white noise/whine from left Creative T20

[Nine Iron]

Just got a pair of Creative T20 second-hand, and I've noticed a very quiet white noise/squeal from the left speaker (not the right). Some notes:

• occurs when speakers are on but not receiving signal

• doesn't change with system master volume/speaker volume or bass/treble adjustment

• doesn't change with speaker placement (even near no possible sources of interference)

• not coming from woofer or tweeter - pressing them doesn't have any effect

I've also found that it's not the left speaker itself. The T20 have the power and signal going into the right speaker, with the left one being driven passively by the right; I've got an old pair of T10's (same arrangement) and I connected the left one of these to the right T20... and it squealed.

After all this, I get down to the right speaker's "left driving" circuitry being the culprit. Any ideas how to fix it? I'm not averse to going in and having a look round, but I realise I'm talking more to electronics engineers, by now, than computer enthusiasts!

Cheers,

M.

 

[Kushiro]

Any chance you could see if your seller will allow a return?

 

[AlienALX]

Sounds like coil whine from the amp to me. The amp will only be in the one speaker usually.

I think he bought them from the MM on OCUK so not sure if the seller will allow a return or not.

 

[Kilbane]

Its sounds like coil whine, only problem there is that the person who you purchased them from probably didn't hear it. Due to most coil whine being in the upper frequency band of audible sound, only a relatively small portion of the population notice it (obviously dependant on the severity).

 

[Nine Iron]

If it is coil whine, is there an inductor in the "master" speaker I can replace? There can't be anything wrong with the slave speaker because it happens with other slave speakers!

It's a weird problem as the master speaker itself isn't affected...

 

[Nine Iron]

Its sounds like coil whine, only problem there is that the person who you purchased them from probably didn't hear it. Due to most coil whine being in the upper frequency band of audible sound, only a relatively small portion of the population notice it (obviously dependant on the severity).

Or he could hear, and was banking on me not being able to... but I can still hear up to 17 kHz. Oops.

 

[Nine Iron]

Update: I've manage to crack the right speaker open and can't hear anything from the internals when the left speaker is plugged in - there's a whacking great coil on the amp board, and it's silent.

This leads me to think it's the RCA/phono connector for the left speaker that's duff - are they known to introduce noice when they're faulty?

 

[Kilbane]

Update: I've manage to crack the right speaker open and can't hear anything from the internals when the left speaker is plugged in - there's a whacking great coil on the amp board, and it's silent.

This leads me to think it's the RCA/phono connector for the left speaker that's duff - are they known to introduce noice when they're faulty?

Only other thing to consider is a ground loop feedback issue. But you tend to get that more when your speakers are not connected to the PC.

 

[Nine Iron]

It's the fact that it's only the passive speaker that's confusing me - got to be the phono, or some interference therewith.

 

[Nine Iron]

I'm seeing some phono-phono ground loop isolaters going cheap on ebay... worth trying one of those? It'll be post-amp rather than pre-amp, but it's the best I can do!