Brand and age would be quite useful. Back in the days when solid-state "high-powered (+/-60 watts)" amplifiers were new, a fair number of manufacturers would maintain a low-level current through their equipment to avoid thumps and bangs during turn-on - that could damage speakers, again back in the day.

Such manufacturers included:

AR
Dynaco
Scott
KLH and others.

That you are getting a 5-6 watt draw is a bit higher than typical, but within the range. An added benefit is that this process 'kept the capacitors wet' as AR described it, helping their longevity in theory.

Peter Wieck
Melrose Park, PA