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M1A Monaural Power Amplifier

M1A with silver faceplate
silver faceplate
M1A back
M1A back
JAN 3 2012 +++++++.

Not fully updateable to the M2 circuitry and performance.

The 8th Annual Positive Feedback Online's Writers' Choice Awards for 2011 - The Best of the Best!

"Designed for music lovers, audiophiles have discovered they meet all of their needs and then some. Almost amazingly, the powerful though small and light weight power amplifiers are almost cool running though the audio quality that comes closest is only from so called "Class A" designs in my experience."

- Karl Lozier - Positive Feedback Online's Writers' Choice Awards for 2011 read the article

JAN 3 2012 +++++++.

The Amplifier
The M1A is a full complementary symmetry bipolar implementation and contains no coupling capacitors in the forward direction. It employs the latest technology in wide band output devices with enhanced low level linearity. Proper stage-to-stage impedance matching insures extraordinarily low distortion and a unique successive stage to output confluence provides a seamless combination of micro/nano-resolution from forward stages and robust controlled power and authority from successive stages. This unified current summation drive stage network eliminates the crossover notch problems common in many solid state amplifier designs. High idle current or class A bias output stage operation is not necessary! The M1A runs cool under most listening conditions and provides a live presentation with none of the hardness normally associated with solid state amplifiers. The output network of this amplifier is resonance free and remains stable even with a 1 micro-Farad capacitor connected across the output terminals. The M1A engenders the fine resolution and liquidity normally associated with tube amplification plus the power and bass control of solid state. Individual voices remain distinct and clear amidst the crescendo full orchestra and chorus. The sound of the M1A is pure and true to the source. It has the clarity, focus in time, and natural sound inherent in all Herron Audio products."

DC Response
The M1A incorporates automatic low level d.c. offset cancellation plus high level d.c. shutdown speaker protection circuits. The effects of continuous low level d.c. at the input of the M1A will be nulled out over time and higher levels of d.c. at the input will engage the shutdown protection.

The M1A has an oversized toroidal transformer capable of supplying enough current to power two amplifiers with the ratings of the M1A. This transformer is designed to have low losses and will run cool under all operating conditions.

Configuration Single-channel (monaural)
Frequency response 20 Hz to 20 kHz ±0.1 dB
Output Power 150 watts @ 8 ohms, 275 watts @ 4 ohms (measurements at 1 khz)
Gain 24 db
Input impedance 220k Ohms
Absolute polarity Non-inverting
Power Requirements 100, 120, 230, 240 VAC. 50/60 Hz. Standard IEC power connector. Toroidal transformer taps internally selected for appropriate voltage
Dimensions 17.6" wide x 4" high (including rubber feet) x 11" deep
Warranty 3 years, parts and labor

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