Hello, I just purchased a used Crack for my first tube amp. The amp worked great initially, the previous owner was kind enough to include a handful of 12AU7 tubes to try out. I enjoyed my first listen but I was looking for a little more bass so I decided to try out a different tube. I turned it off, let it cool down and swapped the tube. It sounded horrible and I lost the right speaker in my HD650’s I figured it was a bad tube. I swapped the original tube back in, it sounds better but I still don’t have the right side speaker. The headphones are fine and I tried different cables still the same. Unfortunately I didn’t build it so I’m not as familiar as I should be but I was wondering if any of you had and tips to diagnose this issue. Thanks for your help in advance.
