Originally developed by the BBC in the early 1950’s, and manufactured by STC and then Coles, the 4038 is known for being a somewhat fragile, but excellent sounding ribbon microphone.
We have been servicing the 4038 for some years, using original ribbons and replacement parts from the manufacturer. Average turnaround time is 2-3 days.
4038 reribbon service
The ribbon in this microphone is .6 microns thin, it is amongst the thinnest ribbons used in a production microphone, so is prone to damage if not placed carefully. Here are are a few examples of what can go wrong:
Ribbon imprint occurs when extreme excursion pushes the ribbon into the screening with enough force to imprint the screen on the ribbon. This is usually due to close placement of the microphone on guitar amplifiers. If the cabinet is moving too much air, it forces the ribbon against the screen, imparting the pattern of the screen on the ribbon.
The ribbon in this microphone appeared to be OK, but suffered from extremely uneven frequency response. Closer inspection revealed some clear glue used by another repair facility that had dried to the pole piece and ribbon, impeding it’s movement.
I can only imagine the life this ribbon lived.