Friday, May 02, 2008

Mod Project on a Low Cost Ribbon Mic

The mic shown on the right is just one of the myriad of differently labeled inexpensive ribbon mics.. They are single ribbon jobs with a plain steel flux frame mounted in a circular body. All of the ones I have seen including this one have only two of the four screws in place - it seems only two line up and the other two do not. Two are enough to keep the frame in the circle. Since this is generic, and not any "brand", it's fair to make this a mod subject for the blog.

Mike at Cascade has fixed the screw line up problem in his mics and has put some effort into other improvements.

Click on the image for a real close-up.

The contact at the bottom is a piece of G10 with a tinned copper trace where the ribbon goes. The flux in the gap measures 3500 Gauss, and the dimensions of the gap and its length, and the overall size of the flux frame, are all the nearest metric equivalents to another common ribbon microphone, but without the stepped sides and grooves.

This mic is generally the same as you see all over the place with various names and paint jobs. It has a hanging EI transformer which is encased in a plated brass tube.

It would be interesting take this apart and give it a good powder coat finish, maybe do something with the magnets and transformer or magnetic shielding, put in new ribbon, and find out what kind of performance we can get. Like the "tube ribbon" we looked at a while back, we got this as a sample.

4 comments:

Anonymous said...

Bob are you going to put Roswellite in it?

Bob Crowley said...

Maybe

Rickshaw said...

If I was a Ribbon Mic modder (wink-wink!) here's a few things I would do:

1. Remove the taped-on mesh
2. Install a wider ribbon. There appears to be a large gap between ribbon and magnets.
3. Look for ways to isolate the structure from the capsule - or use a shockmount.
4. Twist the red/white output wires together.

Hey Bob, does this motor only have one wire? Is the top of the ribbon grounded to the chassis? Or does it have a separate wire we can't see in the photo?

- Rickshaw

Bob Crowley said...

The mesh could be replaced with something else to tailor the response in the low end. It's a quite a bit bassy now, at the motor, on a flat transformer.

I forget if it has one or two wires. I think it has one. In any case it is the same as all the others I looked at, right down to the markings on the PCB/clamp.