Pioneer TX-900 (1970)
A top-of-the-line AM/FM tuner so big it could pass for a receiver — and so sensitive it pulled 57 stations out of the New York air.
Overview
The first thing anyone notices about the TX-900 is the size. Audio (November 1970, p.51) opened its equipment profile by remarking that this "top-of-the-line" tuner from Pioneer is large — as large, in fact, as some of the complete receivers other manufacturers had recently released. That bulk buys a front panel crowded with more controls than a tuner-only product would normally carry, and a layout the reviewer found genuinely thoughtful rather than merely busy.
The cosmetics are period Pioneer at its most deliberate: a light gold-anodized front panel, a black tuning and dial-scale area in contrast, and wood blocks flanking each end of the panel. The panel itself overhangs the chassis and metal wrap by at least a quarter inch on every side, which makes dropping the unit into a custom cabinet forgiving even when the cut-out is ragged. Tuning is done with a large flywheel-coupled knob, and station indication comes from a traveling bead of light that glows dimly off-station and brightens when a station is tuned in — a feature the reviewer called somewhat redundant alongside the signal-strength and center-of-channel meters but "an interesting conversation piece" all the same.
The front-end design is where the money went. Three FETs and two RF stages sit ahead of an IF section using two crystal filters and four ICs, and the resulting numbers are strong across the board: IHF sensitivity of 1.7 µV, 65 dB alternate-channel selectivity, and a 1.5 dB capture ratio. Audio (November 1970, p.51) put the tuner on the bench and found the claims honest, sometimes conservative — signal-to-noise measured 75 dB against a 70 dB spec, selectivity came in at 70 dB against the claimed 65, and full limiting occurred below 2 µV, right about at the IHF sensitivity point. Mono THD measured 0.4% against a 0.3% claim (slightly worse), while stereo THD hit the 0.5% spec exactly. Capture ratio measured 1.7 dB, close to the manufacturer's figure.
In listening, the combination of that sensitivity, selectivity, and capture ratio paid off in a crowded metropolitan dial. Audio's reviewer logged 57 stations on an outdoor six-element Yagi, at least ten of them only 200 kHz apart, with no adjacent- or alternate-channel interference noted — and heard no SCA "tweets" or swishing from five background-music subcarriers even with the treble control wide open. Stereo separation was excellent, though multipath plagued roughly five of the 23 stereo stations received.
The AM section is a genuine bonus rather than an afterthought. IHF sensitivity is 10 µV, image rejection 70 dB at 1 MHz, and the built-in ferrite loopstick mounts on a pivoting bracket so it can be swung away from the metal chassis for better reception. The reviewer noted that most higher-priced tuners of the day omitted AM entirely. Both AM and FM outputs are rated at 1 volt at 30% modulation — which means FM output climbs to roughly 3 volts at full modulation, and Audio measured 3.5 volts, enough to recommend setting the separate AM and FM level controls near midpoint to avoid overloading downstream inputs.
The rear panel carries screw terminals for 300-ohm FM antenna and ground plus an external AM antenna, a BNC coaxial connector for 75-ohm line, two pairs of output jacks (one level-controlled for the amplifier, one constant for tape), a fuseholder, and a switched AC convenience outlet. It also carries a stereo separation trim pot — recessed and screwdriver-adjustable, which the reviewer still objected to on the grounds that a curious owner with a screwdriver can wreck the alignment; Audio (November 1970, p.51) reduced separation from 40 dB to about 10 dB with a minimal turn. The supplied manual, the reviewer pointed out, agrees that the adjustment is critical and cannot be done by ear.
Physically the TX-900 measures 15 15/16 inches wide, 5 9/16 inches high, and 14 inches deep, and weighs 17 3/16 pounds. Power draw is 12 watts maximum at 117 V, 60 Hz. Suggested retail was $259.95 including the metal cabinet — the same figure Pioneer quoted for the companion SA-900 integrated amplifier, and the pair was advertised together as a system for the listener and the experimenter alike.
Audio's verdict was that anyone moving toward separates — or preamp, amp, and tuner — would do well to consider the TX-900 for its performance against its moderate price. High Fidelity (November 1970, p.49) also profiled the tuner as Pioneer's separate offering, listing a 16-by-5 1/8-inch front panel and 11 1/8-inch chassis depth in its equipment notes. For a collector, the appeal is that a period reviewer already flagged the weak point: that rear-panel separation control is a temptation, and one that a previous owner may have already given in to. Buy on condition and check that the multiplex alignment hasn't been "adjusted" by ear.
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