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I had a buddy drop off an older Rode large diaphragm condenser mic for check out, clean up, etc. After getting all the issues with it sorted out, since it came in missing its windscreen the capsule was pretty dirty. With a q-tip and some windex I gently cleaned the outer surface. Right at the end of this I noticed that I was seeing through the gold surface. The windex was "cleaning it off". I was very gentle with it, but still a streak of the gold ended up on the q-tip. So I believe that the gold was acting as one plate of the capacitor setup....great. Is there a way to salvage these or did I just buy this mic?
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The farmer takes a wife, the barber takes a pole.... -
Uh yes, you did. You're removing the sputtered-gold coating that does, in fact, act as one plate in the capacitive mic capsule.
Did you buy it? Probably.
At least it's not a Neumann! :O -
So you are saying that clarity is not always desirable in a condenser mic?Education is what you're left with after you have forgotten what you have learned.Comment
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How does it sound? (or does it still sound?). How good of a buddy is it for? If it's not sounding terrible and you explain things to them...
At least you're not just telling him the problem was a bad capsule, like some less scrupulous than yourself might do.Originally posted by Enzo
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I haven't hooked it up as of yet.....its low priority. I have a feeling he got it for free so I may be able to work it out via a free repair or something. Live and learn....rookie card punched. I used a water based cleaner because it is a delicate capsule. I never thought windex would remove the plating. Oof...
I guess its still usable if I verify that the unidirectional mode uses the side I didn't touch, or swap the wires if not.
Guess it don't matter how careful you are, you still get bit in the ass once in a while........The farmer takes a wife, the barber takes a pole....Comment
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"The more it stays the same the less it changes..."
Originally posted by Enzo
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Aahhhh......someone finally got my .sig reference. Right ahn!The farmer takes a wife, the barber takes a pole....Comment
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Have you seen the version on the 25th reunion? It rocks!Originally posted by Enzo
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As a general rule, you cannot touch gold-sputtered diaphragms with ANYTHING, no matter how innocuous it might seem. Sputtering is a process that forces a molecularly-thin layer of metal onto a non-conductive surface, and it doesn't take much to wipe it off.
Condenser mic frequency and polar response is highly-dependent on both plates of the diaphragm being electrically identical. What you are dealing with here is a highly-accurate, acoustically-variable capacitor whose plates must sense equally.
The downside is that you DID remove some plating. The upside is that, unless you are dealing with Neumann, whose gold-sputtering is second-to-none in accuracy, most of these look-alike mic capsules are made in China and are not as critically accurate. In fact, they suck for the most part, but are really cheap, so most of the lower-end mic manufacturers with buy thousands of them, test them, save the ones that meet their design criteria, and sell of the rest to the next lowest-quality manufacturers. Sh*t truly runs downhill in the mic industry.
So, the amount of gold you removed might not matter much at all. Test it and see if it works. It actually doesn't take a lot to ruin a capsule. Most of them die due to the very contamination you were trying to clean off. It's usually saliva (and whatever is in it!) and moisture from being used (improperly) as a vocal mic. There is a very good reason why auxiliary mic windscreens are used with vocalists in the studio. First is to ward off contamination, second is to maintain distance and hence, wind blasts and pops.Comment
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from what I've read it is possible to clean a capsule but it's a very delicate operation. Something like an expensive sable hair brush plus (apparently tiny amounts of) distilled water (plus alcohol if necessary) is used. Google josephson microphones. Not good for the mic owner/cleaner, but maybe good in that other people can see how delicate the capsules are (and take appropriate precautions when using--try not to get spit on them, etc.).
re: the cheap(mostly China made) condensers and their capsules, it's probably not fair to compare them to German, etc. mics costing so much more. The sound clips I've heard (which vary) I wouldn't say sound so totally awful as to be unusable. Plus, I'm not so sure about this oft made characterization of super harsh ear piercing "Chinese highs" which seems to be repeated over and over on the internet. Maybe there is some (relative) truth to it, but I'm factoring in a herd mentality, plus possible inexperience (placement un-ideal), and possibly loading issues affecting response. Plus not exactly disinterested opinions from parties modding these cheap mics.
Anyway in re: to the mic, perhaps a replacement capsule can be found?Comment
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I wouldn't touch them with ANYTHING. The key to keeping capsules clean is proper use of windscreens and storage. Ask anyone who owns Neumanns.Originally posted by dai h. View Post
Like anything else that has come from Asia, starting back in the days of Japanese import, it is relative easy to make a lookalike, and there's a WHOLE lot of that on the market nowadays. There ARE some VERY good Chinese condenser mics or ones that use selected Chinese capsules. However, once you hear them next to a Neumann, the most common knockoff, it will blow you away. The difference is night and day. AKG, particularly the C451 and C460, are other mics that have been incessantly cloned. The Germans just have a way with microphone design and construction that is unparalleled, period. However, not many people have a budget for these, so the second and third-tier stuff like Rode, CAD, A-T has a definite purpose. To counter this, some German companies have issued stripped-down versions of heavy-hitters like the Neumann U87, AKG C414, but even THOSE can be pricey to some people. However, good recordings start with good mics. People who are serious about recording should consider renting good mics rather than purchasing mediocre ones. It DOES make a difference.Originally posted by dai h. View Post
Sorry folks, I went off on a ramblin' tangent!
