Accuphase T-104 (1978)

FM stereo tuner with quartz-locked frequency synthesizer tuning, released in October 1978

Overview

The Accuphase T-104 is an FM stereo tuner made by Accuphase Laboratory, Inc., originally known as Kensonic Laboratory, Inc. It came out in October 1978 at ¥250,000. Tuning is by frequency synthesizer with quartz lock, covering 76.1 MHz to 89.9 MHz in 100 kHz steps. A memory function stores up to four stations for one-touch recall. A built-in nickel-cadmium battery keeps the tuning data, lasts about one year without power, and recharges automatically when the tuner is powered on.

Specifications

Receiving frequency	76.1 MHz to 89.9 MHz
Tuning system	Quartz lock, frequency synthesizer tuning
Frequency accuracy	Within ± 0.002%
Output impedance	Fixed output terminal: 200 Ω; Variable Output Terminal: 2.5k Ω
Antenna input impedance	Balance: 300 Ω; Unbalanced: 75 Ω
Power	100 VAC, 50/60Hz
Power consumption	25W
Dimensions	Width 466 × Height 188 × Depth 391 mm
Weight	14.1kg
Semiconductor count	Transistor: 43; FET: 3; IC: 42; Diode: 58 pcs; Opto-coupler: 3 pcs

Design

The synthesizer uses a crystal oscillator, program divider and PLL circuit to control the front end electronically through a varactor element. The front end is a two-stage double-tuning design with local oscillation tuning and a tuning buffer. The IF circuit combines a surface acoustic wave (SAW) filter with an LC filter, and gives you two selectivity modes: Normal (low distortion) and Narrow (high selectivity). Stereo demodulation is a PLL demodulator with pilot carrier suppression. A built-in 4-bit micro-computer handles frequency calculation and memory control. There is an S-meter and a modulation depth meter, and a push switch puts multipath detection on the S-meter. The "Tuned" and "Stereo" indicators show tuning status and stereo reception. The pulse tuning function (PAT. PEND) uses an infrared generator and light receiver to mimic the feel of a rotary knob. Also on board are a noise filter, monaural mode switch, muting switch and dimmer switch. There are two outputs, and one has a front-panel level control. A remote station selector with a 5-meter cord is included. The chassis sits in a natural rosewood cabinet, and an optional rosewood cabinet is also available.

Market

Market prices for the T-104 vary a lot with condition. They run from ¥100 for non-working units to ¥86,182 for tested, functional ones. Listings often include a remote control. Some units are sold as "junk" or "for parts," so condition clearly drives the price.