what impacts the sound quality more amp or pre-amp

The nominal impedance of the IIs was 8ohm with 4 minimum. I think the input impedance of the B&K amps was the odd 33.2 kohms (you really have to double check with B&K), the Mapletree get be set with 0-10db or 10-20db gain, so sensitivity should not be an issue, I do think the B&K amps had sensitivity of 1.4v, but should not be an issue with an active line stage.

I think the choice of speaker and then the choosing the amp
to drive them is the most important choices in building a
system; other than the recording and the room, they will
have the biggest impact on the overall sound of your system
- the change brought by digital source and preamp, while
important do not make nearly as much of a difference as the
amp/speaker in my experience. I also agree with Wilysnet
recommendation on an excellent tube preamp selling for a
fraction of the cost of its acoustic competition, though if
I had a tube amp I would go with the even less expensive
Lightspeed Attenuator $450 which is the best sounding volume
control tool I have ever heard if well matched to an amp
(though not very flexible with only one input/output, and no
remote control.

So yes, everything is important....but the amp/speaker is
critical and the most defining pairing for what you system
sounds like. Once you get that right, the rest is relatively
easy (though not foolproof).

It would drive your speakers, but seems like a lateral move from the B&K, I would also worry about such a old amp unless it gets the once over by a tech and possibly its capacitors replaced - it is a early 80s amp - no?

Could you describe what it is that you are trying to change with the sound of your system? Something you don't like about what you currently have that you are trying to improve? That B&K amp is a pretty nice SS amp.

I think you would be well served by trying the Mapletree Audio preamp previously mentioned $760 new, $800 with Blackgate Capacitor upgrade (Made by a retired E.E. Professor/Audiophlie in Canada). I think you would get the kind of change you are looking for as you described it. Do you know the input impedance of ST202? Should be OK with the Mapletree unless less than 20kohm. The Mapletree is wonderfully smooth and full of tone with its use of the 12sn7 or 6sn7 tube.

The nominal impedance of the IIs was 8ohm with 4 minimum. I think the input impedance of the ST202 amps was 24 kohms, the Mapletree has 500ohm output impedance (should be OK)get be set with 0-10db or 10-20db gain, so sensitivity should not be an issue, I do think the B&K amps had sensitivity of 1.4v, but should not be an issue with an active line stage.

I checked my facts for the second posting.