These dynamic microphones were released by GB Bell & Howell
GB being Gaumont British, part of the Rank Organisation in cinematography.
This microphone is considered very interesting for guitar amp or percussion instrument miking and it is especially good (or was!) at high sound pressure levels
We suspect the original manufacturer may have been Philips, Austria although there are online credits to Stuzzi of Germany also designing and manufacturing this microphone.
GB Bell & Howell microphone NON-FUNCTIONING!
Microphone is identified as GB D10/Hi
It also has a serial number, A24554
Released to the market around the mid 1950's
Comes with desk stand
95% sure that the casing is bakelite (dark grey) based on the following:
"clunk" test, has a distinctive clunking sound when the two halves are tapped together
Feels heavy for the size of "plastic"
Rubbing vigorously, I can smell formaldehyde
Dynamic element is unbranded - all metal construction
Measures: 45mm diameter x 22mm deep
Internal impedance transformer, which provides a high impedance output
Base has a 3/8" threaded socket so this microphone can be mounted on a boom or stand.
COSMETIC CONDITION:
Make no bones about this - the microphone is like new.
It has been boxed and hardly used in the past.
It was used by our sound engineer once or twice and then the element bombed out on us so into the cupboard it went!
CASE DETAILS:
NO chips or missing corners etc
NO scratching of the surface
NO cracks
NO case discolouration
NO marks or otherwise to the plated foldover grille - inside it has a very thin cotton like material to act as a barrier protecting the element from airborne moisture (spitting etc)
Internally there is practically no "foam" which would normally be well and truly disintegrated after all these years - no foam to replace.
By all reports from our industry colleagues, not a bad microphone to experiment with, especially for guitar amp or instrument miking
TESTING:
Rewired the line lead, we like to have our microphones with known good quality cables and we used some of our high quality single core audio cable (3mm red sheath) for this.
Fitted a 1/4" TS jack plug - the output is unbalanced.
If desired, it would not be a difficult task to rewire the microphone for a balanced output using XLR instead of the jack plug - see the attached photograph of the circuit.
No real advantage in going balanced though, being high impedance output it would be unwise to run a lead longer than about 20 feet otherwise the "top end" frequency response is going to drop off.
The audio lead fitted is 5 metres or about 15 feet long.
IT NO LONGER WORKS! The impedance transformer is fine but the dynamic element is crook - open circuit.
The original element is "press sealed" there is no way I will attempt to open it up!
This is being offered due to the excellent case with transformer but another element will need to be fitted (easy to do)
I WILL supply the original element so that the size of any replacement can be "matched up"
