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That speaker isn't original. The original was electrodynamic, which means it had a large coil of wire in back which acts as an electromagnet. This is called a field coil. It also serves as a filter choke in the power supply.
You can convert a radio which originally had an electrodynamic speaker to a PM type, but then you have to install a power resistor or a choke to replace the field coil. A resistor is usually used, but then you have to increase the size of the electrolytic capacitors a bit to take care of the hum.
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Ron Ramirez
Ferdinand IN
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Thanks Ron and Jerry for responding. I'am willing to attempt to convert to the PM type speaker in the picture I previously posted. The speaker has a output transformer on it and there's also a filter choke in the chassis. Do I remove or replace these? The 3 wires that come out of the speaker socket on the back of the chassis that go to the output trans. What do I do with them in regards to installing a power resister or choke and what type of choke would I need to use? Any guidance you can give is greatly appreciated. BTW. Jerry I did ck. the speaker. No numbers on it. Mike
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You should be fine with the 10 mfd. Just make sure working voltage is adequate on replacement part. I like to use 450 VDC types pretty much all the time. Of course observe polarity.
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Mike, the other option would be to place an add on the Phorum and see if anyone has an original speaker for the unit. Slim but a possibility. Nice to get that radio back the way it was.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
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Thanks Jerry, I have been looking on ebay and I have a wtb on this forum for a junker set I'll add a wtb speaker. I was wondering if you or someone might know how to set up the permanent magnet speaker I have? I have spent the last 2 months changing the caps and resistors. bought a variac, volt and ammeter and need to get the speaker hooked up so I can power it up. It was with the help of the great people on this forum that got me this far and need someone with the knowledge to walk me through the steps of what to buy and how to wire the speaker into the radio. Really anxious to see what happens when power is applied. Mike
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Mike, well we should assume and you know what that means that someone in the past has used that speaker on that radio. Now, if you have done your job of getting the major e-caps replaced and did a good visual as to what the earlier repair had done. I would just bring it up on the variac slowly and see what is going on. Who knows, it may start making some nice noise? I suspect that if the change over was done properly (again assuming) you might hear some nice music.
Jerry
A friend in need is a pest! Bill Slee ca 1970.
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Thanks Jerry, I'll give that a try. I do have one question. In the picture I posted on page two of this thread, on the speaker you see the output transformer on the speaker frame. It has 6 six seperate solder tabs comming off the primary side. Three on top and three on bottom, under each tab is a number. On the top tabs its #5 , 10, and the letter C. on the bottom tabs its 2.5 , 1.25, and .62 . Is there a way to determine which wires go to which tabs? There is 3 wires on a 4 pin plug that go into a socket on the back of the chassis with one pin out hole blank. Inside the chassis I see one wire goes directly to #80 tube from one pin hole. pin hole 2 has 2 wires ,one going to 42 tube and one going to a cap and to ground of chassis via the bc resistor. the third pin hole has one wire going to junction tab and on to the #42 tube. Looking at the schematic its not clear to me where to connect the 3 speaker wires to the output transformer.Sorry to be so long winded just trying to be clear on my question.