[ARC5] Receiver current drain

[J. Forster]

Mike,

I think a couple of hundred milliwatts is actually wuite a lot of audio.

In school, I built a transistor totem pole stereo amplifier that would put
out about 1 Watt into 4 Ohms. Expecting little, I hooked it to a pair of
AR-3s, which are low efficiency, acoustic suspension, speakers. It was
surprising loud before clipping.

Run at normal voltages and properly matched to a modest speaker, the audio
should suffice for most applications.

YMMV,

-John

================


>>We must remember that in military service, this tube was driving
>> headphones
>>at the 100-200 mW level so there was no requirement to generate a large
>> amount
>>of audio.
>
> Is that really true?  WWII-era aircraft interphone systems (pre-AN/AIC-2)
> did NOT
> amplify the audio of ANY receiver connected to the system.  They simply
> routed
> receiver AF outputs to each station box.  Bomber installations of, say,
> the
> SCR-274-N could worst case have ten headphones connected in parallel to
> the AF
> output of the receivers. (Though most stations would be usually selected
> to the
> interphone amplifier's AF output, itself usually a simple one-tube
> amplifier that
> amplified *only* microphone audio.)
>
> Apparently the AF output of the command, liason, and DF receivers was
> enough to
> meet the demand.
>
>>...some owners have in the past reported adequate audio output into a
>> loudspeaker
>>even with the original value...
>
> In the 1960s, I often used a BC-453-B to monitor maritime Morse around 500
> kHz.
> I got adequate drive for a speaker by using an appropriate
> impedance-matching
> transformer.  No receiver AF tag modifications were required.  (I used a
> 240 vdc
> HV supply.)
>
> Mike / KK5F
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