I went to Trends service center this evening. It so happened that their demo setup included the same DAC that I am using, so I didn't have to do a lot of explaining to the representative there, who actually was very nice and helpful. The issue lies in the AC adaptor. There is a galvanic connection between the +12V output and the "earth", the third terminal, from the mains side. As a result, the 0V output (GND) from the adaptor is actually 12V below the earth potential. The RCA output GND from the DAC, on the other hand, is connected to chassis ground hence at earth potential. When the DAC out is placed near the amp in, I can see tiny spark going between them. We tried couple other 3A versions of the adaptors, the problem persists. The issue disappears when either the 4A versions of adaptor or the benchtop version are used to power up the amp. As a quick fix, they upgraded my 3A adaptor to 4A version for free. It turns out with the 4A version, there is still a relatively low impedance path between the +12V and the earth (~2kohm), which should not be the case for a properly designed ac adaptor (isolation between the DC and the mains side). It could be a non-issue for countries using two-prong plugs and/or the driving equipment has floating outputs. In any case, instead of using the supplied 4A adaptor, I ended up buying a proper ac adaptor elsewhere for use with my TA 10.2 amp, and it is now playing perfectly. The issue isn't a show stopper, and I still very much enjoy the sound from this tiny amp!
Is this issue fixed? I got the same flickering ON indicator when I connect my DAC to the TA10.2 amp. I'm debugging the root cause now. Will post my findings here. Thanks.
The Power ON indicator on my NEW TA10.1 bought in Feb 07 is blinking and flcikering, as if the the power supply is being cut off. Can trend comment if this is faulty set?