What's the difference between a Rel t/9 & T/9i?


I want to use a sub with LS50s that are driven by an Ayre A7e integrated.  The A7e has no output for driving a sub, so I need to use speaker-level.  I'm trying a KEF Kube 10b, but the speaker-level connection is difficult.  The Ref uses a Neutrek Speakon connection that seems much easier.  I might be able to buy a used Rel t/9 for not much more than the 10b.  The least expensive t/9i I've seen is twice the cost of the 10b.

db
Ag insider logo xs@2xdbphd
db, before proceeding with either sub please read the posts by member taww in the following thread, especially the first of his posts dated 4-2-2018, that post beginning with "I have an AX-7e with a REL T-9 and it sounds great, but has some serious caveats...."

https://forum.audiogon.com/discussions/subwoofer-for-ayre-ax-7e

Regards,
-- Al
Thanks, Al. That post by taww and your first 4/1/18 post in that thread have given me pause about using any sub with the A7e. I was planning to connect the left and right speakers to L+L-R+R- block of the KEF 10b, but now I worry about damaging the A7e.

The current setup is balanced analog from an Ayre Codex in DAC mode to the A7e that drives a pair of KEF LS50s. I don’t perceive a need for a sub, given that the setup renders jazz bass very well, and I mostly listen to jazz and chamber music in the living room.

In another setup Ayre QX-5/20, KX-5/20, VX-5/20 drive KEF Reference 1s augmented by a pair of Velodyne HGS-15s with SMS-1 bass management. That can satisfy my lust for pipe organ recitals.

Is it safe to try the 10b if I connect only the left or right speaker? That is, connect to the L+L- or R+R- input of the block but not both. I had planned to add a second 10b if I liked the sound.

I suppose I could return the 10b to KEF.

db
I was planning to connect the left and right speakers to L+L-R+R- block of the KEF 10b, but now I worry about damaging the A7e.
Yes, that would definitely be a no-no.

Is it safe to try the 10b if I connect only the left or right speaker? That is, connect to the L+L- or R+R- input of the block but not both. I had planned to add a second 10b if I liked the sound.
As you’ve seen in the other thread what is probably the greatest concern in connecting a sub to the Ayre amp (either directly or via connections to the speakers) occurs if the two negative inputs of a single sub were to be connected to the two negative outputs of the amp. Depending on the design of the sub chances are that would result in the full amplitude signals on the amp’s negative output terminals for the two channels being shorted together.

However as taww and I explained you shouldn’t connect **either** of the negative input terminals of the sub to a negative output terminal of the amp anyway. (Doing that for one channel **might** work ok, depending on the internal grounding configuration of the sub, but it would violate the cautionary note in the amp’s manual that I quoted in the other thread and might degrade sonics or even cause damage). You would want to connect both negative input terminals of the sub to the amp’s chassis. It would then be safe to connect one positive input of the sub to the amp’s positive output terminal for one channel (or to the corresponding terminal on the speaker), and the other positive input of the sub to the amp’s positive output terminal for the other channel (or to the corresponding terminal on the other speaker). The single sub would then sum the signals for the two channels together, as is desirable when only one sub is used.

Connected in that manner the one remaining issue that is likely to arise would be, as taww explained, that when the amp is turned off the sub is likely to hum.

Good luck. Regards,
-- Al