Hi,
Yes, I can confirm that the Devil's Breath tape is off my master cassette. It was originally recorded on a Sony TC124CS stereo cassette recorder - and while not a revox it was a pretty decent machine in its day. It came with a 10 inch long mic that had two separate mics inside it to pick up stereo sound.
I was disappointed that the speed ran slightly too fast and there has been talk of a new version. Hats off to Erik for the pitch correction. I'm sure with latest technology it could be made to sound even better.