i have the older style triple rec. and recently when i engage the loop it sounds like pure mud or like a blanket is layed over my amp..... is there a designated tube for the loop? i thought it was v4 i changed the tube and nothing changed.....the mud is there on all channels.... plus the amp is only about half as loud when loop engaged even when everything is cranked..... im at a loss and have a big show of 20,000 plus people..... i know the loop always colored my tone a little but now its useless.... i live in the middle of nowhere so taking it to a tech is like 300mi away.....plz help