where to be various brands of tubes

I need tubes for my Supratek Cortese. it come with 4 lne stage output tubes, Tung-Sol vt94D's. one has become very noisy. Are there any substitues that might perform better.
Suggested tubes listed in the manual for this stage are 6J5.
Go to Upscaleaudio.com or call them - Kevin is pretty good at the tube game.
Try Andy at Vintage Tube Services. (www.vintagetubeservices.com)