[Hallicrafters] Headphones

[Roy Morgan]

>low impedance (8 ohm) Yaesu phones ... Unbelievable HUMMMMM

Mike,

Yup. Normal behavior of the combination.

>  C. F. Cannon Co.... how old these things are

I am just guessing, but 30's to the late 40's maybe.  Investigate web sites 
that have earphone collections to find out more. (I did not have any luck 
with a quick search, however.)

>and maybe what impedance?

You can guess by measuring the DC resistance: multiply by 3 or so to get AC 
impedance.

>Can anyone explain why these work so well
>with the old receivers compared to the modern 600 ohm Califone?

They have very little response at 120 cycles which is the frequency of a 
lot of boatanchor radio "hum".

Roy

- Roy Morgan, K1LKY since 1959 - Keep 'em Glowing!
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