Re: Why the use of American valves
The Pro-Electron valve naming system strikes me as more informative than the American system in the absence of prior specific designation knowledge.
For example, from “EF89” one may deduce that the valve has a 6.3-volt heater (the “E”), is a small-signal pentode (“F”), has a noval base (“8x” number) and is of the remote cutoff type (odd final digit, in this case 9, within the 8x series). There are four definite points of information.
On the other hand, 6BA6 indicates a valve with a 6.3-volt heater (leading “6”) and 6 accessible electrodes. The latter is characteristic of pentodes with separate suppressor grid pinouts, but it is also characteristic of heptodes (with internally connected suppressors, e.g. 6BE6, 6BY6) and of conventional AM radio double diode triodes (e.g. 6AT6, 6AV6). So there is really only one point of definite information.
Cheers,
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