How to run a pro Crown amp with only XLS input for a sub-woofer on a home system?

A bought a couple of Crown pro power amplifiers with only XLS inputs several years ago and have had problems with hum, so they have been taken out-of-service.

Recently, I purchased a 7.1-channel pro Denon pre-amplifier with ONLY XLS outputs. On the back of the pre-amp, near the XLS outputs, is a switch for balanced or unbalanced output. The switch applies to all 8 XLS output jacks (7 main channels and 1 sub-woofer). In addition to the 8 XLS output jacks there is an additional RCA jack for an unbalanced sub-woofer pre-amp output.

Currently, I have 7 of the main non-sub-woofer channels running from unbalanced RCA jacks into Denon non-professional power amplifiers. To do this, I'm using XLS-TO-RCA conversion jacks.

Is it possible to power sub-woofers in this system using the pro Crown power amplifier with only XLS input jacks? When I switch the Denon pre-amplifier output from balanced to balanced output, the 7 main channels are not receiving sufficient output to the unbalanced power amplifiers.

It seems like the Denon pre-amp is designed to run all balanced or all unbalanced output sources.

I think they're called XLR connectors. Anyway, why not try it using a similar cabling setup going from XLR unbalanced (Denon) into XLR Crown then to sub.

Does the Crown hum only when using balanced to unbalanced connections or does it hum all the time?

If you are still getting hum and you know the amp is ok in a completely balanced set-up you can look here for wiring suggestions...

http://www.rane.com/note110.html

Good luck,

Warren

...the Crown power amp works well with no hum when driven by the Denon pre-amp via a balanced cable (XLS-to XLS). I have been unable to use this same power amplifier when it is driven the 3 or 4 different unbalanced sources including separate pre-amplifiers and receivers because of a bad hum (XLS-to-RCA).

Does the Crown have a "ground lift" on the back? If so, try it. IIRC, I have to do this on my Crown PSA-2XH or I get some hum. This totally removes it, and obviously, that's why they put it there.

You should tell us the preamp model designation.

The DN-500 AV can be switched between -10 dBV and +4 dBu. That is not balanced to unbalanced, but rather standard consumer level to standard pro level.

The following table is from a Word document. I hope it is readable.

Ruediger

Bezeichnung	V RMS	dBU	dBV
0 dBU	0.775	0.0	-2.2
0 dBV	1.00	2.2	0.0
Std. Pro	1.23	4.0	1.8
Non-Std. Pro	1.55	6.0	3.8
Std. Consumer	0.316	-7.8	-10.0
HiFi alt/min.	0.150	-14.3	-16.5