Ayre amplifier to Subwoofer connections

Al,

You are very good at explaining things! you must be a physics teacher or something. I am familiar with how balanced connections work to cancel noise by summing inverted signals. Your explanation has helped me to understand the issue of the interaction with grounds.

Since I have also done home wiring, I also get your point about the possibility of the negative lead going to common ground through a short of the amp.

I think it makes good sense to use chassis ground (per Ayre's recommendation). It is helpful for me to understand why this is so. I don't think the 6db drop will be a problem.

thanks alot Al - I have seen some of your other posts and appreciate your involvement in the Audiogon community.

drew.

almarg,

A follow up on this.

I connected my r/l speaker outs to the sub, red to speaker positive input and black to chassis ground. The sound was good but not what I expected from the Ayre, the soundstage was compressed into the center and some harshness in instruments such as trumpets etc. As I listened to more music, I definitely felt as though something was not right and started swapping cables. I found that with the either input pulled from the amp, I still got sound from both speakers. Connecting the negative speaker leads both to chassis ground created crosstalk (at about -6b) and so I basically had a very expensive mono system.

So I changed to connecting negative to black speaker input and now everything sounds as it should - which is terrific: great bass, expansive soundstage, space and transparency of instruments (the Ayre is a very musical amp).

Seems to me that the only option is to make sure the sub has no common ground (ground lug on the plug) and connect to the speaker terminals unless I am missing something.

Drew.

Al,

One subwoofer only. What I meant to indicate was when either the left or right input from the DAC is pulled from the Ayre AX7 integrated amp (only one stereo side connected) I hear output from both main speakers (whether or not the sub was on)with the alternate speaker down about 6 - 10 db. When the black leads were removed from the subwoofer amp chassis, there was no crosstalk. Meaning the energy from the balanced negative speaker outs was crossing over and back the negative leads to the main speakers.

So, you are correct and I am having a "duh" moment. When Steve at Ayre suggested grounding the subwoofer speaker connections to chassis ground, he meant on the Ayre, not on the subwoofer. (not a pre-amp chassis as the Ax7 is an integrated that actually doesn't have a pre-amp stage per-se).

I think I get it now and will try the grounding sub negative to the Ayre and not to the subwoofer amp chassis. Although I am still confused about one piece.

Should I do this:

1. Positive speaker outputs on Ayre connected to red speaker inputs on sub.
Negative leads from speaker out to chassis on Ayre - seems like this would ground the mains to chassis as well?

or
2. positive the same
negative from chassis ground on the Ayre to black speaker outputs on sub.?

Drew.

Al,

I get it and appreciate your help - now I am going to leave things as they are and enjoy it.

drew.

Drubin- It sounds like Al helped you figure this out. Ayre did not give very complete instructions.

FYI- you can't use tape out for subwoofer output because it is a fixed output and not connected through the volume control.

Al -

no offense taken - I am glad it did not seem to have any ill effects. I guess since I connected each black to different screws on the plate amp, there was enough resistance to prevent a dead short. At any rate - the amp is the best that I have heard so far and I really do feel that the speaker connections to sub amp provide a better subwoofer integration than the pre-outs. This has been suggested in other places in this forum.

Hope everyone is enjoying some music on this beautiful Sunday morning (here in sunny CA).

drew.

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.

Drubin - you might want to start by calling Steve at Ayre about this one. I am sure they have encountered this issue before.