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D. Aaron Sawyer D. Aaron Sawyer is offline
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Default Using a Y-cable stereo 1.8" (3.5 mm) cables result imbalancedvolumes on 2.1 speakers.

On 2014.09.22 04:48, Ant wrote:
On 9/16/2014 9:26 AM PT, whosbest54 typed:

I recently bought a shielded 6" (15.2 cm) multimedia Y-cable with dual
1/8" (3.5 mm) stereo male to 1/8" (3.5 mm) stereo female [42-2496]. It
was from a local RadioShack store
(http://www.radioshack.com/product/in...ductId=2102969 for its
web site URL -- black color for mine).

Basically, I am connecting and sharing my 2.1" analog old speakers to
this new Y-cable audio adapter to my HDTV and PC's audio jacks (the same
type used for headphones and regular old analog speakers).

It seems like if HDTV is powered on, then only one speaker is louder
than the other. If I disconnect/unplug audio cable for or turn off
HDTV/PC, then my speakers have even audio in both speakers. I tried
disconnecting HDTV's audio cable to an old iPod Touch 1G, and my PC had
no audio at all.

Is there a rule that I cannot have both connected devices to play on my
audio speakers? Or should this work? Or did I buy the wrong cable
splitter?


**If I understand you correctly, you trying to connect two sets of
outputs together. This is dumb. You should ALWAYS use a resistor in
series with each output for safe operation.

Right, connecting 2 outputs and combining them into one input won't work in
this context. I recommend manual switching or a switch box.


I figured out the issue. The extension cable was mono. I replaced it, and it is almost perfect even though playing
computer's audio is lowered with HDTV playing loudly but that's fine for me since I want to hear HDTV more than the PC
during the same time.

So, are you saying it is not possible to play audio from two different devices onto the same 2.1 speakers with a
Y-splitter audio cable?


Oh, it's possible. But it is not wise.

The power output stage of the 'active' device (say, the PC) is driving not only
the speakers, but also the power output stage driver circuitry of the 'inactive'
device (the TV). What happens to the 'inactive' device depends entirely on its design.

Most current consumer audio designs are direct coupled, lacking audio power output transformers
(to save weight and cost), so that the output power transistors' Collector-Base/Collector-Emitter
(or Drain-Gate/Drain-Source) junctions are exposed to the audio output power (voltage x current)
from the 'active' device.

At very low driving power from the 'active' device, the 'inactive' output power stage
devices may survive. The definition of 'low' is governed by the device junctions' diode
peak inverse voltage and current ratings. For silicon, stay under 0.5 V and 200 mA (100 mW).

You may be lucky for a while. The first time you crank your 'active' device output to 11 will
likely be the last time you get to use the 'inactive' device. Heck, you could run both at the
time and let the speakers sort out the current paths. Or get two more Y-splitters and you can
run 4 active devices (TV, PC, Receiver, AC mains(!)) into the speakers. Simultaneously.

Better yet, don't abuse your devices; use a switch box to isolate the TV and the PC from
each other, as suggested above.

Good luck with that. YMMV.