24-08-2017, 07:18 PM
Hi.
Along with the above work done yesterday I substituted two 6BJ6 valves in the RF stages rather than the EF95's. This calmed down the excessive gain and other issues. These valves are just about pin compatible and in my case the extra pin had been wired up. Alignment then was possible and tracking is much better but still not quite perfect. I think that this could be due to the original valves having a screened lead to the grids and the wires being 6-7 inches long whereas the unknown modifier has just used a couple of inches of non screened PVC cable. May be an idea to use screened cable in a loop to give me an equivalent length to get the capacitance correct.
Along with the above work done yesterday I substituted two 6BJ6 valves in the RF stages rather than the EF95's. This calmed down the excessive gain and other issues. These valves are just about pin compatible and in my case the extra pin had been wired up. Alignment then was possible and tracking is much better but still not quite perfect. I think that this could be due to the original valves having a screened lead to the grids and the wires being 6-7 inches long whereas the unknown modifier has just used a couple of inches of non screened PVC cable. May be an idea to use screened cable in a loop to give me an equivalent length to get the capacitance correct.
