Martian Special Radio

[TelePlay]

In my attempt to get the best set of working headphones for the radio, I tried two more tonight. The first was a over the head set I got from Mike's Electronic Parts which Mike claimed to be "High Impedance Piezoelectric Headphones" with the description of the item being

"These are High Impedance Ceramic Headphones. They have an DC resistance of over 20 Million Ohms similar to the above earphones there tested impedance is around 8,000 to 11,000 ohms. They have 1/4 inch mono plug ends and the cord is about 40 inches long. These are very good Crystal Radio Headphones.

Please note if these are not operated from a transformer you need a resistor across the input. Most crystal radios have a resistor in the audio output, if not add a 47K to 100K resistor."

Shown in the first picture below, they proved to be less than impressive producing a sound level about 30% of what I was getting using my Brush Model 200 piezo crystal head phones, the ones with the stiff cloth cord softened with Skin-So-Soft (the fragrance is totally gone now and the cord is still soft). While the seller claimed they are piezo, they did not perform well but I did not try the 47K to 100K ohm resistor across the leads. Will do that at another time. Stay tuned . . .

The second thing I tried was a piezo ear phone I found on eBay for less than $9 (second photo below). That earpiece provided about the same level of sound as my Brush 200's. I say less in that it was only one ear and the Brush headphone was providing sound in both, and with larger diaphragms. When connected in serial or parallel with the Brush headphones, the sound in both the Brush and earpiece stayed the same. Should have bought 2, one for each ear.

One side problem with this crystal radio project is my coming down with a new disease, headphoneitis.

[19and41]

The second one was the unit supplied with most of the germanium, inductor tuned crystal sets sold during the 1958 to 68 time frame.  The rocket, wrist and transistorless radios.

[TelePlay]

For what it's worth, here's a fairly good close up of the whisker on a crystal sweet spot . . .