LSC Rectifier Tube

[jonp]

I pick up my new LSC 2x12 tomorrow - can't wait!!! I always like to keep spare tubes and I have a new Groove Tube GT-5AR4 - can this be used instead of the 5U4 in the LSC?

 

[AJ_Newkirk]

From what I have read on this the short answer is no.

It appears that the 5AR4 will produce lower DC voltage.

 

[AdmiralB]

I can't imagine that it would cause any problems. It'll cause the HV to be about 10V or so higher than the 5U4, but since Mesa biases so cold anyway that wouldn't be a problem.

The result will be a little louder/faster/tighter operation - not totally like the silicon diode setting, but closer.

 

[212Mavguy]

No prob using 5ar4, might sound a bit tighter and brighter, there will be less sag at pick attack at higher volumes than 5u4. The differences will show up at higher volumes more so than low.