[GCTonyHawk7]

Hey guys. I recently ordered the ibasso P2. The device works great, although I've got one rather major issue with it.

One reason I bought the P2 was because it came with the AC adapter to plug it into the wall. I don't want to use it as a portable device, and just want it to sit at my computer.

Hooked up to my PC's sound card is a set of Logitech Z5500 speakers. These have a headphone port on the control center. I simply plug the P2 into that headphone port, plug the AC into the wall, and then plug my headphones into the P2. Seems like it should work and be great. Cuts power to the speakers, sends it to the headphones, and this works.

The catch here is something I never knew about; ground loop. Apparently, because the speakers/computer/P2 are all plugged into the same power grounding, it creates some crazy electrical loop and this loops creates something called mains hum. This hum/buzz can be heard clearly in my headphones when using this setup. To solve this, unplug the AC adapter to the P2, and boom, gone.

Now, this in turn means, it works fine with portable devices, like you'd think. iPod, PSP, DS, they all work fine without this issue. But I bought this for my desktop. Yes, sure, I could just charge it, use it, and then charge it again, but I did not pay $157 for an amp to have an inconvenience like that. I want to plug it into the wall, and not have to worry about that. Not to mention charging it like that all the time wears out the battery so it won't be any good for when I do want to use it portably.

So, in the end, I am looking for a fix. I know I can buy some $80-100 power strips that create their own ground. Don't want to spend that much. Yes, I know there are devices like the following:

PAC SNI-1/3.5 Noise Filter Helps eliminate ground loop noise from your portable music player! (3.5mm plugs) at Crutchfield.com

Although, I fear that could alter sound quality, and again is nearly $30 shipped.

I figure that you guys, with all your experience with this stuff have found ways to solve this. Any way to power the amp over USB? (It is a 12V DC Adapter)

Thank you to anyone that can provide some incite.

Various Info:

- P2 uses a built-in 8.4V 470mAh Li-polymer Batteries or external power
- External power supply: 12V DC
- Battery Life: 11 hours
- Battery Charge time: 3 hours

 

[MONVMENTVM]

Hi!

The D2 which shares the same amp station has some static too. What I (and apparently some more) have done, is to grind off the anodization inside of the case so that the aluminium case can provide a larger grounding surface. I don't know if the P2 has the same issue, but it works on the D2. There is somewhere a thread inside of this forum about this.

 

[HiFlight]

Try reversing the AC plug on various device including ac adapter, one at a time. That often eliminates or greatly reduces hum. If the plugs are polarized, you may need a little file work. You might also try a different AC adapter on the P2

 

[mrarroyo]

Quote:

Originally Posted by HiFlight /img/forum/go_quote.gif Try reversing the AC plug on various device including ac adapter, one at a time. That often eliminates or greatly reduces hum. If the plugs are polarized, you may need a little file work. You might also try a different AC adapter on the P2

As an alternative you could get a cheater plug to reverse the polarity.

The cheater plug is cheap and simple.

 

[GCTonyHawk7]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif As an alternative you could get a cheater plug to reverse the polarity. The cheater plug is cheap and simple.

A cheater plug? Any examples? Not sure what they are, sorry.

Thanks for all the replies.

 

[GCTonyHawk7]

Sorry for the double post, but I've done a bit more research on this stuff, and realized some interesting things.

As for cheater plugs, these are plugs that let you plug a 3-prong device into a 2-prong outlet. Issue behind that for me is that both my Z5500 speakers, and my ibasso P2 use a two-prong setup. This got me thinking about trying a few things. Such as... plugging both the speakers and the P2 into a powerstrip with two 2-prong outlets. This was met with no success.

As far as Switching the plugs around so that left is in the right, that was not successful either, but I did try it.

I tried another AC adapter, and got the same thing.

Filing stuff inside the P2... not sure how I feel about that. Any more info, and why that would help?

So, I am thinking about this, and am thinking maybe the problem lies in the fact that they are both 2-prong adapters on the same circuit. I don't know this, but I am getting to think this. If somehow I made one of them use 3-prongs, would it fix the issue?

Thanks for the help guys.

 

[mrarroyo]

Cheater plug:

You plug it one way, if the hum goes awy done. If it does not rotate and that would reverse the polarity and should get rid of the hum. If it does not unplug everything and start plugging one item at a time starting with the amp then source, then ... when the hum returns use the cheater plug on that unit.

 

[GCTonyHawk7]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Cheater plug: You plug it one way, if the hum goes awy done. If it does not rotate and that would reverse the polarity and should get rid of the hum. If it does not unplug everything and start plugging one item at a time starting with the amp then source, then ... when the hum returns use the cheater plug on that unit.

right, but the thing behind that is that the plugs for the P2 and Z5500 are only 2-prong to begin with. So would something like that really do anything at all?

 

[mrarroyo]

Quote:

Originally Posted by GCTonyHawk7 /img/forum/go_quote.gif right, but the thing behind that is that the plugs for the P2 and Z5500 are only 2-prong to begin with. So would something like that really do anything at all?

Pull the plug and rotate it 180 degrees then re-insert, thus reversing the polarity.

 

[GCTonyHawk7]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif Pull the plug and rotate it 180 degrees then re-insert, thus reversing the polarity.

Did that with the P2, although the Z5500's plug has the one end bigger than the other. So, it can't be reversed.

Maybe this is the key to our problem?

 

[mrarroyo]

Quote:

Originally Posted by GCTonyHawk7 /img/forum/go_quote.gif Did that with the P2, although the Z5500's plug has the one end bigger than the other. So, it can't be reversed. Maybe this is the key to our problem?

That is why you get the cheater plug, you file the wide prong and then you can reverse it.

 

[GCTonyHawk7]

Quote:

Originally Posted by mrarroyo /img/forum/go_quote.gif That is why you get the cheater plug, you file the wide prong and then you can reverse it.

Well, can't filing the prong be bad for it? And in that case, I would not even need the cheater plug. It just seems too good to be true that reversing the plug would fix it all.

Surely there is a reason the plug is like that?