What interconnects are you guys using for bi-wiring speakers? I need a Y XLR based cable.

I've never done that, but I suspect you would do fine using an XLR cable of your choice in combination with a pro-oriented XLR y-adapter such as this one:

https://www.bhphotovideo.com/c/product/134966-REG/Pro_Co_Sound_YMXF2XM_1_XLR_Female_to_2.html

Keep in mind, of course, that regardless of what cabling approach you use your preamp will see a load impedance equal to half of the input impedance of a single channel of your amp.

Regards,
-- Al
 

Cleeds, note that he said more than one "active" XLR output. I interpret that to mean he was referring to the two output connectors on each channel each being driven by its own dedicated output stage, which appears to be the case for the Classe CP-800. But based on schematics I’ve seen at arcdb.ws most or all ARC line stages and preamps which provide two XLR outputs drive both of them from the same output stage, and simply jumper the two connectors together internally. I believe that the same holds true for the great majority of preamps and line stages from other manufacturers which provide two pairs of XLR outputs, and for RCA outputs as well.

In those cases the preamp’s output stage will have to drive the input impedances of both of the power amp inputs to which it is connected, just as if a splitter were used.

And the results could actually be worse than using a splitter, because if a short splitter is placed near the two amp inputs the cable capacitance seen by the preamp’s output stage would essentially be just the capacitance of one cable rather than two. The splitter approach being most likely to provide better results if the preamp’s output impedance is high at high frequencies, and if cable length is long (cable capacitance is proportional to length), and if the cables do not have low capacitance per unit length. In that situation some degree of rolloff and/or undesirable phase shifts may occur in the upper treble region if two long cables are used, which could be avoided or minimized if a short splitter is used in combination with a single long cable.

Regards,
-- Al

Your amp is not differentially balanced and therefore you will hear no improvement. Balanced connections actually have 2 separate circuits ...one for the plus and one for the minus signal. What you have is XLR connections that are there for bragging rights. ..that’s not denigrating your amp...it probably sounds fine. If it were to have true balanced connections, the unit would cost twice as much.

Stringreen, I suspect that you meant to refer to the OPs Marantz 8802A, which is a "network audio/video surround processor/pre-amp/tuner," not to the amp. The model of the OP’s Krell amps has not been stated, and some Krell power amps are fully balanced.

Also, it can be inferred from the specs of the Marantz 8802A that it does in fact provide true balanced **connections**, since the specs indicate a "rated output" that is twice as great for the XLR outputs as for the RCA outputs. What it presumably does not have is a balanced internal signal path, which IMO has no relevance to the questions that are being discussed. And as we’ve discussed in past threads balanced connections between components having unbalanced internal signal paths (and, again, the Krell amps might very well be fully balanced) IMO may sound either better than, worse than, or similar to unbalanced connections, depending on the specific designs.

Regards,
-- Al

From this Krell 7200 datasheet:

The signal path is fully complementary and balanced. Independent complementary pre-driver and driver stages for the positive and negative output transistors make the output stages extremely fast and linear.

Also, the fact that its balanced input impedance is twice its unbalanced input impedance is very likely indicative of a differentially balanced receiver stage being provided for its XLR inputs. That would be the case even if it did not have a balanced internal signal path.

And as I previously indicated, it can be inferred from the specs on the Marantz that its outputs, or at least most of them, are most likely driven from differentially balanced output stages, regardless of whether or not its internal signal path is differentially balanced.

Therefore, as I said earlier:

... balanced connections between components having unbalanced internal signal paths (and, again, the Krell amps might very well be fully balanced) IMO may sound either better than, worse than, or similar to unbalanced connections, depending on the specific designs.

Regarding:

I looked at the pages in the manual and was wondering if I will lose two channels by going with what auximput stated in his post.

As I interpret the reference Auxinput provided to page 237 of the manual you would be able to configure the Marantz such that you could use two left + right output pairs (for example, Front and Front Wide) for purposes of biamping two speakers. But that would apparently require you to use a splitter for the center channel, as well as requiring you to utilize two pairs of output channels on the Marantz for one pair of front speakers. So I suspect it would be best to use a splitter on all three of the channels that you want to biamp with the Krell. The very high 200K impedance of the Krell’s balanced inputs should minimize or eliminate any downside of using a short splitter at its inputs, in conjunction with a single XLR cable per channel of whatever length is necessary.

I can’t answer the last question, about the likelihood of benefiting from the additional power in this specific case, although I wouldn’t be surprised if it does turn out to provide significant benefit.

Good luck. Regards,
-- Al