I have a hartke lh500 that is cutting out. I have replaced the tube and tried plugging in through the effects return so I know that it is a power amp problem and not a preamp problem, and I will need to send it in for repair. I am the second owner so it is not under warranty. Is it better to contact Larry Hartke directly or go through the samsontech website? I tried emailing Larry a week ago and have not received a response. If it is better to contact him directly can one of you give me his current phone number and email? and have any of you had any experience with sending a Hartke amp in for repair? Thanks for all comments/suggestions.