The model 1003 Mono integrated amplifier was launched in 1956. It used very modern styling and an innovative cast-aluminium frame for better rigidity.
The circuit was not particularly innovative, using EF86, ECC83, ECC83, 2x 6AQ5 (EL90). A curious choice for output valves, as the more common EL84 valve could easily have been used. (Note that this circuit, from Gordon King’s 1957 “FM Radio Servicing Handbook” incorrectly shows the feedback capacitor as 700pF. It should be 7000pF.)
10W output in ultra-linear configuration from these two valves was rather pushing their capabilities, and the resulting 1% distortion figure at 8W was not up to the 0.1% capabilities of then-current Leak amplifiers
The review in the Gramophone in December 1956 described it as “First Class”. Gordon King was very fond of Pamphonic Equipment and featured a number of models in his writings in the mid to late 1950s.
The introduction of the tem “Ab-Fi” on the front panel was a Pamphonic attempt at re-defining the conventional “Hi-Fi” rating of top-class amplifiers. “Absolute Fidelity” was a typical Pamphonic claim, not really consistent with the performance of the 1003.
Only 3 years later the final mono integrated amplifier (the 1004) was launched. But by then Pamphonic had already entered the new stereo market with their ground-breaking model 3000 and mono was starting to die.
The 1003 remains a satisfying and visually pleasing amplifier, with a slightly industrial feel, but finished in the house metallic green paint to blend more easily into a domestic decor.
My restored 1003 did sterling service in June 2012, providing fine period-sound music for a Royal Jubilee street party, paired with a huge Pamphonic Victor Senior loudspeaker.
Restoration involved replacement of inter-stage coupling capacitors, the output cathode decoupling electrolytics which had dried out, and a few out of spec resistors. Plus a new set of valves.