27-09-2020, 10:21 PM
Murphyv310 Wrote:Why not use an ECL83 so as only one tapping would be required for heaters and the pilot bulb, or a 12v bulb with the PCL83?
Synchrodyne on UKVRR (hugely knowledgeable about valve choices and what led to them) has provided a couple of answers to explain this.
First, the PCL83 has a more suitable triode for the record player amplifier, with a μ of 17. The ECL83 has a triode with a μ of 85, which would give excess gain. (The ECL83 and PCL83 do have similar pentodes).
Second, and this does tie in with your own point Trevor about the Mazda-Murphy agreement, that Mazda by 1958 were offering the PCL83 in their list of valves... But not the ECL83 (Synchrodyne has a 1958 Mazda data book).
Amie's post on 13th Sept confirms her record player has a Mazda branded valve, which is completely consistent with the second point.
