I agree with Mission. And the way to do this is to purchase BAT, Pass, and Krell amps and figure out which one you like first---then add the tube preamp. With BAT, you probably want a BAT preamp. With Krell you have many options. Pass you need to be careful on what you match it with (impedance-wise)---there is loads of information on this forum about Pass with tubes.
Can you use your Classe integrated as a preamp to do so? Speaker/amp is the critical match before anything else. If it were me I would purchase Krell and Pass and start from there....
Can you use your Classe integrated as a preamp to do so? Speaker/amp is the critical match before anything else. If it were me I would purchase Krell and Pass and start from there....