Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
Thanks Terry N

Hi Terry

An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.

Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.

You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.

Norm

:Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
:Thanks Terry N
:

Terry, if you want better results, either use a choke instead of a resistor, or increase the filter capacitors. The inductance of the field coil was also used, beside being an electromagnet, to filter out some of the 60 or 120 cycle (Hertz to you youngsters) hum, someone on the forum undoubtely knows the exact value you would need to have the radio electrically identical to the original.
Lewis

:Hi Terry
:
: An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.
:
: Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.
:
: You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.
:
:Norm
:
:
:
::Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
::Thanks Terry N
::

Thanks for the reply. Can you tell me why the original speaker will work for a while when I short out the wiring for one of the coil wires to the cone wire? Do you think the speaker has a problem or am I back in the radio?
Thanks again, Terry
:Terry, if you want better results, either use a choke instead of a resistor, or increase the filter capacitors. The inductance of the field coil was also used, beside being an electromagnet, to filter out some of the 60 or 120 cycle (Hertz to you youngsters) hum, someone on the forum undoubtely knows the exact value you would need to have the radio electrically identical to the original.
:Lewis
:
:
:
::Hi Terry
::
:: An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.
::
:: Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.
::
:: You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.
::
::Norm
::
::
::
:::Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
:::Thanks Terry N
:::

It sounds to me that Terry is telling us that the voice coil is open and not the field coil. I have found that mechanical movement of the voice coil can cause it or its braided connection wire to break.

:Thanks for the reply. Can you tell me why the original speaker will work for a while when I short out the wiring for one of the coil wires to the cone wire? Do you think the speaker has a problem or am I back in the radio?
:Thanks again, Terry
::Terry, if you want better results, either use a choke instead of a resistor, or increase the filter capacitors. The inductance of the field coil was also used, beside being an electromagnet, to filter out some of the 60 or 120 cycle (Hertz to you youngsters) hum, someone on the forum undoubtely knows the exact value you would need to have the radio electrically identical to the original.
::Lewis
::
::
::
:::Hi Terry
:::
::: An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.
:::
::: Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.
:::
::: You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.
:::
:::Norm
:::
:::
:::
::::Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
::::Thanks Terry N
::::

I just found out I have a stong magnetic field when the speaker stops working a screw driver sticks to the center part of the speaker real good? Hope this helps.
Terry N
:Terry, if you want better results, either use a choke instead of a resistor, or increase the filter capacitors. The inductance of the field coil was also used, beside being an electromagnet, to filter out some of the 60 or 120 cycle (Hertz to you youngsters) hum, someone on the forum undoubtely knows the exact value you would need to have the radio electrically identical to the original.
:Lewis
:
:
:
::Hi Terry
::
:: An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.
::
:: Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.
::
:: You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.
::
::Norm
::
::
::
:::Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
:::Thanks Terry N
:::

I guess I better let you also know how I have this test speaker wired in. This is the test speaker in my EICO 147A signal tracer and it is hooked up to the voice coil wires with the original speaker still plugged in. Hope this helps.
Thanks again, Terry.
:Terry, if you want better results, either use a choke instead of a resistor, or increase the filter capacitors. The inductance of the field coil was also used, beside being an electromagnet, to filter out some of the 60 or 120 cycle (Hertz to you youngsters) hum, someone on the forum undoubtely knows the exact value you would need to have the radio electrically identical to the original.
:Lewis
:
:
:
::Hi Terry
::
:: An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.
::
:: Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.
::
:: You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.
::
::Norm
::
::
::
:::Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
:::Thanks Terry N
:::

I think I figured it out based on a OHMS test across the voice coil it is open. Can these speakers be repaired? Sorry for being so dumb and asking so many questions but I am learning.
Thanks again, Terry N
:Terry, if you want better results, either use a choke instead of a resistor, or increase the filter capacitors. The inductance of the field coil was also used, beside being an electromagnet, to filter out some of the 60 or 120 cycle (Hertz to you youngsters) hum, someone on the forum undoubtely knows the exact value you would need to have the radio electrically identical to the original.
:Lewis
:
:
:
::Hi Terry
::
:: An Atwater Kent 55C speaker has 4 wires. Two are for the voice coil and two for field. The field coil gives the speaker a magnetic field. At the time permanent magnets weren't strong enough.
::
:: Your replacement speaker has a permanent magnet so doesn't need the field winding. It only takes 2 wires to make it operate.
::
:: You still need something connected to the radio replacing the field. Connect a 1K @ 10 watt resistor between the extra 2 pins of the socket. Don't use just a jumper.
::
::Norm
::
::
::
:::Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
:::Thanks Terry N
:::

