Vacuum Tube Retailer Option

They look like they cater to guitar guys..... you will never find 6dj8 or its cousins at a music store.  Although a lot of their stuff looks like it would appeal to both musicians and hi fi.

TubeDepot is reliable, my issue with them is that a fair amount of NOS tubes that they listed on the website are always out of stock. I ordered NOS 6dj8 tubes from Upscale, they shipped me 7dj8 (same brand) and they are noisy as hell. 

I tend to purchase NOS tubes from Brent Jesse 

Ditto on Brent Jessee Tubes.   Good selection of high quality NOS tubes at reasonable prices, good advice/customer service and quick to ship.

I recommend the seller tubemaze (Not affiliated with him) on ebay. He offers 30 day return policy and his prices are fair. Take that Upscale! (Overpriced and no returns)

Used to buy from Upscale, until he got too uppity. Been buying power tubes from these guys(http://tctubes.com/), for the past decade, with zero problems/much satisfaction and Brent Jesse also(no need to elaborate there). A while back, I had an octet of 1970’s GE 6550A’s in my monoblocks and one managed to short(after over a year of use). I sent the remaining three, from one mono’s quad and they managed to find a NOS match for me.  They said it's readings weren't up to their normal NOS sales standards, so- they gave it to me.   Maybe I’m easy, but- I was impressed.