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How to test an old mic?

calorgas

calorgas

Generic middle-aged man
I've got a couple of 60's mics here with me. One is going on to a friend anyway but the other I may keep or sell. They're old ribbon mics mainly designed for voice recording as I understand it. Made by STC, middle one on the left in the advert in this link:
http://www.saturn-sound.com/images - adverts/advert - stc & transcriptors - hi-fi news - mar' 68.jpg

I'd like to test whether they're actually working OK but it's 40 years since I considered doing anything with a microphone and tbh I don't really know how to go about it! Could I use the tape in/out on my amp in some way and it be audible through the speakers?
 
I suspect that this will largely be down to the connector.
If you Google "microphone test", there are loads of hits, some online testing just using the mic' in on your laptop. That old though, either quarter inch jack, or bare wires, presumably?
 
You need a mic input on a tape deck or your computer may have one in mini-jack form. Plugging it into a PA or guitar amp would work too if you know anyone who has one. If they are ribbon mics they may well need a power source too, but that is something specific to that mic that really you can only find out with research.
 
Thanks for the replies.
I don't have a tape deck but I do have an older laptop with a mini-jack mic-in so that could work. The mics do come with leads, ending with male 5 pin din - not sure if there's an adaptor available for that conversion!? .......Oh, just googled and there is! Not sure whether the wiring would necessarily be correct though.

They don't need their own power source.
 
Never ever blow into a ribbon microphone!!

It will dislodge the ribbon rendering it as useless.
 
I once bought a tatty old Shure SM57 at a street market, the cost was 30 pence. :)

On testing the sound produced was ragged and distorted with low output.

When stripped down, the membrane had become partly detached from the magnet ring.

A light smear of superglue underneath the membrane restored the Mic to a full and undistorted output.

The test was to put the mic out of my kitchen window in souf Landon to record the dawn chorus, a beautiful recording.
 
Darmok said:
Never ever blow into a ribbon microphone!!

It will dislodge the ribbon rendering it as useless.
Click to expand...
Duly noted, thanks :). Luckily I've not done anything to them at all as yet other than to take them out of their leather cases and look at them. Weighty little things!

There's a couple of cheap female din to mini-jack converters on ebay; Type A or Type B, whaddya reckon?
If I can't work out what would work then I may just leave them well alone rather than risk knackering some nice quality vintage kit.
 
Ribbon mics need a high gain preamplifier, especially old ones.

I suspect you'll have noise issues with inexpensive interfaces. I have a Reslo from the same period and there's not enough gain with my Neve preamps.

You should be able to test it with any mic input—but you might not be able to tell if it's undamaged!

Have a look here.

WHAT DISTINGUISHES A RIBBON PRE FROM A STANDARD PRE?
There are 3 distinct features of a ribbon preamp:
  1. Low noise
  2. High gain
  3. High impedance
Where are you based. I'm usually to far away from anyone in Norwich to help!

PS I think yours are the same as these. I love them on drum overheads. Your friend is very lucky if you are giving it away!

Stephen
 
Thanks for the links Stephen.

Yeah it would be great to know if they worked properly but sadly I'm way over on Somerset so I may be stuck with a limited test into a laptop.

The ones here are not those fancy studio mics so probably not quite so exciting, they're 4119 which apparently are 'double ribbon cardioid' mics. To be honest I expect them to be fine as apparently they were only used for voice recording in a domestic setting, although the domed grilles has some slight dints.
 
You could plug a ribbon mike into a moving coil phono stage - you`d get a bit of a squiffy response but you should get enough output to see if it`s working.
 
Most ribbon mics have a built in transformer. other than a few vintage rarities they are permanent magnet and don't need power.
A cassette or R2R deck with "mic in" would be ideal..

Pity they're not 4038's!
 
Arkless Electronics said:
Most ribbon mics have a built in transformer. other than a few vintage rarities they are permanent magnet and don't need power.
A cassette or R2R deck with "mic in" would be ideal..

Pity they're not 4038's!
Click to expand...

I assisted in a recording session in Westminster Abbey using just a crossed pair of 4038s for the whole Orchestra, none of this separate Mic on every instrument and fix it in the mix lark in those days.....
 
Looks like a potentially interesting mic. Half the price of a 4038 which sell for around a grand new these days so I'd expect it to be decent (I'd expect anything by STC/Coles to be fairly decent). A hypercardioid ribbon mic is a really useful thing too. I found a short thread on Gearslutz.

The good thing about passive ribbon mics is that they're pretty simple devices with no electronics to fail. After 40 years the ribbon may well need to be re-tensioned or replaced though.

Stuart at Xaudia is pretty much the authority on British ribbon mics and super helpful. I'd drop him a line and get his advice.
 
Thanks Paul, I may well contact him - it would be interesting to know if he rates them and whether it's worth getting it/them serviced. I'd read that thread you linked to plus there's a handful of other mentions of this model on the web which seem to suggest that they were decent things, but I guess as I have no obvious use for such a thing there's a limit to how much I'd invest in bringing it back to tip-top condition.

I have the part I need to connect the mics to the laptop on the way now, so I'll see if I can do a rudimentary test in the meantime.
 
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