:I think I figured it out based on a OHMS test across the voice coil it is open. Can these speakers be repaired? Sorry for being so dumb and asking so many questions but I am learning.
Thanks again, Terry N

Terry:
A speaker reconer can replace everything in the speaker, voice coil, cone, spider and gaskets, resulting in a "new" speaker. As a matter of fact, I had an after high school job doing just that. The price of reconing a speaker may be about the best money you can put in a vintage radio, if you want to keep the radio original. Someone on this forum can give you better directions to a reconer than I can.
Lewis
P. S. There is a difference between stupidity (dumb means unable to speak) and ignorance. We can cure ignorance.

Depending on the speaker model, you may be able to repair the original speaker and voice coil. Often those old speakers had an internal spider that was supported by a center screw, or a phenolic external spider suspension. Re-coners won't be able to replace it, and they'll probably botch up your speaker. Some good ones are capable of re-using the original. If you could e-mail me some pictures of yoru speaker, I could go about helping you repair it. Many of those older speakers were disassemblable. Often the outside edge of the cone had a ring attached with screws, and almost always the spider was attached with one or more screws. This kind of cone-voice coil assembly is very easy to remove. With those where only the center is removable with screws, the outside edge can be removed by soaking the glue joint with either acetone or water. You must be careful not to get the cone wet. Again, sending me pictures of the cone will really help a lot.

Often enough the flex wires that go from the voice coil to the connection terminals have become faulty. It is easy to either repair the break, or replace the flex wires. Sometimes a voice coil will break internally. Sometimes it is an easy fix and sometimes it is not. Aluminum voice coils are particularily troublesome, since aluminum cannot be soldered. Crimps are used, and corrosion ruins the connection.

If you can find a speaker re-coner that will repair the speaker to original specs, then go for it. If not, I recommend that you attempt to repair the speaker first, before allowing a re-coner to butcher the original suspension. Also, Peter has pointed out a source for inexpensive yet very nice speaker cones (www.electronix.com .... speaker accessories). If your cone happens to be in very bad shape, the replacement cones may work very well for you (they won't be authentic, but will be very nice). Often the speakers made when Atwater Kent was in business had rugged cones, but sometimes they fail. Flexible edges made of rubber, leather, or rubberized cloth, are a fairly easy fix, when they become hard and brittle. Bass improvement is remarkable.

To e-mail me pictures, drag your mouse over my name at the upper left portion of this screen. When it turns light blue, click on it.

T.

Well I tooked the speaker apart and found both coil wires broke under the tape on the back side of the speaker and I repaired them and put the speaker back together and so far so good.
Thanks for all the help.

Terry N
:Depending on the speaker model, you may be able to repair the original speaker and voice coil. Often those old speakers had an internal spider that was supported by a center screw, or a phenolic external spider suspension. Re-coners won't be able to replace it, and they'll probably botch up your speaker. Some good ones are capable of re-using the original. If you could e-mail me some pictures of yoru speaker, I could go about helping you repair it. Many of those older speakers were disassemblable. Often the outside edge of the cone had a ring attached with screws, and almost always the spider was attached with one or more screws. This kind of cone-voice coil assembly is very easy to remove. With those where only the center is removable with screws, the outside edge can be removed by soaking the glue joint with either acetone or water. You must be careful not to get the cone wet. Again, sending me pictures of the cone will really help a lot.
:
:Often enough the flex wires that go from the voice coil to the connection terminals have become faulty. It is easy to either repair the break, or replace the flex wires. Sometimes a voice coil will break internally. Sometimes it is an easy fix and sometimes it is not. Aluminum voice coils are particularily troublesome, since aluminum cannot be soldered. Crimps are used, and corrosion ruins the connection.
:
:If you can find a speaker re-coner that will repair the speaker to original specs, then go for it. If not, I recommend that you attempt to repair the speaker first, before allowing a re-coner to butcher the original suspension. Also, Peter has pointed out a source for inexpensive yet very nice speaker cones (www.electronix.com .... speaker accessories). If your cone happens to be in very bad shape, the replacement cones may work very well for you (they won't be authentic, but will be very nice). Often the speakers made when Atwater Kent was in business had rugged cones, but sometimes they fail. Flexible edges made of rubber, leather, or rubberized cloth, are a fairly easy fix, when they become hard and brittle. Bass improvement is remarkable.
:
:To e-mail me pictures, drag your mouse over my name at the upper left portion of this screen. When it turns light blue, click on it.
:
:T.

