Strange Speaker Ringing Tone

[admin_exported]

Hi,

I've got a Fatman Itube carbon hooked up to a pair of Monitor Audio BR1s which for the most part is absolutely great. However, I've just noticed that when the volume is turned down very (virtually off) I get a low level ringing tone produced by the speakers when I do any of the following:

1. Tap the Itube chassis

2. Tap the side of the speakers gently

3. Tap the bookshelf that unit/speakers are placed on (speakers have blue tack under them)

4. Adjust the amp's input selection or power on/off switch

In fact the noise can be reproduced with the source i.e. actual Apple Ipod off and just the amp/speakers left on. In normal use I won't be doing any of the above and also the ringing is so low I imagine it would get drowned out by the music anyway.

Polarity of cables has been checked and is OK.

Any suggestions as to what might be going on? Is it something I'm going to have to live with or can it be fixed?

Cheers

JP

 

[Andrew Everard]

Valves/tubes are microphonic - ie they work as microphones and will react this way to tapping and so on..

 

[Anton90125]

Some have said that it is this microphony that gives the warm 3D type sound, so in limited amounts it might be a benefit??

Take a look at this site (sorry no hyperlink because of the flaky formatting on the forum software): http://www.upscaleaudio.com/rare/basics.htm

 

[Anonymous]

Andrew,

Thanks for the speedy response.

Is there anything I can do to lessen the effect i.e. damping cones? Or is it pretty much like you say a 'feature' of the valves?

JP

 

[Andrew Everard]

You could try tube dampers, though I'd take advice from the Fatman people first. But basically this effect comes with the territory...