Month: November 2012

22-11-2012

Film Industries M8 XLR mod

Film Industries M8 ribbon mic with XLR
In the days before XLR became the standard microphone connector, most manufacturers made their own custom connectors. The British companies Reslosound, Grampian, Cadenza and Film Industries all followed this practice.

I guess at the time it was a good idea and meant that the company could earn extra revenue for spares and replacements, but 40 or 50 years down the line it is becoming increasingly hard to find good quality  connectors for these mics.
Here is a humble Film Industries mic that arrived without a connector. It was converted to XLR at the owners request. With a bit of care the new connector can be fitted without spoiling the look of the mic. Now it is good to go back into service. Better than being stuck in a box!
08-11-2012

Italian ribbon microphones

Today we took delivery of some interesting microphones from Italy. Here they are with some other resident Italians.

Geloso double ribbon, Framez, Do-Re-Mi 351MN, CM, Magneti Marelli MC46, Riem and Meazzi

From left to right we have ribbon mics by Geloso, Framez, Do-Re-Mi, CM, Magneti Marelli, Riem and Meazzi.  On closer inspection it seems as though some of the different brands came from the same factories.

The motor of the Do-Re-Mi mic is the same as the Framez, and the Riem is a skinny version of the Meazzi. We also know from previous research that Framez and Meazzi were related companies. Magneti Marelli made 74B copies under license from RCA.

We know less about the RCA-shaped CM microphone. In fact nothing at all about it, other than it is a fairly standard design, made for public address use.

It seems as though there was once a a thriving ribbon mic industry in Italy, with numerous brands and models, but I don’t know of any modern Italian ribbon mics.

Update: I found this ad for the Riem ribbon microphone, from the magazine Selezione Radio, Feb 1952.

03-11-2012

Ribbon mic patents

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!

Harry Olson, Marconi, July 1932.  
Improved ribbon mic with tube amp and better housing. Possibly the first tube ribbon mic! 
Olson, Marconi, May 1933. 
Directional microphone with velocity and pressure components connected in series.
Otto Kolb, September 1933. 
Ribbon mic with 1 to 1.5 micron ribbon and holes in the pole pieces for improved air way.
Andrew Swickard, Bell Telephone Labs. July 1936. 
Ribbon microphone with both velocity & pressure sections
Thomas Julian, GEC, March 1944. 
Improvements in ribbon microphones.
Horace Duffell, Radio Gramaphone Development, June 1947
Adustable magnet pole pieces. 
William Cragg, Standard Electric Corp. December 1945. 
Velocity microphone with ribbon supported along its edges
Helmuth Eckardt, Bell Telephone Labs, May 1949. 
Describes a 3-zone ribbon to eliminate distortion and improve frequency response. 
Donovan Shorter & Hugh  Harwood, BBC, March 1953
Improved ribbon microphone design. Looks very much like the STC / Coles 4038!
02-11-2012

The Trashcaster Lives!

Finally the Trashcaster guitar is finished. This started life as some parts on ebay – an old vox body and broken scratchplate, a Squire neck, hardtail bridge and knobs from a Jazz Bass. Add some paint and a pair of home-made pickups…. behold the Trashcaster!
Xaudia ‘Trashcaster’ guitar
The Trashcaster has custom wound big single coil pickups, with coil tap and phase switches, a blend pot, and normal tone and volume knobs. Wiring the blend pot was fun. You have to get the turn direction right otherwise all of the sound disappears! With these controls the guitar has a wide range of tones, and the out of phase sound Nashville tone is definitely something unique!

I have strung this for Nashville tuning, which is the same as the high strings on a 12 string guitar. So when played along with a guitar in standard tuning, it fills in the holes and sounds a bit like a 12 string, but with micro timing difference there is more of a chorus sound to it. You have probably heard this effect on countless records without knowing it.

A couple of coats of clear lacquer helps the slide-on decal blend in. But perhaps I should have called it the ‘Nashmaster’. Too late now! The last job was to file the nut to take the narrower gauge Nashville strings, and to do this you really need a proper set of nut files. They are not cheap but I found these ones on ebay for around £40, and they did the job quickly and accurately.