I spoke to Arthur via email several times. He was always polite, informative and prompt. And I started our correspondence stating that I was looking at a used amp. He was never going to make a penny off of me and he was still excellent to me.
Between his behavior and the way this amp sounds, I am now a Huge fan. 
I doubt plugging 2 headphones in hurt it, assuming the outputs are wired in parallel your still at over 30 Ohms impedance.
The question is if itās worth repairing, if itās the transformer, itās a $20 part, but they are a pain to remove IME, and I donāt know what Lake People would charge you for it.
Worth asking I guess.
Comes out to a combined 35 Ohm load, so completly fine.
As far as I can tell, this amp has two amplification circuits side by side (or it is Class AB, hard to tell without a close up of one of the groups I labeld āAmpā in the picture below.
Overheated and cooked the weakest link. Likely the transformer as @Davidibiza pointed out.
Thank you thatās a good point. I guess the other question is how much would a similar quality amp cost me. Hopefully the repair will be less.
Iāll update on Lake Peopleās response to my mail.
That makes sense. I wouldnāt have thought the weakest link was the transformer but I donāt understand much about these things. Thanks for the labeled image.
Can you tell me how you came to the number 35 for the combined load? Maybe unacceptably ignorant but I donāt know how its calculated.
1/(1/37+1/600)
Parallel resistors R = 1/(1/R1+1/R2)
They arenāt usually the first thing to fail, but if say there was some sort of mains spike it can happen. Can you show us the burn marks on the cover.
Thanks a lot 
So, Fried Reim from Lake People sent me a kind mail this morning offering to fix the amp at the factory for around 100 euros, since the guarantee is expired, I think its fair, and itās a guarantee of quality so thatās good.
I donāt know whether to save up and buy the G111 instead if I can find it used. In the meantime Iāve begun listening to a DT880 on another amp which Iāll make another post for right now.
Thanks again to all for your help.
The fix seems like a nice offer to me. I just saw your other post about the Feliks amp. Having the fixed G109 and that Feliks is quite a combo.
true. It seems like the only thing I really miss out on is the balanced output and 10ohms at 600 watts.
