I don't have one of Don's preamp, but he did a repair/upgrade on one of my old McIntosh C-20 tube preamps and Don's work was superb. He fixed an ongoing problem that I had taken the C-20 in to three other shops for repair. Two of the shops were McIntosh authorized repair shops.
Don not only fixed it, but suggested a couple of additional upgrades and I now have a 50+ year old tube preamp that has measurably better specs than the published specs from original McIntosh sales literature.
And the sound is fantastic!
Toolbox
Don not only fixed it, but suggested a couple of additional upgrades and I now have a 50+ year old tube preamp that has measurably better specs than the published specs from original McIntosh sales literature.
And the sound is fantastic!
Toolbox