1957 Stromberg Carlson Hands Free Phone

[.....]

Finely got around to putting away the great pieces I got from Dave Hunter after visiting him. I had to store most of it in my cargo trailer, as my garage was getting full. I kept out the Stromberg Carlson Hands Free Phone, it is the next project on my list.

[HarrySmith]

That is a very cool phone, I have never seen one like that. Keep us updated on the restoration!

[oldguy]

don't know about the phone but you have a very nice trailer.

[.....]

That is a very cool phone, I have never seen one like that. Keep us updated on the restoration!

Thanks Harry, Will do, it is the very next thing on my list. I have never seen one before either, so it should be interesting.

don't know about the phone but you have a very nice trailer.

Thanks Gary, I got a super deal on it this spring and it works out well for the overflow that my wife can't see.

[Alex G. Bell]

Does it contain transistors or battery operated vacuum tubes such as 7-pin miniature and hearing aid types like the WE 1A speakerphone?  I suppose probably tubes.

Any date markings?  Perhaps there are on the transmitter and receiver.

[unbeldi]

Did you get the small microphone unit that belongs to this set ?  I don't see it in the picture.

[.....]

Does it contain transistors or battery operated vacuum tubes such as 7-pin miniature and hearing aid types like the WE 1A speakerphone?  I suppose probably tubes.

Any date markings?  Perhaps there are on the transmitter and receiver.

Sorry, but I haven't had a chance to have a good look at it yet. Just finishing up another project. As soon as I get it apart, I will post some more pictures and information on it.

Did you get the small microphone unit that belongs to this set ?  I don't see it in the picture.

No, there wasn't any microphone with it. Do you have any pictures of what it should look like? 

[unbeldi]

No, there wasn't any microphone with it. Do you have any pictures of what it should look like?

Here is the entry from the 1960 SC catalog:

[.....]

Here is the entry from the 1960 SC catalog:

This is great information, Thanks!

[HarrySmith]

Here is the entry from the 1960 SC catalog:

Very Cool! I would imagine the microphone would be rather difficult to source!

[jsowers]

That mike was made by Shure and I've seen them in other applications like with tape recorders, so they're not exceedingly rare. Other manufacturers put their names on them, like Bell and Howell, RCA and Revere. They are Shure CR-80, CR-81 and CR-84 that I've seen on a quick check of eBay. They seem to be quite pricey, so good luck finding a cheap one. They have a hammertone paint finish that comes in several different colors like gray, brown, green and beige. Here's a link to one on eBay and all are about $100 or more. Yikes! Keep looking and you may find a cheaper one.

http://www.ebay.com/itm/192253843064

When I started working on school AV equipment about 1980 these mikes were everywhere. I never thought they'd be valuable.

[Alex G. Bell]

No, there wasn't any microphone with it. Do you have any pictures of what it should look like?

I have an identical mike, not as part of a speakerphone, except mine has the original Shure Brothers name tag on it and it has a slide switch on the upper right side which the S-C version might not have.  It's marked "Model 510S" on the back.

Mine measures 1000 ohms DC resistance which is kind of high for a "dynamic" mike but it deflects a compass, so it contains a magnet and it's almost certainly a low impedance "dynamic" rather than very high impedance "crystal" (piezo-electric).  Perhaps the Shure CR-80, CR-81 and CR-84 jsowers mentioned are piezo. 

Piezo ("crystal") is more likely with vacuum tube AV equipment and would be naturally more compatible if the circuitry inside the main unit uses vacuum tube.  Dynamic is more likely if it's transistorized, but 1960 is a bit early for S-C to have produced a transistorized design.

It should be easy to determine the characteristics of all these models on line.  I've found Shure mike catalogs in the past when I was researching a 55S.

[paul-f]

Similar Shure mics are readily available, but you'll probably want to look for one with the proper SC markings like the one in the photo here:

   http://www.paul-f.com/sc1583.htm

[.....]

Similar Shure mics are readily available, but you'll probably want to look for one with the proper SC markings like the one in the photo here:

   http://www.paul-f.com/sc1583.htm

Thanks Paul for the picture and the link to your site. That information will help me out a lot with my restore.

[paul-f]

You're welcome, Doug.

I see I haven't updated that page since 2002.  As I recall, I had a digital camera that was tethered to my computer, as most of the electronics were on an ISA card inside the computer. Those 320px × 240px photos were the maximum resolution!  How things have changed. I should update the page as time permits. I'll also check the paper files for more info.