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Whats Happened To Me Tube Mic?

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Whats Happened To Me Tube Mic?

Postby peddlebreaker » Wed Apr 23, 2014 9:03 pm

Hi guys,

I won't bore you lot with the ups and downs of me trying to get this thing sorted out, no actually I will!

I bought a 2nd hand Groove Tubes GT44 microphone about 6 months back on the promise from an reputable composer of piano music, that it was a sweet little mic that could do magical things if pointed in the right direction.

All was well up until about 2 months ago when the damn thing started getting windy on me. It was making really strange gusty sounds.

I must admit, I am still a complete novice when it comes to electronics and building these pseudo "ears" so the first thing I did was scramble for the mouse and keyboard in search for THE answer on some forum or muso website.

I ended up contacting (without knowing) the actual founder and designer of said microphone, a Mr. Aspen Pittman. Mr Pittman gave some excellent advice and agreed to send me a replacement capsule and 7-pin XLR cable. I must stress here that he did this because I insisted that it must be either of these things causing the problem.

A few weeks later, I received the capsule and XLR cable, beautifully packaged with care by Aspen. I tested the capsule and guess what, still the same windy horrid noise. I went to try the new cable and ARRRGGHH it was the wrong one; a 6-pin, not a 7-pin cable! Not my day!

So I ended up buying a replacement 7-pin XLR lead from Thomann, got it in the post this eve only to find that guess what?? Still the same noise.

Finally common sense kicked in and I opened up the microphone to take a closed look.

This is what I found....

https://drive.google.com/file/d/0B3C54-b16RXia0hpMzVxc25YbjA/edit?usp=sharing

https://drive.google.com/file/d/0B3C54-b16RXiQk1NajRyU1Utazg/edit?usp=sharing

https://drive.google.com/file/d/0B3C54-b16RXiS3JhdFlyWHdWU1E/edit?usp=sharing

https://drive.google.com/file/d/0B3C54-b16RXiZDB2VlM4dWF1TWM/edit?usp=sharing

https://drive.google.com/file/d/0B3C54-b16RXiMDVKZXl4T2ZGcU0/edit?usp=sharing

Is it me or is that capacitor fried? it's even causing the plastic on the 2 black wires to melt!!!

God I'm dumb, I mean why did I not figure this out before? Can anyone help me get this thing fixed? Is it possible?

THANKS
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peddlebreaker
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Re: Whats Happened To Me Tube Mic?

Postby James Perrett » Thu Apr 24, 2014 11:42 am

Looks like someone has been in there with a soldering iron and accidentally melted a few things while soldering something. I'm not sure that the capacitor is fried though.

Those sorts of noises are usually down to contamination on the capsule or on the high impedance section of the circuit board. Usually a good clean is all that is needed but I wouldn't attempt this yourself unless you are very experienced with condenser mic repairs.
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Re: Whats Happened To Me Tube Mic?

Postby peddlebreaker » Thu Apr 24, 2014 12:13 pm

Thanks James, I don't suppose you can recommend any microphone repair specialists?

Cheers
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Re: Whats Happened To Me Tube Mic?

Postby James Perrett » Mon Apr 28, 2014 12:25 pm

Been away so only just seen this. I think that the guy I'd talk to is working abroad at the moment otherwise you would probably have had a PM by now...

Ashley Styles is another name that often crops up in connection with mic repairs.
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Re: Whats Happened To Me Tube Mic?

Postby SimonZ » Mon Apr 28, 2014 1:18 pm

(thanks for the prod James)
Hi peddlebreaker, If a mic is going to get noise problems due to condensation on the capsule then often January and February are the months for it to happen.
Place where you keep it falls below the dew point (say 14 deg C) and you bring it out into a warm room and bingo, windy squealy noises.
I would normally suggest just trying to dry it out thoroughly first but there certainly does look like some clumsy soldering iron damage as well, which needs fixing, the cap does look a bit iffy to say the least, so could also be part of the problem since the messy work implies that the board was probably not cleaned afterwards and fumes from the solder, flux and burnt wires & cap on the high impedance part of the board create leakage paths for the higher voltage parts of the mic, again windy noise.

Sending a PM,
Simon
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