[AMRadio] FW: Homebrew receiver

[Donald Chester]

>My favorite style was the Collins 75a series

I use a 75A4, which is often bashed by the AM folks, but I find it to be 
about the best receiver I have ever tried.  If I find a truly superior 
receiver to the A4, I'll retire mine and change over to that.

The main deficiency of the A4 is the audio.  I use an outboard AF amp (an 
old 50's vintage 10w hi-fi amplifier using a pair of 6V6's in pushpull).  I 
changed the .01 mfd coupling caps in the low level audio stages of the 
receiver to 0.1.  Actually, I just bridged the .1's across the originals, to 
minimise melted plastic insulation on the wiring in the receiver.  I pulled 
out the original 6AQ5 to save unnecessary drain on the power supply and to 
reduce heat generation.  I also clipped out a couple of 510 pf mica caps 
that were added in later models to attenuate the high frequency response.