I have found that if I disconnect my amp the noise goes away. So apparently this would mean a ground loop from the amp?
would a Hum x work if I plug my amp into it or would the amp draw to much current for the hum x? Hum x says not to exceed 6 amps of current draw.
Are you running balanced or SE between the DS and the W4S?
Single ended
Chances are that’s your ground loop as they are both balanced components. Either try balanced cables or a cheater plug on one of them.
Thanks for your response. I asked Bel Canto and they replied “The REF600M amps are ground level outputs, negative out is ground, so hookup is standard” so now I presume that they are not the same as other class D amps (they are NCore but that’s about all I know about them). But before I purchase subs and connect the black REL wire to the amps negative terminal, I still hope to hear back from someone who has them operating like that without issue. I sure don’t want to screw anything up in the amps or in the subs for that matter. Being retired, it now takes quite a bit longer to pay for my mistakes!
To be safe you could just start with the alternative grounding method if you have a grounding lug or post on another piece of gear.
So the amps negative terminal does not require a wire (the black one) even if it is a ground? But normal speaker connections require the black to the (-) ground terminal. So the REL subs are somehow different in this regard? I must say this is quite confusing and even illogical in many ways. Is there a primer or other good source of info on audio signal grounding theory and practice. I feel like I am in kindergarden when it comes to this subject. But thanks again.
With speakers the amp is connecting to a passive device but with a powered subwoofer it is connecting to an active device, the subwoofers amp. All I can do is tell you what I have done with multiple “types” of Class D amps and three different brands of subwoofers. I’m not just guessing or reading something on a website I have actually done it. The subwoofer companies are going to tell you what they think is the “safest” connection for a novice so as to avoid warranty repairs. No matter how explicit of instructions they provide someone will screw it up and try to file a warranty claim.
Ok so being active versus passive is the reason the black ground wire need not be connected at the amp end. Therefore just getting a signal on the hot leg from the positive speaker terminal on the amp is all the sub needs. Thanks for the explanation.
The REL needs only the red terminal of the amp on one wire and somehow the black wire needs to be grounded or, not used at all if the ground comes through an interconnect. On my REL at home connected to Sprout I have the red wire connected to the hot terminal
of Sprout’s amplifier outputs on each channel. Now, of course, we need a return path for current to flow. I could have tied the black wire of the REL to Sprout’s turntable ground terminal but instead I just used a spare RCA cable connected to an unused input
on Sprout to tie the ground of the REL to Sprout’s ground thus completing the circuit.
You don’t want to ground the black terminal of a balanced output amplifier to ground.
Thank you for your help. I hooked up the + l/r on the sub to the + l/r on the amp and covered the - l/r on the amp end with electrical tape and the - l/r on the sub were connected to the speaker neg inputs on the sub. The resulting sound was much quieter. I tried adjusting xo freq, sub volume and phase and could not get things to sound right so I hooked things back up the way they were. I had a hard time getting both the speakers wires and the subs wires into the amps binding posts. I am ordering banana plugs for the subs speaker wires to make this easier and to insure a good connection. I am sending my IC back to have them reterminated as xlr balanced which will require them being fully rebuilt in order to add the third leg. Once that is done I will have hopefully cured the hum and can then try hooking them up again with better results.
Thanks for your inut Paul. I will definetly follow the experienced advice received to not connect the black wire to the amp’s negative terminal. Will try floating and then grounding the black wire to see which is better. But I am still confused on this differentially balanced amp thing where a voltage exists on the negative terminal. I have just read that a mono block amp with balanced inputs is not necessarily a diferentially balanced amp. Can a mono be fully balanced by design yet not be differentially balanced? What benefit does being differentially balanced have then in performance? Obviously this ain’t easy for me to grasp.
No worries. A balanced output on an amplifier is becoming more common that it used, though it’s been around for decades. Our earliest models of amplifiers had what we then called a “bridging” switch that enabled a stereo amplifier to become a mono amp with
more power. In those earlier amps the switch simply inverted the output phase of one channel of a stereo power amp. This meant the left channel (for example) was out of phase with the right channel. If you then placed your speaker between the two red terminals
on the back of the power amplifier, ignoring the black amplifier output terminals altogether, you would have a more powerful mono amplifier.
If you think of it that way, it would be obvious to you not to tie one of those two red terminals to ground because you would short out the amplifier channel.
A balanced amplifier is doing the same thing though in not quite so crude of a way. But, the principal is the same. The main difference from your perspective is that one of the balanced amplifier’s black output terminals should really be red to
signify it is an active output like its mate. (Only, that would be confusing to show two red terminals).