Homebrew Headset/Mic

I know, I just can't seem to let this sort of stuff go but I do like playing with an odd project or two.


Spurred on by activities usually instigated by others here (you Charlie Tango's are a very fine lot ) I decided to extend my SSB capabilities somewhat.
You never know, it might help me garner a few points in the 10m Summer Challenge 2023 with my QRP limits.

I've already made some modifications to my ancient Yaesu FT757gx including a diode clipper mod in the SSB RF section as well as separated the 'MIC/DRIVE' control so that it works in SSB modes also. However, I've never been totally satisfied with the performance of the equally ancient MH-10ES fist mic that came with it, reports range from "good but quiet" to "sounds awful and muddy". Others personal views can be somewhat different from our own but experiments with hooking another receiver up to my laptop and actually viewing my SSB spectrum shows that it is actually lacking in the mid range of the audio spectrum.

The Yaesu utilises a dynamic microphone element but I knew that I could electrically bias an electret element to make it work with it. The first attempt at doing so gave a very 'tinny' or high frequency response so I began a search for answers. (Of which there are apparently many and usually by being parted with wads of cash!)

It was then that I came across the exemplary work of Martin G8JNJ.

He wrote an article for RADCOM a few years back but thankfully shares it on his website :-

https://g8jnj.webs.com/speechintelligibility.htm

(Scroll down the page to the links for his articles.)


I proceeded to scrounge the parts required from my parts bins and came up with my own layout/rendition :-



Managed quite well with my old bear paws and found the 'secret' to my eyesight problems.....add more light!!

I squeezed in another trimmer potentiometer so that I could parallel switch that into circuit giving a lower value and hence higher frequency response. Fuller audio spectrum for 'local' contacts and then high frequency response to hopefully break through with DX contacts.

Oh, go on then....proud my fat old fingers managed so well here's another shot of the board.



Yeah, my parts bins are so old I do have many BC109C's in them! (Not sold on for a rip-off prices for 'boutique' guitar pedals....I'll never be a businessman.)
Any modern general purpose NPN will do the job.


The important part would be the headset/mic equipment to tack onto this little circuit and your choices vary.

You can go the full hog of an expensive new headset, buy some cheaper 'gaming' headsets or do what I did and scrounge some that are no longer used. My wife did some 'test-and-trace' work for the NHS back during the pandemic and had a headset that has since languished in a drawer doing nothing.....so I nicked them!

The damn things were a USB style set rather a separate plugged headphone/microphone affair so I had to do some rewiring. Out with the light and 'best-est' glasses again! (Luckily I was able to re-utilise the 'mute' switch to become the PTT or push-to-talk switch. Flipping handy.)

An old project box, some suitably wired cables and voilà we come up with this :-



The yellow phono cable means I can power the circuit and mic element from the 8 volt accessory port on the back of my old Yaesu. I think I now have every socket on the old girl used up now!

The thinner headset is actually a revelation in that the audio from the headphones is superb and unlike the 'big-old-cans' type I was using before my ears are more comfortable plus I can swap glasses whilst keeping them on. (I have three sets of spectacles, screen viewing, writing and a stronger pair for fiddly jobs like wiring mic plugs!)

The mic is easily adjusted, stays in place, sounds great and whenever I move my head the mic comes with me.

I can easily unplug the phones from the radio when I want to listen through my Big Speaker and just have to remember to unplug the mic when I'm doing some FT8 on my homebrew audio interface. (That might be another project winging its way out of necessity....a switching rack!)


Should do the job and seems to play nice judging by my other receiver recordings and from what Ive picked up on the web and Kiwi SDR's.
 
It's not a "Heil" but then it cost me next to b*gger all either. Right up this old cripples price range.


Plus I do enjoy a project and Amateur Radio presents many examples where you can fulfil such desires.

Enjoy your radio, no matter what it may be.  


All the best,
Victor

26CT3228
M7VIC

Nice one Victor.
I wish i had the ability to do stuff like that.
Well the patience anyway and maybe the room in the shack lol.

Cheers Alan mate.  

The new big desk and wireless keyboard helps give me the space I need for such fun.
(Was a right royal mess whilst building it with notes of cable colours and components abound!!)


Guess what I found whilst digging through the sheds on the nice sunny day yesterday?

....a partial 50m reel of three core mains cable!

Completely forgot I had that too so now I've got to grab a 'volunteer' to rig me up some more antenna wire.
My microphone shenanigans may have to wait a little while.

(Teresa is gonna kill me! )

LOL
T is going up there again ???.

