: 3.17 Vrms for full rated output (balanced) 1.586 Vrms for full rated output (single-ended) Power consumption: less than 125W in standby less than 200W when fully on and at idle less than 2500W maximum Mains voltage: determined by the needs of country for which the unit was manufactured; cannot be reset by dealer or user Overall dimensions: 17.26" W x 6.53" H x 19.55" D Shipping weight: 115 lbs. (52 kg) Connector Complement: two binding posts per channel one 3-pin XLR balanced input connector per channel one RCA input connector per channel two 1⁄8" mini-jacks for remote turn-on and loop-through two RJ-45 modular connectors for PHAST™ communications one IEC AC mains connector Output impedance: less than 0.05, 20 Hz – 20 kHz