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What does S.L.C. mean?(in NAD 3140 amplifier)

This may be a silly question, but, despite nearly 40 years of servicing radio &
audio products, I don't know what S.L.C. stands for, and can't work it out from the amplifier schematic. In addition I'm not too sure how the 'soft clipping' circuit in these amplifiers functions. Having just replaced transistors Q627 & Q628 in a 3140 which was distorting only with the 'Soft Clipping' switched on,
with 2 x 24v zener diodes(as per the service bulletin), I cannot now perceive any difference between 'S/C 'on' and 'S/C' 'off'.

What does 'S.L.C.' meanin NAD 3140 Amplifier?

To answer my own question, I am reliably informed, via another forum, that
it stands for 'Speaker lead compensation', and, from checking the circuit, it
appears to consist of switchable R/C components in a feedback circuit from
the speaker 'hot' side to the input, designed to compensate for problems which may be caused by the use of long(>10M?)or thin speaker wires. If anyone knows differently, please feel free to correct the above statement.