M7 Heritage

An immovable faith, an unstoppable attitude.

Classic M7 preamplifier was released in the late 1980s. It gained fame along with the legendary power amplifier ONGAKU.

While maintaining the emotional sound impression of this preamplifier, it was polished with updated crafts and technologies. Base on a well-thought-out circuit and high-quality parts that were inspected further by our eyes and hands, performance is improved and matching with modern systems is also improved.

On top of specification, wide and stable sound stage, lively emotions, and low noise level are realized.

Phono amplifier unit

The modularization of the phono amplifier realizes advantages of both handwiring and short signal paths comparable to PCB. The signal loop is minimized by placing a decoupling capacitor near the module independently.
The SRPP circuit of ECC803S (12AX7) are adopted for the first stage. 6072 (12AY7) are used for plate follower, cathode follower of the second and the third stage. It achieves a highly accurate equalization with both vivid and quietness.

Line amplifier unit

The line amplifiers are also modularized like a phono amplifier unit, and the decoupling capacitors are located near right and left independently.

Direct couple of plate follower and cathode follower using 6072 (12AY7) achieves the lower output impedance 500Ω and 18Hz cutoff frequency (at 20kΩ load). It has strong driving capabilities.

Power supply, the shunt heater circuit

Rectification tunes is 6CA4. The power transformer and chokes are arranged so that minimum vibration is obtained. 3 kinds of decoupling capacitors are selected for well balance of tonal characteristics. Power supply is strengthened by clearly separating the ripple filter capacitors and decoupling capacitors.

Combining capacitor groups and a newly developed shunt type DC heater power supply circuit, ripples at power line is highly eliminated and heater voltage is regulated within ±5%.

Ultra-high-quality parts

Audio Note original silver foil capacitors, original electrolytic capacitors, silver lead resistors, SSW wiring material, copper main chassis, interconnect KSL-VzII, original RCA Jacks, original power transformers, chokes and a lot. Other parts such as market capacitors and resistors are selected carefully for each specific positions.

Przewód zasilający

Basic structure: Pure silver 4 cores, braided shield
Core structure: 40 strands (2 diameters) with cotton windings
Length: Standard length are 2m

Dane techniczne

Typ Przedwzmacniacz stereo + phono
Wzmocnienie 25 dB (wejście liniowe → wyjście liniowe),
63 dB (wejście gramofonowe → wyjście liniowe)
Pasmo przenoszenia 8 Hz – 280 kHz (+0 dB, -3 dB / przy
obciążeniu 100 kΩ, niezbalansowane)
Wejścia / impedancja Phono RCAx2, niezbalansowane/47kΩ,
Line: RCA 3 pary, XLR 1 para, niezbalansowane / 50 kΩ
Wyjścia RCA x2, XLR x1 (niesymetryczne, obciążenie >20 kΩ)
Szum <0,15 mV (line), <5 mV (phono)
Lampy ECC803Sx2, 6072×2 (Phono), 6072×4 (line), EZ81x1
RIAA ±0,3 dB (30 Hz–20 kHz, z wyłączeniem LCF)
Zniekształcenia (THD) 0,07% (1 kHz, 1 V, część liniowa)
Pobór mocy 38 W
Wymiary (SxWxG) 438 x 160 x 330 mm
Waga 15 kg