Audio Database


Accuphase T-108
120,000 yen(April, 1990 release)

The synthesizer FM stereo tuner which concentrated the outstanding technology and was developed in order to realize the ultimate grade as a tuner.

Alignment by a crystal oscillator is used for alignment for tuning, and the gap by time or a temperature change has decreased. Moreover, the abnormal-conditions distortion and noise by external vibration are hardly made for electronic tuning.

Since it corresponds to many office-ization, a memory is possible to 16 games.
When an electric wave needs to turn ON a filter weakly by an office or the degree of selection needs to be changed, it is possible to set the function according to the radio wave state of the office beforehand.

Besides memory tuning, the manual alignment machine by the rotating knob of a pulse tuning system is carried.
This was developed especially as being the same as that of the Lord of electronic tuning, it produces a pulse, counts this pulse and is controlling alignment frequency by the radiate slit attached to the shaft of a rotating knob.

The input and magnification stage of the front end part used the mixer of double alignment composition and also frequency conversion as the differential FET balance abnormal-conditions machine which used the balun trans, respectively, and interference by the Dainyuu power disturbance is prevented.
Moreover, in order that the PIN diode Attenuator may be carried and the transmitting tower may operate as variable attenuator to near excess Dainyuu power, interference and distortion are not generated in any areas.

Little stable and distorted characteristic has been acquired by combining with the original DGL wave detector of an Accuphase the group delay flat IF filter chosen especially.
A DGL detection system is what paid its attention to the delay time of the output of a high-speed logic IC,A phase angle is delayed 114 degrees so that this may be made into 19-piece series and the minimum and S/N may become best about distortion,This group delay signal and incoming signal were applied to the exclusive OR circuit, the electric potential between two signals was chosen, circuit opening and closing were carried out, the compression wave of the signal wave produced by abnormal conditions was detected in digital one, and the audio signal is taken out. The linear region of a delay circuit is very as large as ±2.5MHz, and, moreover, the differentiation profit straight line characteristic of it having been stable and having excelled is acquired for a non-equalization circuit.
IF filter is using 2 sets, Normal and Narrow, and when contiguity interference is intense, sharp reception focused on a selection degree can be performed by changing to Narrow.

In the stereo recovery part, using the pilot signal for a synchronization included in the incoming signal, the internal oscillating circuit was locked by the PLL circuit, and the exact 38kHz switching signal has been acquired.
In T-108, the system which combined the positive/negative variable reactive circuit controllable on control voltage with a ceramic resonance child with the internal oscillating circuit of this PLL is adopted, and an exact switching signal is acquired in the lock frequency range narrower than before.
For this reason, in this circuit, no adjusting-ization of the stereo recovery circuit was realized, and the characteristic maintenance over a long period of time was attained, and also a temperature change and change of the separation rate by change of line voltage are almost lost.
Moreover, since the lock frequency range is narrower than before, the beat distortion in high frequency is decreased.

The first balance output circuit in a tuner is carried in the output terminal.

The check of incoming signal meter and a multipass is possible for meter by a changeover switch.
A multipass will indicate that a good electric wave is receivable by the multipass minimum, if a meter guide goes into the range of a clear mark.

The noise filter which reduces the noise of the weak stereo office of an electric wave, the muting switch which removes the noise between offices, the mono-switch compulsorily used as a monophonic recording, the output level control which unites volume with other program sauce, etc. are carried.

Remote control is attached so that it can be operated from the distant place.

Surface finishing is traditional champagne gold scratch hair line finishing, and supports both sides on the board of the natural persimmon.

Internal Front

Rating of a mode
Form Synthesizer FM tuner
<Monophonic characteristic>
Received frequency 76.1MHz - 89.9MHz
Practical speed 11dBf(IHF)
S/N 50dB sensitivity 17dBf(IHF)
Standing-wave ratio 1.5
S/N (80dBf input, A compensation) 90dB
(at the time of 80dBf input, ±75kHz deflection, and Normal)
IM distortion (80dBf input, ±75kHz deflection) 0.01%
Frequency response 10Hz-16000Hz+0 -1.0 dB
The degree (IHF) of 2 signal selection
Disturbance wave Normal Narrow
400kHz 70dB 100dB or more
300kHz 30dB 100dB
200kHz 10dB 40dB
Capture ratio 1.5dB
RF inter-modulation 80dB
Spurious disturbance ratio 120dB
Image ratio 100dB
AM oppression ratio (65dBf input) 80dB
Subcarrier oppression ratio 70dB
SCA disturbance ratio 80dB
Output voltage (±75kHz deflection) 1.0V
<Stereo characteristic>
Sensitivity S/N 40dB sensitivity: 29dBf (IHF)
S/N 50dB sensitivity: 37dBf (IHF)
S/N (80dBf input, A compensation) 85dB
(at the time of 80dBf input, ±75kHz deflection, and Normal)
IM distortion (80dBf input, ±75kHz deflection) 0.03%
Frequency response 10Hz-16000Hz+0 -1.0 dB
Stereo separation 100Hz:50dB
Stereo change inlet pressure 20dBf
Antenna 75-ohm disequilibrium (with a 300-ohm balance transducer)
Alignment system Quartz synthesizer system
16-game random memory tuning
Detection system DGL system
Output load impedance
Balanced (balanced XLR type) : 200ohms (100ohm/100ohm)
Unbalanced (disequilibrium) Fixed (fixed output): 200ohms
Controlled(variable output): 1.25kohm (maximum)
Meter Signal strength, a multipass change type
The semiconductor used Transistor: 15 pieces
FET: Five pieces
IC: 32 pieces
Diode: 36 pieces
Power source AC100V/117V/220V/240V, 50Hz/60Hz
Power consumption 15W
Dimensions Width 475x height 115x depth of 351mm
Weight 9.4kg