Radford Electronics
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Radford Electronics is a British audio manufacturer from
Bristol Bristol () is a city, ceremonial county and unitary authority in England. Situated on the River Avon, it is bordered by the ceremonial counties of Gloucestershire to the north and Somerset to the south. Bristol is the most populous city in ...
, founded by Arthur Hedley Radford (G6YA) in 1946. Radford's hi-fi
amplifier An amplifier, electronic amplifier or (informally) amp is an electronic device that can increase the magnitude of a signal (a time-varying voltage or current). It may increase the power significantly, or its main effect may be to boost t ...
s enjoyed a reputation for quality that was "second to none", especially because of their output transformers.


History

Radford began building amplifiers in 1946, and marketed its first hifi-amplifier in 1959. Reportedly, Radford make amplifiers with such low distortion that they had to build their own test equipment to measure it; their test equipment also acquired a reputation for quality. In 1961, the company released the STA range of amplifiers, accompanied by the DSM pre-amplifier. The Series 3 STA25, along with other Amplifiers in the STA range, won critical acclaim. As an expert in
transformer A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
design, Arthur Radford was able to reduce distortion by a factor of ten over the best performing amplifier of the day. The MK11 and Series 3 Amplifiers used a unique pentode phase inverter, which was the result of a joint venture between Dr A R Bailey and Arthur Radford, and was the subject of a detailed article in Wireless World. File:STA15 MK3 and SC22 pre amp.jpg, alt=A photo of a Radford STA15 MK3 amplifier and an SC22 preamp., Radford STA15 MK3 and SC22 preamp File:Glowing radford.jpg, alt=A photo of a Radford STA15 MK3 amplifier with glowing valves., A glowing example of a Radford STA15 MK3 File:Radford STA15 MK3 amplifier.jpg, alt=A photo of a Radford STA15 MK3 amplifier with its top cover removed., A Radford STA15 MK3 amplifier with its top cover removed However, Arthur Radford’s greatest love was for his
loudspeaker A loudspeaker (commonly referred to as a speaker or speaker driver) is an electroacoustic transducer that converts an electrical audio signal into a corresponding sound. A ''speaker system'', also often simply referred to as a "speaker" or ...
designs and the rear termination of drivers. After many years of work he eventually took out a patent in conjunction with Dr A R Bailey for the first
transmission line loudspeaker A transmission line loudspeaker is a loudspeaker enclosure design which uses the topology of an acoustic transmission line within the cabinet, compared to the simpler enclosures used by sealed (closed) or ported (bass reflex) designs. Instead of r ...
. This system was the basis for all his larger designs, and is still used by many well-known manufacturers. Although today, the
valve audio amplifier A valve audio amplifier ( UK) or vacuum tube audio amplifier ( US) is a valve amplifier used for sound reinforcement, sound recording and reproduction. Until the invention of solid state devices such as the transistor, all electronic amplifica ...
s attract the most attention from enthusiasts, the quality of Radford's designs continued into the
transistor upright=1.4, gate (G), body (B), source (S) and drain (D) terminals. The gate is separated from the body by an insulating layer (pink). A transistor is a semiconductor device used to Electronic amplifier, amplify or electronic switch, switch ...
age with the "Zero distortion" series of solid state power amplifiers produced in the mid 1970s, in which THD was reduced to less than the circuit noise level. These, and later products such as the Quad 405 and Halcro range, achieved the near perfect measured performance for which designers had been striving since the earliest days of the industry. Left with no potential for objective improvements in quality, the industry started to concentrate on subjective analysis of designs and products which has, in some cases, led to a revival of interest in valve amplification amongst audio enthusiasts. At its peak, Radford had four factories in Bristol, England, employing 160 personnel producing metalwork, painting, printing, transformer design / production Loudspeaker assembly / test and PCB manufacture, all in house. Another well known Radford product was the "Labpak" low voltage power supply, used in schools and colleges, both in the UK and overseas. As Arthur approached retirement, the company was wound down as there was no one to take it on. After he retired in 1989, Woodside Electronics was formed by John Widgery, who had been apprenticed to Radford Electronics and was responsible for many of the classic designs. Mike Davis joined John as a partner in 1989, and they worked together to launch the
CD player A CD player is an electronic device that plays audio compact discs, which are a digital optical disc data storage format. CD players were first sold to consumers in 1982. CDs typically contain recordings of audio material such as music or audio ...
and update the range of valve equipment as part of the Renaissance series. Arthur died on 21 November 1993, and Woodside continued for a while but finally ended production in Llanbedrog, Pwllheli, North Wales in 2004. Radford
valve amplifier A valve amplifier or tube amplifier is a type of electronic amplifier that uses vacuum tubes to increase the amplitude or power of a signal. Low to medium power valve amplifiers for frequencies below the microwaves were largely replaced by sol ...
s are rare today, and still command high prices on the secondhand market. Much sought after and enthusiastically rebuilt, they are particularly known for classic and restrained physical design and outstanding, listenable sound quality - including a particular ability to drive, very sweetly, the notoriously difficult Quad electrostatic loudspeakers. 2006 brought hope of a rebirth for the brand, with news of plans to begin manufacture of classic valve based designs like the STA 25 Mk III in 2009. Small scale production is now carried on by Radford Revival, a UK craft business dedicated to replicating the classic amplifiers of the company's heyday.


See also

*
Valve sound Tube sound (or valve sound) is the characteristic sound associated with a vacuum tube amplifier (valve amplifier in British English), a vacuum tube-based audio amplifier. At first, the concept of ''tube sound'' did not exist, because practically ...


References

* "RADFORD - Hi-Fi Legend" - Pier Paolo Ferrari - Sandit Editor - Bergamo, Italy - First edition May 2019. {{ISBN, 978-88-6928-313-0


External links


Radford Electronics Ltd
Audio amplifier manufacturers Audio equipment manufacturers of the United Kingdom Loudspeaker manufacturers