wyred 500st mk11 and rel sub r528

The manual also shows connecting the Rel via the Low-Level input, but I'm not clear on where to connect on the Oppo or if it is going to do the same as the speakeron.

REL's theory is that connecting at speaker level rather than at line-level/low level is preferable, because it results in the sonic effects of the amplifier being reflected in the signals provided to the sub as well as in the signals provided to the main speakers. Not everyone agrees with that theory, but I see no reason not to proceed in that manner.

I got the w4s amp because it had balanced inputs and the B&K didn't. Rel said because I had the .1lfe connected that it would act as a ground for the sub ....

Yes it probably would provide an adequate ground, given that the Oppo is connected to the W4S amp. The reason I say "probably," though, is that if the Oppo is connected to the amp via XLR's there is a possibility that the design of the amp is such that the ground on the XLR connectors (pin 1 on those connectors) might be connected to the amp's chassis, rather than to its circuit ground. Which would still probably work ok, but might result in the same hum issue I indicated could arise if the black wire were connected to a chassis screw.

Also, not being familiar with the Oppo, I'm not sure if doing that would result in an LFE signal being sent into the sub that would be unwanted for two-channel listening.

In any event, my suggestion of soldering the black wire to the ground sleeve of an RCA plug, and connecting that plug to an RCA input connector on the amp, is virtually certain to work, and may provide a ground that is "better" (i.e., sonically preferable) than a ground that is circuitously provided via the Oppo. Although connecting the black wire to a chassis screw on the amp is also worth trying.

Regards,
-- Al

I have been told by W4S that the pin location on the Balanced input is 1 Ground 2 Negative and 3 Hot. On the Oppo 2 and 3 are reversed but Oppo has in there set-up menu a way to invert that so they are the same, but I'm also not sure how it's grounded via the XLR input and that is the reason I got the W4S amp to use the XLR outputs from the Oppo. So if I understand what your saying is to connect the Black to the chassis on the W4S or use the XLR inputs and connect the Black to the Right or Left RCA input on the W4S.

So if I understand what your saying is to connect the Black to the chassis on the W4S or use the XLR inputs and connect the Black to the Right or Left RCA input on the W4S.

Yes, those are the alternatives I am suggesting, but be sure to note that I referred to connecting the black wire to the ground sleeve of an RCA plug (that would be inserted into one of the amp's RCA input jacks), ***NOT*** to the center pin of the RCA plug.

Regarding XLR pins 2 and 3, even if those are inconsistent between the Oppo and the W4S everything would still work fine. The only consequence would be an inversion of signal polarity, also referred to as absolute phase, the audibility of which is controversial, at least on most recordings. And which could also be corrected for by reversing the + and - connections to the speakers, although that would also reverse the polarity for any other sources that may be in use.

Regards,
-- Al

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