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1940s Radio Corporation of America OR-1A Loudspeaker Unit (MI-11212)

E

ellabellanee

New Member
Hi everyone!

A few years ago I acquired an early 1940s Radio Corporation of America Loudspeaker Cabinet. It was originally a part of the OR-1A Portable Recording System, which consisted of a 16" MI 11212-B Turntable, a Type 72-D Recording Attachment, Universal Pickup and Arm Assembly, a 12 watt amplifier MI-11212 with dual loud speaker unit.

It was in working condition when I got it (with a Bell 3715 amplifier). However, at some point my boyfriend and I decided to run a Shure Vocal Master into it as a PA speaker... and of course we blew the thing up.

Now, when it receives a signal, it makes a rattling sound. Please see the videos I've linked below:

Older video of the loudspeaker in working condition

Video of the loudspeaker in current (broken) condition

I am seeking advice:

1.) Any idea what might be wrong with the speakers?

2.) What should I do next?
I am located in Wheeling, WV, about an hour west of Pittsburgh, PA. I don't know if I should try to have it repaired (is there someone here who specializes in repairing vintage speakers/cabinets).... or sell it as is.

Thanks in advance! :)

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First of all, that is super cool.

It is a little hard to tell anything from the second video. Can you take one where the perspective is closer to the first video? I am no expert, but it sounds to me like a serious voice coil rub.

My guess is that: That cabinet has a 16 ohm driver that can only take up to 20 watts or so. You hooked it up to a 100 watt PA amp. Maybe you fried the voice coil.

If this is is the case the driver will have to be reconed. You can try Bill at Millersound. Note, he likes calls rather than email. http://www.millersound.net/
 
You'll need to determine if you have blown just one, or both of the speakers.

The OR-1A speaker used RCA's accordion cone speaker(probably MI-6234-A or MI-12435-C, the latter has a whizzer). Kind of an odd duck @ 7 inches diameter. It may be near impossible to find exact replacements today.

Let's see a pic of one of the actual drivers.
 
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