Acquired November 2009, this wireless set dates from the late 1940s or early 1950s. A schools receiver built on the same chassis as the Sound Sales DX Plus One. Unlike the DX Plus One it is a complete receiver with C-L-C filtered power supply and KT61 push-pull output. The output from this set will be of the order of 10 watts; more than enough to fill a classroom or even a school hall. Bands covered are LW and MW broadcast bands only, no short wave band as with the DX Plus One.
Sound Sales produced a radiogram with the same, or similar chassis, reviewed in June 1954 in The Gramophone.
Sound Sales DX Plus Four Radiogram. (Price £47 10s. plus £16 11s. 5d. inc. P.T.)
Circuit : 6-valve comprising frequency changer, IF., detector plus L.F., push-pull tetrode output, rectifier. Negative feedback. Output 8 watts. Valves : 6K7, 6K8, 6Q7GT, 2 x KT61, 5Z4.
Radio : Medium Wave-200 to 550 metres. Long Wave-800 to 2,000 metres. Variable selectivity.
Motor : Collaro Type AC3/544 with Studio " P " pickup.
Controls : Tuning (with large circular dial calibrated in wavelengths), volume, wavechange, Radio/gram., selectivity switch, tone (for records only), motor speed, on/off switch.
Loudspeaker : to in. m/c, in horizontal bass reflex compartment in lower portion of cabinet, with diffuser on front of cabinet operating both for loudspeaker and for vent of enclosure. Provision for 3 ohm extension speaker.
Cabinet : Massively built, finished in walnut veneer. 32 in. high by 31 in. wide by 18 in. deep.