Original poster: "Jonathan Peakall" <jpeakall@xxxxxxxxxxxx> Hi All, I have recently obtained four 833A's and plan on making a TC with one of them. I'd like to find a way to test the tubes. Oddly, my none of my tube testers have a socket for 833A's :-0. So, any suggestions as to how to test them? Thanks, Jonathan www.madlabs.info