Im taking my SC in for a full service soon but as it hadnt been fired up for a few weeks i thought id give it a blast this weekend. I set it up in the spare room and flicked it onto stand by while i had a brew and let the valves all warm. Came back in, plugged the bass in and flicked on the power......nothing happened, no noise, no nothing. I looked in and all the EL34's were glowing niceley....i couldnt fathom out what was wrong. Then i checked the back......id put the jack lead for the cab into the Effects Loop input and not the Cabs socket. I quickly switched it off (even tho im a valve newbie i know never to turn on an amp with no load). Anyway, i re-connected the lead correctly and tentively switched it all back on. The amp is working fine now but having had it on standby with no load for a good 20 mins im wondering what damage i could have done to it? Its going in for a service soon and i may well be taking up Mr Foxton on a great offer of some EL34's but just wondering what damage i could have done to the amp