Equipment does not match

It is highly unlikely but possible that your pre amp and amp have a impedance mismatch but one I would investigate along with the correct toggles in place and that your room acoustics support the music your are playing. I will leave this with the more experienced hands. Could you be as specific as possible regarding the power suck ou and which point it occurs at.

Actually, that looks to be a pretty well matched system that should perform quite well.

The Rotel amp would seem to be a pretty good match for the speakers. The ARC tube preamp woudl also seem to be a good pairing. WHat is the input impedance of the Rotel? If less than 30000 kohm it might not be the best match for a tube pre-amp, but should still sound pretty good in that setup.

Whenever tubes are involved and sound heads south, always check and make sure the tubes are good and performing as they should. Either keep good spares to swap in and out to see which work best. Have the tubes tested if possible.

Next I would suggest confirming if speaker placement might be tweaked for better results.

Some more detail on what does not sound right exactly would help.

It could be equipment, but it's probably not. Could you please describe your room (dimensions, type of surfaces, rugs, etc.) and how you've positioned your loudspeakers and listening area.

Dereck, Did you mean the Rotel is 125W? The SP17 is a preamp and doesn't power the speakers per se. However, my research indicates that the RB 1080 produces 200W @ 8 ohms. In one review, the measurements indicated that the Burmester could be a tough speaker to drive. The AMT tweeter in the B25 is very revealing and many amplifiers can become hard sounding when driving difficult loads - the AMT will convey this in a heartbeat. There's also the possibility that what's bothering you is jitter from the source component.

There are many possibilities here. As mentioned above, we still need some info about your listening environment and what is is that you're unsatisfied with in your system (I know it can be hard to put into words sometimes).

I'm not disparaging the Rotel amp - it's a nice, solid component but I don't think it's in the same league as the SP17 and certainly not the B25s. More refined downstream components will reveal flaws in upstream components in most systems. Dick

I've heard modern AMT type tweeters recently in Goldenear Aon3 speakers off Rotel class gear compared to other speakers/tweeters a/b. The GOldenears were the most "polite" in teh high frequencies actually. Some will find that nice but some used to more oonventional tweeters like soft domes for example might miss some of the "bite" that other tweeters may be more prone to. Dynaudio Esotar tweeters are a good example I think.