Building a ribbon microphone

[überfuzz]

I've been tinkering with a routing machine. I just felt like learning how to craft with such a machine. And while doing so I thought, hey, why not mix pleasure with pleasure. To plan is to build a ribbon microphone.

Here are some pictures of the first motor chassis I routed. First without magnet and then with.

[JHow]

I've been tinkering with a routing machine. I just felt like learning how to craft with such a machine. And while doing so I thought, hey, why not mix pleasure with pleasure. To plan is to build a ribbon microphone.

Here are some pictures of the first motor chassis I routed. First without magnet and then with.

Nice work. Very interesting project. I will be interested in how you work out he ribbon.

[überfuzz]

Nice work. Very interesting project. I will be interested in how you work out he ribbon.

Well, yeah, I've got the ribbon part worked out in my head. But I fear that the real mounting might be very tricky.

Edit, I forgot to mention. I have got 2,5 µm Alu foil that I'm going to corrugate for the ribbon. I need to amplify or transform the signal. That part is still somewhat dim.

[bbsailor]

Well, yeah, I've got the ribbon part worked out in my head. But I fear that the real mounting might be very tricky.

Edit, I forgot to mention. I have got 2,5 µm Alu foil that I'm going to corrugate for the ribbon. I need to amplify or transform the signal. That part is still somewhat dim.

Use this Edcor Ribbon Microphone transformer. http://www.preservationsound.com/wp-...11/12/RMX1.pdf

The output impedance of the Ribbon Mic transformer should be in the range of one fifth to one tenth the input impedance of you mic input circuit which is typically between 1.5K ohms to 3K ohms for a bridging impedance on the Mic transformer. A 1 to 37 Turns Ratio transformer has a 37 X 37 or 1369 impedance ratio. This means that a Ribbon that is .2 ohms and a wire lead that is .02 ohms should produce a transformer output impedance of 1369 X .22 or 301 ohms which should work with a 1500 ohm to 3K ohms mic mixer input impedance.

I hope this helps?

bbsailor

[überfuzz]

Use this Edcor Ribbon Microphone transformer. http://www.preservationsound.com/wp-...11/12/RMX1.pdf

The output impedance of the Ribbon Mic transformer should be in the range of one fifth to one tenth the input impedance of you mic input circuit which is typically between 1.5K ohms to 3K ohms for a bridging impedance on the Mic transformer. A 1 to 37 Turns Ratio transformer has a 37 X 37 or 1369 impedance ratio. This means that a Ribbon that is .2 ohms and a wire lead that is .02 ohms should produce a transformer output impedance of 1369 X .22 or 301 ohms which should work with a 1500 ohm to 3K ohms mic mixer input impedance.

I hope this helps?

bbsailor

Well, I'm looking into how to handle the signal from the ribbon. If I'm not able to muster a good transformer myself I'll go for this one: http://www.lundahl.se/wp-content/upl...13/05/2915.pdf Lundahl manufactures and ships top notch transformers.

I'll post more info as I go along.

[überfuzz]

I simulated the magnetic flux between the two magnets in comsol. Turns out I can amplify, or more like channel, the flux so that the field between the magnets are 10 times stronger. Next up, iron!

[überfuzz]

Today I found time to tinker with my microphone. I routed the chassis with windscreen.



The chassis is made out of ordinary construction steel. It's a bit rusty at the moment, but I figure I can get it shiny with some polishing.

[überfuzz]

Top day I did a lid, or top cover, for the microphone. You wont see it on this picture, but every part of the motor chassis etc fits really tight. Perfect!



Next thing to fix is a bottom lid with an XLR-plug. I still haven't figure out what puff cover to use... Woven wire and some cloth maybe (I guess I need to experiment some to get a good result).

[überfuzz]

I continue my spamming of this thread...

This is the whole chassis.


Bottom lid (mustered it today).

[bbsailor]

I continue my spamming of this thread...

This is the whole chassis.
[ATTACH=CONFIG]29325[/ATTACH]

Bottom lid (mustered it today).
[ATTACH=CONFIG]29326[/ATTACH]

Uberfuzz,

The ribbon mic looks good! How does it sound?

Joseph Rogowski

[überfuzz]

Thanks!

I haven't mounted the microphone motor yet. I'll post more stuff here as I go along.

[überfuzz]

It's incredible what 600 followed by 1200 sandpaper, and the proper amount of beer, can do.



Next step is, on the inside, mounting the motor, transformer etc. Also, the chassis is going to be polished at some point.

[überfuzz]

I added a woven mesh. The idea is that it will protect the sensitive ribbon. I think I'll add an even finer mesh to.


I had a hard time getting good focus in this picture, sry.

[überfuzz]

The microphone is more or less finished now.

[überfuzz]

I stumbled upon this old thread. The microphone is finished and sounds very good. It's still subject to my tampering/modding though. :-) At the moment I'm toying the idea of adding a jfet stage to boost the out signal, which is somewhat low. I'll try to see if I can upload some sound files.