Re: AE7EU Top Level PCB Mod

Diver Martin <diver.martin@...>

I like the SSM2167 for one big reason: Simpler package.  While QFN is easy to do in a mass-production environment and I've never even had a problem with my hot air station, I hate QFN's/ TDFN' (Tiny Damned Frickin No-leaded packages) when doing prototyping or small quantity stuff.  

For the first run of this PCB, I'm sure there will be problems, and being able to probe the pins directly is always nice.  It's an extra dollar in low quantities, but the compression part is nice. I added it to my design, made a few changes, so I should be pretty good to go with this first revision.

That said, in my many many years of making circuit boards, I have had a design work and fit_exactly_ as intended and specified only once in my life.  It was quite the celebration!  With this particular system, I'm sure there will be no exceptions to my rule that there's always a revB :)


Moved mic/speaker output headers outwards by 0.2" to make front panel mating better
Added SSM2167 mic amplifier, variable resistor for gain, adds speech compression (1:1 to 1:10)
Other features not stated earlier, S-meter and SWR measurement.

Here we goooo......

On Thu, Jan 11, 2018 at 8:24 AM, Jerry Gaffke via Groups.Io <jgaffke@...> wrote:
The MAX9814 could work well
But be aware that while the AGC will reduce gain when your audio level gets too high,
it will also increase gain when there is nothing but background noise.
So during pauses in speech, your friends will be impressed by the sound of the
apparently monstrous cooling fan required to cool the mighty uBitx. 

Might be worth looking at the SSM2167
You can disable the speech compression feature if that's not what you want.
Still provides AGC style gain reduction when audio levels get too high,
and also reduces gain when audio levels are too low.

Jerry, KE7ER

On Thu, Jan 11, 2018 at 07:51 am, Michael Hagen wrote:

I used the MAX 9814, follow the datasheet suggestions. Set the final output with a pot.


Martin Held - AE7EU
If there aren't any questions, then what is there to learn?

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