Hi there, I purchased a Pan Am with my 2 Audeze headphones and I was wondering if you could help identify my stock tubes. I posted pictures in this post: http://www.head-fi.org/t/626204/alo-pan-am-desktop-portable-headphone-amp-dac-impressions-and-reviews/555#post_10461171 Looking at some of the other pictures online, my tubes look more to me like the russian military tubes than the Chinese 6AK5, but I figured I'd double check. Assuming they are in fact the Chinese 6AK5, I noticed that the Russian military tubes have been unavailable on your site for a while. Do you think that's something that will come available again at some point, or is it a gone forever deal? BTW, should there be any fundamental sonic differences between the 2 gain settings? I seem to get a lot more bass/treble relative to midrange on the high setting as compared to the low. Thanks for any advice/information you can share with me on my first foray into tubes!