Dangerous fault using app

Posted by: ray sheldon on 15 September 2017

Anybody experienced this using the app on NDX...

A few months ago the volume on the SN2 was turning clockwise by itself when using the app on my smartphone to control the NDX when streaming from US. This happened a couple of times and fortunately I was close by to act before I ruined the speakers.

Obviously I've got the SN2 and NDX linked with the remote cable. And I'm using the volume control on the app.

It hadn't happened for a while until last weekend when me and the girlfriend were listening to some tunes, this time using the app on a tablet. I had to jump out of my seat and wrestle with the volume knob whilst it was being forced clockwise.

Clearly I won't be using the app in another room in future leaving sprinting distance from upstairs for e.g.

What is causing this I wonder?

Best,

Ray.

Posted on: 20 September 2017 by Huge

geepee posted:
From personal experience, I can assure you that an amplifier rated at 15 watts per channel can easily blow a tweeter in speakers rated at 80 watts. I had inadvertently plugged a CD player (output approx 1 volt) into an input of the amp which was expecting 100mV. When I turned the volume up, the amp went into clipping and the ultrasonic harmonics took out a tweeter. Well, that's my theory.

Yep, except that it's more HF than ultrasonic - with a square wave (i.e. hard clipping) the harmonics are predominantly odd order generally reducing in intensity at each successive harmonic (it'll be very roughly a 1/n relationship). That's what took out the tweeter, it's a well known effect.

Posted on: 20 September 2017 by geepee

I actually meant to write HF rather than ultrasonic !!