Luxman T-310 (1973–1975, with some sources citing 1974–1975 or 1976)
The export-only tuner that brought Dolby B to FM—where high fidelity met noise reduction in a rare, meticulously engineered package.
Overview
Marketed exclusively outside Japan, likely due to limited domestic interest in Dolby-encoded broadcasts, the T-310 was aimed at European and North American audiophiles who demanded more than just tuning accuracy. It delivered, with a 4-gang FM front end, dual-gate MOS-FETs in the RF stage, and a phase-locked-loop (PLL) multiplex decoder that minimized distortion even under weak signal conditions. This wasn’t just a receiver component; it was a statement that the tuner deserved the same engineering rigor as the amplifier or preamp.
The Dolby B circuit wasn’t an afterthought. It was fully integrated, with calibration (CAL) detectors and meter adjustments allowing users to align the decoder for optimal performance—capable of reducing noise by up to 10 dB on compatible broadcasts. That same circuit could be looped through a tape deck, doubling as a cassette noise-reduction hub. In an era when tape hiss was the enemy, that dual functionality made the T-310 a quiet powerhouse in a high-end system. And with a mono signal-to-noise ratio of 80 dB and stereo separation of 40 dB at 1 kHz, it wasn’t just clever—it was technically outstanding. HiFi-Stereo (April 1977, p.125) noted that distortion measurements for comparable Luxman tuners were "the lowest we have ever read for any tuner at any price," and while the review didn’t name the T-310 specifically, the engineering lineage suggests it would have performed no worse.
Key Features
4-Gang FM Tuning with Dual-Gate MOS-FET Front End
The T-310 uses a 4-gang variable capacitor for FM front-end tuning, a design that ensures precise tracking across the 87.5–108 MHz band. Paired with dual-gate MOS-FETs in the RF stage, this setup delivers an IHF sensitivity of 1.8 µV (10.8 dBf) and a muting threshold of just 3.0 µV (17 dBf), making it exceptionally good at pulling in weak signals without amplifying noise. This combination was a hallmark of high-end tuner design in the mid-70s, and Luxman executed it with their signature precision—low distortion, high selectivity, and rock-solid stability.
Five-Pole Phase Linear and Linear Delay Filters
Situated between three ICs and the IF amplifier, the five-pole Phase Linear and Linear Delay filters shape the intermediate frequency response with surgical accuracy. These filters are critical to the T-310’s 70 dB alternate channel selectivity and 90 dB IF rejection, allowing it to isolate desired stations even in crowded band conditions. By minimizing crosstalk and phase anomalies, they also contribute directly to the 40 dB stereo separation at 1 kHz—performance that rivals or exceeds many tuners twice its age.
Hermetically Sealed Coils in MPX Decoder
Temperature drift can wreck stereo decoding accuracy, especially in the multiplex (MPX) stage where timing is everything. To combat this, the T-310 uses hermetically sealed coils in the MPX section, ensuring consistent performance across operating temperatures. FETs control the audio gates, providing fast, low-distortion switching that preserves signal integrity—particularly important when decoding Dolby B-encoded broadcasts where timing errors could compromise noise reduction.
Three-Stage AM IF with Switchable Filters
The AM section is no afterthought. It employs a 3-gang design with three IF stages and 18 dB/octave switchable filters, backed by voltage regulators for clean power delivery. This allows for strong adjacent-channel rejection, evidenced by an 85 dB IF rejection spec and 80 dB image rejection.
Phase-Locked-Loop Multiplex Decoder
Instead of a traditional Foster-Seeley discriminator, the T-310 uses a phase-locked-loop (PLL) multiplex decoder. This design offers superior stereo separation and lower distortion, especially under weak signal conditions. It’s one of the reasons the tuner maintains a THD of just 0.15% in mono and 0.3% in stereo, despite the added complexity of the Dolby B circuit. The PLL design also improves capture ratio, rated at 1.0 dB—meaning the stronger signal quickly dominates during multipath interference.
Dolby B Noise Reduction with Calibration
The defining feature: a full Dolby B noise reduction system for FM broadcasts. Unlike passive implementations, the T-310 includes calibration detectors and meter adjustments, allowing users to fine-tune the decoder for optimal performance. This wasn’t just tacked on—it was integrated with the same care as the rest of the circuitry, capable of reducing noise by up to 10 dB on compatible broadcasts. Few stations ever adopted Dolby FM, but for those that did, the T-310 delivered near-silent backgrounds between the notes.
Tape Loop, 4CH Output, and Dual Multipath Outputs
The T-310 doesn’t just receive—it routes. It includes a tape loop for recording, a 4CH output (likely intended for quadraphonic systems, though not decoded internally), and two multipath outputs. These latter jacks let users monitor multipath distortion in real time, a clever diagnostic tool for optimizing antenna placement. The FM frequency response is rated at 20 Hz to 15 kHz (+0.2 / -1.8 dB), with a subcarrier product ratio of 60 dB ensuring clean stereo demodulation.
Historical Context
The T-310 was the last in a lineage that included the WL500, WL550, and T-550—models released between 1970 and 1973. Positioned as a complement to Luxman’s L-308 or L-309 preamps, it filled a niche for high-end system builders who demanded more from their tuner than basic reception. Its export-only status meant it never appeared in Japanese catalogs, likely due to limited domestic demand for Dolby FM. The T-300, its closest sibling, was functionally identical except for the absence of the Dolby FM circuit and related switches—making the T-310 the sole model in the series with this feature. Originally priced at 1,798 Deutsche Mark, it was a premium product from the start, aimed at audiophiles in Europe and North America who valued both innovation and build quality.
Collectibility & Value
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