18-01-2018, 10:52 AM
The use of 13V valves in that set is interesting - where did the 13V come from in the first place?
Because of the use of lead acid accumulators, early valves ran off 2V, ignoring that the nominal voltage of a single cell is actually 2.1V. Similarly this increased to 4V but by the time that 6V ranges were introduced, manufacturers obviously decided it was time to account for the previous discrepancies and the standard became 6.3V. Then 12.6V for 12V operation.
I think 6.3V valves started off in the US but they were certainly standard in the UK towards the end of the 30s.
So why 13V? And weren't there 6.3V or 4V versions of the valves used in this AC set to avoid the non-standard secondary winding on the mains transformer?
Because of the use of lead acid accumulators, early valves ran off 2V, ignoring that the nominal voltage of a single cell is actually 2.1V. Similarly this increased to 4V but by the time that 6V ranges were introduced, manufacturers obviously decided it was time to account for the previous discrepancies and the standard became 6.3V. Then 12.6V for 12V operation.
I think 6.3V valves started off in the US but they were certainly standard in the UK towards the end of the 30s.
So why 13V? And weren't there 6.3V or 4V versions of the valves used in this AC set to avoid the non-standard secondary winding on the mains transformer?
