I am thinking about buying a 2/50/2 power amp and was wondering if anyone can tell from the serial number whether or not it has the switch on the inside to be able to use 6L6 tubes. I know that the newer ones don't have it anymore. The serial is J0010754.

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Straight from the website.

Three years in the making, the small-but-mighty Two/Fifty/Two is an affordable dual 50-watt sweetheart that features a pair of premium EL34 power tubes in each channel.

Its spacious well-ventilated chassis provides maximum air flow to the diagonally mounted power tubes. The fan even switches automatically to high speed when Class A mode is engaged to ensure reliable performance under demanding conditions. Note the dual 6l6/EL34 switches on the power tube mounting bracket.

With its variable damping, voicing and presence controls, and Class A mode, there's simply nothing comparable to this amazing piece of pro-quality gear. Players and recording engineers tell us this is the best-sounding power amp ever made
I don't give a shit if you listen to me or not