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Negative Peak Compression boards for Cobra 29

relisted 10 more - https://www.ebay.com/itm/203463953101

The 1st auction was for 5 sets of 2 boards at $49.72,
2nd auction was for 2 more sets of 2 boards at $49.72.
3rd auction is for single boards at $29.32, this is now the 4th auction.
And, I ordered one yesterday from the 3rd auction.
And, yes, I goofed up, forgot that the 1st two auctions were for sets of 2 boards each auction.
 
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I agree. All those 955 radios he pumps out are about 1k each. I hear him over the air all the time when skip roll... Loud gritty sounding radio.
I hear no hifi at all

I did hear one guy on the air that said he was running a D-Rail radio and I kinda called him out on it. I told him it it couldn't be a D-rail because it really sounded good. He said he knew about that because he saw the vids, but also knew that D-
Rail has shit turned up way to high during demonstration vids. So he ordered one, fully decked, and when he got it he had is buddy talk to him while he went out in the mobile. He had his buddy adjust the carrier, the peak and the modulation while they chatted. He has it set up now where that radio REALLY sounds good. What I don't understand is that, if D-Rail is installing all this crap, wouldn't you think he'd know how to make it sound good?
 
This appears to be the Clipper/Compressor circuit...
upload_2021-5-23_11-36-24.png
Special thanks to all whom are listed in this thread...

There are "two" circuits on the board, one for Variable - the other for the "compression" - which uses a "Zener" and swamped with a resistor to reduce the clipping distortion "clamp" effects. Looking at the board, the Zener band appears to a 5.1~5.6V type which when you place it in line with a Clipper Diode already present from the output of the Mod transformer - the diodes "clamping" effect is on all the time. - only stops or becomes evident once your Zener reverse biases then the Resistor takes over until the Zener breaks down again.

The Cap on the bottom is the "smoothing" filter.

So the "negative part" is what the Zener reverse biases and stops clamping - shutting off the Directional effect of the Zener and allows the Resistor to do the work.

What keeps the Zener from blowing up is the Resisters voltage drop across itself - these two work to clip the audio waveform. But drop wattage thru both - so they won't take too much power so this could be an Achilles heel for the design. Be very careful with this.

And so you know, that what is shown on the eBay listings is not how you Should install the board, if you wanted compression - the photo shows you a working method - but uses the "JP36" variable holes used for the 2nd part of the board, which is the actual variable.

Caveat Emptor!
 
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What I don't understand is that, if D-Rail is installing all this crap, wouldn't you think he'd know how to make it sound good?

The lust for and the spending of the almighty dollar taints the ears.

"" I just spent $999.99 on my new derailed Stryker, I ain't hook it up yet, but the guy I gave the money too said it sounds awesome""

"" I don't care what you say, my derailed radio swings better than any radio I have ever owned.
All you f,*%#÷s saying it sounds like shit are just jealous because you can't afford it.""
Personally,
I do like the part about having to open your new derailed radio and adjust it back to were you can understand it...

Priceless.

73
Jeff
 
I've gated him many times and would describe his audio as gritty. However the man can and has sounded "HIFI". Have a gate somewhere..he said he could sound clean, And he did sound very good! Then he went back to his d-rail sound.
What the hell is a dial-a-bird peak and dial a bird average????
I would bet he'd sound cleaner if it sold him radios.
 

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    EVAN/Crawdad :love: ...runna pile-up on 6m SSB(y) W4AXW in the air
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