Headphones question

[r***@optonline.net]

I currently have two pair of Sennheiser headphones hooked up to my Sony 4k TV.
Earlier this year, when I hooked the second pair up, the volume on both dropped.
I posted here, and based on recommendations, I bought a small amplifier which
can handle four headphones. The hookup right now is about a 25' cable from the
TV to the amplifier, then the two headphones plugged in. Volume is fine now.

My question is I'll soon be moving things around and I'm wondering if it would
matter if I changed the placement of the amplifier to closer to the TV. I'd have
a short cable coming from the TV to the amplifier, which instead of being on the
floor behind my sofa, would be inside a cabinet with the cable box and DVD
player. Then two long cables (should be about 25') going from the amplifier to
the headphones. Basically, does the amplifier need to be near the end of the
long cables or is it alright if it's at the begining of the run? I hope this
makes some sort of sense. Thanks.

[J G Miller]

I'd have a short cable coming from the TV to the amplifier

If you think about it, this is actually a better arrangement.

With analog signals, which is what you have with the audio output
to the amplifier and then to the headphones, there is always the
problem of lowering the signal to noise ratio, particularly with
longer cable runs.

This means that the amplifier has a less clean signal to work with,
and the noise as well as the good signal get amplified.

With a shorter cable run from the source to the amplifier, the amplifier
will potentially be amplifying a cleaner signal (less chance of noise
introduced or distortion over a long cable run).

Since the purpose of the amplifier is to amplify the level of
the signal, what comes out of the amplifier and then goes
down the long cable to the headphones should be of sufficiently
high signal level to provide an acceptable level of volume in
the headphones.

So the overall principle is, if amplifying an analog signal (analog audio
signals, radio/tv [digital tv is still transmitted with "analog" waves,
but the information it contains is a digital bytestream not an a modulated
analog waveform), do it as close to the source as is feasible.

If on the other hand you were feeding a digital audio signal (coaxial SPDIF
or optical output from your source), the position of the digital/analog
converter would not make any difference whether it was on a short run or long
run of cable provided that the maximum length for reliable transmission of
the signal was not exceeded.

[r***@optonline.net]

Post by J G Miller

I'd have a short cable coming from the TV to the amplifier

If you think about it, this is actually a better arrangement.
With analog signals, which is what you have with the audio output
to the amplifier and then to the headphones, there is always the
problem of lowering the signal to noise ratio, particularly with
longer cable runs.
This means that the amplifier has a less clean signal to work with,
and the noise as well as the good signal get amplified.
With a shorter cable run from the source to the amplifier, the amplifier
will potentially be amplifying a cleaner signal (less chance of noise
introduced or distortion over a long cable run).
Since the purpose of the amplifier is to amplify the level of
the signal, what comes out of the amplifier and then goes
down the long cable to the headphones should be of sufficiently
high signal level to provide an acceptable level of volume in
the headphones.
So the overall principle is, if amplifying an analog signal (analog audio
signals, radio/tv [digital tv is still transmitted with "analog" waves,
but the information it contains is a digital bytestream not an a modulated
analog waveform), do it as close to the source as is feasible.
If on the other hand you were feeding a digital audio signal (coaxial SPDIF
or optical output from your source), the position of the digital/analog
converter would not make any difference whether it was on a short run or long
run of cable provided that the maximum length for reliable transmission of
the signal was not exceeded.

Thanks a lot J G. I understand what you're saying.