I bought an ASL MKII amplifier from him. Very good communication, excellent support and he taught me a lot of things about tube amplifiers. The shipping was really fast and very well packaged. I highly recommend dealing with him.
I suggest you buy your dad some symphonies of CPE Bach (Bach's son) his music has been forgotten for ages, but now he's considered a great musician, his symphonies and piano concertos (newly recorded) are fascinating.
I also recommend choral works of Buxtehude, Bach's teacher and model. You can find them all on Amazon.