Eurotubes "Pro One" Bias Probe Evaluation.......Plus: Make Your Own Bias Probe

This video covers a lot of ground. First, we discuss Cathode Current vs Plate Current Measurement, then we bias a SE amp both manually and using a Eurotubes Biasing Probe, with a comparison of results. Second, we bias a DE amp both manually and using a Eurotubes Biasing Probe, with comparison of results. Finally we see how to build our own biasing probe using readily available materials. NOTE: Construction and use of a home-built probe is recommended only for viewers who have ample experience with all electronics safety procedures. Extra Features: With Jack & KC's help, we open four incredible gift boxes from generous viewers, and we return to the War Eagles Air Museum Car Show. The Eurotubes "Pro One" Bias Probe uses no batteries, and directly measures Plate Current (no need to subtract Screen Current). The PC is displayed in mA and the PV is simultaneously displayed in VDC. By converting the mA reading to Amps, the Plate Dissipation can be calculated by multiplying PV x PC. The ET probe is calibrated at 180mA +/- 0.1mA @ 700VDC and can handle PV's greater than 1000VDC. It works equally well with both cathode biased and grid biased output tubes. NOTE: I have no affiliation with Eurotubes. The bias probe being evaluated was contributed by a viewer who paid full retail for it. ALSO: Because some output tubes use Pin 1 as a Suppressor Grid connection (i.e. EL34) you should add a connection between Pin 1 in both the probe socket and the base in the wiring diagram shown at 35:03. Link to become a Patreon Patron:   / uncledougsvintageamps   PayPal account for donations: [email protected] Link to Eurotubes Website: www.Eurotubes.com (503) 659-7401 MENU: Plate Current vs Cathode Current @ 01:50 Proper SE Bias Procedure Discussion @ 04:35 Performance of Manual SE Bias Procedure @ 07:16 Performance of Eurotubes SE Bias Procedure @ 12:51 Comparison of Results for SE Amp Circuit @ 14:05 Manual Measurement of Screen Current @ 15:08 Open 1st Gift Box w/Jack & KC @ 16:39 Performance of Manual DE Bias Procedure @ 19:31 Performance of Eurotubes DE Bias Procedure @ 25:33 Comparison of Results for DE Amp Circuit @ 26:46 Open 3 more Gift Boxes @ 27:38 Final Discussion of Eurotubes Bias Probe @ 29:36 Build Your Own Bias Probe @ 32:08 Closing Statements @ 45:58 Car Show @ 47:27