Hifimediy T1 DC Offset problem

[activexp]

I recently bought a T1 amp and now have it all set up and working with a SMPS300R. Out of curiosity I checked the DC offset and found that the right channel was within the specified 0 - 10mV but the left channel was way out, over 200mV. I attempted to adjust it but found that the voltage was steadily dropping off by itself. After a few minutes it had dropped to 100mV. If I set it close to 0mV with the preset pot, after a while it's dropped to a minus value or out of range 😕

There's also audible hiss on the left channel whereas the right channel is silent. Even with no load the heat sink on the chip gets quite warm. Is this normal?

I wonder if the chip is faulty or if there's another explanation for the noise and the weird behaviour of the left channel DC offset.

Any comments most welcome as I'm a relative n00b when it comes to the technicalities of class D amps.

Cheers,
Steve

P.S. The amp works OK and sounds excellent (apart from left channel hiss).

 

[norazmi]

I think chips not fault, maybe wrong component value or some component faulty, Dc offset should not go up and down at idle, it must be stable like another channel of ur amp.