in the last two weeks I've had trouble with the XLR DI output on my Trace SMC300 amp head- I've had problems with it cutting out at venues before, but thought it was just the plugs not fitting properly/ having dirt on the contacts, as the socket is rigidly (or so it seems) mounted to the front panel. after it causing loads of noise through the PA, and the soundman having to switch to an external DI box for the 2nd time I opened the amp up today and found the solder joint between the legs of the socket and the circuit board had come loose- an easy fix with a soldering iron and some solder. it seems fine now. However, this never happened with my old (and cheaper) Laney G150, as the DI socket was connected to the board by wires, and not soldered directly to it. It looks like this problem might recur in the future with the Trace also, on nearly every Trace SMX or older SM series amp I've seen in rehearsal studios, the jack input sockets have come loose/broken altogether, and are impossible to tighten without a box spanner, as they're recessed into the front panel. don't Trace think about these things????? fortunately, they've fitted conventional metal sockets on my amp, but they're soldered directly to the circuit board......I see further problems ahead.