Bloody sub

[Speedskater]

Did I miss this information?

Sub #1
1] Brand?
2] Model?
3] Does it's power plug have?
a] 3 pins?
b] 2 pins, but one is bigger than the other?
c] 2 pins, but both are the same size?

Sub #2
1] Brand?
2] Model?
3] Does it's power plug have?
a] 3 pins?
b] 2 pins, but one is bigger than the other?
c] 2 pins, but both are the same size?

 

[Speedskater]

As a temporary solution, you might be able to find this Radio Shack:

Ground Loop Isolator

Model: 270-054 | Catalog #: 270-054
price $19.90

Ground Loop Isolator : Isolators | RadioShack.com

In the real world, they work a lot better than their specs would indicate.

***********************************************************

Be warned, it could even be a TV or fridge in a different room, but, on the same electrical circuit. It could even be the broadband internet modem or set top box coax cable. Pretty much anything on the same circuit and having a ground path.

Those are interference sources, not part of a ground loop.

 

[TLS Guy]

As folks have mentioned before, you definitely have a 'Ground Loop' situation. The humming is happening because your devices have multiple paths to ground (4 power points). In one or more pairs of devices you have signal interference due to two parallel ground paths.

This is not uncommon and it can be easily resolved. It will take patience and a systematic approach to get to the root cause.

It takes two to tango. It's clear the new subwoofer is creating a ground loop situation. The question is, which other device is contributing to the loop?

Leave the new sub plugged in and humming. Now one by one disconnect other devices, starting with the older sub till the hum stops.

When you have found the other device, you know they both need to be on the same power point, even if it means simply moving them into the same surge strip.

Be warned, it could even be a TV or fridge in a different room, but, on the same electrical circuit. It could even be the broadband internet modem or set top box coax cable. Pretty much anything on the same circuit and having a ground path.


Worst case scenario, nothing else is working in terms of finding the other device causing the loop, start looking for isolation transformers. Something like the Australian version of this, Ebtech Hum X Ground Loop Hum Exterminator | Sweetwater.com and put the new subwoofer on it.

I'm not convinced this is a ground loop.

He has Paradigm pw2200v2. There does not seem to be a user manual available and as usual there never was a service manual. He has a JBL-1200 as well I think. As far as I can tell from pictures neither of these subs have grounding plugs. If that is so this is not a ground loop.

Now as far as I can tell the Paradigm has left and right low level inputs, but the right input also doubles as a line out. Since this has to be a buffer amp situation, it must be a very strange circuit that allows this input to double as a line out, and probably something pretty crude.

As I understand it the JBL is fed from this line out.

Now sub plate amps are in general among the very nastiest audio devices to ever see the light of day, especially the power supplies of these devices.

I suspect there is a difference of potential on either the live or ground on the JBL that is fed back to the line out, which is also an input. I suspect that is the heart of the problem.

If unplugging the JBL from the mains stops the hum, then that is the issue.

If that is so then try connecting the subs using a Y connector from the receiver and don't daisy chain them as I understand they are connected now.

If it hums after that, then there is no solution to his problem except to use better designed and built units.

 

[agarwalro]

As far as I can tell from pictures neither of these subs have grounding plugs. If that is so this is not a ground loop.

HA! I didn't even think of that.

If that is so then try connecting the subs using a Y connector from the receiver and don't daisy chain them as I understand they are connected now.

Now that you mentioned it, I feel this should be the way two mono subs should always be connected.

Hopefully, the changing the daisy chain subs to a Y gets rid of the hum.

 

[Bryceo]

Argh I'll swap the main power to the unit witch does the tv receiver DVD player ps3 and 360,


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[Bryceo]

These subs arnt mono they need a left and right input with run down a single cable to a y spliter


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[Adam]

These subs arnt mono they need a left and right input with run down a single cable to a y spliter

Hi, Bryce. What are your two subs? If one of them is the Paradigm PW-2200 v2 like Mark mentioned, then you can use the input labelled "LFE-IN SUB IN" as a single input even though there are a left/right input.

 

[Bryceo]

My local audio guy said try plugging the main sub in to the power strip all your components are plugged in to this will be the last thing I do before I ues the receiver ground and start grounding my RCAS, cause there is a pico fuse in the receiver that stops line noise etc back feeding the line, and maybe I've popped that on the sub pree out channel maybe I haven't


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[Adam]

My local audio guy said try plugging the main sub in to the power strip all your components are plugged in...

Sounds familiar.

 

[TLS Guy]

My local audio guy said try plugging the main sub in to the power strip all your components are plugged in to this will be the last thing I do before I ues the receiver ground and start grounding my RCAS, cause there is a pico fuse in the receiver that stops line noise etc back feeding the line, and maybe I've popped that on the sub pree out channel maybe I haven't


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Listen up Bryceo.

Get a Y cable and plug the single end into your receiver LFE out. Now plug one RCA out into the left input of the Paradigm ad the other into the JBL.

That will probably solve it. If not the problem is insoluble. Now get to it and stop whining.

 

[Bryceo]

Wait where did jbl and paradigm come from? I have a yamaha and another yamaha :/


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[Adam]

Wait where did jbl and paradigm come from? I have a yamaha and another yamaha :/

What models?

 

[afterlife2]

Hell will freeze over before he give you an answer. lol

 

[TLS Guy]

Wait where did jbl and paradigm come from? I have a yamaha and another yamaha :/


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Sorry, Rojo had a post right next to yours.

However unless you post the models you have, and whether they are three pin or two pin mains connectors we can not help you. You seem to have zero understanding of the issues involved and that is why you still are in trouble. If you miss important details you have found out already, our advice is useless.

 

[Bryceo]

Yst-sw300s they have 3 point mains your ideas did not work so I picked the second one up and threw it away
Well not really just sent it back to where I bort it from, 2 subs can get stuffed I was happy with 1 doing all the work, and now I don't have to switch between thanks for your help but I don't need it anymore the second sub is gone!

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[agarwalro]

All's well that ends well .

 

[lsiberian]

Moral of the story. If it ain't broke don't fix it.

 

[slipperybidness]

Moral of the story. If it ain't broke don't fix it.

Haha. Yup. Every now in then you just hit a huge problem with an upgrade that wasn't there before. I've certainly had to scrap some great plans that didn't work out like I expected.

 

[afterlife2]

Moral of the story. If it ain't broke don't fix it.

Nope if it is broke, then throw it away.

 

[rojo]

Moral of the story. If it ain't broke don't fix it.

Whew. I thought for a little while the moral of the story was, "Rojo ruins everything."

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