Valve Radio and Audio Repair Handbook

Chapter 9

Practical receiver design (1): battery operated TRFs

Chas E. Miller

The basic single valve grid leak detector with reaction receiver described in the previous chapter is capable on its own of giving acceptable results for anyone willing to listen only with headphones. However, since most of us prefer to use loudspeakers, more valves have to be employed to amplify the output of the detector suitably; this subject has already been covered in Chapter 7. In theory it would be possible to add as many stages of amplification as necessary to make even the weakest of stations audible through the loudspeaker, but in practice this would be unsatisfactory. An ordinary grid detector, even with reaction, still has relatively poor selectivity, that ...