Here’s a look at my latest… a ribbon mic motor under test on my bench. Right now, it sounds pretty good. In fact, I’m tempted to just toss it into the case and call it done as it is, but I’m going to wait a bit. I can see some tiny problems with this one that I’d like to correct first. I’m not sure if you can tell in this photo, but the ribbon has a very slight curve… it’s closer to the magnet on the middle on one side, and the edges on the other. This is probably due to the way I corrugated the ribbon, using a fluted dowel pin and rolling it on a mousepad. This method works, but it is hard to get an even amount of pressure, and I probably pressed down a hair more on one side than I should have.
Still, it sounds quite nice. It has a fair amount of output, though I might like to squeeze out a bit more signal. A more accurate assessment will have to wait for a new ribbon… I’ve bought a “Paplin Crimper” on ebay for $15, which should be adaptable into a better ribbon corrugator. It’ll at least be an improvement on my current method.
I’m especially pleased with the transformer on this mic. I managed to get a pair of these from Les Watts. He has them wound for use in his microphones, and they have specifications that rival some of the best ribbon transformers available. Of course, it’s hard for me to tell what is due to the transformer and what’s the result of my ribbon motor design. Hopefully I’ll be able to source some cheap Chinese ribbon transformers soon so that I can compare the two.
Remaining work on this microphone is a new ribbon and adding some ground connections, but apart from replacing the ribbon, it’s just a matter of wiring it up and screwing it closed. The shell will certainly affect the sound to a degree, but I don’t think it will be too detrimental… the EM shielding that a mic shell provides will likely be an improvement, though I’m not hearing much in terms of self noise as it is.
Here’s a voice test MP3 of this mic just as it appears in the photo above. This isn’t a critical test, just a check to hear if it’s working. It’s on my workbench, not the perfect place for this… I hear reflections from the rear, and the fan noise from the laptop is audible. The cable being used to connect the mic was quite prone to noise depending on it’s position… I just placed everything where the noise was lowest. The mic is connected directly into an M-Audio Duo interface, sample rate was 44.1. Have a listen… comments and opinions are most welcome.