There is virtually no information available anywhere about the ART 01A that we can find. We have found an identical version of this reverb with MXR 01A badging, and on some models a notification on the front panel that it is manufactured by “mfg by ART Applied Research & Technology Inc” so I think it is safe to say that it is an ART product that MXR licensed.
There is also an MXR 01 which is also virtually identical, but has the manufactured by ART written on the back panel. It also sold for significantly more than a Lexicon PCM 60 at the time! The MXR 01 was reviewed in May 1984 by Mu:zines, so we figured the 01A would have been released the following year in 1985. If you have any information to share on this reverb, please contact us.