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Ralph Barone[_3_] Ralph Barone[_3_] is offline
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Default Ethan Winer's Null Tester

Don Pearce wrote:
On Tue, 13 Nov 2018 10:11:44 -0500, Mike Rivers
wrote:

On 11/13/2018 9:30 AM, wrote:
It is the common MISconception that the load must be terminated.

If the load end is mismatched, but the source is properly terminated,
the reflection will be absorbed by the source. The load will not see
any reflections so the response AT THE LOAD will be flat.


Why are we talking about megahertz and gigahertz in an audio newsgroup?
At audio frequencies and for cable lengths normally used around the
studio (and much less, circuit board traces) reflections and standing
waves in electrical connections are irrelevant.

In a situation where you're transferring power, having the source absorb
the reflected power means you're losing power where you want to go.

Of course standing waves are indeed significant when talking about sound
pressure rather than volts and watts. But let's not try to apply what
Ethan, among others, has taught us about standing waves to the frequency
response in an electrical conductor.


Mostly it doesn't matter, but one day someone may find themselves
using extra long cables. And it is never a bad thing to understand
mechanisms beyond one's usual horizon. Think of all those early
transistor amps that oscillated hard at several MHz, and nobody knew
why they were frying tweeters because they were only analysed up to
20kHz.

d

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If you find yourself using cables "that long", you should be using fibre
optics.