Replacing the tube is really a piece of cake.
No special tools are required other than a very small Phillips head screwdriver that will be used to remove the top metal piece of the Aphex Channel enclosure.
I also recommend you grab yourself a pair of rubber gloves and wear them when handling the tube. You want to make sure you don’t put any fingerprints on the glass area of the tube. Doing so, can cause the tube to over heat and decrease longevity and sound quality.
Once you have the top piece removed from the Aphex, it’s time to gently remove the copper fastener that holds the tube firmly in place. Go easy here. You don’t want to bend any of the copper prongs on the bottom of the tube. I found that pulling upward while at the same time using constant pressure to remove the base of the tube from the socket works best.
Reverse the process to install the new tube and test everything before finally sealing up the Aphex Unit.
Congratulations! Everything should be good to go.