13-06-2022, 07:02 AM
Hi Adrian. That's a nice looking set with neat layout.
For anyone interested there are probably thousands of articles on the World Radio History site as there are many of the old mags and articles from those days. They inspired me and I have one I constructed, inspired more in the era of the 1930's.
It is two valve, roughly looking period (but not accurate) as I used a 6K7 for the RF amp and 6н8с (Russian double triode) for the detector and audio. I used the 60V suppy I use for rod pentodes for the supply, which works well. Many of the designs of the period state that the detector voltage is best around that anyway. My coil former is home made, using 40mm water pipe with the ribs made from right angle plastic strip (obtained from a model shop) glued on. It has three coils, input main and reaction , the design of which was a popular one obtained online. I was lucky to get some very period looking chokes from John Birkett in Lincoln (sadly no longer I understand). Working on lower voltages and currents enabled me to use one of those miniature transformers more intended for transistor equipment for headphone output. I worked out impedances somewhat at the time but don't remember the details. I can provide the transformer type though if anyone is interested. It seems to work Ok but is obviously not period. One of those little RS ones designed for valves may be better but I had several of the little transistor ones of different types / ratios.
I did start on a rod pentode version but have done little with it recently, currently looking at superhet ideas. For me, there is something about a period looking layout though. I do have a fairly ancient looking variable capacitor with SM drive and another pair of the same valves so an update after learning from the first beckons lol.
For anyone interested there are probably thousands of articles on the World Radio History site as there are many of the old mags and articles from those days. They inspired me and I have one I constructed, inspired more in the era of the 1930's.
It is two valve, roughly looking period (but not accurate) as I used a 6K7 for the RF amp and 6н8с (Russian double triode) for the detector and audio. I used the 60V suppy I use for rod pentodes for the supply, which works well. Many of the designs of the period state that the detector voltage is best around that anyway. My coil former is home made, using 40mm water pipe with the ribs made from right angle plastic strip (obtained from a model shop) glued on. It has three coils, input main and reaction , the design of which was a popular one obtained online. I was lucky to get some very period looking chokes from John Birkett in Lincoln (sadly no longer I understand). Working on lower voltages and currents enabled me to use one of those miniature transformers more intended for transistor equipment for headphone output. I worked out impedances somewhat at the time but don't remember the details. I can provide the transformer type though if anyone is interested. It seems to work Ok but is obviously not period. One of those little RS ones designed for valves may be better but I had several of the little transistor ones of different types / ratios.
I did start on a rod pentode version but have done little with it recently, currently looking at superhet ideas. For me, there is something about a period looking layout though. I do have a fairly ancient looking variable capacitor with SM drive and another pair of the same valves so an update after learning from the first beckons lol.
