|500,000 yen(one set, the July, 1981 release)
Monophonic power amplifier which thought as important "the Output load impedance
of an open-loop is low", and "a large current supply power source and an output
stage", and was developed in quest of the ideal of power amplifier in order to
carry out the ideal drive of the speaker.
The output stage constitutes
the broadband bipolar transistor of Pc(collector loss)200W from a 12 parallel
push pull (a total of 24 output transistors). Thereby, all the electric power
capacities were set to 4.8kW, and have obtained sufficient margin.
order that an output transistor may improve the heat dissipation effect, it is
divided into 2 sets and attached to the large-sized heat sink on either side.
Since heat combination is not carried out, if it becomes imbalanced thermally,
the tendency will be accelerated, only one side is overheated, and both of heat
sinks develop into destruction of an element. In order to prevent such thermal
unbalance, the bias balance circuit is adopted. This circuit attaches to the
other party's heat sink the element connected to the base of an output element,
detects temperature, has the structure of controlling bias current, and is
carrying out operation stabilized by considering it as the mutual almost same
The drive stage consists of MOS FET for electric power
magnification which is the original of an Accuphase, and it has performed a low
impedance large current drive and improved the characteristic of a high region
Moreover, since a heat characteristic works in the
direction which stabilizes a bipolar transistor, the bias current of an output
stage is stabilized. for this reason -- it is possible to make emitter
resistance of an output stage low -- 12 [ furthermore, ] -- parallel more,
equivalent emitter resistance became low with 1/12, and the switching distortion
of it generated in order that the bias of an output transistor may cut off is
The predrive stage consists of cascode connection push pulls, and is reconciling the outstanding high region characteristic and large amplitude operation without a Miller effect.
Moreover, comparatively big
bias current is given to 24 output elements, and Output 5W has become a pure
Class-A operation domain.
The circuit is constituted from all the
traditional magnification stage push pulls of an Accuphase, and has improved
many characteristics of an open-loop to a limit.
The input is received by
dual FET and has adopted cascode bootstrap differential push pull composition.
While obtaining the big profit by cascode bootstrap, the high region
characteristic has been improved, and the distorted increase by the rise (change
of an input level control) of input impedance is prevented.
By the push
pull input circuit by dual FET, a direct current did not occur to an input but
the input capacitor can be removed. However, in this state, when the large
preamplifier of direct-current leak is connected, direct current occurs in an
output, and it has a bad influence on a speaker.
In M-100, while
intercepting a direct current, applying a direct-current return with
direct-current servo amplifier, direct-current drift generated in a circuit is
The peak power Direct-reading equipment by a digital
system is begun in the world, and it carries in power amplifier.
circuit, the output signal of amplifier was changed into the magnification which
is easy to read with a range changeover switch (Attenuator), and is inputted
into the peak wave detector. All the ripples by the side of + and - are arranged
with the direction of the + side here, the peak value of a signal is held at the
following step, the peak value is sent into a 12-bit A/D converter, and it
changes into a digital signal. A digital signal is inputted into a 4-bit
microprocessor, converts voltage into electric power by a microprocessor, and
displays the peak within a definite period of time on a choice and LED.
Moreover, the signal which tells what a setup and the reset signal which
newly starts a hold of hold time were generated, or the signal and display range
of a range change exceeded is also outputted from the microprocessor.
range change is four, x1, x0.1, x0.01, and x0.001, and, thereby, can carry out
the Direct reading of between 0.001W - 999W in triple digits.
It is 3/30
kind, and for 0.5 second and 3 seconds, if a range is used for 30 minutes, the
hold time can read the peak value of record one side, it is comparing with the
standard signal of a test record, and can know the maximum cutting level.
The outside 磁 type precision large-sized meter which can supervise an
output with dB and a watt value other than a digital display is carried.
Even -60dB (0dB=500W, -60dB=0.0005W) can be read with a logarithm
25 contact rotary switch for communication machines
and the full-scale step type Attenuator by high precision metal tunic resistance are carried.
-23dB, -26dB, -30dB, and -infinity can be chosen in the accuracy of ±0.1dB 0 - the 1dB step between -20dB, and henceforth.
low filter which cuts a low-pass unnecessary noise is carried.
The cutoff frequency can choose four kinds, 10Hz of a subsonic-speed domain,
17Hz, 30Hz that demonstrates power by business use, and 50Hz. Moreover,
as for the slope characteristic, all are -12 dB/oct.
These changes attached the relay only
for each frequency in the substrate circuit, and have controlled this relay with
the switch of the front panel.
The phase switch which reverses the phase of an output signal to an incoming signal is carried. It is possible for this to unite the phase between channels.
Moreover, bridge connection can be constituted using M-100 of two per channel,
and it can upgrade for 1.6kW of 8-ohm loads.
When using two or more
M-100, the hold start timing of a digital display will shift.
synchronized signal terminal for synchronizing this and carrying out a
simultaneous start is carried. Thereby, the timing of a relay of the output
circuit at the time of power-source ON-OFF can also be united with a digital
A 1.5m cable with a connector is attached, and there is also a 5m
cable as an option.
The input terminal carries the business-use canon
type connector besides the usual phono jack.
When installing in the bad
place of the heat dissipation effect, or when performing the Oide power drive
over a long period of time, the optimal fan for heat dissipation is an option.
The fan can attach with a rear panel.
The wood panel of persimmon
finishing of 24mm thickness is an option.
||Monophonic power amplifier
|Continuation average output
20kHz, 0.01% of distortion)
|THD (20Hz - 20kHz)
||0.01% (between 2ohm-16ohm, 0.25W - a
continuation average output)
|IM distortion (EIA)
||20Hz-20kHz±0dB (at the time of a
continuation average output level control MAX)
0.5Hz-400kHz+0 -3 dB (at the
time of 1W output level control MAX)
0.5Hz-140kHz+0 -3 dB (at EIA, the time
of 1W output level-control 6dB)
|Dumping factor (EIA)
||300 (50Hz, 8ohms)
||2.6V/20kohm (at the time of a continuation
0.12V/20kohm (at the time of EIA and 1W output)
|Input level adjustment
||Step type Attenuator
are [ 0 - the 1dB step between -20dB, and ] 25 contacts of -23dB, -30dB, and
Error: Less than ±0.1dB
|S/N (A compensation)
||130dB (at the time of a continuation average
output input short-circuit)
100dB (at EIA, the time of 1W output input
|A low filter
||10Hz/17 Hz/30 Hz/50 Hz, -12 dB/oct
|Power output meter
||A logarithm compression peak directions
type, -60dB-+3dB, and an output Direct-reading scale
|Digital power display
||It is a watt display about the peaking
capacity at the time of 8-ohm load.
|Display digit number :
|Display range :
||It is a Direct reading about 0.001W-999W by
|Hold time :
||0.5 second, 3 seconds, 30 minutes
|Frequency response :
||20Hz-20kHz+0 -0.2 dB
|Pulse reply error :
||It is +0 about 100Hz one wave. -0.4 dB
|The semiconductor used
||Transistor: 57 pieces
FET: Five pieces
IC: 21 pieces
Diode: 65 pieces
|Power supply voltage
||175W (at the time of no inputting)
(Electrical Appliance and Material Control Law)
780W (at the time of 8-ohm
load 500W output)
||the width 480x height 232(piece -- it
includeds) x depth of 476mm
||Timing cable (1.5m)
||Side wood A-14 (one set with attachment lug, 16,000yen)
Fan for heat dissipation O-81 (one set, 8,000yen)
Timing cable TC-11 (10m, 3,000yen)