CV1285

I respectfully ask the members who are most interested in the precise determination of tube data to please help resolve a dilemma that eludes me.

I have had for quite a long time what appear to been 2 original ST14-shaped tubes made by Sylvania (they are still in what I believe are the original Sylvania cartons) and have the number 1285 printed on the top. They are in the early green and black carton and the outline designation 14Z is printed on the package.

I have seen several times a tube matching the ST 14 outline, with the octal base, and it is identified as the CV1285, a dual triode, and also cross referenced as replacement for the ECC31 tube. The tube data identifies the tube as having the 6.3V filament voltage, and other characteristics.

However, my Hickok tube tester data sheets list the following to test a "1285" tube:

FILAMENT: 25.0 V

SELECTOR POSITIONS: 7 2 5 0 - 3 4 8 0

BIAS: 0

SHUNT: - - -

MULT: X10

PRESS; S4 (indicates low plate position)

MIN. MUT. COND: 500

The above test data for the Sylvania 1285 does not agree with the data that we have listed for the CV1285. I would be most appreciative if a member could enlighten me on this small matter.

Respectfully,
Robert Sarbell Attachments:

• Sylvania1285carton (45 KB)
• Sylvania tubes (53 KB)

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I apologize for the stupid question. . . . . . . .I have determined the exact nature of the peculiar "1285" tube.

It can be thought of as a dual triode or equally well as a tetrode, and both are perfectly acceptable answers.

Respectfully,
Robert Sarbell

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