Bathroom speakers buzzing

[AJLComputers]

Hi guys

I have just added some speakers to my bathroom ceiling, they are connected to an amplifier in the loft and that connects to an iPhone in the wall outside the bathroom. Everything seems to work fine but as soon as the iPhone goes to sleep there is a very faint buzzing, if I click the home button on the iPhone then the buzzing instantly stops so I don't think it's interference from other electrical items or a grounding issue but I don't know how to resolve it.

Any ideas?

p.s. Apologies if this is in the wrong forum, I really wasn't sure where it belonged. Mods, feel free to move it if necessary.

 

[supraTTman]

It sounds like you may have a pick-up problem on the amp to iPhone lead.

Do the following checks:

1). With iPhone on and playing, pause the track. Is the buzzing present?
2). Disconnect the audio lead from iPhone. Is the buzzing present?
3). Disconnect the audio lead from iPhone. Short out the inner & outer pins on the 3.5mm jack plug. Is the buzzing present?

 

[AJLComputers]

1) No buzzing
2) buzzing gets worse
3) buzzing gets even worse

Does this help, I really hope I don't have to replace the cable as it's in the wall now!

 

[supraTTman]

OK - roughly what I expected.

1). How long is the iPhone to amp cable?
2). Are you using a quality double-screened lead for this cable?
3). Are there any mains cables within a few feet of this audio cable?

 

[AJLComputers]

1) about 4-5 meters
2) No, unfortunately the cable I ordered didn't arrive in time so I had to chuck in one that I had laying around.
3) there is a light switch next to where the iPhone is mounted so there is the power cables for that.

I guess other than replacing the cable that is now tucked into the wall there isn't much I can do right?

 

[supraTTman]

So it's:

1) Bad news
2) Bad news
3) Bad news

I don't think you will be able to eliminate the buzzing completely without a wire change - painful I know .

We may be we able to improve things without going to this length .

Some more questions:

4). Is the iPhone standalone (i.e. on it's own battery), or is the phone plugged into a docking station for charging?
5). Is the loft amplifier earthed ? If so how?
6). Is there scope for reducing the length of the phone to amp cable in the loft by moving the amp right to the point where the cable appears in the loft? This may mean lengthening the speaker cable and the mains cable feeding the amp. (A long speaker cable is unlikely to pick up mains hum, a long audio input cable is very likely).
7). Is there a sensitivity control on the PA input to adjust the level of audio it sees to avoid distortion?
8). If you turn up the iPhone volume full-bhuna, is the music way too loud? Hopefully YES.