tzh21y ;
I don't have Kt88's but I do have the Black Treasure 6CA7's .
They did sound bad , good , bad etc. during the break in process . The break in
took at least 200 hrs until they opened up .
I don't think that you have really given your BT's a chance with just that few amount of hours . Plug them back in , put a dynamic CD on repeat and leave the house ! It may take awhile longer .
Good Luck .