Topic: Building mics

[illconditioned]

First you'll ruin a bunch of the caps doing the mod (they're tiny). Then, out of the many caps you've succeeded in modding, you've got to match them for output and frequency response. They vary quite a bit on both, I'm afraid.

how many caps did you use before you found a pair that were closely matched?

If you purchase 100 pcs from Digikey you will find 40 or so good matches. But it really does depend on your source of the capsules. I can sell you a matched pair for $10.00 I have about 1500 WM-61 capsules here at my shop.

Very nice offer, Chris.

As I've said earlier, there is room for both DIY and vendors on this board.  Nothing can beat the learning experience of DIY, but sometimes you've just got to put down the soldering iron and pick up the bottle of beer instead.

  Richard

[bdasilva]

I built many many sets of mics in my 1/8" days... Many people did.. Chris, richard... and you can make a decent recording... I recorded my only Dead show with a set. It did however delay me over a year from getting REAL mics and REAL recordings.

[bdasilva]

I own 4 sets of his mics... I stand corrected.

[digifish_music]

There is no reason you can't get a REAL recording from WM61A, or sundry other capsules on the market . . .

http://www.naiant.com/images/Orchestra_MSH-1.mp3

+T That's intriguing, the stereo separation in particular, great recording, how were the mics placed and what mods if any to the capsules (if any?).

digifish

[digifish_music]

That's actually kind of a funny sample, because it's a mix of three spot mics in the orchestra. 

That explains it! I was listening to one of the most well-defined orchestras I had ever heard from a stereo pair...except that it wasn't a stereo pair

Yes, I also found your site and read your FAQ, good stuff.

I have BTW got some great recordings from simple WM61-As soldered straight onto a mic cable with no mods (and only minimal attempt to match caps).

digifish.

[marksk]

the wm-61s are omnis. what about for cardioids? the transound tsb-120a's look nice (http://www.jlielectronics.com/transsound/electrets/tsb-120a.htm), but people at micbuilders say they're noisy and prefer the tsb-140a. how would you make the element into something usable? would you be able to place it in a tube and make some vent holes behind the element?

total n00b here, so i'll probably embarrass myself, but i'm looking to learn.

thanks!

[illconditioned]

the wm-61s are omnis. what about for cardioids? the transound tsb-120a's look nice (http://www.jlielectronics.com/transsound/electrets/tsb-120a.htm), but people at micbuilders say they're noisy and prefer the tsb-140a. how would you make the element into something usable? would you be able to place it in a tube and make some vent holes behind the element?

total n00b here, so i'll probably embarrass myself, but i'm looking to learn.

thanks!

I've got a collection of various capsules like this.
I suggest you go over to the Yahoo group "micbuilders".  Much more DIY over there.
I like the tsb-140a too.  They are really nice for ambient type recording, or for voice.
Not as nice sounding as AT853 or Sennheiser MKE40, though, IMO.
Some people over at Micbuiders have used them to make very cool instrument and/or vocal mics though.

  Richard

[marksk]

i've been a member of micbuilders for a while and am one of the n00bies you mention. i'm starting to read it regularly and am looking at older posts. i'm making a pair of mics with a couple of capsules from Chris's offer from earlier in the thread. i'm ordering parts from digikey to make greenmachine's battery box (or one from the files section of micbuilder's, http://tech.groups.yahoo.com/group/micbuilders/files/Ken%27s%20stuff/) and the pre-amp that can be found at http://www.geocities.com/ferocious_1999/md/tompolk.html. i was looking at the tsb-120's for a pair of cardioids. it looks like a two wire mike, so i could use the same battery box. what are you using to mount it? can you post some pics?

[marksk]

This link also shows you how to power the mics.. as well.. good luck and the brass tube we all use to build mics are made by k&s Engineering and you can buy them at most hobby stores. Next thing you need is a good soldering iron and make sure you buy lots of capsules because your going to burn thru a few of them. Also make sure you have plenty of patients and remember to use something to heat sink the capsule when your soldering it I use a pair of large alligator clips to wick away the heat so the capsule does not get damaged. There is also a kit at radio shack I forget what they call it but its got some tools for soldering in it and one of the tools is a nice heat sink that also works great for soldering capsules..

i wasn't able to find brass at the hobby shop by me, but that did have aluminum. will that work?

thanks!!