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Yeah, that's one way to do it. This is only done as a last resort, i.e. there are no replacements available. And it may not get everything off of the capsule membrane. A Q-tip is a definite no-no. I've heard that they can also be cleaned ultrasonically.Originally posted by dai h. View Post
4 years ago, when I worked on microphones, the custom German capsules cost 26 times more than the Chinese capsules cost us. In the end, you're mainly paying for that capsule. Everything else in the mic is relatively cheap.Originally posted by dai h. View Post
And the problem with the "Chinese highs" was usually due to there not being any "Chinese lows", basically a noticeable lack of low end.
To be fair, the Chinese capsule quality actually got better over time, though.Comment
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sure but that doesn't help in a real world situation where a capsule has gotten dirty.Originally posted by jrfrond View Post
This is what I read FWIW:
http://www.josephson.com/clean.txt
http://www.prodigy-pro.com/diy/index.php?topic=19953.0
(Sorry, these are in Japanese! But I'll give you the gist of these.)
(This one is from the online diary of a repair guy who works for a (mostly) web based discount music store. He says he very carefully removed some black fibrous dust on the capsule surface of a Rode NT2 and got it working again. (He doesn't say what he used.))
マイクロホンの修理実録 ! サウンドハウスサービスマン日記
(This one is from a guy who runs a rehearsal/recording studio, and he basically chanced disassembly on a noisy NT2(was just going to buy some new mics otherwise), found a layer of some thin black stuff, tried cleaning it with tissue paper(!) and got it to work normally again.)
RED HOT ｻ
(King of going off on a tangent, but anyway) re: mic sound quality it seems that the old standbys (SM57 and SM58) are actually pretty good sounding ('course they've already been used on countless recordings), but what the mic output has come to see typically over time has changed (and perhaps consequently their peceived output). That is, older stuff usually had a step up transformer (with a pretty good step up ratio--1:5, 1:10, etc.) to increase the tiny output. On many modern low cost mixer preamps, there is no input transformer (too expensive, heavy), so more gain is required, the output can end up being more noisy and poorer in sound if the gain increase is accomplished through decrease of feedback. Also, since the 57 and 58 contain a transformer, seeing a relatively high input impedance (though it helps with not losing signal voltage) can cause ringing which can contribute further to poorer sound quality. I suspect in many cases a user never gets to hear the "true quality" of the SM57 and 58(except perhaps on recordings), and ends up with the conclusion that they are out-of-date, obsolete, etc. and that the low cost higher output, lower noise condensers are superior mics even though these mics can be pretty good sounding (relative to the expensive Neumann, etc.).
Thanks. Interesting point I'll keep in mind. (I've done a slight bit of modding on an MXL603S which uses a Schoeps circuit that many of the other cheap condenser mics use, and increasing the output coupling caps seemed to be a common mod suggestion.)And the problem with the "Chinese highs" was usually due to there not being any "Chinese lows", basically a noticeable lack of low end.
From what I understand, there are more expensive mics with Chinese parts (though I'm assuming the QC must be more stringent than the cheaper stuff).To be fair, the Chinese capsule quality actually got better over time, though.Comment
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The interesting thing about condenser mics is, they're basically the same as piezo pickups. Too heavy a loading resistance on the capsule causes loss of low end.
But, they have much lower capacitance than a piezo pickup, so the loading resistance needs to be much higher. I heard that a good condenser mic head amp can have an input resistance of 100 gigaohms.
To get that kind of impedance, things like component quality, construction quality, even quality of plastics and cleanliness start to matter. So that is one possible explanation for "Chinese highs": the bass is leaking away because of too low a load resistance.
I've got a pair of Rode NT5s and they're not too bad for the money. (I bought them on recommendation from Eric Persing.) Rode used to rebadge Chinese stuff, but they started making their own mics in Australia. Yes, they work better upside down
The other "good" mic I have is a SM57. I got it for micing guitar amps, and believe it or not, it does that pretty well.
As for transformers vs. no transformers in mic pres: Practically no mic pres have transformers any more. The reason is that transistor design got good enough that they can deliver near theoretical noise performance from a 200 ohm source. Transformers were really best for tube-based pres. Tubes give lousy noise performance at 200 ohms, they're better suited to higher impedances, so the transformer makes a big difference. 1960s vintage transistors probably had the same problem.
The input transformer is still great when you're working in really aggressive environments with lots of interference. It kills RF and so on."Enzo, I see that you replied parasitic oscillations. Is that a hypothesis? Or is that your amazing metal band I should check out?"Comment
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Fact is, *both* Chinks and Aussies walk upside down, so their mics should match each other very well [Rode used to rebadge Chinese stuff, but they started making their own mics in Australia. Yes, they work better upside down]
Juan Manuel FaheyComment
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