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mat.w.'s picture
Last seen: 2 years 4 months ago
Joined: 06/05/2014 - 15:41
Posts: 1
Hard drive and power supply adaptor creates speaker hum

I have ripped my CD collection to an external hard drive and play using Musichi software on a netbook and Cambridge DAC via a Quad amp to Quad ELS speakers. Not the easiest to set up but done now. However I am suddenly getting speaker hum when switching the power supply adaptor on and even more with the hard drive on. Its a new problem, all worked well at first. #

I have isolated each and every component and its those two items that are the issue. I assume its some form of feedback. I have swapped power adaptors and hard drives but the problem still returns. 

Any solutions or explanation?

John Duncan's picture
Last seen: 2 weeks 6 days ago
Joined: 08/01/2008 - 17:25
Posts: 23210
RE: Hard drive and power supply adaptor creates speaker hum

This is quite common - how is the netbook connected to the DAC?  And is it the external hard drive power supply or the netbook's itself which is causing the problem?

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iMark's picture
Last seen: 2 days 9 hours ago
Joined: 16/05/2008 - 12:21
Posts: 653
RE: Hard drive and power supply adaptor creates speaker hum

Do you have a tuner connected to your amp? You may have groundloop hum. 

If you have a tuner connected, try detaching the aerial lead. If the aerial causes the hum, you could try a ground loop insulator.

Do you get hum if the power supply on the netbook is detached?


In a previous setup I had a terrible hum when my stereo receiver was connected to the cable radio socket an my computer was also connected to the receiver. I solved this by putting a filter cable on the aerial cable.

Good midfi stuff, nothing High End.

scene's picture
Last seen: 1 week 7 hours ago
Joined: 25/09/2008 - 12:48
Posts: 3155
RE: Hard drive and power supply adaptor creates speaker hum

You could try some clip on ferrite cores around the power cables (if they haven't got them already) - this may help.

AV: Marantz SR7009; Monitor Audio RS-LCR, Silver 8i, RXFX; Pioneer KRP500a; Sony BDP-S760
HiFi: Arcam 85; Acoustic Energy Compact 1; Arcam DV79 (as CDP), ProJect Debut II

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