Alternatively, I have an old Philco 11 inch speaker [Model Ay-32-9087-1) with a 4 pin connection. The audio transformer is center tapped. I placed a ohmeter across the leads for the field coil and had a reading of 680 ohms.
Can the Philco speaker be used in the Atwater Kent until I locate an Atwater Kent replacement? If so, could you procide instructions for wiring?
Thanks for your help.
Steve
Use your Philco speaker since it has a push-pull output transformer. The original AK field had a resistance of 1100 ohms. Since your Philco speaker has lower resistance you may want to add 400 ohms, 5 watt or greater, in series.
Philco would sometimes connect the center tap of the output transformer to one side of the field which was used as B+.
For the AK you will need to remove this connection and bring 5 wires from the speaker. The two outside wires from the push-pull transformer goes to each 45 tube plate. The center tap goes to B+. The field connects between chassis and center tap on the high voltage winding of your power transformer.
Check the schematic. If you don't have one it should be available here on nostalgiaair.
Normally the difference in field resistance wouldn't matter but in the AK70 a divider is across the field which supplies negative bias to the 45 tube grids.
Norm
: I am looking for a speaker for an Atwater Kent Model 70-L1; Serial number on chassis is 6,234,881. A 5 pin connection is required. If anyone has one please respond to my email address (larsons@home.com).
: Alternatively, I have an old Philco 11 inch speaker [Model Ay-32-9087-1) with a 4 pin connection. The audio transformer is center tapped. I placed a ohmeter across the leads for the field coil and had a reading of 680 ohms.
: Can the Philco speaker be used in the Atwater Kent until I locate an Atwater Kent replacement? If so, could you procide instructions for wiring?
: Thanks for your help.
: Steve
: Use your Philco speaker since it has a push-pull output transformer. The original AK field had a resistance of 1100 ohms. Since your Philco speaker has lower resistance you may want to add 400 ohms, 5 watt or greater, in series.
: Philco would sometimes connect the center tap of the output transformer to one side of the field which was used as B+.
: For the AK you will need to remove this connection and bring 5 wires from the speaker. The two outside wires from the push-pull transformer goes to each 45 tube plate. The center tap goes to B+. The field connects between chassis and center tap on the high voltage winding of your power transformer.
: Check the schematic. If you don't have one it should be available here on nostalgiaair.
: Normally the difference in field resistance wouldn't matter but in the AK70 a divider is across the field which supplies negative bias to the 45 tube grids.
: Norm
: : I am looking for a speaker for an Atwater Kent Model 70-L1; Serial number on chassis is 6,234,881. A 5 pin connection is required. If anyone has one please respond to my email address (larsons@home.com).
: : Alternatively, I have an old Philco 11 inch speaker [Model Ay-32-9087-1) with a 4 pin connection. The audio transformer is center tapped. I placed a ohmeter across the leads for the field coil and had a reading of 680 ohms.
: : Can the Philco speaker be used in the Atwater Kent until I locate an Atwater Kent replacement? If so, could you procide instructions for wiring?
: : Thanks for your help.
: : Steve
Norm,
Your directions worked perfectly. The speaker is functional until I can locate a replacement AK.
Thanks again.
Steve