Hello All:

Who remembers the Sonic Cushion, a 47 light bulb wired in series with a
speaker, and a low ohm pot. Mounted in a small square plastic box.

This circuit used the 47 light bulbs variable element resistance vs
variable current, as a sound cushion for SSB. Works prett good.

I have one wired in and think I have it right!?!?!?!?

Any web sites on this?

Jay in the Mojave

On Sat, 16 Sep 2006 20:14:53 -0700, Jay in the Mojave
wrote in :

Hello All:

Who remembers the Sonic Cushion, a 47 light bulb wired in series with a
speaker, and a low ohm pot. Mounted in a small square plastic box.

This circuit used the 47 light bulbs variable element resistance vs
variable current, as a sound cushion for SSB. Works prett good.

I have one wired in and think I have it right!?!?!?!?

Any web sites on this?

Jay in the Mojave


Light bulbs have been used for years for compression in line amps and
preamps, and have even been used as regulators in some older tube-type
signal generators. But I've never seen one on a speaker except as a
dummy load. Your circuit probably combines both functions. Try looking
at compression circuits on epanorama.net.

Jay in the Mojave wrote:
This circuit used the 47 light bulbs variable element resistance vs
variable current, as a sound cushion for SSB. Works prett good.

Jay, not sure what you mean by cushion... please explain.

www.telstar-electronics.com

Hello TE:

During the 70's when a lot more SSB activity was on the CB Band, like 16
LSB, (27.155 Mc) and the big rig guys could slide down to 27.150 or even
27.145 with there ham rigs, or modified cb radios. And a bunch of CB
Radio Clubs sprang up. It was great!.

The poor design of the CB radios had a problem when the Squelch was set
to remove the background noise, then a strong SSB station would come
blasting in actually hurt your ears, you couldn't hear the far away SSB
stations, as you needed to turn up the Volume to hear them, hoping a
near by strong SSB station didn't come in blasting you out of your
chair. The AGC in the receiver was at fault.

The Sonic Cushion would allow the far away stations, and not so loud
stations, and Loud Stations to have closer audio levels going to the
speaker. So that you are not constantly adjusting the Volume Control up
and down. It was a real problem.

There where trick audio buffer amplifiers out there and they worked quit
well. But you had to be with a group or the in crowd to have access to
one of these constant Volume Buffer Amplifiers.

So many of these Sonic Cushions where sold at CB Breaks, and even CB
Stores. It is pretty clever. It uses the variable resistance of a GE 47
light bulb element as the audio cushion.

The audio from the radio is feed across the end terminals a 25 ohm, 2 or
3 watt Pot. The ground and wiper is then feed to the GE 47 Light Bulb
and speaker. The GE 47 Light Bulb is in series with the speaker coil.

The Radio Volume is turned up to say half way or even more. The Sonic
Cushion is then adjusted to allow a nice comfortable listening level.
The light bulb lights to the radios audio output, and of course brighter
for loud SSB stations, which the light bulb has more resistance when
more current is flowing thru it, and less resistance when a lower
current is flowing thru it, then leveling the audio voltage feed to the
speaker.

I have a Heil DSP External Speaker, connected to a Icom Pro 746 Radio,
and it could use a slight degree of audio leveling, or cushioning. For
SSB and CW. Its a big help when the beam gets turned around and
different stations come crashing in.

Jay in the Mojave


Telstar Electronics wrote:
Jay in the Mojave wrote:

This circuit used the 47 light bulbs variable element resistance vs
variable current, as a sound cushion for SSB. Works prett good.


Jay, not sure what you mean by cushion... please explain.

www.telstar-electronics.com

Jay... good explanation. Do you feel the audio AGC in todays radio has
been improved to the point where you don't need such a device?

www.telstar-electronics.com

Hello TE:

Yep I sure do.

Not only do they need a good tracking AGC, but a variable audio level
control that would adjust the audio levels from all stations the same or
at least with in a few dB of each other. A Automatic Level Amplifier
can't be to hard to run down off the net.

The Sonic Cushion does a very good job with all this. Worth the parts
and time to experiment with. With the rigs DSP (Digital Signal
Processing) Noise Reduction, digital filters, attenuator, and nose
blanker, the addition of a sonic cushion will also help, I think.

By being able to rotate the beam away from atmospheric noise and
unwanted stations is also a big help. The use of the beams rejection and
rigs attenuator and filters, its amazing what unwanted stations signals
can be put in the noise. Even loud and strong local signals!

The Moonraker 4 has a 45 dB null 110 degree's off the front of the beam,
by turning the beam null to the unwanted signals direction will drop em
like fly's.

Jay in the Mojave


Telstar Electronics wrote:

Jay... good explanation. Do you feel the audio AGC in todays radio has
been improved to the point where you don't need such a device?

www.telstar-electronics.com

"Jay in the Mojave" wrote in message
...
Hello All:

Who remembers the Sonic Cushion, a 47 light bulb wired in series with a
speaker, and a low ohm pot. Mounted in a small square plastic box.

This circuit used the 47 light bulbs variable element resistance vs
variable current, as a sound cushion for SSB. Works prett good.

I have one wired in and think I have it right!?!?!?!?

Any web sites on this?

Jay in the Mojave

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

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

"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.

Hello Jimmie D:

No I didn't think of that! Maybe worth a try.

I have a good friend on 40 that is going to send me a custom circuit
that is supposed to do all this, and has a smart squelch to. We will see.

Jay in the Mojave

Jimmie D wrote:

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.