Subwoofer for Ayre AX-7e?

@taww, thanks for the good info. Between the commonality of circuit ground and chassis ground and your finding that the RCA inputs are apparently treated as if they were balanced the design is certainly different than what I was envisioning. So, yes, my suggestion of connecting a sub’s negative speaker-level input terminal to the ground shell of an RCA input connector would not be suitable, for either you or the OP.

Just as a matter of curiosity, though, I wonder if the tape out RCA connectors are being provided with a balanced pair of signals, or if (as I would expect to be more likely) the ground shells of those particular connectors are connected to circuit ground. Although even if those ground shells are connected to circuit ground it would seem unlikely that connecting the negative sub wire to one of them would provide any benefit compared to a chassis connection, given that you’ve found chassis and circuit ground to be common.

Best regards,
-- Al

great thread guys. It's funny, because it made me think of what system I'd put together for a second room in the house.  I'd probably get the Vandersteen 1's and then a Belles Aries integrated or another used Ayre AX7e with Audioquest Rocket speaker cables and then a good source.  

The cool thing about the 1's is that they scale up really well.  I have a friend who has them and has put them in his main system on occasion (all top Audio Research ref gear) and marveled at how good they sounded.  To me that's a wonderful test to see how good a speaker really is.  I loved those old Bud Fried designs.  Thanks for bringing up that name.  

@OP...
As others have suggested, contact Ayre for the best advice.
I am sure you will be impressed with the Vandy 1's. 
B

@jazztherapist the AX7e definitely sounds best with a balanced source, but I’ve found it quite acceptable with single-ended, e.g. my Monarchy NM24 tube DAC still sounds quite good, as does the single-ended output of the PS Audio DirectStream DAC vs. its balanced output. Ayre apparently made some adjustments in the Evolution revision that improved performance with single-ended. YMMV though depending on the setup.

@almarg that’s an interesting question. I went and checked though and it appears the tape outs are also floating. I don’t have a schematic but it seems like Ayre is pretty consistent and obsessive about keeping everything truly differential and isolated.

@ctsooner if you go the AX7e route, definitely try it with upgraded input and supply caps. Little discussed fact, the AX7e is capacitor coupled at the input due to the bipolar input stage (AD844 opamp to be precise), and this has a large influence on the sound. The stock metallized polypropylene caps are quite transparent, but a bit lean/bright as Ayre was wont to voice their stuff back then. (I’ve heard they mellowed out a bit with the Twenty series, but haven’t heard them - dying to try the AX5 Twenty.) I’m using Jantzen Alumen Z-caps with terrific results, uber smooth and just a tiny hint of romanticism but still detailed and transparent. Also upgraded the supply caps to larger Mundorfs which improved dynamics, filled out the bottom end and made the mids and highs cleaner and more complete. The combination of those upgrades has made my system tremendously resolving yet natural and fatigue-free - vs. the stock unit, it’s more filled out and organic, and much less grainy - less "solid state" if you will. With the DirectStream Junior DAC, Silverline SR 17 Supreme speakers and Audience cables, I’ve reached a new level of "closeness to the source" that reminds me of listening to live mic feeds back in my conservatory days. The only thing I’m craving now is more power and low-end grunt, so looking at some more $$$ options like the AX5, Pass, Herron, Constellation, etc...

Also don’t forget to tape the heatsinks as Charlie suggested, takes some of the upper midrange glare off. :)

taww, I was just saying it would make a great little system.  My main system is a pair of Vandersteen Quatro CT's in Audi Havana Black, Ayre AX5/20, Ayre QX5 DAC/HP AMP/streamer, Mac mini rebuilt by Steven Nugent with Paul Hynes LPS and Steve's silver umbilical cord.  I use an Audio Quest TOTL WEL balanced interconnect, AQ Diamond USB cable and AQ Castlerock speaker cables.  I use an AQ Niagara with Basis cable for power distribution.

Upgrades on the way or about to happen include a new The Memory Player https://www.thememoryplayer.net with the built in DAC and Sam is installing a headphone amp/jack for my Empire Ears custom Phantom's.  That will replace the Ayre QX5 adn the Mac mini.  I will then be thinking about the new Vandersteen's mono blocks either run directly from TMP or with a top preamp.  I also love the new to US Gryphon integrated amps, so who knows.  

Constellation makes some great gear too.  My buddy loves his.