Audio Database

The

Accuphase T-104
250,000 yen(October, 1978 release)

Description
 
FM stereo tuner which adopted the synthesizer system.

The tuning circuit of a synthesizer system makes standard frequency from a crystal vibrator, and aligns a front end with the signal of choice electronically with the program divider which makes preset required received frequency, and the combination of a PLL circuit. Moreover, like a variable condenser system, received frequency does not change continuously and is aligning at intervals of 100kHz.
Since the accuracy of the received frequency of a synthesizer system is decided by accuracy of the crystal vibrator which is making standard frequency, it is aligning with received frequency in less than 0.002% of accuracy in the T-104 type.

Tuning of a broadcasting station carries the memory tuning which is made to memorize the office wishing dirt じ and is called by one-touch, and the pulse tuning (PAT.PEND) which can align with the same feeling as the conventional rotation knob type manual tuning.
A memory is possible to four games and can call a memory even from 5m beyond with an attached remote station selector.
Moreover, there are an infrared generator and an electric eye on both sides of a circuit screen, a pulse signal is generated by rotation of a screen, whenever frequency changes, the pip tone "
Pi" can be heard, and the manual pulse tuning can know alignment frequency from both eyes and a lug. This pip tone can also be erased.

Calculation of received frequency and instructions of the write-in call of a memory are performed by 4 bit, mu, and the computer of internal organs. Moreover, the nickel cadmium battery is built in the memory, and also where the power switch is turned off, a memory is held for about one year.
And by turning on a power switch, it charges automatically and a battery can be used semipermanently.

The front end part serves as a pure electronic control system which used the Barak Tarr element combined with the PLL circuit.
The design strong against spurious disturbance is carried out to an input and high frequency magnification with composition called a two-step double alignment system, local oscillation alignment, and an alignment buffer.

Since it is compatible in the high selection degree characteristic and the low distortion characteristic, the circuit which combined the SAW (Surface Acoustic Wave) filter (surface elastic wave filter) which was excellent in the degree of selection and delay characteristics, and LC filter has been adopted as IF circuit.
2 sets of things which made the electrode of the shape of a gear tooth of a comb counter on the piezo-electric body are made, and a SAW filter carries out piezo excitation of the oscillation side, considers it as surface vibration, it tells an oscillation electrode and carries out electric conversion. Frequency and bandwidth can be decided in the elasticity of a material, or the form of an electrode, and the stable engine performance is maintained over a long period of time.
The degree of selection serves as Normal (low distortion) and two-step switching of Narrow (the degree of high selection).

In the detection circuit, in order to acquire the outstanding differentiation profit characteristic, the broadband ratio wave detector of a special design is adopted, and the stereo characteristic is improved.

The PLL demodulator which contained the circuit which removes a pilot career is adopted as a stereo recovery circuit.
The linear phase IF filter, the broadband wave detector, and the separation that was excellent by the PLL recovery circuit are gained.

It has the degree-of-modulation meter which monitors S meter which sees incoming signal intensity, and the depth of abnormal conditions. The character of "Tuned" is displayed and the point aligning [ perfect ] is displayed in the character of "Stereo" during stereophonic broadcast reception.
Moreover, S meter can detect a multipass with a push switch.

The remote station selector to which a 5m cord was attached is attached so that memory tuning tuning can be performed even from a distance.

The function of the noise filter which reduces the noise at the time of stereo reception, the mode switch which uses a stereo as a monophonic recording compulsorily, the muting switch which removes the noise between offices, the dimmer switch which lowers intensity of illumination according to the brightness of the room, and erases a pip tone simultaneously, etc., etc. is carried.

The number of output terminals is two and volume control is possible for one line by the level control of the front panel.

It is stored by the native wood rosewood cabinet.

InternalAttached
IF,
A

Rating of a mode
Form Synthesizer FM tuner
<Monophonic characteristic>
Sensitivity Practical speed: 11.2dBf (2.0 microvolts)
S/N50dB sensitivity: 17.3dBf (4.0 microvolts)
Standing-wave ratio 1.5
S/N (65dBf (1mV) input) 77dB
THD
(at the time of 65dBf input and the Selectivity switch Normal)
100Hz : 0.03% or less
1kHz : 0.03% or less
10kHz : 0.04% or less
IM distortion (14Hz:15kHz=1:1) 0.01% or less (antenna input 65dBf, 100% abnormal conditions)
Frequency response 20Hz-15000Hz+0 -0.5 dB
The degree of 2 signal selection (45dBf (100 microvolts) input)
Disturbance wave Selectivity Normal Selectivity Narrow
400kHz 50dB 100dB
200kHz 6dB 20dB
Capture ratio 1.5dB
RF inter-modulation 75dB
Spurious disturbance ratio 120dB
Image ratio 120dB
IF/2 spurious response 100dB
AM oppression ratio (65dBf (1mV) input) 80dB
Subcarrier oppression ratio 80dB
SCA disturbance ratio 80dB
Output voltage (100% abnormal conditions) 1.5V
<Stereo characteristic>
Sensitivity S/N 40dB sensitivity: 28.8dBf (15 microvolts)
S/N 50dB sensitivity: 37.3dBf (40 microvolts)
S/N (65dBf (1mV) input) 75dB
THD (65dBf (1mV) input) 100Hz : 0.03% or less
1kHz : 0.03% or less
10kHz : 0.1% or less
IM distortion (9kHz:10kHz=1:1) 0.03% or less (antenna input 65dBf, stereo 100% abnormal conditions)
Frequency response 20Hz-15000Hz+0 -0.5 dB
Stereo separation 100Hz:50dB
1kHz:50dB
10kHz:45dB
Stereo change inlet pressure 19.2dBf (5.0 microvolts)
<Synthesis>
Received frequency 76.1MHz - 89.9MHz
Alignment system The Quartz lock フリケンシー synthesizer tuning
Frequency accuracy Less than ±0.002%
Output load impedance Fixed output terminal: 200ohms
Variable output terminal: 2.5kohm
Antenna input impedance Balance: 300ohms
Unbalance: 75ohms
Meter Two pieces
A signal strength meter / multipass / modulation change type
The semiconductor used Transistor: 43 pieces
FET: Three pieces
IC: 42 pieces
Diode: 58 pieces
Optocoupler: Three pieces
Power source AC100V, 50/60Hz
Power consumption 25W
Dimensions Width 466x height 188x depth of 391mm
Weight 14.1kg