The third radio in the trilogy of radios I made.
Again a MW & SW radio, images attached. This radio is the most unusual one of the three. I posted a link to it in the past. It uses the same steel grey painted chassis system as the EF98/OC16 radio and again the engine turning thick stainless panel.
This one uses a modified Eddystone dial, the cutouts for the meters were not there originally but made to resemble some Eddystone radio dials. The dial also had a string of miniature incandescent lamps added.
The thing that makes this radio unusual is that it contains no transistors and no valves either.
The active devices are Fetrons, which are a three terminal device constructed from two high voltage Jfets in a modified cascode configuration.
These were once predicted to "take over the world" as plug in valve substitute, but they came and went in the 1970's quicker than an LED digital watch. They have the higher gain and lower noise than the 6AK5 pentode, but ho heater, little noise and zero microphony. They are called "TS6AK5"
To get reasonable audio output I paralleled 4 of them in Class A.
This radio has a very high gain and low noise and good selectivity, it also utilizes an extra IF stage.
The wiring is again teflon, ceramic "valve" sockets and stainless steel hardware to conform to my construction practices.
The radio runs from a 90V battery (or power supply) the power light on this radio is a 70V striking voltage neon lamp. Again it uses an industrial power switch for MW/SW band change, in this case pulsing latching Teledyne RF relays. The S meter (and volt meter) added to the dial are high quality ex avionics helicopter parts, I repainted/labelled the faces and added internal incandescent lighting.
The Fetron story is quite something, the formal article on this radio is here that also contains the original historical documents on Fetrons:
http://worldphaco.com/uploads/WORLDFETRON.pdf
The S meter circuit uses two high voltage Teledyne Jfets.
I made the radio really as a tribute to the Teledyne company, Their products over a lifetime have always impressed and inspired me with the magic combination of innovation & quality.