TU 8600 Red Plating


2018-08-12 11:50 pm
I have a TU-8600 300B amp with all of the upgrades (transformers, resistors, caps) but Gold Lion 300B tubes. One of the tubes is red plating.

Diagnosis and Prognosis anyone?

Yep! just like vk said. check your voltages! I wish the manual included tolerances. My 8600 ended up red plating a couple of times, each time was with Gold lion tubes. JJ tubes did better. But eventually a pair of gold lion fried aa few components on the left channel. my voltages were higher than the manual stated. I ended up using a step down transformer, 120 to 110, that's used in Japan. voltages came down to within a few volts of what the manual states, amp runs a lot cooler too. It's been almost a year and no more red plating