[Elecraft] Sorta OT - assistive technology assistance

[Walter Underwood]

Since you are dead set on building one from scratch, start here.

https://www.google.com/search?q=audio+mixer+circuit

You'll see a lot of four-channel mixers because quad op-amps are cheap, under $1.

This one has the pots before the op amps.

https://www.allaboutcircuits.com/projects/build-an-audio-mixer/

This one has the pots after the op amps.

http://www.theorycircuit.com/audio-mixer-circuit/

I’d be interested in the parts cost after you have chosen a design.

wunder
K6WRU
Walter Underwood
CM87wj
http://observer.wunderwood.org/ (my blog)

> On Jan 10, 2019, at 11:36 PM, Richards <jrichards at k8jhr.com> wrote:
> 
> THANK YOU for the several replies to my mixer circuit question - both on and off the list.  Unfortunately, few actually answered the original question,  most often advising me to abandon the project or mix on a computer sound card.
> 
> First - Thanks, Steve, for your input based on personal experience.   While I am familiar with your mixer, Tom prefers a device with stereo channels and outputs for both headphones and powered speakers. The model under consideration has only two control pots, making it easier to manage.   Tom truly appreciates your personal input and direct correspondence off list.   He puts a lot of stock in your take.
> 
> Second - Tom prefers a simple hardware solution.   Locating a manual control next to the rig is much easier (for him) to manage, than mixing with a computer sound card.   Navigating multiple operating system windows is a serious challenge because he cannot see the monitor or use a mouse.  This is not the preferred method for a contest or snagging rare DX before a pileup ensues.  Mixing on a computer would be very inconvenient;  close your eyes and try it some day!   It's easy for you to say ... but, not so easy for my friend to do.
> 
> Third -  We can simply purchase a commercial product  (I recommend the Rolls MINImix MS22s stereo mixer, with just two pots, and outputs for both headphones and speakers)
> 
> UNFORTUNATELY, THAT DEFEATS THE WHOLE POINT BEHIND MY QUESTION.
> 
> While I do NOT wish to look a gift horse in the chops, or appear ungrateful for the advice received so far;  money is not the object as I want to LEARN how this type of circuit works, and do a favor for a friend, in one stroke. Advising me to save money and just buy a turn-key, off-the-shelf solution hardly fits the HAM RADIO TRADITION of experimentation and self-determination,  and teaches me nothing about circuit design.   I was hoping to build something MYSELF- earning that heady sense of self-satisfaction that accompanies the completion of a successful home brew project.  Considering all the experts on this list, including world class board certified AES audio man Jim Brown, I figured a simple summing circuit would be a snap.
> 
> I close this thread with a big THANK YOU on behalf of my  ... um ... "client,"  whilst I repair to the proverbial drawing board to renew my search for a simple summing circuit.
> 
> Happy trails to all.       JR
> 
> (We return you to your regular daily programming content)     ;-)
> 
> -----------------------------------------------------
> 
> 
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