Audio Database

The

SANSUI AU-8500
118,000yen(around the 1973 time)

Description
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The Integrated Amplifier of the tone-quality serious consideration design which inherited the basic performance which was excellent in AU-9500 which made full use of the Audie technology of an SANSUI, and was completed in pursuit of the basic performance to the limit.

Full use of the material and technical expertise which were selected carefully was made, and low-distortion-ization of stability or a high fidelity play in a large play band is measured.
Circuitry serves as a whole page hardwired-connection OCL pure complimentary scheme which adopted the constant current drive system as the predrive stage and with which it adopted the parallel push-pull circuit of Tsuyoshi Oide and a low distortion as the output stage.

The special feature of a parallel push-pull circuit is that the linearity of the current characteristic of a power transistor can choose and use a good fraction. Moreover, since the large-sized heat sinker is adopted, heat-dissipation quantity value is good and the stable low distortion operation is obtained by the Oide power.

A power transistor and the predrive stage are used as another power source, and are making the predrive stage drive on a high voltage.
Furthermore, the drive stabilized regardless of the load variation by making the stage of a drive into a three-step Darlington connection etc. is possible.

There is the phase margin as one measure to measure the stability of amplifier. This is judged by in [ less than ] what times a phase is from the stability limit, when the feedback gain of the amplifier itself is lost.
In AU-8500, the large enough phase margin is taken not only to super-low-pass one but to a super-high region, and the stability under all load-intensity requirements and the robustness are improved from the equalizer part to the main part.

The equalizer circuitry has realized 300mV of maximum permissible inputs by the high voltage supplied from two constant-voltage regulated power supplies, the three-step direct coupling system of a low-noise transistor, and +-.
Moreover, RIAA deflection used a low-noise transistor, little resistor with error, and a capacitor for the element, and has guaranteed the value of }0.5dB in 30Hz - 15kHz.
The it1 noise generated at the time of a switchpoint switching used +-power source, and has prevented it by setting base potential of the first rank to 0.

The good large-sized power transformer of a regulation and the capacitor of 15,000 micro Fx2 are used for a power-source part, and stable +-power source is supplied to it.

The protection network which combined the relay and the electronic circuitry, and the double protection network which uses an immediate judgment fuse are adopted. Furthermore, the current limiter circuit restricted so that the collector current of an output stage and the driver stage may not flow more than fixed by an overload is built in, and a power transistor is certainly protected in accordance with four immediate judgment fuses.
Moreover, a transient cancellar circuitry is offered on a pre out, and further, since the relay circuit serves as the audio muting, the unpleasant pop noise at the time of power activation does not generate it.

Using a positive rotary switch of operation, low and loud sound are carried by }15dB by step 3dB, and inside sound carries T.T.C. (triple tone control) in which variable [ of }5dB ] is possible at a 1dB step.
T.T.C. Amplifier adopts low-noise FET of a high input impedance as the first rank, and serves as NF type of the three-step hardwired connection and the two-step hardwired-connection circuitry.

A switching (750Hz, 1.5kHz, and 3kHz) is possible for the frequency point of an inside sound coordination. Moreover, it has a defeet switchpoint and a flat property is also acquired.

The exclusive active filter circuit system of 12 dB/oct is adopted as a row / high filter.
In a 12kHz cut-off frequency, the surge in a mid range is not generated in a 50Hz cut-off frequency, and a high filter does not generate a low filter.

A tapes monitor circuitry is two lines. If there are the two decks, either can also perform tapes reprint and the monitor under reprint can also be performed.

4ch adapter circuitry is carried.

The noise reduction (N. R.) adapter interconnection circuitry is carried.

The muting switch of a 20dB damping is carried.

5 position mode selector of Stere Reverse, Normal, Mono L+R, L, and R is carried.

The loudness switchpoint is carried.

The headset jack is carried two lines and one sound of a speaker of them goes out.

A three-line interconnection is possible for a speaker system.

The input impedance of Phono2 is switched to 30kohms, 50kohm, and 100kohm.

The level adjuster which can unify each input level is attached to Deck1, 2, and AUX.

High impedance type mike input termination.

Four AC outlets are carried.

The thumb of an aluminum Naked with a sufficient feel is adopted.

Rear Equalizer
Internal

Rating of a mode
Form Integrated Amplifier
Output power (rated distortion)
Effective output (both channel operation, 20Hz - 20kHz) : 60W+60W (8ohm)
Effective output (both channel operation) : 90W+90W (4 ohm, 1kHz)
64W+64W (8 ohm, 1kHz)
Effective output (one-side-channel operation) : 110W/110W (4ohm, 1kHz)
70W/70W (8ohm , 1kHz)
Music power (IHF) 240W (4 ohm, 1kHz)
180W (8 ohm, 1kHz)
THD (Output power) Preamplifier part: 0.05% or less
Main-amplifier part: 0.1% or less
Synthesis: 0.1% or less
Cross modulation distortion (Output power) Preamplifier part: 0.05% or less
[70Hz:7kHz=4:1, SMPTE]
Main-amplifier part: 0.1% or less
Synthesis: 0.1% or less
Power Band Width 5Hz - 40kHz (IHF, rated distortion)
Frequency characteristic (at the time of 1W output) Main-amplifier part: 3Hz - 50kHz, and +0 -1 dB
Synthesis: 15Hz - 30kHz, +0.2dB-1dB
RIAA deflection 30Hz - 15kHz, }0.5dB (Phono1, 2)
Load impedance 4ohm-16ohm
Dumping factor 50 (8ohm)
Input sensitivity/input impedance
(1kHz)
Phono1:2.5mV/50kohm
Phono2:2.5mV/30kohm, 50kohm, 100kohm
[maximum permissible input 300mV, THD 0.5%or less]
MIC: 2.5mV / 50kohm
Tuner, AUX(level adjustment is possible):100mV /, 50kohm
Tape Monitor1, 2 (PIN) (level adjustment is possible):100mV / 50kohm
2 (DIN):100mV of Tape Monitor / 50kohm
4ch, N.R.Adaptor:100mV /, 50kohm
Main Amp: 800mV / 50kohm
An Output voltage/Output load impedance Tape Rec1, 2 (PIN):100mV / 1.5kohm
2 (DIN):30mV of Tape Rec / 70kohm
4ch, N.R.Adaptor:100mV /, 1.5kohm
Preamplifier (Output power): 0.8V/1.5kohm
[maximum output and THD 0.5%or less] :5V
Crosstalk (Output power 1kHz) Phono1, 2, MIC: 50dB or more
Tuner, AUX: 50dB or more
Main Amp: 60dB or more
A hum and a noise (IHF) Phono1, 2:75dB or more
MIC: 65dB or more
Tuner, AUX: 85dB or more
Main amplifier: 100dB or more
Tone control Bass: }15dB (20Hz), a 3dB step
Midrange(Defeat, 750Hz, 1.5kHz, 3kHz): }5dB (1.5kHz), a 1dB step
Treble: }15dB (20kHz), a 3dB step
Loudness (volume-30dB) 50Hz:+10dB
10kHz:+8dB
A low filter 50Hz:-3dB(12dB/oct)
A high filter 12kHz:-3dB(12dB/oct
The semiconductor used Transistor: 58
FET:2
Diode: 33
Zener diode: Five
Power dissipation 140W (a maximum of 450 VA)
Dimensions Width 500x height 140x depth of 347mm
Weight 20.5kg