Hum in the subwoofers.

A

audioholic212

Audioholic
Hi.

I know this question might have been asked a number of times and I tried to understand the answers for different scenarios, but, still couldn't figure out what to do.

Here is my problem. I bought two HSU VTF2-MK3 subwoofers a month ago and I hooked up only one. I noticed that sometimes the sub would give a humming noise eventhough there isn't anything playing.

Anyway, once I tried moving the sub cable away from some power cord, the hum would go away.

Today I hooked up another sub almost 20 ft away. And soon as the sub cable touches the y-adaptor, the hum is unbearable ( I set the volume on both the subs to 1/2). So, I thought the sub is getting interference from some power cable, so, I unplugged the power from the single power conditioner, and tried connecting the sub. The hum is STILL there. I think from the threads I have read, some of the outlets are not grounded. But, I don't know what and how to do something about it.

By the way, the first sub is a feet away from the receiver and the second sub (which I tried hooking up today) is almost 17 ft out connected by probably a 35 ft monoprice RCA cable.

Please help.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Hi.

I know this question might have been asked a number of times and I tried to understand the answers for different scenarios, but, still couldn't figure out what to do.

Here is my problem. I bought two HSU VTF2-MK3 subwoofers a month ago and I hooked up only one. I noticed that sometimes the sub would give a humming noise eventhough there isn't anything playing.

Anyway, once I tried moving the sub cable away from some power cord, the hum would go away.

Today I hooked up another sub almost 20 ft away. And soon as the sub cable touches the y-adaptor, the hum is unbearable ( I set the volume on both the subs to 1/2). So, I thought the sub is getting interference from some power cable, so, I unplugged the power from the single power conditioner, and tried connecting the sub. The hum is STILL there. I think from the threads I have read, some of the outlets are not grounded. But, I don't know what and how to do something about it.

By the way, the first sub is a feet away from the receiver and the second sub (which I tried hooking up today) is almost 17 ft out connected by probably a 35 ft monoprice RCA cable.

Please help.
You have a ground loop. This is a common problem and occurs when you have resistances between grounds. I assume the subs have three pin plugs and not two and that the subs are plugged into different outlets. If that is correct you need to plug your subs into your power conditioner.

As a test try lifting the grounds on the subs with cheater plugs, and report what happens.
 
A

audioholic212

Audioholic
Thank you TLS guy. I will try the cheater plug to one of my subwoofer that is way out in the corner.

But, how come my other sub which is near the power conditioner and connected to it, also, sometimes gives me the hum? When that happens, it goes away when I move the sub cable around.
 
TLS Guy

TLS Guy

Seriously, I have no life.
Thank you TLS guy. I will try the cheater plug to one of my subwoofer that is way out in the corner.

But, how come my other sub which is near the power conditioner and connected to it, also, sometimes gives me the hum? When that happens, it goes away when I move the sub cable around.
In that case you may have a bad cable.
 
A

audioholic212

Audioholic
You mean a bad sub audio cable? Or a bad sub power cable?

Also, I checked and the sub woofer power cable for the VTF2-MK3's is two pronged. Maybe I can change the polarity of the cable (read it in a thread somewhere in here) and try it out?

I will also try to get a cheater plug to try it out. Oh, I am sorry, I just realized that cheater plug will not work since my power cable is already two pronged.
 
Last edited:
TLS Guy

TLS Guy

Seriously, I have no life.
You mean a bad sub audio cable? Or a bad sub power cable?

Also, I checked and the sub woofer power cable for the VTF2-MK3's is two pronged. Maybe I can change the polarity of the cable (read it in a thread somewhere in here) and try it out?

I will also try to get a cheater plug to try it out.
If the subwoofer power connectors are two prong, then a cheater plug will not help. I meant a bad RCA cable not the power cable.

If the connectors are two prong, then there is leakage of voltage to at least one of those subs, chassis. This will either be a design problem or a fault.

Make sure you change and use good high quality RCA cables. I hope it is your cables, other wise we have a difficult problem.

By the way I hate class D sub amps and their horrid switching power supplies. I would never own one myself.
 
AVRat

AVRat

Audioholic Ninja
What Y-adapter are you using? Several years ago when I purchased my duals, I had a bad hum with one type but it vanished when I used another.
 
A

audioholic212

Audioholic
Thank you all.

Looks like I got rid of the hum by turning off everything and setting the HSU to lowest volume(on the sub), and then, turning on my receiver and then, slowly turning up the volume on the sub.
 
L

lejack

Enthusiast
I would contact HSU, by phone or email. They respond very quickly, often by Dr Hsu himself.
 
picture_shooter

picture_shooter

Full Audioholic
Thank you all.

Looks like I got rid of the hum by turning off everything and setting the HSU to lowest volume(on the sub), and then, turning on my receiver and then, slowly turning up the volume on the sub.
I cant imagine it solved the problem. :(

What happens if you "now" go to the back of the sub amp and crank it up? Does the hummmmmmmmmmmmmmmmmm happen again?

BTW... those are some bad moFo subs you got there!!!!!!!!
 

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