Quicksilver Mid Monos vs AES Sixpacs

I have no experience with the Quicksilver's, but it looks like the main difference is that they'll give you 50W in ultralinear, while the AES is designed to run in triode. There are members that could describe the sonic differences between those modes much better than I.

I'm currently using the Six Pacs to drive a pair of MMG's (4 ohm, 86db) along with a Hsu Sub.

I'm not sure if you are in the NJ area, but I think that Audio Connection carries both lines.

Well, I had 89dB 6 Ohm speakers that were also a very benign load to the amp & I selected the AES Sixpac after doing a fair bit of research.
I selected these amps because I liked the fact that the feedback could be made 0 & that the EL34 tubes were being used in triode mode. I felt that using the EL34 in triode was the best option because of it being far more linear than using it in U-L or pentode mode. My Sixpac had the upgraded transformer hence outputted 60W/ch. I used a NOS GE 12BZ7 in the input stage to excellent effect - it took a very good sounding amp up a few notches & made it a great sounding amp. Plus, the GE 12BZ7s were relatively cheap so it was a win-win situation for me.
IMHO EL34 in triode mode gets my vote any day over any other mode of operation.

Thanks for your responses guy's....I can't believe that no one has done a direct comparison of these two popular amps?

I think your best bet would be to read the individual reviews for each piece and then go and try to listen to them. There aren't that many AES dealers (Upscale Audio and Audio Connection)and I've never looked into the Quicksilver gear (though it looks mighty nice). I seem to remember seeing at least 1 Quicksilver piece along with the Six Pacs in the listening room at Audio Connection. John Rutan might be able to give you some more info.

Since I am buying used I really think it is inappropriate to go in for a listening session in a brick and mortar store if I am not going to buy. It would be my best bet, alas I have to go with opinions on Agon!