GE Superadio III awful with headphones

[lthanlon]

A relative recently gave me a General Electric Superadio III that she found at a church rummage sale for $15. The radio is in mint condition and came in its original box. I wouldn't characterize its AM DX abilities as especially super, although it does pull in a fair number of distant stations, especially after dark.

The two speakers produce excellent sound, but when listening with headphones or earbuds, the background hiss makes serious DXing impossible. (Late at night, I need to listen with headphones to not disturb other members of my family.)

I've never owned or operated any Superadio models before; is this headphone-hiss problem typical?

Leigh Hanlon
Chicago, USA

[13dka]

According to this thread

https://antiqueradios.com/forums//viewt ... 82&start=0

this could be a general problem with them. Alas there is no remedy listed, also not on this site with modifications:

http://earmark.net/gesr/sr3.htm

High impedance headphones could mitigate the problem a little as an easy option, particularly if you use 8 Ohms cans some 32 Ohms or higher could help.

[Andrew (grayhat)]

According to this thread

https://antiqueradios.com/forums//viewt ... 82&start=0

this could be a general problem with them. Alas there is no remedy listed, also not on this site with modifications:

http://earmark.net/gesr/sr3.htm

High impedance headphones could mitigate the problem a little as an easy option, particularly if you use 8 Ohms cans some 32 Ohms or higher could help.

aside from modifying the radio,. I wonder if a simple external audio filter may be of help

[lthanlon]

Thanks for the ideas! I'll look into higher-impedance headphones.

[13dka]

I wonder if a simple external audio filter may be of help

Anything that allows for turning up the radio's volume (to lift the audio over the amp's noise floor) and reducing it on the other side will help.

[Andrew (grayhat)]

in such a case

http://www.qrp.gr/tmaf/



[edit]

the original filter along with infos about its working can be found here

http://www.qrp.gr/tmaf/The_Magical_Audio_Filter.pdf

it's basically a double audio filter implementing both a passband and a notch, the original one was mostly aimed at CW, but with the modification at the first link above, it can also be used for AM/SSB due to the ability to adjust the width of the passband, the notch is then used to remove whatever unwanted adjacent signal/noise, notice that, if desired, the circuit may be further extended by adding a second or a third notch stage