Proper matching of output to input.


#1

What is typical of proper matching of components . As the output imp of the Pwd to the input imp of an amp . For me it’s about my. active cross over that is in between the Pwd to active CO and then the amps. All balanced . Can some one explain a typical good Mach as apposed to a bad one. Now I am asking for system synergy as with the correct sound levels , just imp matching.



Thanks in advance.



Al


#2

To sum it up, the output impedance of the source component should be lower than or equal to the input impedance of the next device in line. If you are all balanced then you should match already and have no further worries.


#3
wglenn said: the output impedance of the source component should be lower than or equal to the

[INPUT_IMPEDANCE / 100] of the next device in line ...

#4

So it’s just like speakers and headphones. The output must be = or lower then the divice connected to it.



Thanks



Al


#5

This is a complicated subject. It depends on what the goal is (for example, if you want maximum power transfer you want the impedances to match) and the nature of the connected equipment. Typically, in home audio were signal voltage variations are most important - not transferring power, we want the output impedance to be as low as possible



Here is a nice article that will get you going: http://www.soundonsound.com/sos/jan03/articles/impedanceworkshop.asp


#6

blockquote>valer_valer said: [INPUT_IMPEDANCE / 100] of the next device in line …



Yes if you need to bridge the source and the load this would be plenty. Most devices (I hope) would have enough voltage capability to handle a lower ratio in a single ended hookup situation. Using the low Z inputs this would all be matched, assuming that the devices are built to conventional standards.





alrainbow said: So it’s just like speakers and headphones. The output must be = or lower then

the divice connected to it.





Sorta kinda. The final connection should be as closely matched as possible if the power amp has an output transformer or is otherwise impedance sensitive. A speaker impedance below the amp’s rating may draw a very large amount of current at driver resonant frequencies in the low octaves potentially causing damage. The difference lies in what is being transferred. At line levels it is the voltage which matters, at speaker level it is current. Impedance ratios used in the speaker end of things are, for most amps, determined largely by the impedance of the speaker which is generally in the 2-8 Ohm range for home audio. Higher speaker impedances would result in a safe operating range for the amp but little power transfer = wimpy sound, and impractical to say the least.

Elk beat me to it! :))

#7

Ok i undserstand . And thanks for article elk

And now my next post is about resolution ?

Al


#8

Great reading thAnks elk. I will have to read it a couple of times , it is interesting that even the cables Ina balanced system has it’s own imp and this too matters.



Al


#9

Yes, a properly designed and well implemented fully balanced system is a magical thing.


#10

Large input impedance is not necessarily a good thing. Output and cable capacitance may become a problem. I never tried it myself as I use PWD volume regulator, but I trust a source that claimed that using a pot less than 600Ohm in a passive volume regulator and as low as 60Ohm! provides significant SQ improvement over 24kOhm pot, even though the output stage was not designed for such low load.