I just took my blues jr. Out of storage. After plugging it in it popped a power tube. It might have been handled rough in transit. I checked out electronics, everything looked pristine. I installed 2 gold lion power tubes. Let them heat up well and played. Clean sounds great but amp rattles/rumbles at breakup. Especially on g string. This amp never was used much in past. Not even broken in. Any advice on where to start troubleshooting would be appreciated. Only rumbles after 3 on master dial and 2 on volume. Fat switch makes it worse. I have ordered pre amp tubes. Most likely the problem. Thanks for listening.