If I swap the tubes out of my amp before they actually fail is it worth it to hold onto the old tubes in case of new tube failure or even to experiment mixing the old preamp tubes with the new ones (assuming I buy different brands/tube types for the preamp)? Just wondering because I plan on retubing soon by removing the 3 12ax7 EHX's in my preamp in favor of a 5751, a 12ax7, and a 12at7. I figure I should keep the EHX preamp tubes just in case I don't like having non 12ax7s in my amps V1 or V3. Thanks
Well if you keep the ones you have now you can troubleshoot later on if you think there's a problem with your pre amp valve.
I'd keep the old tubes. You'd never know, they'll come in handy.