So... wow. I had a Mesa F100 amp gathering dust unused that I bought on a whim a while back, didn't mesh with, and put up for sale. Found a buyer. Decided to plug it in to test everything works before the appointment, and just randomly plugged in through a Tube Screamer (which I somehow never tried before). And.... DAYUM!!! Boring bassy amp suddenly got SASS and bite, even at non-deafening volumes... Almost regret putting it up for sale now.