"craigm" wrote in message
...
William Sommerwerck wrote:

As that time draws close, you'll have to turn the radio up a little
more to get the same volume, but you probably won't notice. Then, the
sound will become a little distorted, and you might eventually notice
that. Not too much later, what you describe will happen. (The FM
section takes more power than the AM and will stop working sooner.)

I've never seen a radio in which the tuner sections are separately
powered. Compared to the output stages, they draw little current.

Since the topic of this thread is the GE Superadio, you should look
at the schematics of the radio to provide some validity to your statement.
According to the schematics, both the Superadio I and Superadio III
remove power to the tuner circuits not being used.

My statement is completely valid -- I've never seen one.


While the tune sections may draw little current relative to the audio
circuitry when performing at full output, at lower output, the extra
current can have a significant impact on battery life.

If they draw little current -- relative to the audio stages -- then they
cannot have a "significant" impact on battery life.


And very few radios -- the GE P970A being an exception -- have
separate AM and FM tuners. We never established if this was the
case with the Superradio.

However, if your definition of tuner includes all the circuitry from the
antenna to detected audio, the Superadio I and III do not have separate
tuners as they both have common IF circuits.

I asked about this several weeks ago, but no one responded.

If these radios have common IF strips, then what sections of the circuitry
are there to be shut off when not in use?

FM/AM radios commonly use the same transistors for the RF amplifier, the
mixer, and LO. Are these Superadios different?