Hum and poor output - Behringer EP4000, Rolls MB15b, Yamaha RX-V667

[MY99 2.5GT]

Receiver: Yamaha RXV663 - http://usa.yamaha.com/products/audio-visual/hifi-components/stereo-receivers/rx-v663_black__u/

Amplifier: Behringer EP4000 - http://www.amazon.com/gp/product/B001U5JFNM/ref=oh_aui_detailpage_o01_s00?ie=UTF8&psc=1

Line Converter: Rolls MB15b -http://www.amazon.com/gp/product/B0002IL4B4/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

Cables: http://www.amazon.com/gp/product/B00KO8VY4O/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

I wanted to run dual subs so I took the plunge and bought an EP4000 along with a pair of RCA to XLR cables. After plugging everything in I thought the input phase of the amp was defective because even with the gain at max no sound was coming out.
After further research, and toggling dip switches on the amp, someone from Parts Express recommended that I buy a line converter. I ordered the Rolls MB15b from Amazon along with male/female XLR cables.

I plugged everything in today like this:

Receiver Subwoofer Out RCA -> Rolls MB15b -10db in -> +4db XLR Out -> Behringer XLR input

Behringer pins are as follows:
Right - 1,3,8,10
Left - 2,4,5,6,7,9
gain on the behringer turned all the way up

Receiver side crossover set to 80Hz, receiver's subwoofer level turned all the way up, level on the Rolls turned half way up, the subwoofers are audible but very weak and I'm hearing audio well above 80Hz through the woofers. An audible hum is present that seems to increase exponentially when turning the level up on the Roll's. As well, with the level at 100% on the Roll's, Behringer at 100% gain, Receiver's subwoofer level at 100% my pair of Cerwin Vega VMax 15.2 woofers don't move or play even close to the same level as when driven by a cheapy BASH500 plate amp.

Not sure what is going on, any help is greatly appreciated as I'm about to return the behringer and rolls in favor of something like the Dayton SPA1000.

 

[WaynePflughaupt]

Receiver's subwoofer level at 100% my pair of Cerwin Vega VMax 15.2 woofers don't move or play even close to the same level as when driven by a cheapy BASH500 plate amp.

Are you saying the same receiver has no problem driving the subs via the BASH amp? If so then the Behringer is obviously defective.

Regards,
Wayne A. Pflughaupt

 

[MY99 2.5GT]

That is correct, the BASH500 has no trouble generating plenty of bass from a single sub output on the receiver.

 

[highfigh]

That is correct, the BASH500 has no trouble generating plenty of bass from a single sub output on the receiver.

Have you used some kind of tone generator to verify that the speaker cables are configured correctly? Have you set the dip switches to the original positions, in order to find out if the amp works for full-range? Is there a way to just use RCA or TRS cables to find out if the signal chain is functional?

Verify the cables and signal chain before declaring that the amp isn't working properly.

 

[MY99 2.5GT]

The speaker wire is connected to the twist poles and are wired correctly.
I installed a ground loop isolator on the sub woofer preamp output rca connection from receiver, same hum results.
I tried plugging the Rolls into a battery backup to eliminate any potential power line noise, same hum results.
I just tried a different rca cable, same hum result.
I also tried bridging the amp by rewiring the speaker wire output, changing dip switches appropriately only to find the same hum is present.
I think I'm done fooling around with this thing. It's going back to amazon.