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

 

2 - RF7ii

1- RC64ii

4- RS400

 

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.

[robbiey60]

 

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

 

2 - RF7ii

1- RC64ii

4- RS400

 

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.

 

I have an EP4000 running 2x 4ohm loads into twin 15s with a Dspeaker antimode 8033, it is ridiculous lol. To fix the hum I had to cut the ground wire inside the XLR adapter. I cannot remember where I read it but some googling should give you more info. I also read that some receivers dont provide enough of a signal in the sub preout when running with pro gear, something about level differential? I did have to turn the amps gain up to 3/4 but audessey still sets it around -6 I think, and it kicks *ss. Before the antimode the subs were still crazy, this has just refined them. I will have to check the switch settings on mine, what final ohm load are you running and is it in stereo, bridge mode or parallel mode? Also double check you have the cutoffs off.

Edited April 4, 2015 by robbiey60

[MY99 2.5GT]

Found this: "Let's explain the signal ground lift in more detail. The hum current in a ground loop flows in the

audio cable shield, and can induce a hum signal in the signal conductors. You can cut the audio

cable shield at one end to stop the flow of hum current. The shield is still grounded at the other

end of the cable, and the signal still flows through the two audio leads inside the cable.

So, to break up a ground loop, disconnect the cable shield from pin 1 in line-level balanced

cables at the male XLR end (Figure 4). You can either cut the shield, or plug in an inline audio

cable ground-lift adapter."

From here: https://www.google.com/url?sa=t&source=web&rct=j&ei=t04fVenoF8XvarLCgdgM&url=https://cdn.shopify.com/s/files/1/0247/3799/files/preventing_hum_and_rfi.pdf&ved=0CB8QFjAA&usg=AFQjCNGBoHQXnCinx56z1qCWfDUAixe_tg&sig2=KQYtdWoSysuT4umk74T9VQ

[CECAA850]

I just used a cheater plug on my power cable to get rid of the ground loop hum on mine.  That was about 8 years ago and it's been fine ever since.  If all your dip switches are correct, an Art Cleanbox will get your signal up to where it needs to be.

[derrickdj1]

I use a cheap ground loop isolator like this:

[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.

[CECAA850]

Have you tried a cheater plug on the power cord?

[robbiey60]

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.

Did you try cutting the ground wire in the adapter? As soon as I did that the hum stopped.

[CECAA850]

Did you try cutting the ground wire in the adapter?

 

That's the same as using a cheater plug.  It should take care of his problem.

[babadono]

It sounds like MAYBE the amp is bad. You can prove/test this by shorting the inputs to the amp with just the speakers hooked up. Is the hum still present? If so the amp is bad.

[babadono]

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.

OP,

 Anything further with your problem?

[dewthedru]

This sounds exactly like the problem I had with my Stonehenge builds with the Behringer 3000DSP. Reversing the amp plug fixed the loud hum.

The low output was fixed by throwing an Art CleanBox Pro between my receiver and the amp. Boosted the sound by a ton.

Now I have to start working on room placement and tuning.

[MY99 2.5GT]

Sorry for the delay in responding.  I traced the issue back to a bad output phase on my old Yamaha RX-V667.  Shortly after posting I couldn't get any signal from the Sub-Out RCA jacks.  Unfortunately it took my old BASH 500 amp with it somehow and screwed up 2 brand new amps that I ordered from Amazon (Thankfully I was able to return them).

 

I now have a new Denon Receiver and a pair of iNuke 1000 amps that work perfectly.

 

Sadly my Cerwin Vega VMax 15.2 car speakers in home theater boxes isn't too impressive in a large room so I'm thinking of upgrading to a single (or potentially dual) Stereo Integrity HST-18's and an iNuke 6000once they become available for order again.