As Bob very correctly indicated, the 8 volt maximum output of the preamp is irrelevant. A preamp with a significantly smaller maximum output specification would not help the problem you are trying to address (everything else being equal), and if that number were much lower than 8 volts a new problem might even result, clipping of its output stage on high volume peaks.
What is relevant is the preamp's gain, which as Dave indicated is a factor of 5 (200mv in producing 1v out), which is a gain of 14db. That is certainly NOT particularly high.
Also as Bob correctly indicated, the power amp input sensitivity of 1.68 volts is a fairly typical number, and most power amps with similar output power ratings (200W in this case) will therefore have similar voltage gains.
Your speakers appear to have a sensitivity rating of 91db, which is higher than average but just slightly.
Therefore to the extent that it is meaningful to identify a "culprit," Bob's suspicion is probably correct. The DAC is probably putting out an excessively high voltage.
But whether it is or not, as I indicated in my previous post a simple solution is to insert in-line attenuators.
Regards,
-- Al
