So I went down to the local music shop and picked up some groove tubes preamp tubes(12at7c). Popped em in, warmed them up..and..well, they seem to work. The only concern I have is they are not glowing. I had to turn off the lights to even notice any glow at all. Of course i cant return them. Are they dead? Did I install them Wrong? Do groove tubes Suck in general? Any input would be much appreciated.