Thanks, John (Roxy54) :-)
I agree that it is likely to be a great combination, assuming the amp (which may be something like 20 years old) and its tubes are in top condition. And its three output taps and six feedback settings (including zero feedback) would provide a great deal of flexibility in fine tuning the sound.
Confidence is also added by the very benign impedance characteristics of the speakers, as shown in
Stereophile’s review. And while its 83.5 db measured sensitivity is about 14 db less than the sensitivity of my speakers, if the XA30.8 has been able to provide enough power for the OP’s purposes I would expect that the VAC amp would as well.
As to how the sonic character that would be provided by the VAC amp would compare with what the XA30.8 is providing, I wouldn’t want to speculate beyond stating a suspicion that it would be a bit richer sounding. While I’m now using a Pass XA25, that is a considerably different animal than the Pass .8 amps, with which I have no experience.
Finally, I’ll point out that the BHK preamp is described as being fully balanced, while providing RCA as well as XLR outputs. So I suppose a possible downside of going to the VAC amp would be that since it only provides unbalanced inputs the potential advantages of the preamp’s fully balanced design might not be entirely realized. Personally I wouldn’t be too concerned about that, as the great majority of the preamp’s fully balanced internal signal path would still be utilized, but I know that would be a consideration to some.
Good luck. Regards,
-- Al