I have an SVT-CL which I purchased about 2 1/2 years ago, and last week I noticed one of the tubes was not lighting up when I fired her up. The bias indicator lights were also showing that there was a bias issue. I removed the faulty tube and placed it into another socket to ensure that it was indeed just a bad tube and it checked out. After deliberating for a while I decided to order an entire new set of Sovtek 6550WE's which the amp came stock with in the first place. My question is this: Since the amp has the bias indicator LED's, would it be feasible for me to replace the tubes and bias them myself? Or would it be wise to take the amp and new tubes to a tech to let him do it? I have very little experience with tube replacements. Thanks!