[Tapsnap]

Hi everyone,

I'm new to this phorum and new to electronics. I have a question about a Philco speaker that I have. It came from a 1934 Model 14x. I am trying to find out the specs for this speaker. Is there a place where this stuff is posted?

The information on the speaker is 32-9035G 9-3 which is printed on the field magnet coil. The Output transformer has the number 32-705 2N and there is a U-3 printed on the big iron back.

Specifically, I am trying to find out:

1. The impedance of the speaker coil.
2. The operating voltage of the electro-magnet.
3. The primary and secondary impedance of the output transformer.
4. The operating voltage and current of the output transformer.
5. The output wattage of the speaker.

I have measured the speaker coil resistance and it measures 2.3 ohms. I'm guessing that it might then have a 3 ohm impedance?

The Resistance of the Electromagnet measures 1123 ohms. Does that sound about right?

The resistance on the primary of the output transformer measures 170 ohms and the secondary measures 0.6 ohms. Does all this sound right?

Thanks for your guidance.
Daniel

[klondike98]

Welcome to the Phorum!

Lots of info on speakers is available for download in the Downloadable Files section and then click on the speakers.zip file and unzip it. Line 185 of the excel spreadsheet shows the U-3 speaker info.

[Radioroslyn]

The model 14uses Philco's class A triode connected push/pull 42 tube w/a 42 driver. This set up is designed to achieve 10w with very low distortion. In the triode configuration the 42's operate at a lower impedance (abt 6K) than in the typical pentode configuration (abt 14K).

[Tapsnap]

Thanks, that's really helpful. The info on this speaker shows that the rated field current is 70mA and the DC field coil resistance is 1140 ohms. So the working voltage for the field coil is 80 volts, right?

[morzh]

Rated current does not mean actual current drawn. The current will depend mostly on the working regime of the output stage. Which will change somewhat depending on the output power. But the actual current will probably be less that the rated current.

[Tapsnap]

So, what kind of voltage would work best for this field coil? Is there a max and a min working voltage that I should keep within?