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[email protected] jurb6006@gmail.com is offline
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Default Speakers and wire length

If you really want the scoop on tis, here is the technalia. (sp)

An amplifier has what is called a damping factor. Tube amps are usually low, solid state amps are higher. Just looked and yours is rated at 25. this assumes that means into eight ohms. This is because that is what all the other readings are taken at.

the damping (or dampering n the old days) factor is the ratio of the speaker impedance to the effective impedance of the output of the amp. what is means is the amp is an absolutely perfect voltage source with unlimited current, but there is a resistor in series with it.

Since your damping factor is 25, that means the effective output impedance of the amp is one twenty-fifth of eight ohms. Tht is about 0.32 ohms, which is probably the value of the emitter resistors, but those do NOT determine the output impedance and therefor the damping factor. They are almost always witin the feedback loop so their resistance is nullified, mostly that is..

A higher damping factor means that the voltage output is not affected as much with variations of the load impedance. For example, if you connect another speaker to the same cannel, the original speaker will not decrease in vlume. Instead of the voltage dropping, the amp puts out more current, to maintain the voltage output which is determined by the input and your settings..

I have a Phas Linear 400-2, which has a damping factor of 1,000, actually the highest I have ever seen. It is not just done with feedback, it takes current drive to do it, which is how it does do it. With enough feedback you can enhance the damping factor, but then the amp could become unstable with highly reactive loads. It makes for enough math to give you a headache, better off just to design it to not need too much feedback.

NOW TO THE QUESTIO ! TADA !

Here's a table on wire resistance :

http://www.interfacebus.com/AWG-tabl...esistance.html

Let's just say you are using 16 guage wire which has a resistance of four ohms per thousand foot. Of course there are two wires so that means eight ohms, IF you are using a thousand feet. If the impedance of the speaker is a perfect eight ohms, you will lose exactly half of the power. It is also not in the feedback loop so that means when the speaker impedance is lower, like at lower bass frequencies, there will be more loss which will affect the low end.

But you are not using a thousand feet. Let's take it as 100 feet then, one tenth. That means that if the damping factor of the amp was infinite, after the wire you are left with a damping factor of ten. Is it one tenth of the load (speaker) impedance. At twenty feet, which is one fifth of that, just multiply by five because that's the side of the equation you are on.

The actual damp(er)ing factor as seen by the speaker itself is the vector sum of the wire resistance or other inpedance and the actual source resistance (damping factor/load) of the amplifier in quesrtion.

In other words it realy doesn't matter all that much. Also you could just kick it up to 14 guage, which is only 2.5 ohms per thousand feet.

All in all you are not going to hear that much difference. It takes ten times the power to seem twice as loud. A doubling or halving of power results ion a very small difference in percieved volume. It is a bit easier to discern when it comes to frequency response/tonal balance, but not all that much.

A fifty foot run that introduces 0.2 ohms resistance, with a speaker that is eight ohms but drops to two ohms at 25 Hz (if it can even reproduce that), will have a loss at 25 Hz of ten percent of the voltage.

Double or half the voltage is APPROXIMATELY 3 dB. the difference here, I am pretty sure is not even one dB, and even the most golden ears in the world will have a hard time hearing that.

So indeed, all the hype about monster cable and all that **** is just that - hype. On a long ruin you CAN hear the difference but you will have to do a a/b compare to notice. I actually have. I used to have a bench that was set up so I could do that.

Funny though, that some people would probably prefer the "degraded" sound. Really.