wyred 500st mk11 and rel sub r528

I would strongly recommend that you do NOT make the common mistake, in the case of amps having balanced or bridged outputs, of connecting the black wire to a negative output terminal of the amp. Depending on the internal grounding configuration of both the amp and the sub, that creates at least a slight possibility of damaging the amp. And even if doing that appears to work satisfactorily, as in Xti16's case, it is not ideal from a sonic standpoint if only one sub is being used. What would happen in that situation is that instead of the input circuit of the sub simply summing the signals for the two channels together, it would give approximately 10 db more emphasis to the channel to which the black wire is connected than to the other channel, according to my calculations.

Regards,
-- Al

I moved the black wire to the chassis ground on the Avvik U300 and heard no difference. I'll leave it there since connecting to the speaker binding post may cause a problem.

I moved the black wire to the chassis ground on the Avvik U300 and heard no difference. I'll leave it there since connecting to the speaker binding post may cause a problem

Al - My Bad. I heard no difference because the tracks I played at the time had no extended lows in the music. After playing around with some tracks known with deep lows I found the Rel B3 wasn't doing anything. So in MY case I returned the black wire to the speaker output post. Here is a link to the U300 specs. Not sure what the virtual ground is.
http://www.aavik-acoustics.com/u-300.html

Hi George,

I see nothing in the description of the U-300 indicating that it has balanced or bridged outputs, although there are some references to input circuits being balanced. And my understanding is that the issues you referred to in your initial post regarding class D designs (not having balanced or bridged outputs) just involve certain (perhaps just older) ICEPower modules which by design have very large DC offsets (tens of volts) on both the + and - output terminals.

I couldn't find a manual for the U-300, but usually the manual for an amp having balanced or bridged outputs will include statements cautioning against grounding the negative output terminals.

Also, after looking at the manual and the schematic for the Bryston B100 you referred to earlier, it appears to me that while a lot of the circuitry is differential the outputs are not.

Best regards,
-- Al

Thanks Al - Guess I have been lucky