Ok so I got my multimeter. The reading between heater pins 4 and 5 when the jumper is set on the 6JI side is ~7.2v, which I'm not sure if that's correct or not since you stated they should be 6.3v in that position. Now the fun part comes - I switched the jumpers over to the 408A side, this time with the bottom cover of the amp removed and facing up, and as soon as I turn it on I see smoke. When I take a closer look with a flash light, I see that pin 5 of the right heater has been over-soldered, and the solder is connecting with the leftmost (408A side) K1 jumper pin. So yeah, I will definitely be sending this back for a refund and will order my replacement directly from LD so I get warranty coverage. Thanks for the help guys...I'm off to a rough start with audiophile equipment so far, but I won't give up