My new (used) Chinese OTL valve monoblock amps are mis-behaving .... - significant hum thru the speakers and a "ticking" from one amp (again thru the speakers). Curiously, the ticking can be shown to be caused by only one of the monoblocks, but it comes thru both speakers (and also thru small rear/surround speakers which aren't even connected to the OTL amps!). But turn off the 'problem' amp and all the ticking disappears. I'm using the amps with my Thiel CS2.3 speakers - quite a low impedance in places. But the amps are rated at 40W and even when driving quite hard the transformer cases get quite warm but not hot. Just doing some on-line research (why didn't I do this [B]before[/B] buying the amps? :rolleyes:) I see that [I]high[/I] impedance loads are the thing to use OTL amps with ..... :( .... so probably Thiels aren't ideal then ;) BUT - would component damage result or should the amps just sound wimpy and/or distorted? (they don't). I bought the amps on eBay - if I've caused the damage, I can't really complain to the seller! Advice from them who knows about such things please !!