Upgrading a stock 12AX7 tube from your preamp can yield a big improvement in tone. Here are four 12AX7 tubes for your arsenal. I’m moving to an FET-only amp and no longer need these.
Each tube is described below with corresponding hi-res photo. Vintage Telefunkens often go for $50 or more. The JJ new is about $14. This is a packaged deal: Your price for all four: $65 shipped via USPS to CONUS only, PayPal only.
The last numbers were the electronic test results when I purchased these a couple years ago. All except the first have been sitting in a drawer unused since then.
Telefunken ECC83 12AX7 smoothplate 50-56 
Telefunken ECC83 12AX7 smoothplate 50-53-32 
Telefunken ECC83 12AX7 smoothplate 50-56 JJ Electronic ECC83 12AX7 110-105 
