UK Vintage Radio Repair and Restoration Powered By Google Custom Search Vintage Radio and TV Service Data

Go Back   UK Vintage Radio Repair and Restoration Discussion Forum > Other Discussions > Homebrew Equipment

Notices

Homebrew Equipment A place to show, design and discuss the weird and wonderful electronic creations from the hands of individual members.

Reply
 
Thread Tools
Old 9th Jan 2021, 9:11 pm   #1
Uncle Bulgaria
Octode
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 1,049
Default 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...
Uncle Bulgaria is online now   Reply With Quote
Old 9th Jan 2021, 9:14 pm   #2
Radio Wrangler
Moderator
 
Radio Wrangler's Avatar
 
Join Date: Mar 2012
Location: Fife, Scotland, UK.
Posts: 16,735
Default 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
__________________
Can't afford the volcanic island yet, but the plans for my monorail and the goons' uniforms are done
Radio Wrangler is online now   Reply With Quote
Old 10th Jan 2021, 9:15 am   #3
Diabolical Artificer
Dekatron
 
Diabolical Artificer's Avatar
 
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 5,810
Default 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.
Attached Thumbnails
Click image for larger version

Name:	DSC03183.JPG
Views:	88
Size:	158.9 KB
ID:	224260   Click image for larger version

Name:	DSC03184.JPG
Views:	86
Size:	162.7 KB
ID:	224261  
__________________
Curiosity hasn't killed this cat...so far.
Diabolical Artificer is offline   Reply With Quote
Old 10th Jan 2021, 10:15 am   #4
Terry_VK5TM
Octode
 
Terry_VK5TM's Avatar
 
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 1,526
Default 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.
__________________
Terry VK5TM
https://www.vk5tm.com/
Terry_VK5TM is offline   Reply With Quote
Old 10th Jan 2021, 2:02 pm   #5
Uncle Bulgaria
Octode
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 1,049
Default 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.
Attached Thumbnails
Click image for larger version

Name:	IMG_20201030_183207.jpg
Views:	75
Size:	82.6 KB
ID:	224271  
Uncle Bulgaria is online now   Reply With Quote
Old 11th Jan 2021, 12:42 pm   #6
Uncle Bulgaria
Octode
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 1,049
Default 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!
Uncle Bulgaria is online now   Reply With Quote
Old 12th Jan 2021, 2:52 am   #7
Terry_VK5TM
Octode
 
Terry_VK5TM's Avatar
 
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 1,526
Default 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.
__________________
Terry VK5TM
https://www.vk5tm.com/

Last edited by Terry_VK5TM; 12th Jan 2021 at 3:00 am. Reason: Add pin connect info
Terry_VK5TM is offline   Reply With Quote
Old 13th Jan 2021, 7:28 am   #8
Diabolical Artificer
Dekatron
 
Diabolical Artificer's Avatar
 
Join Date: Jul 2009
Location: Sleaford, Lincs. UK.
Posts: 5,810
Default 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.
__________________
Curiosity hasn't killed this cat...so far.
Diabolical Artificer is offline   Reply With Quote
Old 13th Jan 2021, 11:11 am   #9
Uncle Bulgaria
Octode
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 1,049
Default 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.
Uncle Bulgaria is online now   Reply With Quote
Old 13th Jan 2021, 12:04 pm   #10
Trigon.
Pentode
 
Trigon.'s Avatar
 
Join Date: Jun 2018
Location: Buckinghamshire, UK.
Posts: 202
Default 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
Trigon. is online now   Reply With Quote
Old 13th Jan 2021, 1:33 pm   #11
dglcomp
Heptode
 
Join Date: Jul 2016
Location: Portland, Dorset, UK.
Posts: 529
Default 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.
dglcomp is offline   Reply With Quote
Old 16th Jan 2021, 1:43 pm   #12
Uncle Bulgaria
Octode
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 1,049
Default Re: Shure SM10A microphone boom bracket and pre-amplifier

Thanks all!
Uncle Bulgaria is online now   Reply With Quote
Old 25th Jan 2021, 11:46 pm   #13
Terry_VK5TM
Octode
 
Terry_VK5TM's Avatar
 
Join Date: Oct 2010
Location: Tintinara, South Australia, Australia
Posts: 1,526
Default Re: Shure SM10A microphone boom bracket and pre-amplifier

Quote:
Originally Posted by Uncle Bulgaria View Post
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!
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.
__________________
Terry VK5TM
https://www.vk5tm.com/
Terry_VK5TM is offline   Reply With Quote
Old 8th Feb 2021, 7:33 pm   #14
Uncle Bulgaria
Octode
 
Join Date: May 2016
Location: Cornwall, UK.
Posts: 1,049
Default Re: Shure SM10A microphone boom bracket and pre-amplifier

Thanks to Diabolical Artificer, it's trebles all round!
Attached Thumbnails
Click image for larger version

Name:	Headphone bracket.jpg
Views:	35
Size:	49.2 KB
ID:	226311  
Uncle Bulgaria is online now   Reply With Quote
Reply

Thread Tools



All times are GMT. The time now is 9:19 pm.


All information and advice on this forum is subject to the WARNING AND DISCLAIMER located at https://www.vintage-radio.net/rules.html.
Failure to heed this warning may result in death or serious injury to yourself and/or others.


Powered by vBulletin®
Copyright ©2000 - 2021, vBulletin Solutions, Inc.
Copyright ©2002 - 2021, Paul Stenning.