Ayre amplifier to Subwoofer connections


I am trying this question again with a more specific title to try to get responses . . .

I am intending to hook an Ayre, fully balanced amplifier to a subwoofer via the high level (speaker) inputs. Ayre has told me NOT to connect negative to black but to chassis ground. A balanced amplifier cannot be connected to anything with a common ground.

The subwoofer amplifier manufacterer (O-Audio) says the plate amplifier has no common ground by virtue of the fact that it only connects 2 prongs to the outlet.

I have also heard that other audiogoner's have connected Ayres to subs via the red and black speaker connections without a problem. How have you accomplished this?

Can anyone explain to me in more detail what is up with this technically and what connections I should be using.

Additionally, can you tell me the pros and cons of connecting the speaker leads to the sub from the speakers vs the amp. Does it have to do with length, noise, etc?

thanks to everyone in advance!
drewh1
Drubin,

I am not using this scheme. After researching, I determined that the only way that a ground connect failure could occur is for the subwoofer amp to fail and short everything to ground. Since my O-audio subwoofer amp does not have a common ground connection, I am hooking both negative and positive leads as normal as this is a very remote possibility. Also the O-audio is a digital amp. I do know of someone else using Ayre with Martin Logan subs who connects both Pos and Neg terminals and has no problems.

You must determine that your amp does not have a common ground connection. It may not be enough to simply lift the common ground from the plug if you have one. The amp I have did not have a three prong plug, only two.

This doesn't directly answer your question, I know but may give you an alternative connection.

drew.
Interesting. The REL has a three-prong plug. I will say that I think the system sounds better connected the standard way (i.e., not to chassis ground), but that may be the 6db volume difference at work. I don't want to blow up the Ayre of course, but...
I have a new question on this subject. How do you connect a stereo pair of subwoofers to a fully balanced stereo amp, such as the Ayre.? The REL cable for each sub has two channels of "hot" (red and yellow) plus a ground. I assume that, for each sub, you would connect both hots (or just one?) to the plus side of the appropriate channel on the amp. But what about the grounds? Would you connect both subs' grounds to the chassis?
Drubin - you might want to start by calling Steve at Ayre about this one. I am sure they have encountered this issue before.
Drubin -- Yes, you would want to connect both hots (yellow and red) to the plus output of the corresponding channel of the amp, and both subs' grounds to amp chassis.

The subs' electronics sums the difference between its red and black together with the difference between its yellow and black inputs. If you connect both red and yellow to the + output of a fully balanced amp, and black to ground of the amp, then since two identical signals are being summed together, the mono signal the sub provides to its driver will be proportional to the output of that channel of the amp.

If you were to connect sub black to amp negative for the corresponding channel, then as we discussed earlier in this thread you create, under some scenarios, the risk of damaging the amp. However, fwiw, the other downside of doing that which I had mentioned (creating an imbalance favoring one channel in the summation to mono) would not occur in this situation.

Regards,
-- Al