CAT rules! It could work either with SS or tubes almost all brands you can ever imagine. The key trick is its low output impedance. Yet it doesn't have the best possible maximum output voltage as it could reach in certain units upto 20V.
If the pre's output impedance is too high compared to the input impedance of poweramp than the output impedance becomes a part of circuit and divides voltage(i.e. eats a portion of such) passed onto the next stage.
Example: if your output pre impedance is 1kOhm and input impedance of amp is 10kOhm than 1/10th part of passed voltage is lost 'without reaching' the input of amplifier.
If the pre's output impedance is too high compared to the input impedance of poweramp than the output impedance becomes a part of circuit and divides voltage(i.e. eats a portion of such) passed onto the next stage.
Example: if your output pre impedance is 1kOhm and input impedance of amp is 10kOhm than 1/10th part of passed voltage is lost 'without reaching' the input of amplifier.