I have a Sonic Frontiers SFS 40, maybe similar to the Amp 1, and I used to have an Anthem Pre 1, which I consider a very fine preamp for any system. The Pre 1 handles LP's, the Pre 1L is line stage only. Both are a little scarce these days. Of course if you arfen't playing LP's I'd recommend a passive preamp, assuming your digital source output is good.