Quicksilver V4 or Sonic Frontier Power 2

I am looking on opinions on these two amps, sound characteristics, tube biasising and replacement issues, ability to drive 87db speakers, etc.

Thanks and Happy Listening.
I use the V4s to run my Vandersteen 3A signatures (also 87db, I believe). They are fantastic amps -- warm, rich, never fatiguing, built like tanks, and they barely need biasing. Mike Sanders is also a pleasure to deal with.

They are not the most powerful amps, however, so think carefully about your listening habits and room size. I had some clipping problems before I added powered subwoofers to my system, which allowed the V4s to concentrate on the mid and upper frequencies (which is what they do best).
Bsal, I thought the V4s put out about 110 watts with the EL34s and close to 160 with KT-88 tubes. Are you driving thme that hard??
I haven't owned the Sonic Frontiers Power 2, but have owned the Sonic Frontiers SFS-80 (80 wpc) and now own the V-4's.

My experience with the SFS-80 & the V-4's have both been great. Both are built like tanks, good reliability, easy biasing, and both have decent drive.

I have only heard the Power series in showrooms, which was when I had my SFS-80 and always thought they sounded a little less "tube like" and more analytical. Perhaps some liked that, to me though it was a move in the direction away from which they established themselves. Not my cup of tea.

I think I have stated before, I prefer my tube amp "sonic signature" to be just a slight bit on the warm side of neutral.

The V-4's I currently own are configured with KT-90's and Mike Sanders told me he tested them at 170 wpc before he shipped them. I am running 4 Ohm 91 db speakers at this time, but by no means are they short of power! I can barely use 20% of the preamp volume control... They seem to have an amazing reserve of power & control.

If you decide to go the Sonic Frontiers line, I would suggest looking for the SFM-160 monoblocks over the Power 2's from what I heard *and remember* with my ears in the past.
I had heard the V4 driving a pair of Vandy 5. The bass was a little loose but the mid-range was jaw dropping.

I don't know if it can drive your 87db speaker. There are too many variables to consider other than just sensitivity such as the impedance of the speaker, the size of your room, how loud you like to listen, the kind of music you play, how far are you sitting from the speakers, etc... I am afraid you might have to try it out to find out.