the Studer A820 is listed in this blog

As listed in this 1990 interview on the Music Magazine Archive

Steve Albini utilized a Study A820 Master Record while recording The Breeders' "Title TK" album.

"Recorded to GP9 on a Studer A820."

"Within Kingsway, a large foyer doubled as a listening area, while through an archway to the left there was a control room containing a 1976 custom API console that had formerly been housed at the Record Plant in New York. Twin stacks of 1965 Tannoy Gold monitors had been imported from Abbey Road, while the rest of the gear included a Studer A820 with Dolby SR, a 12-channel Neve desk," states this article about Sheryl Crow and her producers.

Used to track Outkast's Speakerboxx/The Love Below.

Used to record Come Away With Me, as mentioned by producer Jay Newland in this transcribed March 2005 interview.

"The first time I heard Norah Jones sing at a rehearsal before our initial sessions, I knew she had a truly great voice," says Jay. "I only mention this because it's the crucial first link in the chain. The recording chain for 'Don't Know Why,' as well as most of the rest of the record, was a Neumann M 49 microphone into a Manley tube mic pre. We tried other mics, a [Neumann] U 47 and a [AKG] C12vr, but the M 49 had the right amount of 'air' while maintaining a real fullness and warmth. The tube pre was also warm but a little less colored than, say, a vintage Neve pre, which I love in many cases. This went into one side of a Manley Vari-mu compressor with a fast attack and release setting. The threshold was high so it was barely hitting the compressor. The Vari-mu can also be very transparent, which is why I liked it for this application. This went to BASF (Emtec) 900 analog tape at 15 ips on a STUDER A820 with Dolby SR. Although I like Pro Tools HD, we did not use Pro Tools on this session. No Auto-Tuning. The console is custom built by Al Fierstein, owner of Sorcerer Sound, and is called Acoustilog."

The hardware is impressive: an E-series 48-channel SSL with total recall; Westlake BBSM10 and NS10 monitors; a recently acquired Mitsubishi 850 32-track; 24-track Studer A800III; Studio 3 synchroniser; Sycologic MIDI Matrix; Studer A820 2-track; Technics DAT player; Macintosh II computers; a whole range of effects, including Lexicons, AMS, Focusrite PSU121, Teletronics LA24 limiter/compressor ("they're like gold dust. It sounds great on my voice"), SPX90s and so on.

Used to track Outkast's Speakerboxx/The Love Below.

2:17 in this official Igorrr music video released in 2020 shows this machine playing a piece of the new Igorrr song Parpaing.

Mary J. Blige's use of the Studer A820 Master Recorder was confirmed by Prince Charles Alexander in an interview, stating: "We used Studer A820 tape machines, and we might have had A827’s also. Anyone who knows their technology knows that a Studer A-820 and A-827 were like the Mercedes Benz and Rolls Royce of analog tape machines."

Ariwa Sounds is Mad Professor's studio in London since 1979. There is an extensive list of the studio gear provided on the website.