Crack - Rattling sound with 230 volts

[hpleung]

Hi,

So I recently built a Crack wired for 230 volts. I tested it in the USA (with a 110 => 230 volt converter) and it worked fine. Dead silent when no music.

Then I brought it to the UK - the music plays fine. But there is a rattling sound which seems to be coming from the transformer (most likely). Some form of a vibration.

If I push down on the transformer with my finger - the rattling sound is reduced. There is no sign of loose bolts that needs tightening.

Also sometimes, with random luck, there is no rattling sound when powered on. But then it will come back again when powered on again.

The music through the headphone is perfect at all times, even when there is a rattling sound from the transformer.

Any idea on what could be going on?

Thanks.

[Paul Birkeland]

I would still tighten the bolts down a little bit more.  Is your country 50Hz or 60Hz mains?  The PT-10 was designed to work on both, but it's still helpful to know. 

What I would definitely do is to perform a voltage check just to be sure the amplifier is electrically working properly, as some faults will allow the amplifier to still output sound but will overload the transformer.