Amplifier input tech question

Attenuation/division of the volume pot has nothing to do with its resistance and depends on the angle of rotation alone. You should get full power at about 1 o'clock.

Tpreaves,
The JC 2 manual suggests setting the amplifier gain controls (if any) so that the volume control on the JC 2
is between 11 o'clock and 1 o'clock during normal listening. That is (according to the manual) the "sweet
spot", where the channel tracking is closest & the distortion is lowest. As stated above, I intend to purchase
a new stereo amp or two mono block amps. The intent of the
question, is to learn about the impedance and voltage measurements and what they mean, as far as finding a good match. I will ultimately choose the amp or amps by ear,
but I do want to consider getting the JC 2 into its
"sweet spot".

Amandarae,

Thanks for your suggestion. I think that may be a little more radical approach to this issue than I'm willing to pursue. And, I am going to purchase a new amp or amps not
a new preamp.

Ahhh, I stand corrected. Buy an amp with a volume control in the input circuit then. Or have an amp with much less input impedance instead of the 22K.

Goodluck!

>>"My guess is that there is also a relationship between the preamp output voltage"<<

That's the relationship you want to look at not impedance

The Aragon 8008 amp has an input sensitivity of 1.68 volts according to the factory spec

That means a signal of 1.68 volts will drive the amp to it's full rated output of 200watts

Your Parasound JC2 pre can put out as much as 8 volts which is 4 times more than you need to drive the Aragon

It seems that the Parasound's output voltage is directly related to it's input sensitivity

From the Parasound site it states that a 200MV input signal will output 1 volt at the JC2's output ... so if your source (Dac) is putting out 400MV it would probably be just about right to drive the pre so the pre would output about 2 volts and not drive your amp into overload

But your PS Audio dac probably puts out 2 volts to the JC2 pre and causes the JC2 to output the full 8 volts

This 8 volt output from the JC2 is way to much for the 1.68 volt input sensitivity of your Aragon ... so you have to turn the volume control on the Pre down, so as not to dive the amp into overload

This is probably why you can't turn the volume control on the Pre up pass 9 oclock

Simply put the 2 volt output of your dac is driving the JC2 pre amp to full gain and outputs 8 volts to your amp which is way to much ... so you turn the volume control down to 9 oclock so as not to over drive the amp

Volume controls are attenuators and can only turn volume down by adding resistance ... the more you turn the volume down the more resistance you add to the circuit

The more resistance added the less transparant the signal will be

So ideally you would like to have your volume control turned all the way to 1 oclock where there is little to no attenuation or resistors in the circuit to reduce transparency

Here are two links which may explain it better than I did

http://www.rothwellaudioproducts.co.uk/html/attenuators.html
http://www.rothwellaudioproducts.co.uk/html/how_attenuators_work.html

HTH Dave