I am working on an old phonograph. The speaker has two coils attached. Can someone explain the purpose in two coils?

Thanks

Rick, what's the model number? Your speaker might have the output transformer attached, it may have a field coil, bucking coil and something rigged. The model number will help get the specifics. You could get the generalities of a speaker by doing a search too.

Bill VA

:I am working on an old phonograph. The speaker has two coils attached. Can someone explain the purpose in two coils?
:
:Thanks

:Rick, what's the model number? Your speaker might have the output transformer attached, it may have a field coil, bucking coil and something rigged. The model number will help get the specifics. You could get the generalities of a speaker by doing a search too.
:
:Bill VA
:
::I am working on an old phonograph. The speaker has two coils attached. Can someone explain the purpose in two coils?
::
::Thanks

Bill,
Thanks some reading cleared things up. This speaker has no permanent magnet so it could be a field coil or a bucking coil. I do not have a model number or manufactures number for this phonograph. The speaker has the number RS-9604 on it. A schematic would make thing much easier. I have a Photfact number 203-15 that looks close in as far as the tubes, capacitors and ballast resistor is concerned. As I look closer at the circuit I see many differences. So I will continue to redraw the circuit and see if it makes any sense when I am done.
Thanks,
Rick
Mathews, VA.

::Rick, what's the model number? Your speaker might have the output transformer attached, it may have a field coil, bucking coil and something rigged. The model number will help get the specifics. You could get the generalities of a speaker by doing a search too.
::
::Bill VA
::
:::I am working on an old phonograph. The speaker has two coils attached. Can someone explain the purpose in two coils?
:::
:::Thanks

Well, you know what the output transformer looks like, right? The secondary is connected to the voice coil. If there's anything else connected in series, that would be your hum bucking coil. The big coil in back, where the magnet goes on a modern speaker, is your field coil. It'll be of a high resistance unless it's an auto speaker. Auto speakers don't usually have hum bucking coils, though, so it's hard to confuse coils on them. The hum bucking coil on your speaker is probably wound right next to the field coil, but uses thick wire, and, of course, is of a very low impedance (possibly too low for your meter to measure...like .1 ohms).

Thomas

Tom,
I am not sure I know what the output transformer looks like. On the back of the speaker I have a rectangle of copper (?) inside is a coil and down the center is a steel rod. Attached to the copper is the second transformer smaller in size. Three wires feed the speaker. 1) from pin 8 of the Rectifier, 2) from 20 mfd cap.,3) from pin 3 of the audio output tube plate. This appears to be in series with the output tube. A book I have by Clayton L. Hallmark has a good figure in it, almost exact right down to the wire colors.
Thanks for the help. Once I get done drawing the schematic of how things are I will post it for inputs.

Thanks Again! This forum is great.

Rick at curajlofts@cs.com

:Well, you know what the output transformer looks like, right? The secondary is connected to the voice coil. If there's anything else connected in series, that would be your hum bucking coil. The big coil in back, where the magnet goes on a modern speaker, is your field coil. It'll be of a high resistance unless it's an auto speaker. Auto speakers don't usually have hum bucking coils, though, so it's hard to confuse coils on them. The hum bucking coil on your speaker is probably wound right next to the field coil, but uses thick wire, and, of course, is of a very low impedance (possibly too low for your meter to measure...like .1 ohms).
:
:Thomas

This question was already posted on the ARF forum by Rick.

Dave

Rick, you have actually identified the spkr xfmer from the field coil/electro-magnet yourself. Think of a steel rod with a coil around it= electromagnet.
So the coil/steel rod is your field coil/spkr magnet. The "other" xfmer is your output xfmer to spkr by process of elimination. The use of the large coil both in the rectifier circuit (as a choke) and as the magnitizing coil around the steel rod as the spkr magnet does confuse. Pat

Pat,
Thanks for the input. It does get confusing at times and I am thankful for this forum to be able to bounce things around.

Again Thanks!

Rick
Curajlofts@cs.com

:Rick, you have actually identified the spkr xfmer from the field coil/electro-magnet yourself. Think of a steel rod with a coil around it= electromagnet.
:So the coil/steel rod is your field coil/spkr magnet. The "other" xfmer is your output xfmer to spkr by process of elimination. The use of the large coil both in the rectifier circuit (as a choke) and as the magnitizing coil around the steel rod as the spkr magnet does confuse. Pat

The field coil will have its two wires going to the rectifier and the electrolytic. The output transformer will have its wires going to the electrolytic and the plate of the output tube. Current from the rectifier flows through the field coil and into the radio. Some of this current also flows through the output transformer and into the plate of the output tube (or, if you've read any of my other posts, you may have found one that describes the current as flowing from the negative point to the positive point, which it actually does...flows from cathode to anode....but most people think it flows from positive to negative......not to confuse you much more.....you just want to know which one is the field and which one is the output trans).

Thomas

Thomas,
Yes, this is how phonograph is wired. When I complete the schematic I am drawing I'll post it on my web site at I presently have one posted which is similiar to this phonograph. Sure would be easier if someone would have left the manufactures ID in place. The good side is I am learning more step forward.

Thanks Thomas! I do try to read as many posts as possible.

:The field coil will have its two wires going to the rectifier and the electrolytic. The output transformer will have its wires going to the electrolytic and the plate of the output tube. Current from the rectifier flows through the field coil and into the radio. Some of this current also flows through the output transformer and into the plate of the output tube (or, if you've read any of my other posts, you may have found one that describes the current as flowing from the negative point to the positive point, which it actually does...flows from cathode to anode....but most people think it flows from positive to negative......not to confuse you much more.....you just want to know which one is the field and which one is the output trans).
:
:Thomas

I'm not saying that you should read all of the posts....just saying that if you read some of my other posts, you may have come across what I wrote. I think that if you read all of the posts on this web site, you'd go cross eyed.

T.

cross eyed!!!!!!!!!!!!! to say the least!

Later!
Thanks
Again!!

Rick

:I'm not saying that you should read all of the posts....just saying that if you read some of my other posts, you may have come across what I wrote. I think that if you read all of the posts on this web site, you'd go cross eyed.
:
:T.

Good luck.

Thomas

Thomas... Hummm....was that a compliment?
.. what was that?

Nothing...just wishing good luck.

T.

Most likely in addition to the voice coil it also has what is called hum bucking coil. The name says it all.

Richard