This set was sold as a kit as the Osram Music Magnet (GECoPhone) in 1929, it has a metal chassis and front panel with oak end panels and lift-up lid. It is a battery set and has 3 valves, and very little else! There are two waveband coils, six condensors, one resistor, an L.F. transformer and that is it! - Simplicity. When I aquired this set it was in fairly original condition, but the condensors had lost their capacity. It was easy to repair the bakelite condensors by removing the nuts from the terminals and then applying a hair dryer to the base to melt the pitch. As the pitch melts push down on the screw threads and out pops the old capacitor. Put in a new capacitor (250 Volts DC Working), of the correct value and reassemble. It is a messy job, but save the pitch that melts out so that it can be reused. If you are really careful it is possible to repair these capacitors and still have it looking completely original. (If you are a real purist!)
The original valve line-up was: S.215 (Screen grid H.F.), H.L.210 (Detector), and D.E.P.215 or P.T.235 (L.F. Amplifier) although there are quite a few equivalents still available.
It is interesting to hear Osram's description of the Music Magnet: "This new and remarkable circuit is probably the most efficient as regards range which it is possible to obtain with 3 valves. The use of the OSRAM Screen Grid Valve in the H.F. position ensures reception of many distant stations with great ease of tuning; and the introduction of the new OSRAM Pentode Valve in the L.F. stage brings the results of such a set up to those recently obtainable from a set using 5 valves. The circuit operates with excellent quality of reproduction, and for local, alternative, any many foreign programmes, the Pentode Valve is not required." - Modest Eh?
The 2 MegOhm grid leak resistor had gone open circuit so I removed from it's spring clips and carefully soldered a miniature resistor between the brass end caps and clipped it back into place with the resistor underneath. The original L.F. transformer had been replaced by a Ferranti one which worked well but I managed to get an original GECoPhone transformer (BC.710 - 3:1 ratio) from a fellow Music Magnet enthusiast, Simon Millington who was exhibiting his restored and working set at the