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An Inexpensive Audio Processor for Receive

from Greg Danes, KJ4DGE on May 12, 2017
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An Inexpensive Audio Processor for Receive

By KJ4DGE

I came across in my two-mile walk last week a jewel in the rough. Of course the main idea was to use the cassette players to make my Dadís radio station broadcast tapes into digital then another idea came to me. First let me back up. How many times have you seen old audio gear out by the curb for the trash pickup? Granted in most cases its there because it has a problem, But in some cases like mine itís just OLD!

Reel to reel and cassette are 50 years old and the majority of people can afford a OK stereo these days with CD/MP3 and without breaking the bank. Luckily for me when I got it home and cleaned it up everything works! The only thing missing is the phono player but I have no albums so itís not missed.

So now I can transcribe my Popís cassettes into MP3ís. But then it hit me. This throwback to the 1970ís has a graphics equalizer built in! -- So why not take the sometimes poor or weak audio from a Ham station and run it through that? IF nothing else it makes for an interesting project and it had zero cost.

Granted, todayís rigs have all kinds of bells and whistles to tailor audio out. DSP, audio filters and there are high end add-ons that also can be bought from Autek and a host of other companies. I am not a cheapskate, just poor in the pocket so I have to think outside the box perhaps. Also I am not talking ďboom-boxesĒ unless they have the multiple control equalizer. You can find these all-in-one stereos at almost every Saturday yard sale for the price of a lunch at Wendyís. So as time goes along I will test this out.

See pic below
73 KJ4DGE

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An Inexpensive Audio Processor for Receive Reply
by W3TTT on May 12, 2017 Mail this to a friend!
I already have a stack of high end quality stereo components. I posted on eBay and no takers. Looks like no one is interested in what was (once) a top-of-the-line system.
On the other hand, I built an audio filter for CW, and it works nicely, and is much smaller and uses less wattage in the cottage.
It is funny or ironic (same thing) about old gear, especially consumer goods like stereos or TVs. My neighbor put out on the curb a perfectly good color TV with remote. He bought a flat screen, and no one wanted the CRT set. It is big and heavy, but it will work forever.
In my younger days, I would grab such a set and cannibalize the good parts. I would put the parts in my junk box and probably never use them, but it filled up the junk box. But a long time ago i got rid of the junk box. Now I can afford new parts for any of the projects that I want to build. Except for tuning capacitors that come from old radios. Which brings me to a conundrum. Why destroy a radio just to build a radio? It would be one thing to scavenge a non-working radio, but to scavenge a working radio just to build another?
 
RE: An Inexpensive Audio Processor for Receive Reply
by K6CRC on May 12, 2017 Mail this to a friend!
Ham improvisation in action.
 
RE: An Inexpensive Audio Processor for Receive Reply
by KD6VXI on May 12, 2017 Mail this to a friend!
I, too, am amazed at how high end audio now means nothing.

My sons are being brought up to cherish my audio system. Klipsch, Yamaha and JBL, but it works.

I couldn't tell you how much is invested, but I'm looking at pennies on the dollar for everything but the Heresy line of speakers.

Sad.

To keep this on topic, AM ops have been doing this for a while. For even better effect, tap of the detector in an old non dsp set and you find how good am, and to a lessor extent, ssb can sound. A good eq can make a rag chew a lot more enjoyable, especially if you don't have dsp, etc.

--Shane
KD6VXI
 
RE: An Inexpensive Audio Processor for Receive Reply
by K6CRC on May 12, 2017 Mail this to a friend!
'Looks like no one is interested in what was (once) a top-of-the-line system. '
If you have an old Fisher, McIntosh, or Scott TUBE audio system, putting it on eBay will result in a spectacular bidding war. Restored Fisher500 receivers were going for close to a grand when I last looked. Not that long ago, I found one on curb...

Even the top solid state stuff from the past isn't worth much though. It just didn't sound that good, especially when compared to current ClassD amps.
 
