Here are some upgraded, modified and generally pimped mics that we have put together for customers.
In each case the microphone gets a new ribbon, upgrade transformer and a few other tweaks, along with a shiny new badge.
Here are some more ribbon microphone related patents, both US and British, from the 1930s, 40s & 50s.
The diagram (above) is from one of the patents, and may be the first tube ribbon mic!
A few weeks ago we received this rather forlorn looking box of Melodium bits for service!
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| Melodium 42B stripped down to parts |
The good news was that all the important parts were there, and despite some corrosion, the magnets and the transformer were on good shape, which meant that this vintage gem could be restored to some of its previous beauty.
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| Melodium 42B repaired and re-ribboned |
The mic was stripped down and all the parts cleaned up in the ultrasonic bath. Then the magnets and some other bits were painted to stop the rust returning, and the motor reassembled. Dino (the owner) wanted to retain the vintage look of the mic, so the grills were straightened, de-rusted and then given some clear lacquer rather than being refinished. New grill cloth gives some protection against pops and wind blasts.
Then it was put back together and a new cable fitted with XLR output. And of course a new ribbon. The mic looks pretty damn cool!
Thanks to Dino Jakobsen of The Why Project.
The good old BBC have made many of their research and development reports available through their website, spanning 1944 through 1996.
1945
The Crosley ribbon velocity microphone.
1953
Lustraphone VR53 ribbon microphone
The design of the PGD and PGS ribbon microphones.
The EMI microphone Type 2351E.
Tannoy microphone Type MD. 422.
1956
Design of the PGD and PGS Ribbon microphone Part 2
1958
RCA BK5
1961
Reslo RB
1965
Beyer M160
(Thanks to Santiago Ramos for sending the links.)
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| Failed magnets in a T-Bone microphone |
The coating around the magnets had peeled away, allowing the rare earth magnets to oxidise and expand. This process of course destroys the ribbon too. The magnets can be replaced, but may not be worth the expense.
I have seen a few microphones that look like this, and the worrying aspect is that it seems to happen spontaneously, possibly because the coating on the magnets was not of high quality, or perhaps they were scratched or cracked on installation.
Nearly all manufacturers now use neodynium magnets for their microphones, and I fear a epidemic in the future.
