[ARC5] My mil phones - solved.

[Kenneth G. Gordon]

On 2 Jan 2015 at 17:20, Dennis Monticelli wrote:

> They are probably HC -43B/U

Yes. That's correct. I just looked.

> which were made for Geiger counters.

Oh. That's the reason for the BNC then...

>  These are
> darn good phones if you take care to match impedances for max power transfer.
>  1mVrms is plainly audible and that equates to 50 pico watts.

Oh. OK. Well, then I guess I'll have to learn how to use them correctly.

I bought them off eBay some time ago because I have always felt that 
headphones should have the highest impedance available, especially for 
crystal sets...

>  I use my pair
> for crystal sets where the impedances are naturally high and sensitivity
> paramount. 

OK. Well, I have not yet had a receiver with high enough impedances yet I 
guess.

> BTW, the datecode on the sealed package that my NOS phones came in was 1990.

Seems to me that mine was in that region too.

OK. Well, I'll have to reevaluate these. Thanks, Dennis.

Ken W7EKB