I bought my original t.amp S-75 Mk II way back in September 2013 and through a series of events my studio wasn't ready so that I could install it until April 2014. Sure enough, April came and I cracked open the box, mounted it into the rack, wired it all up and switched it on. Worked a treat right away.
After my initial, brief testing, I turned it off and carried on wiring other parts of the studio. Around half an hour later I turned the unit back on to test another bit of equipment and the power light turned from green to red after a minute or so. At the same time a relay-like "click" came from the unit.
I thought I must have overloaded it it or something (even though I knew I couldn't possibly have) so I turned it off, put all the levels down to zero and turned it back on again. This time the power light stayed perpetually red. No green light at all.
I went through a process of unplugging everything, waiting 3 minutes, turning everything back on and off again but nada, zilch, nothing. It seemed the unit was dead, so I left it and went for some food.
A few hours later I came back and switched it on again and to my surprise the green light came on again and all worked as before. Hurrah! Except, after a few minutes the same red light of death appeared and that was the end of that. Again.
I contacted Thomann and they immediately sent out a replacement once I'd returned the damaged one - free of charge - and it was all sorted within a week.
I have no idea what went wrong initially but the replacement is a-ok. Had I have bought this from another vendor I probably would have had to fight to get a replacement sent out after 7 months but I have to hand it to Thomann, their after-sales service is simply spot on - which is one of the reasons I keep coming back time and time again to them even if it does take a little longer to arrive to the UK from Germany than a UK-based shop.
As for the new amp, well, it's a great little unit and plenty loud enough for a small studio. I'm running it into JBL Control 1's as they're so unforgiving to mix with and the combination works well. My only slight gripe is that because it has a real transformer - and not a switch-mode power supply (and the reason why the amp is so heavy for its size), it does exhibit a slight 50Hz mains hum. It's not bad, don't get me wrong, but if you're planning on mounting this onto a desk rack and mix quietly, then the hum could transfer into your desk and hence be amplified and become an audible problem. So, if you are going to desk mount it I'd stick some absorbing rubber underneath the desk rack to prevent this.
Oh, and it's built like a tank. I expect this will outlive every other item in the studio.