James,
a widely used design is to wire the sources together via some resistors,
and get some gain by a following OP-amp. The resistors could be made as
pots to adjust volume.
I built one for my guitar amp, if you look into DIY guitar electronics
you'll find plenty of design ideas.
here is mine:
https://www.log49.com/index.php?/archives/18-For-my-guitar-Pre-Amp,-Effect-and-Mixer.html
Note that you may have to add some extra capacitors to block RF, not all
readily available mixer boxes pay attention to that, really.
73 Gernot DF5RF
Am 10.01.2019 um 00:03 schrieb Richards:
Good Day.
Background:
I am assisting a blind ham who also suffers some hearing loss. I
suggested using headphones to attenuate ambient environmental noise as
he operates. The rub is, he needs to hear both his receiver AND his
computer (which provides audible feedback when logging contacts and
performing other duties.)
Question:
Can anyone suggest a simple passive (or active) mixer circuit schema I
can build for him to safely mix audio signals from his transceiver
headphone jack with audio signals from his computer sound card
headphone jack?
Discussion:
While there are multiple commercially produced simple and complex
mixing products in the marketplace, I would prefer to build an
inexpensive, small footprint solution we can easily incorporate in his
station to minimize clutter and the number of cables, jacks, and
controls -- he contends with plenty of that already. I suppose one
solution might be a simple Y-adapter cable, but that seems too easy
and I wonder whether we should isolate the signals and/or grounds in
some way? (e.g., I do not wish to cause any "Pin-1" grounding issues,
and etc.)
Any traction? Can anyone point me to an appropriate circuit
schematic or other resource? I don 't mind doing homework, and while
I enjoy building stuff and I am familiar with the basic concepts
involved, I could use a leg up on this project, especially to keep it
simple and easy to build and implement. Please reply off list if this
question is too far off topic, although I suspect there are many hams
who might be interested in the result, besides similarly situated
disabled operators.
Thank you - James - K8JHR -
---------------------------------------
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