Small Diaphragm Mics - DIY

I have looked high and low - but can I find any info on DIY SD mics - nope!
Here is hoping that the mic gurus can enlighten me

I have looked at the DIY pages for LD mics and have learnt an awful lot (god - your guys metalwork skills leave me speechless)
I understand the differences between SD and LD (thanks to Harvey Gersts Big Mic Thread)
http://www.kset.org/music/pub/ChatWithHarvey.pdf

If you built them - with very small fingers - where would you get the capsules from?

To be quite honest - I play acoustic guitar much better than I can sing - so the SD is more practical for me...

I guess the easiest way would be to find a donor mic - MXL603 has a fairly good capsule - look for the long thread on that mic.

Or you could get hold of an Oktava MK012 which comes with three capsules (i haven't heard this).

I tubified a neumann KM75, but I'm a vandal!

And of course you can record acoustic guitar very well with a LD mic.

Stewart

Easiest place to start is with the Panasonic capsules - available from Digi-Key. Noisy, by pro standards, but cheap and easy to work with.

I was thinking of the Neumann SDs .. KM84 etc..

797Audio seem only to sell Electrets (well I think they are electrets as the voltage is in the range 1.5v to 4.5v)
e.g.
http://www.797audio.com/chanpin/huatong/mic%20cartridge/qzxx/60.gif

I just can;t seem to find any SD non-electret capsules for sale - anywhere

The best way is to buy something like a MXL603. Then you could try a Royer circuit. A KM84 circuit or just mod the stock 603. A nady cm90 is about the cheapest OK capsule, about $50.00 from MF in the USA good for learning with. I like the 603 capsule better.

I heard two beringer b5s the other day they sound BAD. I think it is the electronics I did not like some of the parts I saw maybe that why they are only about $90.00 each USA with two capsules.

Most manufacturers sell SD capsules seperate as heads for mic pres with interchangable capsules. The capsules are in enclosures but that's because the enclosure is part of the capsule.

You could probably buy a used AKG CK-1 capsule cheap. Also the Røde NT3 capsule sounds good. I believe it's the same as the one in the MXL603.

I was wondering if the G7 project could be adapted to a SD project?

Look at all the tube and solid state schematics you can find on the web.

Not much different between a LD and a SD cardiod circuit except transformer size. With tubes you have 2 BASIC circuits CF and Plate out.
AKG C60 C61 sony C800 standard CF, Royer is a little different. U47,U67 Brauner VM1,sony C800G, ELA M250,251 C12, KM5x etc.................................................plate out, triode gain stage 6:1 to 11:1 transformer out

The size makes it harder to find a good transformer that can fit in a SD body. If you do find a good one like something in a KM5x it will cost some money.

pick a capsule and body size then find the good parts that can fit.

Read the meta a few time and take notes alot of info in there.

thanks Gus,

It's true I havn't read the threads much yet. I got two of the G7
boards with the intent of doing a pair of SD mics because I figured it
would be OK .

cheers
Lance

what about Schoeps. Is that stuff any good?

I saw a picture of a new SD microphone at www.josephson.com the main body was fatter than the capsule. I think it is in the 600 series of microphones. I forgot the link to it.

It might give you an idea of a way to use the G7 boards.

Do you want a side address SD or an end address SD.

Look at pictures of the neumann, RTF? Blue big bottle and Hiller bottle microphones for Ideas. IIRC neumanns prototype M50 was a capsule mounted to a bottle type microphone. If you are happy with the size the bigger transformer etc might sound REALY good. It is hard to pack good stuff in little SD microphones. Maybe your question will start a new style DIY SD use of the G7 circuit. This could be a cool thing!

There is alot to to read at the meta. I wish I had something like that when I started looking for microphone information. It might take a few reads to find things what you need.

side address SD is good with me. I have a couple CMV563 mics to use as a guide.

I guess matched capsules and transformers would be the first thing to plan.

[quote author="cjenrick"]what about Schoeps. Is that stuff any good?[/quote]
" Carmen meets Kharma Live " used all Schoeps for recording

I DIY'ed an Altec M30 type of mic - similar to the lipstick mic but 60V polarization voltage. I used an AKG CK61ULS and it's my main acoustic guitar mic.

About the metalwork thing - I'm trying to DIY a small diaphragm capsule, but I think I want to finish my large ones first. I'm just preparing drawings right now, maybe I will try machining one soon. I am leaning towards a glued diaphragm assembly like the Neumann M7, but I don't have my heart totally set on that method. These things take a long time to get right so I expect to have a DIY'ed SDC capsule in maybe March or April.

[quote author="Gus"]I saw a picture of a new SD microphone at www.josephson.com the main body was fatter than the capsule. I think it is in the 600 series of microphones. I forgot the link to it.

[/quote]
Hey Gus, to me it seems the challenge there would be housing the side address capsule. It would certainly challenge me, that's for sure, although I want to give it a try. Wishing I still had my old metal lathe.

uk: check out the MXL990. It's sd side address body size about the same as a TM103. It's the same capsule as the 603s. 770 also, a little longer body.

Guys - many many thanks
Dale - I will follow your progress with great interest
I am not a electronics genies - not even a good newbie - but I can spot the use of a generic mic body with interchangeable SD or LD heads
Just wondering whether a generic circuit/transformer would work in both scenarios

http://www.schoepsclassics.com/

Look here for some ideas.

[quote author="Gus"]http://www.schoepsclassics.com/

Look here for some ideas.[/quote]

Ha, the one on the left of the intro pic is hilarious! It's the famous Schoeps Shrunken Head mic! Thank you Gus, that's good stuff. I almost sort of like the clam shell grills, interesting piece. Pretty soon we're going to be comparing notes on lost wax casting tecehniques. :wink:

just a note: AKG c60 as well as some older mic's by schoeps, hiller etc. used a cathode follower design to have a sufficiently low output Z for the head amp to be able to drive a few meters of cable, so they could place the xformer outside of the mic body (=in the PSU), where size doesn't matter. this does mean a few meters of unbalanced connection, but obviously it must have done the job - otherwise it wouldn't have been used commercially.

might be worth considering when building an SD mic...?

The cooler CF is the Royer one. You can have fun adjusting the power supply voltage and changing the cathode resistor to different values.