The Forseti Pre Amplifier was supplied with an outboard PSU which
connected via an encaptured lead which terminated in a 5 pin
"XLR" connector. Pre-amplified outputs are provided both via
unbalanced RCA connectors and balanced XLRs. There were two tape loops
and three line-level inputs, plus an additional line level input which
could be upgraded to a moving magnet phono input using one of two
optional plug-in boards. In addition, the APD21A offered balanced inputs
Independent input and record output switching are provided.