Topic: Mic problem (loud humming)

[ChrisV]

So I am testing out my mics here at home.   I just got the cables recently so this is my first time actually trying them out.   And as I turn the levels up there is a very loud audible hum or buzzing that is coming from one of the mics....so loud that even in dead silence it is showing up on the meters big time on one side but nothing on the other.    So I tried to narrow down the problem by swapping the mic caps with the bodies and when I did that it switched sides.   So I've determined it is something wrong with one of the caps.    I am thinking I may need to get these serviced unless someone else can figure out a solution to the problem.   The mics in question are the Superlux SMK-H8K (if that matters).

If anyone has any ideas of what could be causing it please chime in.  Thanks!

[F.O.Bean]

has to be the damn caps, try switching the xlr's too, that was a common problem on my 480's till i tightened a screw on the body

[BCostigan]

Sounds like it may be some kind of grounding issue....though I'm not sure how the cap could be mis grounded?

[Swampy]

Ya, thats what cables will do if they have somthing out of wack...

[ChrisV]

I tried tightening it on as much as possible but it didn't help....thanks for the suggestion though.

I am pretty sure it isn't the cables because I switched them up and it switched sides.  Unless it is both of the cables conflicting with only one of the caps in the exact same way.  But I am positive it isn't the cables because I tried plugging the mics directly into the UA-5 and same problem.

I just made a massive discovery though...when I touched the mic it stopped the hum/buzz completely.    So all I need to do is hold the mic the entire time I am recording ;p

So perhaps it is a grounding issue then?

[blu666z]

Hey Chris.  Don't know much about those mics.  Are the caps removable?  If so, could it be a problem with the caps connecting tightly?

-Kevin

[johnw]

I was thinking that electret capsules only had a + and - wire, and that the ground is added in the body stage. but I could be wrong. If it stops when you touch the mic it sounds like a ground problem. Just to be sure, you have the High Z set to low, you have switched cables and the hum stays with the same mic, you plugged the mic bodies directly into the UA5 (no cable) and the hum stays with the same mic. If you have the mics plugged directly into the UA5 and switch only the capsules, the hum moves to the other channel? If all this is true, then it does sound like a grounding issue in that capsule. When I got mine, the capsules were really hard to unscrew, so I didn't bother trying to hard. I believe yours were from the same place, and were a new pair. Is it possible that when you unscrewed or rescrewed the capsule, some of the threading broke off, or the capsule is not threading on correctly? If possible could you take a picture of the capsule off the body?

[ChrisV]

Yep, the caps are removable...it is how I isolated it to a problem being with those.  Have switched everything around every possible way and the one cap is the common denominator.

They unscrewed fairly easy and screw back on so that they are very snug.  Examined both pieces' threads and they both appear exactly the same and in tact.   I'll see if I can take a few pics to post with them off anyways.

[johnw]

I guess what I'd probably do is call up the seller (Earthshaking music right?) and tell them you got a bum pair. They seemed like pretty decent folks, and I bet they'd replace them no problems. If they won't or you don't want the hastle, you could try grounding the cap to your mic stand. I'm thinking just  strip the ends off a 6" piece of wire and tape one end to the cap and the other to a metal part of the stand. Not entirely sure this would work, but I bet you'll probably go with option #1 anyway. Hope this works out for you. Go Lux!

[rustle]

I guess what I'd probably do is call up the seller (Earthshaking music right?) and tell them you got a bum pair. They seemed like pretty decent folks, and I bet they'd replace them no problems. If they won't or you don't want the hastle, you could try grounding the cap to your mic stand. I'm thinking just  strip the ends off a 6" piece of wire and tape one end to the cap and the other to a metal part of the stand. Not entirely sure this would work, but I bet you'll probably go with option #1 anyway. Hope this works out for you. Go Lux!

 Chris,
   Go with option #1 .

 Outside, Option #2 would turn your stand into a Lightning Rod

peace,
 Russell

[utahtaper]

has to be the damn caps, try switching the xlr's too, that was a common problem on my 480's till i tightened a screw on the body

I had this same problem with my 480's. It totally sounds like a grounding issue. Especially when you mention that it goes away when the mic is touched.

[ChrisV]

Thanks for the input guys...I am going to contact Earthshaking tomorrow.

[F.O.Bean]

has to be the damn caps, try switching the xlr's too, that was a common problem on my 480's till i tightened a screw on the body

I had this same problem with my 480's. It totally sounds like a grounding issue. Especially when you mention that it goes away when the mic is touched.

utah, when you had that problem, did you tighten the screw on the bodies???

i had a similar problem and did that and BAM, problem solved

[utahtaper]

Hey Bean,
Yea totally, the one screw on the body down by the XLR connector. Tightened it and golden.  

[ChrisV]

Just an update....got in contact with Dave @ Earthshaking Music and arranged to have me send them direct to the manufactor(Avlex) and they should either repair or replace my busted mic(s).   Sent them off yesterday and hopefully I can get the things back in time for next week.