TLS49 is correct, of course. The fixed-level outputs of the integrated amp are most likely configured similarly to how the tape outputs on many older preamps were implemented. Namely, the input signals are routed to the source select switch, and the selected signal is then routed through a resistor to the fixed-level output jack, for each channel. So the tubes and transistors in the unit are not in the signal path between the input jacks and the fixed-level output jacks.
Regards,
-- Al
Regards,
-- Al