RE: An Inexpensive Audio Processor for Receive Reply
by W4KVW on May 12, 2017 Mail this to a friend!
I'll stick with my ClearSpeech Base DSP Modules & DSP Speakers.They work wonders with the flick of one switch. That's about as good as it gets & they don't take up another whole desk for space.

Clayton
W4KVW
 
RE: An Inexpensive Audio Processor for Receive Reply
by AC7CW on May 12, 2017 Mail this to a friend!
WW2 surplus audio filters for CW did a great job. They were completely passive so they didn't add noise to the passband.
 
Excellent Topic Audio equipment from past days! Reply
by AA7LX on May 13, 2017 Mail this to a friend!
Wonderful idea! Tell us how your project turns out-- funny, I'm just now looking at the Clear Speech technology unit to add to my IC-718 in addition to adding a installed filter I just purchased for it.
 
RE: Excellent Topic Audio equipment from past days! Reply
by KW6LA on May 13, 2017 Mail this to a friend!
AA7LX-
The IC 718 suffer from dynamic blocking of adjacent signals, The ClearSpeech Base DSP Modules & DSP can help out. I had one on a HR-2510, cheap radio and it was pretty amazing.
Now it does not add fidelity like an equalizer in the home stereo, or have the old DBX / Dolby filters. Itís really great for CW filtering. The speaker that came with mine was crap, and last
Ten minutes before gutting the filter for a better speaker. The author is not talking about some brick wall filter, just better listing pleasure for those who like that. Many Hams like their radios
to sound like a Tuna can with the notch filter /on. To each there own !!
 
An Inexpensive Audio Processor for Receive Reply
by N6JSX on May 13, 2017 Mail this to a friend!
This is a good teaser but it lacks DIY proof. Sorry but this maybe a novel idea but it lacks the de4tials to close the deal....

Since most of HAMdom has become button-pushers you need to rewrite you intent/details for the demographics of eHAM or it will go on deaf ears (no DSP included, haha).
 
An Inexpensive Audio Processor for Receive Reply
by DL8OV on May 14, 2017 Mail this to a friend!
It works.

Sat above my transceiver is a stereo equalizer that I picked up at a flea market for 20 Euro because some of the knobs were missing. Replacement knobs for the sliders were 3-D printed and now I have a working unit. What can it do?

1) Boost everything from 250 Hz to 4 KHz and cut everything else. The immediate effect is that all audio sounds like a long distance telephone call but it's great for pulling speech out of the noise.

2) Boost everything at 750 Hz and cut everything else. You now have a CW filter.

3) Got a hetrodyne on a received signal? Boost everything except the hetrodyne frequency and cut the frequency of your whistle. It's gone.

4) Want steeper filter curves? Wire the left and right channels in series.

Best 20 Euro I ever spent.

Peter DL8OV
 
RE: An Inexpensive Audio Processor for Receive Reply
by K9MHZ on May 14, 2017 Mail this to a friend!
CRC, you're not kidding about the bidding wars over Fisher tuners, etc. Got into several and lost each time. Probably a blessing, actually.

BTW, the new Integra (and others) are phenomenal. Kind of like a Collins vs. IC-7300 comparison today.

(Sorry for the thread veer.)
 
RE: An Inexpensive Audio Processor for Receive Reply
by K6CRC on May 14, 2017 Mail this to a friend!
'CRC, you're not kidding about the bidding wars over Fisher tuners, etc. Got into several and lost each time. Probably a blessing, actually.'
It was a blessing. If you like the sound of tubes, check out DYITUBE.COM. Use your Ham DYI skills to build a 'modern' tube amp for a fraction of the cost of a worn-out and likely dangerous 'classic' tube amp on eBay.
Sorry for the digression, everyone.
 
RE: An Inexpensive Audio Processor for Receive Reply
by KJ4DGE on May 15, 2017 Mail this to a friend!
In reply as to "falling on deaf ears of Button Pushers", all the things that have been articles here on EHAM.net were never written with button pushers in mind. Nothing wrong with having all those buttons to push, but I came from a era called "Heathkit" and you had to install the buttons and solder the wires before pushing them, otherwise they did nothing.....:)
 
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