You can use a PM speaker. Does your radio have an Audio Output Transformer? Often they were mounted on the original speaker and may have been removed along with it.
A 1000 ohm 10 watt resistor will work for a field replacement. Be sure to mount it away from heat sensitive components as it will be very warm.
The resistor will not be as effective in reducing hum as the field. It may be fine but if hum is a problem you can increase the filter capacitor value. The use of 22 mfd @ 450 volts will do the job.
Norm
: someone has cut the speaker from this radio. i plan to replace it with pm speaker. do i just replace the coil with a 1140 ohm resistor. would 1k be ok? also on this set do i need to put a cap in to filter. maybe 10uf? do i replace with 8 ohm?
: thanks,
: eddie
Hi Eddie
: You can use a PM speaker. Does your radio have an Audio Output Transformer? Often they were mounted on the original speaker and may have been removed along with it.
: A 1000 ohm 10 watt resistor will work for a field replacement. Be sure to mount it away from heat sensitive components as it will be very warm.
: The resistor will not be as effective in reducing hum as the field. It may be fine but if hum is a problem you can increase the filter capacitor value. The use of 22 mfd @ 450 volts will do the job.
: Norm
:
: : someone has cut the speaker from this radio. i plan to replace it with pm speaker. do i just replace the coil with a 1140 ohm resistor. would 1k be ok? also on this set do i need to put a cap in to filter. maybe 10uf? do i replace with 8 ohm?
: : thanks,
: : eddie
The PT291 will work. The 42 tube should feed into 7000 ohms impedance, DC resistance will be much less. The exact impedance isn't critical. Since you have a Universal Output Transformer, try different taps for the best sound quality.
Some radios only have three wires going to the speaker even though there is a field. One wire will be from the 42 output tube to the transformer. One wire directly from the rectifier to resistor and the final wire is B+ for your radio. This wire connects to the output transformer as well as the field (resistor).
You do need a 1000 ohm wire wound resistor. 100 ohms is too low. Unless you find a choke with a 1000 ohms coil the resistor is the best way to go. Call around to Radio/TV repair stores. It will cost a little more but resistors are still cheap.
Norm
: thanks norm,
: the output transformer was mounted on the speaker. i have a universal from aes, pt291, i think is the number. i only have 3 wires from the chassis, which is a little confusing to me. are the input to the output transformer and the input to the coil the same one? i can't find a local supplier of the 1k power resistor. the biggest radio shack has is 100 ohms at 10 watts. is there any other options on this? do i need to check the resistance of the output transformer when figuring how much resistance i need to replace the coil?
: eddie
: Hi Eddie
: : You can use a PM speaker. Does your radio have an Audio Output Transformer? Often they were mounted on the original speaker and may have been removed along with it.
: : A 1000 ohm 10 watt resistor will work for a field replacement. Be sure to mount it away from heat sensitive components as it will be very warm.
: : The resistor will not be as effective in reducing hum as the field. It may be fine but if hum is a problem you can increase the filter capacitor value. The use of 22 mfd @ 450 volts will do the job.
: : Norm
: :
: : : someone has cut the speaker from this radio. i plan to replace it with pm speaker. do i just replace the coil with a 1140 ohm resistor. would 1k be ok? also on this set do i need to put a cap in to filter. maybe 10uf? do i replace with 8 ohm?
: : : thanks,
: : : eddie
: Hi Eddie
: The PT291 will work. The 42 tube should feed into 7000 ohms impedance, DC resistance will be much less. The exact impedance isn't critical. Since you have a Universal Output Transformer, try different taps for the best sound quality.
: Some radios only have three wires going to the speaker even though there is a field. One wire will be from the 42 output tube to the transformer. One wire directly from the rectifier to resistor and the final wire is B+ for your radio. This wire connects to the output transformer as well as the field (resistor).
: You do need a 1000 ohm wire wound resistor. 100 ohms is too low. Unless you find a choke with a 1000 ohms coil the resistor is the best way to go. Call around to Radio/TV repair stores. It will cost a little more but resistors are still cheap.
