Most everyone is familiar with the 5Y3 problem in the LSS. In short, the LSS puts just a little too much strain on the 5Y3 rectifer tube which results in high failure rate of these tubes from arcing. Most folks have "solved" the problem by using a NOS rectifer, which is a bit more durable than modern Chinese or Russian ones.
Mesa does have a no cost fix for LSS owners, but has been quiet on exactly what the fix is.
In the Sept issue of guitar player, Gerald Weber writes about a simple mod to solve this type of problem (although in this case he's writing about a vintage Fender twin.) He says it will work for any 5AR4, 5U4, 5Y3, 5V4, or 5R4 rectifier tube.
The mod is to remove two red wires from pins 4 and 6, and move them to pins 3 and 5. Then, connect one IN4007 diode between pin 3 and 4, and a second diode between pins 5 and 6. Banded ends of the diode are facing pins 4 and 6.
He goes on to say this mod prevents unwanted AC hi voltage of the plates of the rectifier tube, and prevents arcing.
Can anyone who's had the Mesa factory mod confirm that there are two diodes added to the 5Y3 tube socket?
Mesa does have a no cost fix for LSS owners, but has been quiet on exactly what the fix is.
In the Sept issue of guitar player, Gerald Weber writes about a simple mod to solve this type of problem (although in this case he's writing about a vintage Fender twin.) He says it will work for any 5AR4, 5U4, 5Y3, 5V4, or 5R4 rectifier tube.
The mod is to remove two red wires from pins 4 and 6, and move them to pins 3 and 5. Then, connect one IN4007 diode between pin 3 and 4, and a second diode between pins 5 and 6. Banded ends of the diode are facing pins 4 and 6.
He goes on to say this mod prevents unwanted AC hi voltage of the plates of the rectifier tube, and prevents arcing.
Can anyone who's had the Mesa factory mod confirm that there are two diodes added to the 5Y3 tube socket?
