06-01-2019, 08:36 PM
Well that's a good question.
You might have noticed by the schematic that the 50 is a trf set. Trf stands for tuned radio frequency in layman's terms it means that it a couple of rf amps, a detector and audio ouput stage.
+'s
It's not particularly selective so the audio frequency response is typically better than the average superhet.
Easy to service/simple design.
-'s
Broad selectivity may have it hard to separate strong stations that are close in frequency.
No avc. This means that as you tune across the dial if you set the volume control so the strong station is at a comfortable level weak station won't be heard and vice versa adjust it for a weak station and the strong station will be very loud.
I little trickier to connect an external audio input to as the the "volume control" controls the rf gain and the level of signal that comes from the ant. This is why the volume control has two sections.
Not sure about distortion from the detector stage but if it seems excessive there are way to deal w/that.
Common issues are caps, out of tolerance resistor (20%) is spec, open primaries on the rf coils. I had one w/a replacement power transformer, since that set uses 2.5v tubes the pt is hard to come by and expensive.
Always good to check output transformer and field coil for resistance.
GL
You might have noticed by the schematic that the 50 is a trf set. Trf stands for tuned radio frequency in layman's terms it means that it a couple of rf amps, a detector and audio ouput stage.
+'s
It's not particularly selective so the audio frequency response is typically better than the average superhet.
Easy to service/simple design.
-'s
Broad selectivity may have it hard to separate strong stations that are close in frequency.
No avc. This means that as you tune across the dial if you set the volume control so the strong station is at a comfortable level weak station won't be heard and vice versa adjust it for a weak station and the strong station will be very loud.
I little trickier to connect an external audio input to as the the "volume control" controls the rf gain and the level of signal that comes from the ant. This is why the volume control has two sections.
Not sure about distortion from the detector stage but if it seems excessive there are way to deal w/that.
Common issues are caps, out of tolerance resistor (20%) is spec, open primaries on the rf coils. I had one w/a replacement power transformer, since that set uses 2.5v tubes the pt is hard to come by and expensive.
Always good to check output transformer and field coil for resistance.
GL
When my pals were reading comic books
I was down in the basement in my dad's
workshop. Perusing his Sam's Photofoacts
Vol 1-50 admiring the old set and trying to
figure out what all those squiggly meant.
Circa 1966
Now I think I've got!
Terry
![[-]](https://philcoradio.com/phorum/images/bootbb/collapse.png "[-]")
