Topic: Mic building with WM-61A capsules, valuable information

[lordbelial]

Just found this site Googling.

http://www.uwm.edu/~type/116/Trek01/BuildingMics/WM-61A_BrookBuildsMics/WM-61A_BrookBuildsMics.html

They don't seem to perform the linkwitz mod (cut the trace between the source terminal of the capsule's internal FET and case ground), but anyway, helpful if you're a little bit lost in how to build you a pair of omni mics with this cheap and reliable capsules.

[digifish_music]

Just found this site Googling.

http://www.uwm.edu/~type/116/Trek01/BuildingMics/WM-61A_BrookBuildsMics/WM-61A_BrookBuildsMics.html

They don't seem to perform the linkwitz mod (cut the trace between the source terminal of the capsule's internal FET and case ground), but anyway, helpful if you're a little bit lost in how to build you a pair of omni mics with this cheap and reliable capsules.

Greetings,

Yes nice site. It's the Lyman Miller mod BTW... [ http://www.linkwitzlab.com/sys_test.htm#Mic ]

I have made binaurals and hydrophones out of the WM61-A's and not done the mod either. It's about increasing the ability to operate in high SPL environments. Honsestly, it's not necessary IMO for the sort of recording most people do.

digifish

[lordbelial]

Just found this site Googling.

http://www.uwm.edu/~type/116/Trek01/BuildingMics/WM-61A_BrookBuildsMics/WM-61A_BrookBuildsMics.html

They don't seem to perform the linkwitz mod (cut the trace between the source terminal of the capsule's internal FET and case ground), but anyway, helpful if you're a little bit lost in how to build you a pair of omni mics with this cheap and reliable capsules.

Greetings,

Yes nice site. It's the Lyman Miller mod BTW... [ http://www.linkwitzlab.com/sys_test.htm#Mic ]

I have made binaurals and hydrophones out of the WM61-A's and not done the mod either. It's about increasing the ability to operate in high SPL environments. Honsestly, it's not necessary IMO for the sort of recording most people do.

digifish

Yesterday I tested my homemade binaurals with a minidisc using the mic-in input directly from plug-in power at a Chimaira's show (metal). as far as you can imagine, my ears are still bleeding and, of course, plug-in power was not enough bias for my mics to handle that sound pressure so they couldn't handle it.

Today I'll repeat the test but with a home-made battery box.

Pictures on the way.

[lordbelial]

Picture of my first home made mic.



I think i'm gonna spend the rest of the day working on the battery boxes. Time to gather for components spread all over my room....

[digifish_music]

Picture of my first home made mic.



I think i'm gonna spend the rest of the day working on the battery boxes. Time to gather for components spread all over my room....

Classy looking job there +T.

I chose to dismantle cheap headphones doing mine to get a low-profile right-angled plug.

digifish.

[sunjan]

Useful info, deserves a bump!

I found some other DIY links for other WM-61A projects, I though it would be good to gather them all in the same thread.
There's a bunch of photos, measurements and drawings, maybe they can serve as inspiration?!

http://phreakmonkey.com/projects/monkeyphones/
http://www.uwm.edu/~type/audio-reports/PanasonicWM-61A_OtherBinauralRigs/WM61A_Webpage_Caps_Mounts.html
http://www.audioxpress.com/magsdirx/ax/addenda/media/danavaras2861.pdf
http://www.christianmusicweb.com/microphones/mic_project.html

[boojum]

Make 'em well enough and they will be Earthworks.   ;o)

[thrush]

Hey ho.

Bought a pair of these teeny tiny mics to make a stealth mic set for my zoom h2. just wondering if I’ll be able to plug straight in without the need for a pre amp.

The h2 specs for the external mic in are as follows:

ZOOM SPECS
[EXT MIC IN] 1/8" stereo phone jack(Plug-in powered:2.5V, Input impedance:20k Ohm, Input level:-20/-30/-40dBm)

I just noticed on the mic spec sheet that the Impedance for the mics is:

“Less than 2.2 k Ohm”

Is it a case of the h2 impedance being ok because it is larger than the mic impedance? i think i read that a 10:1 impedance ratio between mic and recorder/mixer is ok.

Also, does the fact that the Zoom provides 2.5 volts of phantom power mean that i won't have to build a battery pack?

thanks,

noober

[bdasilva]

I am a moderator of the Yahoo micbuilders group.  I invite anyone interested to join our little group and build some mics.  Its insane some of the recordings I made with a set of 6$ mics.

It's insane the fine mics that Jon makes out of small capsules.

[thrush]

thanks dood!

[thrush]

ok so i've tried this and i think i have the woring wrong. i followed the istructions as per the instructions in one of the above links:

Solder the bare wire from the left headphone speaker to the ground wire on the mic element that will be installed in the right earphone. Then solder the colored wire from the left headphone speaker to the Output, V+ terminal of the right mic element. Using the soldering iron, melt a hole large enough to accomidate the mic element in the headphone.

is this right? do i only solder to the "-" of one mic and the "+" on the other?

[heyitsmejess]

ive gotta ask...how hard would it be for someone with zero electronics experience to make something like this (or these)?

http://www.mp3forkidz.com/mic/blum.html

im intrigued and facinated, but me + solder = bad

[thrush]

having trouble with this. i read about 600 ohms across the - and + of each mic. this means i blew them? the first link in this thread says they should read about 1400?

[thrush]

unless i've somehow shorted/blown these mics i'm not sure whats going wrong. i re-wired it again. tested with a meter across the + of the mic and the tip of the 1/8" jack and the - with the sleeve, with perfect connectivity. when i plug it into the H2, nothing. 

and as i say before there is 600 ohm across the - & + of the mics, so i don't think i blew them...

[Gutbucket]

Hi ploffer, welcome to the forum.  Great ideas there. 

However we really try to keep talk of steath recording, stealthly around this public forum.  Otherwise we may end up loosing those opportunities. Could I ask you to please delete the post above.. or modify it to eliminate all the undercover details?  Thanks! and I mean no offence to you, I like your thinking.

If possible, try to keep discussion of these techiques restricted to private messages to other members in good standing, using the PM icon under their avatar.