Amplifier Input Impedance

Audiolabyrinth, if you have an amplifier, tube or solid state, with a 100KOhm input impedance, any preamp tube or solid state will work with it.

The general rule of thumb is that the source have an output impedance that is no more than 1/10th of the value of the load.

But there is a caveat- if there is a coupling capacitor at the output of the preamp, the value of the cap will interact with the output impedance of the preamp- meaning that it may be considerably higher at 20Hz than it is at 1000Hz. For this reason I feel that the output impedance at 20Hz is an important value, as it can effect apparent bass response (FWIW our preamps have the same output impedance at 2Hz, 1KHz, 10KHz and 100KHz).

If the output impedance is higher at 20Hz than 1KHz, you may experience a lack of bass with amplifiers that have a low input impedance.

Thankyou Ralph, You are the man in my book!, I do learn alot from you and Almarg, the both of you gentleman are a asset to us all!, I agree, my 100kohm amp does not lack in bass at all., help me out here, what is 1/10th of 100kohms?

help me out here, what is 1/10th of 100kohms?
Audiolabyrinth

that would be 100KOhms = 100,000 Ohms divided by 10 = 10,000 Ohms or 10KOhms.

The general principle here is that when the output impedance of the preceeding unit is 1/10th the input impedance of the proceeding unit, the output impedance of the preceeding unit has little effect on the (music) signal transfer - you get 90%+ of the (music voltage) signal to transfer & there is (very) little loss.
hope this helps.

This did help, Thankyou Bombaywalla.

I notice on my set up ,
Preamp : Reimyo output impedance is 560 ohm ,
Power amp: AES superamp AE 25 input impedance is 150,000 ohm .
This gives ratio of 267 times . Does it mean I have a total mismatch ? But I find my system sound very sweet , detailed and enjoyable .
I am no expert on such things , so will appreciate some explanation from FM s here .