How on earth...?

[Nuuk]

I have had a few problems with my hi-fi system lately after (but not all resulting from) the addition of a sub woofer.

I had located and remedied a problem in the sub woofer controller circuit and another in my CD player but somehow, things just didn't sound right.

The music played, imaging was OK, but the timing was out, clarity a little impaired and it just didn't sound right.

Today I tracked down the problem. I have a separate PSU for each channel of my Gainclone amp and on one supply, the neutral mains connection had become disconnected.

BUT the PSU still measured +/- 26 VDC on its output and I can't understand how this could be.

At first, I thought that perhaps the circuit was being made through the zero volt wires in the amp circuit but the PSU still measured correctly even without the amp being connected.

Can anybody explain this one?

[phase_accurate]

I have a separate PSU for each channel of my Gainclone amp and on one supply, the neutral mains connection had become disconnected.

It depends on what you actually mean by "neutral mains connection".

If it is the conection between the tranformer center-tap and ground then the voltage might very well look symmetric (to some degree at last) if measured without load.

The best thing to understand what was going on would be to draw a small diagram showing where exactly the connection was missing.

Regards

Charles

[Nuuk]

The connection that was 'broken was from the mains supply to the input (fuse) of the PSU.



(Hope thiswill do, I have to go out now)

[owen]

The break works like a capacitor.... AC voltage would then fluctuate as normal (50 Hz cycles), but would be massively current limited. Your break may well have had a small touch contact patch as well, that would bring the current availibility up to a more usable level, but transients would have been delivered from the meagre charge in the caps.. no small wonder the sound was 'off'....

Breaks in the flex really does it for DC....

Owen

[Nuuk]

Thanks for the reply Owen. The break was 'complete' ie the wire had come out of the terminal block altogether.

As you say, 'no wonder the sound was off'