Thoughts on the 9/15 Dudley Manlove Quartet Performance… and some amp woes
On Saturday 9/15 the Dudley Manlove Quartet performed at a private event in Seattle. We arrived on time and loaded in for sound check. When I picked up my trusty Boogie Lonestar to set it up, I noticed the 5U4 rectifier tube wasn’t seated in its socket, so I pushed it back in. Then I set up my equipment, including the Furman power conditioner and plugged in the amp. And powered up. And nothing happened. Few things in this world match the sickening feeling of turning on a piece of equipment and having it not function. I pulled out the fuse and verified it was blown; in fact, the fuse was blackened inside indicating a high voltage failure. Egad… after the previous bout of amp woes I was wondering if I was cursed!
Rather than attempting to troubleshoot the amp further I made an emergency phone call to my wife, who saved me by bringing me my backup amp. Yes, I realize that’s above and beyond the call of duty. I expect that I owe her a tropical vacation for this heroism.
The gig went great and we had a lot of fun. Once the gig was over I had the opportunity to delve a little further into the Lonestar situation. What I discovered was the 5U4 Rectifier tube had come loose and broken off its orientation key, so when I reinstalled it I must have accidentally inserted incorrectly. The pins were in the wrong holes in the socket, and the fuse immediately blew. What makes this especially odd is that this amplifier has both solid state and tube rectifiers, and you can switch between them based on the amp’s output setting; if you have the amp in 50w mode you can selected either the solid state or tube rectifier, and in the 100w mode it’s solid state only. I always have the amp in 100w mode for maximum headroom, but apparently even when the switch is set for solid state rectification the 5U4 tube is receiving power from the input transformer. So the incorrect orientation of the pins cascaded a failure and the fuse blew. My amp technician strongly recommends using the amp without that tube in place at all (!) which seems odd to me. I’m considering the possibility of replacing it with an octal-base solid state rectifier just in case the amp gets set in 50w mode at some point. Given that I had just replaced all four of the power tubes, having the rectifier also give me trouble was frustrating. But at this point I’ve got the full complement of power section tubes replaced and all should be good.
I swear, I better not have any amp problems anytime soon. It makes for a some grumpy moments.