I'm new to the forum, but thought I'd take a moment to share my success with Bob's M-125 monoblock kit. I purchased a pair with Sovtek tubes and with a week of spare time, voila', I had an operational set of subwoofer amps to drive my monster, spiral bass horns.
My initial impression was favorable, but I couldn't get over the roundness of the bass notes. I expect kick drums to have an edge and plenty of slam. It took a while for me to sort out the problem, I've even ordered the WZ68 rectifiers and 12BH7 tubes, hoping for improvement, but in the end I remembered that Bob's amp's don't invert phase as do most amplifiers. My system is tri-amped and the mid-bass amp inverts, after flipping the M-125's banana jacks over to reverse the phase, the slam came back--in spades! This is something to remember, Dynaco fans.
Just for kicks, go to my website to see the spiral bass horns (and many other horns) I hope you enjoy the pics.