: Norm
:
: : thanks norm,
: : the output transformer was mounted on the speaker. i have a universal from aes, pt291, i think is the number. i only have 3 wires from the chassis, which is a little confusing to me. are the input to the output transformer and the input to the coil the same one? i can't find a local supplier of the 1k power resistor. the biggest radio shack has is 100 ohms at 10 watts. is there any other options on this? do i need to check the resistance of the output transformer when figuring how much resistance i need to replace the coil?
: : eddie
:
: : Hi Eddie
: : : You can use a PM speaker. Does your radio have an Audio Output Transformer? Often they were mounted on the original speaker and may have been removed along with it.
: : : A 1000 ohm 10 watt resistor will work for a field replacement. Be sure to mount it away from heat sensitive components as it will be very warm.
: : : The resistor will not be as effective in reducing hum as the field. It may be fine but if hum is a problem you can increase the filter capacitor value. The use of 22 mfd @ 450 volts will do the job.
: : : Norm
: : :
: : : : someone has cut the speaker from this radio. i plan to replace it with pm speaker. do i just replace the coil with a 1140 ohm resistor. would 1k be ok? also on this set do i need to put a cap in to filter. maybe 10uf? do i replace with 8 ohm?
: : : : thanks,
: : : : eddie
The resistor needs to be 1000 ohms. That's not the same as 1000k.
Right, hook one end of resistor to wire from the rectifier and the other end to the screen grid of the 42.
Connect the output transformer to the plate of the 42 and the other wire to the screen grid, same place the resistor was connected. Be sure to use the screen grid and not grid #1.
Norm
: norm,
: just to be sure....i hook the wire from the rectifier to the 1000k resistor, hook the other end going into the trans. also hook the wire that comes from the grid on the 42 tube to this terminal. hook the other wire coming out of the trans and going to the plates. am i on track?
: : Hi Eddie
: : The PT291 will work. The 42 tube should feed into 7000 ohms impedance, DC resistance will be much less. The exact impedance isn't critical. Since you have a Universal Output Transformer, try different taps for the best sound quality.
: : Some radios only have three wires going to the speaker even though there is a field. One wire will be from the 42 output tube to the transformer. One wire directly from the rectifier to resistor and the final wire is B+ for your radio. This wire connects to the output transformer as well as the field (resistor).
: : You do need a 1000 ohm wire wound resistor. 100 ohms is too low. Unless you find a choke with a 1000 ohms coil the resistor is the best way to go. Call around to Radio/TV repair stores. It will cost a little more but resistors are still cheap.
: : Norm
:
: :
: : : thanks norm,
: : : the output transformer was mounted on the speaker. i have a universal from aes, pt291, i think is the number. i only have 3 wires from the chassis, which is a little confusing to me. are the input to the output transformer and the input to the coil the same one? i can't find a local supplier of the 1k power resistor. the biggest radio shack has is 100 ohms at 10 watts. is there any other options on this? do i need to check the resistance of the output transformer when figuring how much resistance i need to replace the coil?
: : : eddie
:
: :
: : : Hi Eddie
: : : : You can use a PM speaker. Does your radio have an Audio Output Transformer? Often they were mounted on the original speaker and may have been removed along with it.
: : : : A 1000 ohm 10 watt resistor will work for a field replacement. Be sure to mount it away from heat sensitive components as it will be very warm.
: : : : The resistor will not be as effective in reducing hum as the field. It may be fine but if hum is a problem you can increase the filter capacitor value. The use of 22 mfd @ 450 volts will do the job.
: : : : Norm
: : : :
: : : : : someone has cut the speaker from this radio. i plan to replace it with pm speaker. do i just replace the coil with a 1140 ohm resistor. would 1k be ok? also on this set do i need to put a cap in to filter. maybe 10uf? do i replace with 8 ohm?
: : : : : thanks,
: : : : : eddie