I never knew about these guys. I'm sorry to hear Turnswitch has passed away.
I never have listened to an AM radio. That was the first thing to go in anything I owned. I prefer all the improvements myself. Purist or not, you can't see the difference but you can sure hear it. They are so many places to convert a vintage radio these days to modern capabilities it isn't funny. Personally, I stick with the guy who has been doing it since before the others ever got the idea. More than likely they got the idea from Mike Hagan
www.mikehaganantiqueautoradio.com . I'm sure he'd do a straight restoration as well. But he was a pioneer in vintage radio to modern conversions and he gets my business. He's the best in my eyes