Quad FM2 Valve Tuner

Key Features

The FM2 uses a classic valve front end: a permeability-tuned RF section using two valves and a pair of low-loss ganged ferrite cores, feeding a five-valve IF strip and a Foster-Seeley discriminator for FM demodulation. This is followed by a built-in stereo multiplex decoder using a diode-ring demodulator circuit, allowing reception of stereo FM broadcasts via the dedicated stereo indicator lamp on the front panel, alongside the tuning indicator lamps either side of the illuminated dial scale.

As a genuine valve design from the late 1960s, the FM2 has a distinctive set of operating characteristics that collectors and users of vintage equipment should be aware of and which we are happy to explain. It takes around 15 minutes from switch-on to fully thermally stabilise, during which slight tuning drift is normal and a small retune may be needed. Most significantly, the tuner’s internal de-emphasis circuit and stereo decoder are designed around a 100kΩ output load; driving it into a modern preamplifier with a lower input impedance (commonly 47kΩ or less) will result in audibly reduced bass and a duller overall sound, as the high-frequency de-emphasis curve depends on seeing the correct load. The original Quad 22 preamplifier presents this correct loading by design. For use with other amplifiers, a simple buffer stage or appropriately specified loading resistors can resolve this and is a widely documented modification within the vintage Quad community; we are happy to discuss this further with interested buyers.

Technical Specifications

(Sources: Radiomuseum.org, citing original Acoustical Manufacturing Co. technical data; pinkfishmedia.net and Quad Spot, citing original service literature and component schematics)

• Type: Valve FM Stereo Tuner with built-in PSU and multiplex decoder
• Demodulation: Foster-Seeley discriminator
• Stereo Decoder: Diode-ring demodulator, transistor-based multiplex circuit
• Tuning: Permeability-tuned, ganged ferrite cores
• RF Section: 2 valves
• IF Section: 5 valves
• Frequency Range: 88–108MHz (VHF/FM band)
• Power Consumption: 30W nominal
• Mains Voltage: Selectable 200/210/220/240V, 50–60Hz
• Fuse Rating: T 160mA
• Serial No.: 4049
• Years of Production: 1968–1971
• Country of Origin: England (Huntingdon, by the Acoustical Manufacturing Co. Ltd)

Important Owner’s Notes

The FM2’s output is designed to drive a 100kΩ load, as found on the original Quad 22 preamplifier. Connecting it to an amplifier or preamplifier with a significantly lower input impedance (such as the common 47kΩ found on many modern designs) will noticeably affect the tonal balance, particularly in the bass. This is a well-documented characteristic of the original circuit design rather than a fault, and is straightforward to address with a simple buffer or loading arrangement if required. We are happy to discuss this further with any interested buyer.

Why Buy From Us

With over 40 years of experience in the Hi-Fi industry, we are well placed to assess and test equipment of this type. Every item we list is fully inspected and tested before sale — this unit was checked by Andrew in our workshop.

When you buy from us you can expect:

• Full inspection and testing prior to listing — not simply a visual check
• A 3-month guarantee on every item we sell
• Transparent descriptions with no omissions
• Professional packaging to ensure safe delivery
• After-sales support available by phone or email should you have any questions

Summary

This is a single-unit listing. The Quad FM2 is a genuinely desirable valve-era FM stereo tuner from one of Britain’s most celebrated hi-fi manufacturers, and this example is in mint condition complete with its original box — a excellent find for the serious Quad collector. Confirmed working by Andrew. Please feel free to get in touch with any questions prior to purchase, including guidance on correct loading for use with non-Quad amplification.