Here is a subject that has a lot of misinformation associated with it.
There are some differences in sound between different brands of tubes you may choose to install in your amplifier. For instance as a general rule Groove tubes tend to provide a much harsher ( edgy ) sound particularly in guitar amplifiers, less so in bass amplifiers than say JJ tubes. However aside from the harshness of groove tubes I find that most of the other main stream brands are similar in sound quality. The one place I find a big difference is reliability. The tubes we use here at the shop are all pre tested and burned in for maximum reliability and sound quality. The JJ tubes that we used to prefer to use in repairs have recently dropped in reliability so we have switched to using tung-Sol tube. So far we have been having excellent results with them in all types of tube amplifiers. There are of course NOS tubes and other rare tubes that have a nice tone and a hefty price tag, but in most situations and for most people they are not worth the hefty price tag. When we do a repair we will of course use any tube that you desire for your tube amp repair, but in most situations find that our customers are very pleased with our choice of Tung-Sol tubes for their amp repair.
Randy Morgan ….. Owner & head technician at All Service Musical Electronics Repair