Accuphase T-107 (1985–1991)

A quartz-synthesized FM tuner that Accuphase built to a standard, not a price. Collectors still argue it belongs with the best varactor tuners ever made.

Overview

The Accuphase T-107 came out in Japan in July 1985 at ¥99,800 and was built through 1991. Accuphase's own literature calls it a synthesizer FM tuner. It tunes by counting crystal oscillations rather than by dragging a variable capacitor across a dial. Tuning accuracy is quoted at ±0.002%, held by the crystal oscillator. That matters less on a strong local station and a lot more when you're trying to hold a marginal signal steady for an hour.

The T-107 was made in Japan by Accuphase Laboratory, Inc., the company originally known as Kensonic Laboratory, Inc. It sold in two front-panel finishes - the traditional champagne gold, and a black version designated T-107B. The optional A-11 wood cabinet, finished in natural rosewood, was sold separately at ¥16,000. It accounts for the second set of dimensions in the spec sheet: the bare body measures 445 × 107 × 330 mm, while the cabinet-dressed unit measures 463 × 131 × 338 mm. Weight is 5.8 kg, and it draws just 12 W from a 100 VAC, 50/60 Hz supply. The semiconductor count is 16 transistors, 2 FETs, 22 ICs, 59 diodes, and 18 LEDs, so a good deal of this tuner's behavior is decided in silicon rather than by a knob.

The T-107 is remembered for its position more than its parts count. Collectors and tuner specialists have described it, alongside the Tandberg 3001A, as the high-water mark for varactor-based tuners. The same body of opinion holds that it performs sonically on par with the Kenwood KT-917, though it may not match that tuner's RF performance. So it is praised for what comes out of the audio stage, not for pulling in the weakest signal on the dial.

Key Features

Quartz Synthesizer Tuning with 12-Station Memory

Tuning is quartz-synthesized. The manual's German-language edition says the desired signal is received with crystal-controlled precision across a claimed range of 0.002%, and that acoustic feedback produces almost no microphone effect and no noise. A tuned channel stays put with minimal distortion and almost no frequency drift over time or with temperature swings. The head unit's receiving range is 76.0-90.0 MHz. That is the Japanese FM band, which matters to anyone outside Japan. A band-conversion thread has turned up on a Russian forum from an owner trying to move a Japanese-market T-107 onto a different band. That is not a trivial job.

Memory holds 12 FM stations. Manual tuning is one-step, one-touch, and holding the button accelerates the frequency change. Pressing Auto engages automatic sweep tuning, which stops at the adjacent station. The digital frequency display uses a static method that does not generate noise.

DGL Detection: 19 Logic ICs, 114 Degrees of Delay

The DGL (Differential Gain Linear) detector is the T-107's signature circuit. It works by exploiting the delay time of a high-speed logic IC. Nineteen of them are connected in series, and the phase angle is delayed by 114 degrees so that distortion is minimized and signal-to-noise is optimized. The delayed signal and the input signal are fed to an exclusive-OR circuit, and the potential between the two signals opens and closes the gate. The delay circuit's linear range is extremely wide at ±5 MHz, and the circuit requires no adjustment, so the differential gain characteristic stays stable and linear over time. Accuphase's own documentation pairs the DGL detector with a specially selected group-delay-flat IF filter to arrive at a stable, low-distortion capture ratio.

Double-Tuned Front End

The front end is double-tuned between the input and amplifier stages across two gangs. The T-107 shares this design with the T-105 and T-106. Accuphase's stated purpose is interference rejection: double tuning in the front end greatly improves RF intermodulation caused by large input interference waves. RF intermodulation is quoted at 80 dB, and image ratio at 120 dB.

Normal and Narrow IF Filters

Two sets of IF filters are installed, Normal and Narrow, switchable from the front panel. The selectivity numbers explain the switch better than any description. In Normal, two-signal selectivity is 70 dB at 400 kHz, 30 dB at 300 kHz, and 8 dB at 200 kHz. In Narrow, those figures become 100 dB, 80 dB, and 30 dB. The 200 kHz figure, 8 dB rising to 30 dB, is the one that counts when a strong adjacent station is sitting on top of the one you want. Narrow trades bandwidth for selectivity, and the manual says switching to Narrow enables sharp reception with a high degree of selectivity when adjacent interference is severe.

Resonator-Controlled Stereo Decoder

The stereo demodulation section locks its internal oscillator to the 38 kHz pilot signal via a PLL. The T-107 combines that PLL with a ceramic resonator and a variable positive/negative reactance circuit controlled by the control voltage. Per Accuphase, this gives a lock frequency range narrower than conventional designs, which reduces beat distortion at high frequencies. The demodulator needs no adjustment and holds its initial characteristics over the long term, with channel separation largely unaffected by temperature and line-voltage variation. Stereo separation is quoted at 50 dB at 100 Hz, 50 dB at 1 kHz, and 40 dB at 10 kHz.

Metering, Filters, and Output Control

The front-panel meter switches between signal strength and multipath, and the dBf scale is direct-reading. The manual's instruction is practical: when the input signal level reads on the dBf scale and the multipath indicator sits within the clear mark range, the tuner is receiving high-quality signal with minimum multipath. The T-107 also carries a noise filter for reducing noise on weak stereo stations, a music switch to mute noise between stations, and an output level control for matching the tuner to other program sources. Outputs are split between a fixed output at 200 Ω and a variable output at 1.25 kΩ maximum, with output voltage quoted at 1.0 V at ±75 kHz deviation. The antenna input is 75 Ω unbalanced, with a 300 Ω balanced converter supplied.

Historical Context

The T-107 arrived in July 1985 as part of Accuphase's run of high-performance digital tuners, following earlier models like the T-100 and sitting in the product family alongside the T-101 and T-106. Contemporary coverage in HiFI-Stereo (February 1991, p.91) highlighted the model's electronic tuning, 12-station random memory, auto sweep for FM reception, and double-tuned front end that rejects interference and IM. It shares front-end design elements with the T-105 and T-106, but it is specifically noted for significantly lower noise than the T-106. Production ran through 1991, roughly a six-year run. A 1987 manual and a 1991 catalog survive, along with a service manual.

Collectibility & Value

The T-107 is described as very rare, and the asking prices are all over the place. Documented market prices for 2023-2026 typically fall between €350 and €480. Several individual asks sit above that range: a black example in collector condition was listed at €575, and a unit in Yekaterinburg was advertised at 97,500 ₽. A single eBay listing for an "ACCUPHASE Tuner T-107" carried a price of $1,109. Those figures are asking prices, not confirmed sales, and they are not directly comparable, with different currencies, conditions and markets.

Condition matters more than usual here. Some listings explicitly flag defective units, and the Japanese-market 76-90 MHz tuning range is a real constraint for buyers outside Japan who want the tuner to work on their local band without modification. A repair video covering a replacement of the FM input terminal exists, and a service manual is in circulation. Beyond that, documented common failure modes and spare-parts availability are thin, and there is no established service literature describing what typically goes wrong on these. Buyers should confirm band coverage and working condition before committing to a price at the top of the range.