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Post by phonogfp on Mar 7, 2009 11:02:07 GMT -6
About ten years ago, I stumbled across this gadget in an antique shop. It was pretty dirty, but I could just make out the "Davis Phonograph Company" lettering on the trademark. I'm still not sure what this was designed to do, as I don't know a capacitor from a resistor. But I think I recognize an amplifier in there, plus a volume pot, so my guess is that this device allowed the owner of an acoustic talking machine to use a magnetic pickup to play records through a radio speaker - without using a radio. I'd be interested in knowing for sure, and I'm confident that you electrical-guys out there will know... Here's a shot of the device, with a cylinder record for scale. Dimensions are 6 1/2" wide x 6 1/2" deep x 8" tall:  Here's a couple of shots of the innards. Power cord is to the left:   Here's a closeup of the Davis decal on the top plate:  And finally, here's a photo of a Davis triangular phonograph, from Phonographs With Flair. Sorry about the crookedness - - couldn't get it properly aligned on my scanner. Hope you enjoy the photos, and I'll appreciate any information you 1920s fellows can offer on this. How about the NAME of the device for starters?  George P.  |
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brad
One Spring Motor
Posts: 41
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Post by brad on Mar 7, 2009 18:25:35 GMT -6
George Paul,
The vacuum tube is a "tuning eye" or "Magic eye". They were introduced to the market in the mid 30's and were used as an indicator to visually show a level. In the case of an amplifier, it would show the relative amplification level. In a radio receiver they were typically used to indicate received signal strength.
Looking at the innards, it does not appear to be a radio so it is most likely an amplifier.
So this thing dates to the mid 30's at the earliest. Now the only question is: Was this used with a reproducer pickup to play an accoustic phonograph through a speaker, or to play a radio through a phonograph horn?
My vote would be for the former as by the mid 30's speaker technology was maturing an radio's with internal speakers were being sold. There were probably a fair number of folks that had a new radio and an old phonograph and old speaker laying around.
An interesting unit to be sure.
Brad
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chucka
One Spring Motor
Posts: 13
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Post by chucka on Mar 7, 2009 20:00:59 GMT -6
Not an amp, not an "eye tube"
The tube is a BH rectifier, circa 1926. The unit appears to be a homebrew filament supply for a radio, probably using 199 tubes. The control would be used to adjust the filament voltage.
The Davis plate was most likely just a piece the builder found in his junk box and it looked nice.
Chuck
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brad
One Spring Motor
Posts: 41
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Post by brad on Mar 8, 2009 17:17:49 GMT -6
I could have sworn that was an eye tube, however, I haven't come across one in several decades. If it is indeed a rectifier then Chuck is most likely right.
If it is homebrew, seems like someone went to a lot of trouble to utilize the "Davis" plate and cut holes for tube to protrude.
Perhads Davis marketed it for a radio?
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Post by phonojim on Mar 8, 2009 20:04:30 GMT -6
I think it could be a power supply for a battery radio. The components definitely have a '20s look to them. That case looks factory built, although it could have originally been made for something else and re-used for this. It's hard to say without seeing it. Moo, could you post a couple of pictures of just the panel (both sides)? That might give us more clues.
Brad, I see why you thought that tube was a tuning eye but I think it looks more like an early diode or triode. Also, any eye tubes I've seen had concave targets. I think what we're seeing is intended as some sort of shield.
PJ
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Post by Panatrope on Mar 8, 2009 20:44:12 GMT -6
Yes it's a power supply ,and i don't think it's home made ....the BH is a cold cathode rectifier
used in most all popular supplies in 1927-28 ,one of the most popular was the Majestic super b
eliminator Don
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Post by phonogfp on Mar 8, 2009 20:50:19 GMT -6
Poor Moo live about 900 miles from this device, so I'll be a pal and take the photos for him! Here are shots of the front and back of the top plate. It's made of the same material as the control panels of 1920s radios (Bakelite?).   Here's another photo of the interior of the device, with the pot moved to show the component beneath it. (I thought this was an amplifier.)  And finally, here's a photo of the bottom. The power cord enters the base from the left through a routed channel, then upwards into the interior. I fully confess my ignorance of most things electrical, but this device's construction argues against it being a home-brew - especially the top plate. These plates were not used on Davis phonographs, so unless a basement tinkerer had a spare Davis decal handy, how could this piece of (Bakelite?) have been so labeled? And why? George P.  |
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Post by phonogfp on Mar 8, 2009 20:57:53 GMT -6
Yes it's a power supply ,and i don't think it's home made ....the BH is a cold cathode rectifier used in most all popular supplies in 1927-28 ,one of the most popular was the Majestic super b eliminator Don If this is a power supply for a radio, to what are the 6 leads bundled together fixed? And to what are the 2 separate leads fixed?  My guess (again - an uneducated guess) was that the 2 separate leads went to an electrical phono pickup, and the 6 bundled leads were attached to a speaker. Please straighten me out - - and thanks!  George P. |
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Post by Panatrope on Mar 8, 2009 21:08:32 GMT -6
well it's packaged differently than the ones i have seen but the choke (i believe there is a transformer under the tube since the power cord is channeled there) look like one i had once
that was made by Kellogg switchboard company .... might be an OEM for Davis
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Post by Panatrope on Mar 8, 2009 21:22:55 GMT -6
George the thing was used as a battery eliminator the bundled wired are for B+,135,90,45,22.5
Volts DC ,it appears that the 2 wires enter the cabinet then go into the cable??? if so they are most likely for connection to an A (filament) supply or battery Don
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Post by phonogfp on Mar 8, 2009 21:31:17 GMT -6
Don, Thanks very much for your help! I'm barely hanging onto the electrical language, but I think you're saying this thing had NOTHING whatsoever to do with phonographs - right? If so, it's out on the curb tomorrow morning... Thanks again, Don - - George P. |
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Post by Panatrope on Mar 8, 2009 21:40:15 GMT -6
nope it's a RADIO item ....don't toss it!! Don
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Post by phonojim on Mar 9, 2009 12:52:37 GMT -6
Sorry George, my brain got scrambled. I agree with Don: don't toss it. Some radio guy out there can use it. And thanks for the extra pix. It looks authentic to me.
PJ
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Post by phonogfp on Mar 9, 2009 15:58:58 GMT -6
Jim/Don, Of course I won't toss it... Even though it's a radio item (if I'm to believe you!), it still has a phonograph company's name on it! Thanks to everyone for their help with identifying this thing. (I still think it has too many leads to be a simple power source...! Just wishful thinking, I guess...) George P. |
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Post by MTPhono on Mar 9, 2009 16:37:17 GMT -6
....and I was hoping you would throw it out hard enough to land somewhere near NW Montana....it's a cool phono-related item if only in name!
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