Best Source for Replacement/Upgrade Tubes??

I bought a bevy of Electroharmonix tubes from www.tubedepot.com. They had the best prices I could find for new production tubes, and their shipping was super fast. Can't say about NOS tubes, though, if that's what you're looking for.
Brent

i bought a pr. of NOS cryo, that im very happy with from ATSI advantage tube services,561 434 3799,info@tubeman.com,friendly fast service!

I 2nd the good results from The Tube Depot. I've purchased 6550s, KT90s, 6FQ7s, and 5751s from them. Always low prices, great service, a low shipping charges (US$4).

Oh yea...great products too. :-)
.

Whatjd,

I would highly recommend Andy Bouwman at Vintage Tube Services. You can check out his website at www.vintagetubeservices.com. He is located in Rockford, Michigan.

Andy has as knowledgeable about tubes as anyone you could find. He basically has been a student of the vacuum tube since he was a teenager.

I have purchased a number of NOS tubes from him. The results of adding these to my system has been nothing short of miraculous.

Good Luck!!