Maybe they are spent as the Sovteks usually do vocals last on the list. When they are on the down side they start to sound bright (brittle) and thin. Is this what you are experiencing? The Audioasylum.com tube forum should have the search feature back up next week. Try doing a search under your amp and see what people are using in it with good results (other than Sovteks). This will give you an idea, anyway, of what to look for.