[Church-Audio]

This link also shows you how to power the mics.. as well.. good luck and the brass tube we all use to build mics are made by k&s Engineering and you can buy them at most hobby stores. Next thing you need is a good soldering iron and make sure you buy lots of capsules because your going to burn thru a few of them. Also make sure you have plenty of patients and remember to use something to heat sink the capsule when your soldering it I use a pair of large alligator clips to wick away the heat so the capsule does not get damaged. There is also a kit at radio shack I forget what they call it but its got some tools for soldering in it and one of the tools is a nice heat sink that also works great for soldering capsules..

i wasn't able to find brass at the hobby shop by me, but that did have aluminum. will that work?

thanks!!

Aluminum is fine. Its easy to work with just get a pipe cutter and your off to the races.
The only reason why I like brass is you can solder to it and maintain a good quality shield. Aluminum will act as a shield as well but not as well as brass and the ground cant be solidly connected to it. You could use conductive epoxy like I did in the good old days.. But its freaking expensive.. Another trick is to use heat shrink on the mic leads then use muffler tape on the outside of the capsule and then wedge it into the tube that way you get a better contact for ground. Also fill the back of the tubes up with 5 minute epoxy its critical you get a good seal I find that some of these mic capsules leak in the back end and putting epoxy on them actually helps the low end response because no more air is getting out of the back of the capsule. This only applies to omni capsules like the WM61.
Chris

[marksk]

i finally finished making my mics this morning.  i'm going to test them during lunch, but need a way to clip them on my glasses. i thought attaching a bobbie pin to them but i don't have enough hair for the pins to hold on to.  where's a good place to find some small clips? another thing i thought of was to use elastic to hold them onto the arms of my glasses.

thanks!

[marksk]

is anybody familiar with the primo em-135 as a capsule for cardioid mics?

http://www.primomic.com/products/em-135.htm

thanks!

[marksk]

should have said 135 above. fixed the link

[Roger Gustavsson]

Hello marksk,

Was trying to post a message in the micbuilder forum but it never went through...

I am not doing any stealth recordings. I have seen that some people want a little bass cut while reocrding via the PA system. Primo EM21 is popular among "stealthers", not that much bass drop. Look here:

http://tinyurl.com/5axps6

I am using that capsule myself. It is a part of my Nakamichi CM300 microphones. EM23 is the omni capsule. Can you get the EM21 and EM23 capsules from Primo? I could not! They just told me I need to order a larger number. I would certainly be interested to get some spare ones. Just let me know if you can get hold of them! If you want the whole microphone, it is the EMU-4535. There is also a "shotgun" available.

Roger

[illconditioned]

Hello marksk,

Was trying to post a message in the micbuilder forum but it never went through...

I am not doing any stealth recordings. I have seen that some people want a little bass cut while reocrding via the PA system. Primo EM21 is popular among "stealthers", not that much bass drop. Look here:

http://tinyurl.com/5axps6

I am using that capsule myself. It is a part of my Nakamichi CM300 microphones. EM23 is the omni capsule. Can you get the EM21 and EM23 capsules from Primo? I could not! They just told me I need to order a larger number. I would certainly be interested to get some spare ones. Just let me know if you can get hold of them! If you want the whole microphone, it is the EMU-4535. There is also a "shotgun" available.

Roger

I asked about em23 and they are quite expensive.  Something like $50 or maybe even more.  Note that this is the cap *without* the FET, so you'll need that.  I think there is an em68 or something like that too.  I'm guessing (based on appearance and what others have said) that this is what is inside the AT822/825 mic.  If so, this is a very nice capsule, nicer than the em23 imo.  I really like the sound for acoustic recording.  Not so much for amplified rock.  The em68 comes with a fet as well, so it is ready to use.  I forget the price for this, but it was somewhere around $50 each too.  I was at one time considering getting four of these to build an ambisonic mic, but have moved over to omni capsules now.

  Richard