Audio Database
M-1000
Commentary

This monaural power amplifier was developed as the first full-scale high-output power amplifier for consumer use for the new era of audio.
Not only high output but also high sound quality is emphasized, and the technology developed by AccuPhase is used to pursue maximum performance.

It is composed of a balanced system in which two push-pull drive unit amplifiers of all stages are bridge-connected to improve the performance.
By adopting a balanced method with a transmission system dedicated to plus and minus signals, in principle external noise is cancelled, and at the same time distortion generated in the amplifier is also cancelled by the output circuit, making it possible to extract pure signal components.

Each unit amplifier has a deluxe configuration of 14-parallel push-pull, and the output transistor is specified to have a collector loss of 150W and a total of 56 output transistors in two units.
In addition, a large solid aluminum radiator is attached, and it can be used without a radiator fan under normal conditions.

The output stage is arranged so that it can be switched to the operation state which matches each condition so that large power can be taken out in any load impedance.
By switching the low load impedance with the switch for switching the applied voltage, large currents of 1600W at 1 Ω load and 1100W at 2 Ω load can be extracted.

In order to improve the quality of the signal input amplifier circuit, we have adopted a class A cascode differential push-pull method at the input stage of all power amplifiers.
Cascode circuits are used for high-frequency amplification and other applications. Therefore, they provide stable operation over a wide frequency band, good input linearity, and a wide dynamic range.

The operating point is strictly set so that each element of PNP and NPN is not cut off by the input signal against the switching distortion at the small output generated at the output stage.
MOS FET equivalent to non-switching class A drive is used for the front stage driving the last stage. Moreover, it is composed of cascode push-pull. MOS FET is also used for the front stage driving the signal to this MOS FET.
This provides a stable output stage with little distortion from low output in the noise region to high output in the rated output.

The power supply consists of two independent transformers, which are connected in parallel for a total power supply of 3 kva.
As a result, the impedance of the power supply from the amplifier side is halved and the maximum power capacity is doubled.
The filter capacitor is also equivalent to a power supply of 66000 μ Fx2.

The output meter is equipped with an analog meter of peak display type and a digital meter that displays the true value of power.
The analog method displays the power dB scale and the equivalent power by peak value.
The digital meter detects the true value of the voltage and current supplied to the speakers, uses an analog multiplier to determine the power and displays the true value.
The display range is 4 digits and there are 5 positions of 2W, 200W, 2000W and 10000W maximum range switching. The hold time is 4 positions of 0.5 seconds, 3 seconds, 75 minutes and infinite.

The inputs are equipped with balanced and unbalanced inputs. These inputs can be selected by the switch inside the front sub-panel.

There is no need for a heat radiation fan under normal operating conditions. However, a fan is sold separately for setting in a place where heat radiation effect is bad or for driving a large output for a long period of time.
The fans are designed to fit inside the sideboards on both sides.

Natural Persimmon finished boards are used on both sides.

Model Rating
Type Monaural power amplifier
Continuous average power
(between 20 Hz to 20 kHz)
Normal Load Imp. Operation (0.01% distortion factor) 4 Ω : 1800W
8 Ω : 1000W
16 Ω : 500W
Low Load Imp. Operation (distortion factor 0.05%) 1 Ω : 1600W
2 Ω : 1100W
4 Ω : 550W
Total harmonic distortion factor 1 ~ 4 Ω load : 0.05%
4 ~ 16 Ω load : 0.01%
IM distortion factor 0.003%
Frequency characteristic 20 Hz ~ 20 kHz, ± 0 dB (Continuous Average Output, Level Control MAX)
0.5 Hz ~ 150 kHz, + 0 -3.0 dB (at 1W Output, Level Control MAX)
0.5 Hz to 80 kHz, + 0 -3.0 dB (Level Control -6dB at 1W Output)
Gain 28.0dB
Load impedance Normal Load Imp. Opaeration : 4 ~ 16 Ω
Low Load Imp. Operation : 1 ~ 4 Ω
Damping factor 200(EIA 50Hz)
Input sensitivity
Normal Load Imp. Operation 3.56 V (8 Ω load, continuous average output)
0.12 V (8 Ω Load, 1W Output)
Low Load Imp. Operation: 1.87 V (2 Ω load, continuous average output)
0.06 V (2 Ω Load, 1W Output)
Input impedance Unbalanced : 20k Ω
Balance : 40k Ω
S/N (A-corrected) 125 dB (Input Short, Continuous Average Output)
95 dB (Input 1k Ω, 1W output)
Analog type output meter Logarithmic compression peak display type
-60dB to + 3 dB and output direct reading scale
Digital output meter
Format True power display type
Display Range Direct reading of 0.001W ~ 9,990W by range switching
Significant digits 3.5 digits
Range 2 : 0.001 to 1.999W
20 : 0.01 to 19.99W
200 : 0.1 to 199.9W
2000 : 1 to 1,999W
10000 : 10 to 9,990W
Accuracy Less than 2 kW : 3% + / - 5 counts
2 kW or more : 3% + / - 50 counts
Hold time 0.5 bar, 3 seconds, 75 minutes, ∞
Semiconductor used 99 tr, 13 fet, 31 ic, 142 di
Pwer 100 V, 117 V, 220 V, 240 V, 50Hz/60Hz
Power consumption No input : 120W + 120W
Electrical Appliance and Material Control Law : 600W + 600W
8 Ω load rated output : 800W + 800W
External dimensions Width 481x Height 239 (Including Legs) x Depth 489 mm
Weight 47.2kg
Sold Separately Heat Dissipation Fan O-83 (¥ 10,000)