Shure SM10A microphone boom bracket and pre-amplifier
 

I've just got a Shure SM10A microphone and want to mount it on my Koss Pro 4AA headphones which have a screw for the purpose. I wondered if anyone had a spare boom bracket or if I'll have to fettle one up. I believe it was originally included in the microphone's accessories. I think it's just a plate with a hole for the screw on the spring clip the microphone uses to attach to its headband, and another for the thumbscrew clamp on the headphones. However, the photograph of this attachment method in the manual is too small to make out.

It has an XLR plug and I presume I'll need a preamplifier to run it into my computer, and provide an unbalanced TRS output. Has anyone got a fun circuit for this? Valves or solid state would both provide a suitable project...

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Stick to solid state. with valves you'd have to arrange protection from connection/disconnection turn on/off transients. One false move destroys the audio codec chip which will be SMT and on the computer motherboard.

David

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Don't have a bracket sorry, but do have the original leaflet if you want it, see attached. As you say the pic isn't too detailed.

Andy.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

This should do the trick https://service.shure.com/s/article/...language=en_US

Where it shows "image", look to the bottom of the page for the link to the jpg.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Thanks all. Good tip, David. I can think of many other reasons why a little solid-state device would be better for my desktop too!

Andy - I have the headphones (already replaced the shrunken pads and added some foam inside to prevent my ears hitting the mesh) so that end of things is sorted. They did come from a charity shop in their original box, but I think are missing that leaflet. If it's going begging at your house I'd be glad to give it a home.

Terry - good digging there! Unfortunately that's the picture I have in the Shure instruction leaflet that came with the microphone (great moustache). It seems the bracket's nothing more complex than a piece of alloy, but as I have very rudimentary facilities at the moment (see the picture of where I have been cutting dovetails) I was trying to avoid a very cold afternoon working with small pieces of metal that won't end up as nice as the kosher part! Pure laziness, I agree.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

So, any thoughts on pre-amp circuits? Perhaps I just need an XLR-TRS adaptor for PC use? I am not au fait with the requirements for dealing with balanced/unbalanced signals, or whether a dynamic microphone can be plugged directly into the computer so all advice welcome!

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

As far as I know, all PC are designed to accept electret mic's, so there will be a bias voltage on the mic socket - not good for dynamic mic's that aren't phantom powered.

Some older PC's used to allow the option of turning this bias off, I don't think modern PC's do.

It may be as simple as fitting a cap in series with the line or else just a single transistor mic pre amp.

XLR connections -
Pin 2 + line
Pin3 - line
Pin 1 shield

For 2 pin operation
Pin 2 line in
Connect pin 1 + 3 to gnd.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

I tried a proper mic into my PC mic IP, it was hideous, lots of hum. The only way I've managed to get decent speech and sound is with a AI & DAW.

Andy.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

I just had to sit down looking at the prices of USB audio interfaces with XLR on Canford! Surely someone's made a clone of one of these for the impecunious? I have (through the good offices of this forum) got a Behringer mixer with XLR capability, but it's not suitable for putting on a desk with very limited space. Any suggestions for a small, USB box that will do the trick? Ideal if there's a DIY circuit. I checked DIY Audio but terms like 'USB' and 'XLR' are too small to search for and I quickly get into a morass of specificity.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Search for a USB to XLR 'cable' rather than 'interface'. Should be less than £10.

Cheers

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

The little Behringer 302 looks like a good product if you need simple I/o and having the advantage of it having phantom power if needed at a later point ~£40, there is also the UM2 interface for ~£30.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Thanks all!

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Brain dead, the old way of interfacing dynamic mic's was with a transformer - low impedance side to mic, high impedance side to audio input.

Usually a transformer in the 1:4 ratio range should be suitable with a capacitor in series on the audio input side so it doesn't short the bias voltage.

Re: Shure SM10A microphone boom bracket and pre-amplifier
 

Thanks to Diabolical Artificer, it's trebles all round!