Hi OldHector-- I did not build this amp, I bought it from a DIY Audio member, so I'm not sure which varistors are installed. I have changed back to a 5AR4 rectifier tube over concern about power up voltages.
One other peculiar thing is that with the 6L6GC tubes pictured above, I noticed that one side sounded louder than the other. Switched around the tubes and the lower sound followed. Next, the tubes were tested and one showed a higher transconductance than the other- 3200 and 3400 respectively. I removed the PCB and noted that one of the 1500 uF caps is bulging and one of the 0.22uF caps is delaminating, looks like it is unraveling. Ordered new caps, but won't be here until Friday.
The funny thing is that the stronger transconductance tube is the tube that that produces the lower sound.