Linkwitz Mods On Panasonic WM61A Mic - Page 3 - diyAudio
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Old 16th August 2009, 05:26 PM   #21
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Quote:
Originally posted by Conrad Hoffman
FWIW, I've always found these small capsules a disappointment because the noise floor isn't that low. It's just the nature of the beast. The 1/2" B&K capsule on our SPL meter at work is about 25 dB better, but the mic alone costs about $1K!! The big studio condenser mics you can get for about $70 (imports) have a great noise floor, but the response is invariably tweaked to sound "good", not flat. I haven't yet found the perfect diy measurement mic.
I would think that in a measurement mic the noise was secondary. DIY'ers tend to want them for speaker measurements where high SPL is more important. B&K's most accurate are the 1/4" or less where flatness is more important. A great compromise is the CP-3 capsule for an old Nakamichi CM-300 if you can find one.
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Old 16th August 2009, 10:27 PM   #22
teleman is offline teleman  Norway
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I was wondering if it is possible at all to drive these mics on a dual +/-9 v supply for better signal symmetry?
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Old 22nd September 2009, 10:36 PM   #23
teleman is offline teleman  Norway
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I think, I may have found an easier way to wire these modified Panasonic WM61A mic capsules.

All that requires is "Adhesive Conductive Copper Foil"

These can be bought from many sellers on the E-Bay.The ones I bought are 30mm x 4 metre rolls for £3.99, which are very useful for EMI shielding in stomp boxes or where the circuit is prone to EMI.

Cut a little strip of the foil a bit longer across the roll, ie:a little longer than the height of the mic & just wrapp it around the mic capsule to cover the rim of the capsule as well.
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Old 22nd September 2009, 10:43 PM   #24
bigwill is offline bigwill  United Kingdom
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Quote:
Originally Posted by teleman View Post
I think, I may have found an easier way to wire these modified Panasonic WM61A mic capsules.

All that requires is "Adhesive Conductive Copper Foil"

These can be bought from many sellers on the E-Bay.The ones I bought are 30mm x 4 metre rolls for 3.99, which are very useful for EMI shielding in stomp boxes or where the circuit is prone to EMI.

Cut a little strip of the foil a bit longer across the roll, ie:a little longer than the height of the mic & just wrapp it around the mic capsule to cover the rim of the capsule as well.

Brilliant.
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Old 22nd September 2009, 11:09 PM   #25
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Quote:
Originally Posted by teleman View Post
I think, I may have found an easier way to wire these modified Panasonic WM61A mic capsules.

All that requires is "Adhesive Conductive Copper Foil"

These can be bought from many sellers on the E-Bay.The ones I bought are 30mm x 4 metre rolls for 3.99, which are very useful for EMI shielding in stomp boxes or where the circuit is prone to EMI.

Cut a little strip of the foil a bit longer across the roll, ie:a little longer than the height of the mic & just wrapp it around the mic capsule to cover the rim of the capsule as well.
So do you solder to the foil? I'm not quite sure how it is used.
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Old 23rd September 2009, 12:21 AM   #26
teleman is offline teleman  Norway
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Yes! Since the foil is conductive & adhesive on one side you'd only need to cut a small strip,peal off the protective layer & wrapp it just about 1mm sticking out of the capsule.Now when you bend the top of the foil it will cover the rim of the capsule as well. Then solder the wire to the 'sected ground trace & the foil covered case together as you would normally.
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File Type: jpg WM61A Wiring-4.jpg (78.9 KB, 702 views)

Last edited by teleman; 23rd September 2009 at 12:49 AM.
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Old 23rd September 2009, 01:55 AM   #27
teleman is offline teleman  Norway
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Thank you, Bigwill!
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Old 23rd September 2009, 08:08 PM   #28
bigwill is offline bigwill  United Kingdom
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I have some thin copper tape lying around and I wrapped some around a pre modded capsule just to see how it fitted and it works well! Well done, I should have thought of this myself!
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Old 23rd September 2009, 09:09 PM   #29
teleman is offline teleman  Norway
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Yes Bigwill,..I couldn't agree more...why didn't I think of this before?!he..he..

ZAP...I tried Fig;B from the circuit you supplied & and another given on Photo Bucket using;

Drain R = 4.7k
Source R = 4.7k
DC blocking/op cap on Source =470nF (0.47uF)

However,using 1uF-10uf elect.caps on the source/op,I found the bass a little undefined or "sagging".Further,this didn't help much since my input buffer is a series-non inverting-high impedance opamp circuit,hence 470nF feels just right.

The mic works very well indeed! Thanks.

Last edited by teleman; 23rd September 2009 at 09:23 PM.
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Old 4th January 2010, 11:04 PM   #30
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i think that schematic better than linkwitz mode

has 7db gain..insted of loss in regular datasheet configuration ..linkwitz mod has no gain
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