Allied 333 (1960s)

Tube AM/FM stereo receiver built by Pioneer and sold as a budget alternative in the U.S. under Allied and Knight brand names.

Overview

The Allied 333 is a tube AM/FM stereo receiver made by Pioneer in the mid-1960s. In the United States it was sold under the Allied and Knight brand names as a re-badged Pioneer SX-34. It puts out 11 watts per channel and uses 13 tubes, including a horizontal "Tuning Eye" tube for visual tuning indication. You get a headphone jack, a speaker off/mute switch and a tape/record slide switch. The wide slide rule dial covers FM stereo, FM mono and AM. It is known for a warm but detailed sound, works best with high-sensitivity speakers (e.g., 95dB) and benefits a lot from restoration.

Specifications

Power Output	11 watts per channel (RMS/Continuous)
Weight	Approximately 28 lbs (without case); +5 lbs with optional wood case
Tube Complement	13 tubes: 4x 6BM8, 2x 6BA6, 1x 6BE6, 1x 6AU6, 1x 6AQ8 (9F), 1x 6AQ8 (9D), 1x 6AN8, 2x 12AX7
Speaker Impedance	8-ohm or 16-ohm selector

Design

Under the chassis the Allied 333 is wired point-to-point, and the wiring is described as messy. The power supply is a voltage doubler with two 100uF @160V capacitors in series. The electrolytics are old, including Elna dual-can types. The volume control is a Noble dual 1-megohm audio-taper potentiometer with balance and loudness built in - inner knob for the left channel, outer for the right. The stock coupling capacitors and tone/loudness circuit capacitors are considered low quality, and they contribute to a "muddy" sound. The RIAA phono stage has 50pF and 200pF capacitors, and four 6BM8 tubes share a 50uF @25V cathode capacitor. The receiver originally came with a two-prong power cord and has hum adjustment pots.

Context

The Allied 333 and its sibling, the Knight 333, were sold in the U.S. as budget-friendly alternatives to higher-end tube receivers. The identical Pioneer SX-34 was sold in Japan. The price was $129.95 in 1969, with an optional wood case for $14.95. It targeted cost-conscious audiophiles seeking solid performance from a .

Market

In good condition, the Allied 333 sold for $150 - $200 in 2018, and models with the rare wood case reached $250. It is considered a collectible entry-level tube receiver, but it typically needs refurbishment, especially recapping and volume potentiometer repair. The potentiometer is a known failure point, prone to imbalance, tracking issues and incomplete muting. Rebuild costs are estimated at ~$100 in parts plus labor, with recommended upgrades to the power supply, coupling and tone circuit capacitors. Squeal on input switching may call for replacing the multiplexer capacitor, and heavy bass distortion often improves with power supply cap upgrades.