tacitapproval. My 2nd build is having some issues as well, and I'll be looking at it. Can you measure the DC offset, and keep an eye on it. What I mean is power it on, measure the DC offset (before the e12 if you can). Watch both channels or find the one that is tripping the e12.
What I am finding with mine is that the DC offset climbs with time, on the right channel. It bounces around, albeit slowly, but it is significantly higher than the left. The left is at a few mv at most.
I was just wondering if your problem is similar.