Ola amigos; I have a Lab Series L7 which I am pretty sure is the same amp with 4 ten inch spkrs instead of 2 twelves. I can only get normal volume using one low gain input. The other three inputs are much lower volume than it must have come from the factory. A fellow amp dude from another forum suggested checking the input op amps. That sounds to me like there may be a weak link in those input chips because you say your L5 works good after correcting that problem. Any thoughts ??
thanks
thanks