Was discussing an issue in Tapeheads.net and found this, the sound quality seems very good for (1967) Type 1 tape and no NR (listening with DPL 2 music).
For many years, it was generally thought that compact cassette fidelity was severely limited until the 3 head cassette recorders began to show up in 1973 (Nakamichi 1000 and the like), but I guess this tape helps prove that wrong.
Kirk Bayne