Why not call ARC? They were always very helpful when I would call them about the ARC amps and preamps I owned, and they have supported their older products admirably.
ARC SP-6 Warmup time
I just bought an Audio Research SP-6 preamp. It takes about ten minutes after powering on for the power lamp to stop blinking and the unit to start passing signals. Other than that it sounds perfect on all inputs. Is this at all normal? Does it indicate something is about to fail? Ten minutes to warm up is more than annoying.