I have recently been generously given this STC4113 cardioid ribbon mic which is rather in need of some TLC. The socket on the bottom is badly damaged and I don’t even know if it works. I think that it will make a nice little restoration project. However, as yet, I haven’t fathomed out how to take it apart!
The 4113 was designed by Michael Gayford (STCs chief designer) who was also responsible for the 4104 noise-cancelling lip mic, and played a key role in designing the famous BBC / STC4038 which is still made by Coles today.
In today’s money 11gns (ie £11.11s) is worth about the price of a Shure SM58
Although it was the cheapest of STCs microphones the 4113 features an unusual and innovative design and Gayford’s patent (filed in 1963) makes interesting reading.
Michael Gayford’s Patent for the STC4113
The plastic horn arrangement used in this mic to create a cardioid polar pattern appears to be somewhat similar to the one that is to be found in the Beyer M260. In both mics the plastic horn causes a shift in the phase relationship between the front and rear of the ribbon thereby modifying the polar pattern from the usual figure of eight to hypercardioid in the case of the Beyer, and cardioid in the STC.
So on with the restoration. My first job is to sort out that connector…….. I will report back.
SOME WHILE LATER……………………………………………………………………………..
The connector problem has been solved. Preh, the company who made the original connector still make exactly the same connector. So I have bought a brand new replacement!
Having prised off the grill it was immediately obvious that the ribbon was in need of replacement. So I decided to take the whole thing to pieces and re-build it! As you can see in the pictures below the plastic horn is glued to the circuit board, which makes it a bit of a pig to get apart! After prising it all all round with the blade of a knife the glue eventually gave way without breaking the board. Phew!!
And now all I need to do is to make an new ribbon, line it up in that gap, get it nicely tensioned and do up the clamps without breaking it!!!!!
This may take some time …………………………………………..
Da Dah!
Fully restored and repainted !! OK now to find out what it sounds like……………….
CLICK HERE for my first recording which is a simple voice test.
And now for something completely different………
Martin Mitchell's Microphones 
Hi Martin.
Nice post, and good to see that patent! I found that these mics are mostly glued together and not easy to pull apart.
The connectors fit the standard bayonet style DIN plugs which are still available. I might have some if you get stuck.
Stewart
LikeLike
Thanks Stewart.
I had an awful feeling it might be glued. Oh well that will be fun! I have just ordered exactly the same connector (same brand!) from CPC Farnell. Might also have a go at repainting it. Any recommendations on a supplier for disgusting grey/green paint?
Martin.
LikeLike
Hello Martin,
Get a pin and gently ease the grill away, it should come as it is just held with friction.
John.
LikeLike
Thanks John. Came off really easily.
LikeLike
Hi Martin
LikeLike
Hello, in the process of repairing the same model mic. How does one determine the correct tension of the ribbon? Being corrigated, I’m assuming the tension is tight enough to prevent the ribbon from moving freely but loose enough not to pull the corrigations flat!
LikeLike
Hi Evan, What you describe is, I think, the right approach. Just tight enough not to sag. I think I had about 5 goes before I managed to get it looking ok. So Good Luck!
LikeLike