Where do you guys buy tubes?

Tube World for rare exotic NOS!

No regrets ever!

On seeing what you want and what it's for, I second Ghosthouse in suggesting that you get them from ARC.

McShane and Kevin@Upscale.  However, two that I'm currently using were eBay.

WOW!!!! Andy from Vintage Tube Services is a super super nice person.  Helped answering all my questions even he don't carry the tube that I am looking for.  If I am looking for NOS in the future, this is the place I will do business with.  Two thumbs up for Andy at Vintage Tube Services.

  

I've had excellent experiences with both "tctubes.com" (Tyler and Chelsea are a pleasure to deal with, and they really know their stuff) and  Brent Jessee at “audiotubes.com" who is an expert with all kinds of tubes.  I bought two matched quads (four years apart) of Genelex Gold Lion KT-77's from tctubes, and have been extremely satisfied.  More recently, I bought a set of five "small tubes" from Brent Jessee ..... a matched pair of GE JG 5751 backplate triple mica premium military grade (12AX7 spots), a matched pair RCA 12AU7 Cleartops (12AU7 spots) and a single Telefunken ECC82 smooth plate diamond mark (center 12AU7 spot) ..... for my Rogue Audio Cronus.  Fantastic tubes making beautiful music.  Life is good !