Re: GEC BT336 possible tube change
According to my 1968 Mullard data book the AW47-91 is a suitable replacement for the 7601A and CME1901, it has a 1" shorter neck and the only circuit change required is the addition of a 21Ω 2W resistor in series with the heater as it's a 6.3V type as opposed to 12.6V for the GEC/Mazda. The heater current for all three types remains the same at 300mA.
The AW47-91 was superseded by the A47-14W, the latter having a tinted faceplate.
John.
Last edited by jayceebee; 27th Jan 2018 at 10:42 pm.
Reason: more info
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