Re: Sound card question
On Fri, October 2, 2015 12:10 pm, Doug wrote:
> You didn't mention that you want to add _speakers_. You might need a
> small amplifier after the Y-adapter, since the speakers will be low
> impedance--4- or 8 ohms. Visit ramseykits.com and find some small audio
> amplifiers in kit or assembled form. They are probably overkill for your
> purpose, but cheap enough. A 14W stereo kit, CK154, will run on 12 to 16
> VDC at 1A. $26 for a kit, or $34 assembled. You
> provide an enclosure and a wall-wart to drive it. (The "14W" rating is for
> 7W per
> channel, and I would expect that it's a peak rating, since 16V at 1A is 16
> Watts
> _input_ power! I would guess that rms power is more like 2 or 3 Watts per
> channel.)
In this context, mis-use of terms "impedance" and "power" is adding
nothing but confusion.
A pair of powered desktop speakers designed to plug into the output port
of a computer is a commodity item which can be purchased for about twenty
dollars at any computer store. Everything is packaged nicely and there is
a volume control, a tone control, and a power supply which plugs into a
120V wall receptacle; the power output is several Watts. The load which
these amplified speakers present to the audio source (computer,
transceiver, or whatever) is in the range of ten thousand Ohms to a
hundred thousand Ohms; in other words, the speakers present no significant
load on any audio line to which they are connected.
RLH
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