"Jay in the Mojave" wrote in message
...
Hello Jimmie D:

Ok good deal, yeah thats what I was talking about.

My Sonic Cushion only used one light bulb, but that was for a old Johnson
350, 2 channel SSB only transistorized radio I used back in the 60's and
70's.

Yes you needed to turn up the volume, then turn up the pot, and it worked
quit well.

I will have to try the two GE 47 bulbs and 5 ohm resistors and see what
happens.

Another thing we use to do was install two diodes cross polarized across
the speaker terminals to soften the blast from a old high voltage tube rig
that, sent a blast of voltage when the radio was unkeyed. Like a General
Radiotelephone Super MC-11A.

Thanks for the reply, Ah the memeories.

Jay in the Mojave

Charlie Alpha 5

Jimmie D wrote:

Hi Jay , yeah I remeber those as an automatic volume control. Boy that
was back in the 60's. I know I can date it back to between probably 67
and 69 when I first heard of it because I used one on my old
Hallicrafter. The Halicrafter had AVC but this worked better for keeping
you from getting blastedd by a strong signal that suddenly appeared when
you had everything cranked up to hear a weak signal. Bulb would have to
be in series and resistor in paralell because the bulbs resistance goes
up whenever more current flows through it. If it works it must be right..
That is to say I dont remember either but I do remember it using two
bulbs and the model I built was to be used with headphones. You had to
crank the volume on the radio way up and then use a control on the box to
adjust it to listenng level.

Ok I found something that is just opposite what you wanted, I dont do
ascii drawings so I will have to discribe it to you.
Imagine a bridge circuit made of two #47 bulbs and two 5 ohms resistors.
They are wired so the resistors dont connet to each other and the bulbs
dont connect to each other but the bulbs do connect to the resistors.
Input is through a pair of opposite corners of the bridge and output is
through the other pair of opposite corners. At first I thought that you
could reverse the position of the resistors and diodes to get what you
wanted but after describing it I realized you would still have exactly
the same circuit. Cicuit is in CBers Handybook

Have you thought about putting a photo resistor in paralell with or
replacing your resistor, light from the bulb wuold casue the resistance to
decrease this should make the circuit more responsive. Its been a long time
since I played with photoressitors so I dont remember what kind of
resistance range they have. If they get low enough this could work pretty
decent.

I never thought that trying to do this on an 8 ohm circuit was such a great
idea. Doing it at sayy 100 ohms might be better using a lower wattage bulb
than the #47. Even at 8 ohms I thought a 3 volt flashlight bulb may do
better.

I never tried these ideas though because I took another route building my
own select-o-ject and incorporating an AVC circuit into it.