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advice for buying a used mic? Condenser Microphones
Old 10th December 2010
Lives for gear

advice for buying a used mic?


Looking at a well-worn KSM44 but don't have another to compare to... how do I tell if the capsule has "lost it's luster" due to possible smoke, dust, impact, etc...? I don't have another 44 to compare it to.

Anyone care to lend their preferred methods for testing out used condensor mics???
Old 11th December 2010
Lives for gear
jmikeperkins's Avatar
You can test the capsule by breathing on it just enough to give it a small amount of moisture to see if it cuts out. A (condenser mic) capsule that is close to needing replacement will cut out for a second or two after you breath on it and then come back on. A good/better condition capsule will not cut out at all if you breath on it. The tiny extra weight of the moisture from your breath on a bad capule will cause it to hit the back plate and that is what makes the sound cut out, when the diaphram pops back into place, then the sound will come back on. I can understand a sellers reluctance to let you breath on their mic's capsule, but that is probably the best way to test the capsule. You can and should also make a visual inspection of the capsule to make sure it looks like there is still a reasonable amount of gold left on the capsule membrane (but a lot of mic capsules will continue to sound fine even when some of the gold has obviously been removed).

The other thing I would recommend is to buy a name brand used mic where service and parts are still available. Neumann, for example, still services virtually every mic they ever made going back to the 1930's! I know that if I buy a used U87, no matter when it was made (1967-present) and no matter what might go wrong with it in the future, it can be fixed and returned to like new condition because and the original capsule is still being manufactured. If you buy a silver AKG 414EB from the 1970's, with the prized original brass ring CK-12 capsule, and it goes bad, you have a problem because that capsule is long out of production. The modern plastic ring replacement from AKG (also called a CK-12!) is different, not as good, and having the replacement capsule drops the value of the mic by one half. I don't think there are any replacements at all for many of the vintage AKG dynamic mic capules like the one in the classic D12.

You should not have any problems getting parts for the Shure mic in question, but you can't say that about everything out there. Other than the capsule test, listening to the mic in general, and making a visual inspection, the only other thing would be to make sure the seller is reliable and honest. There is certainly nothing wrong with buying a used mic, and if you want a vintage piece you don't have any other choice, but you will always have to take some risk buying used.
Old 11th December 2010
Lives for gear

Thanks for tips! Much appreciated! Haven't heard about the capsule "breath test" before. :-)

I've actually got the mic in possession from a dealer with a good return policy. Looks like this one was on the road for a bit, judging by the case and a scuff on the mic itself, but seems to work fine. So far so good. (just vocal testing so far)

What's the best instrument (or method) to test the high-end and transient response of a LDC like the 44?
Old 11th December 2010
Gear Guru
John Willett's Avatar

The breath test also shows contaminants on the diaphragm.

These absorb moisture and the mic. will start to crackle if you breathe on it. A good clean capsule would not crackle in this way.
Old 11th December 2010
Lives for gear

Okay... I'll admit I'm a little nervous to try this given all the precautions I've heard about not exposing condenser capsules to moisture and humidity...
Old 11th December 2010
Lives for gear
audiogeek's Avatar

Honestly, a KSM 44 wouldn't really be old enough to have "lost its luster" due to dust, smoke, whatever, just based on regular use.

Barring actual damage to the capsule from a fall, or water or whatever, you're probably in good shape.
Old 12th December 2010
Gear Head

Not true about Neumann parts.
Many now are unobtanium, especially for the U47 and U49.
You can still get capsules that will work in those mics from Neumann.
Neumann does stock parts for the later models, including some for U67s and almost all parts for U87s, U89s and all of the mics manufactured recently.
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