That last more than 5 years before the gap in the socket pin opens up enough to break contact on the grid pin? octal EL34 type valves seem to have pins about 2.2/2.3 mm diameter. Failing socket pins , measured cold , a gap in the Y as large as 2.1mm. Luckily I've found a NOS McMurdo , British made socket that I will rob 4 of the pins from, for the 4 grids, as physically compatible in the base matrix. These unused ones measure 1.7/1.8mm in the active part of the Y gap. The failed ones from 2007 have reduced metal in the region where its required , the 2 prongs , except for a swelling at the contact point , measure in cross-section .7x.9mm down to the 2to1 middle of the pin . The older ones measure .55 x 1.4mm , the 1.4mm dimension in the sense that you want it , for long-term/hot-cold cycling strength. Any modern makes have engineering drawings disclosing these pin dimensions ? has the metal composition changed/ trade secret formulation lost?
- posted
11 years ago