Well done Victor a nice new toy 

Another great write up Victor and very tidily put together. You really do have great electronic constructional talent. Love the clear photos again which will help others if they want to follow in your footpath with a similar project.

Cheers Lionel.  


Thanks Neil mate.  

(I wish I could design the damn circuitry in the first place. )

Good stuff mate.  Reminds me, I must get round to fitting the pre-amp board in my spare (Chinese copy) FT-817 mic.

Cheers Jeff.  

Was a lot of of fun putting it together and pleased with the results so far. 

Is your preamp board one of the units that has a speech processor device in it as I've seen quite a few references to the Analog Devices SSM2165 and wonder how they fare?

Either way I wish you well with it.

(Flipping shame they discontinued the FT817 and replacement 818, lovely little rigs by all accounts.)

Victor wrote:

Is your preamp board one of the units that has a speech processor device in it as I've seen quite a few references to the Analog Devices SSM2165 and wonder how they fare?

Either way I wish you well with it.

(Flipping shame they discontinued the FT817 and replacement 818, lovely little rigs by all accounts.)

Well, according to the advert, it has.  Haven't referenced the chip, but it was so cheap when I found an article from someone who did the mod, and having a cheap spare mic so I could compare to the original, I thought "why not?"

https://www.ebay.com.au/itm/225024772771

I got lucky with my FT-817ND - mate was selling it, and it had the Sotabeams DSP kit fitted, as well as a few other goodies. 

I also bought the CW filter from an eBay seller in Japan and the board from a Polish HAM who makes them up, so I will have a 500Hz filter in it soon to for a lot less than the full Collins one cost from Yaesu...when you could actually buy them!

Nice one with the heads up on those pre-amp boards Jeff.

(Will help anyone else wishing to build similar units but with the ease of modular construction.)


I see the SSM2167 has superseded the earlier chip and handily can even run from low voltages. Helpful that the FT817 has a +5 volt power pin on the mic lead and with such a small board more easily placed within a fist mic body.

You did well with your 817 then and nice to hear it'll be fully kitted out too.

Victor wrote:

You did well with your 817 then and nice to hear it'll be fully kitted out too.

I now have more radios than days in the week, and no time to use them.

So, best thing to do with the time I do have, is build more kits! Wife is thrilled……not!

This long weekend, if I don’t get out, I have a ZM2 tuner to finish building, and my QRP Guys tunable EFHW kit turned up too.

A pretty neat job Victor and I'm very much with you on the recycle approach for building kit rather than buying the latest shiny gizmo. I guess we are both old fashioned hams at heart!

I enjoy seeing your projects and must compliment you on the wooden knobs you have turned on your wood lathe for some bits of kit. They look really good.

Thanks Ace, that means a lot and much appreciated.

I do enjoy recycling, repurposing and utilising anything I have to hand to come up with the goods. It isn't always the easiest path to take but it does keep the brain going puzzling out solutions.

I post up not in any effort to boast, but to show what is possible with limited resources and hopefully provide interesting content to the forum. 

('Old fashioned Hams' - Hee! It's one concept I like.)

Victor wrote:

Cheers Alan mate.  

The new big desk and wireless keyboard helps give me the space I need for such fun.
(Was a right royal mess whilst building it with notes of cable colours and components abound!!)


Guess what I found whilst digging through the sheds on the nice sunny day yesterday?

....a partial 50m reel of three core mains cable!

Completely forgot I had that too so now I've got to grab a 'volunteer' to rig me up some more antenna wire.
My microphone shenanigans may have to wait a little while.

(Teresa is gonna kill me! )

Has your rigger been in to the loft yet?
How do you feed that antenna farm up there?
Spectrum communications do a 95 ohm twin feeder (look at details on their site) and I have a length of it which
is surplus to requirements - if it would be of any use to you pm me your address and I will send it to you plus a mystery item FOC.

Hi Richard,

She certainly has mate!
Made a very fine job of untangling the 88 foot of lawnmower lead adding on some more cable to give me a 135 foot doublet.  

The whole shebang is fed by the same cable with some home made spreaders (from discarded plastic curtain track!) to give me six inch ladder line. Advantage is that I only have two small holes in the shack ceiling and it swings freely in the loft. No weather up there so no wind, rain, snow, ice or corrosion to contend with.

Bless you and a big thank you for the offer of the 95 ohm twin feed, your generosity is much appreciated. However the current feed line system is serving a grand job and I would rather you keep hold of it or pass it on to someone in more pressing need. I hate to sound somehow unappreciative but really do appreciate the offer.


All the best to you,
Victor