Impedance Matching, how important is it.

[[DANGERDAN]]

Ok so i have been a bit bored of the htpc section and thought id come spice things up a bit, cause im really bored OGM haha.

Anyway figure why not bring up a subject that could be relevant to our equipment and technology that we use today, so let the battle begin.... i mean discussion.

Preamps were designed in their original days as a first stage amplification as all or most sources were a low line level output of around 10mv and were amplified to a more acceptable voltage of 1v+, this would ensure that the Power amp which is the second stage amplification delivers the current sufficient enough for a acceptable output.
So the first stage and second stage phase were important for a sufficed power output, but this is not all that the preamp was made for, it has to also adjust the impedance to match with the power amplifier because the low level line output is not the same and can cause distortion so its important to match the signals as best as possible to avoid this. There are other things a preamp does but i dont think its relevant in this discussion as they are too minor.
So impedance matching how important do you think it is ?, do you think pre amps are still needed because of this requirement or should it be nothing to worry about (from a audiophiles perspective).

[STEvil]

Depends on the equipment.

[[DANGERDAN]]

Can you elaborate on that ??.

[STEvil]

whats to say? If you use an old record player with a 2011 receiver it might work fine or it might not.... and if you use a newer cd player with a really old receiver its going to be less than likely to work. Its all about what you're using.

[[DANGERDAN]]

Yea cause of impedance matching because newer equipment is designed differently for matching purposes no ?.

[STEvil]

yes

[[DANGERDAN]]

Whats the rule of thumb when matching impedance between equipments ??.

[[DANGERDAN]]

found my answer

In the good ol' days of telephony and radio, impedance matching (using transformers and passive filter networks) was the norm as one wanted the maximum transfer of power from one device to another. 600 ohm source and load impedances were common.

With today's gear, one is only intereseted in impedance bridging and we want the maximum transfer of voltage between devices. As a rule of thumb, a 1:10 relationship between the output impedance of say a preamp and the input impedance of a power amplifier will ensure flat frequency response and minimum signal degradation especially if you have a long cable run.