Very good!!!!!!!!!! Good luck to you! Let us know how it sounds. Let me know if the speaker has a leather or rubber surround, and what its condition is. Majestic speakers had that design, and when it gets hard, bass suffers, but once the old rubberized cloth is replaced with fresh thin suede, the bass is out of this world.

T.

I think its is leather but still is pretty flexible. I did poke a hole in the cone when trying to disassemble the speaker but I repaired it with silicone and it don't sound too bad although I am not sure how they did sound.
Thanks again, Terry
:Very good!!!!!!!!!! Good luck to you! Let us know how it sounds. Let me know if the speaker has a leather or rubber surround, and what its condition is. Majestic speakers had that design, and when it gets hard, bass suffers, but once the old rubberized cloth is replaced with fresh thin suede, the bass is out of this world.
:
:T.

Well I found the speaker does crackel when played at higher volume. But at least it works. Don't know if the problem is it the speaker or if the radio has a concern. I really need to hear one that is working right because I don't know what the sound quality was back in 1929.
Thanks for any input.
Terry N
:Hello Everyone, Well I finally figured out why this radio would stop working. The speaker has a problem. I have a test speaker hooked up to where the small wires go to the speaker cone and it plays good. I ran across this by accidentally jumping across one of the big wire to the coil to one of the small wires on the cone and the radio would play for awhile and then quit again. I would short the two wires out again and it would play for awhile again. Now I hooked up this test speaker where the small wires go to the cone and the thing plays great. I am a newbie can someone please tell me how this speaker works. I am used to only two wires going to a speaker on modern radios but this one has four wires going to it. I sure would appreciate the education.
:Thanks Terry N
:

The sound quality in 1929 was excellent, though many radios lacked negative feedback, so they tended to have too much response in the mid-range. If you're curious about that one, I can give you a very simple little circuit that you can use in your radio. It'll make wonders happen.

Regarding crackling, though, you may have loose connections, or a wire that's bumping something metal (be sure that all wires have sleeves of flexible cloth on them). You could have a problem in the radio. Disconnect the speaker's voice coil and connect another speaker to the radio's output (transformer). If you still hear crackling, then the trouble is in the radio (or the output transformer). Such causes could be: arcing output transformer, arcing tubes (especially in the output), microphonic tubes (especially if a tube has a partial short or bad connection inside), arcing capacitors (most likely in the output section), faulty resistors and other connections, and possibly a few other things.

The radio should, with RF stating being the exception, produce clean and warm sound. It should be quite enjoyable with the wiring per factory specs (of course my negative feedback circuit can make it even better).

T.

I would like to have that negative feedback circuit. I did hook up a test speaker and the crackle is still present. I have a tube tester and all the tubes checked good. I hope the 45s are good for what I have seen on the price of them. I would really like to recap this radio but they are all in tar. I was going to replace the quality cap but it is in tar with the output transformer. These are really neat radios but are very hard to work on especially for a newbie but I am learning. Guess I am hooked now.
Thank again, Terry.
:The sound quality in 1929 was excellent, though many radios lacked negative feedback, so they tended to have too much response in the mid-range. If you're curious about that one, I can give you a very simple little circuit that you can use in your radio. It'll make wonders happen.
:
:Regarding crackling, though, you may have loose connections, or a wire that's bumping something metal (be sure that all wires have sleeves of flexible cloth on them). You could have a problem in the radio. Disconnect the speaker's voice coil and connect another speaker to the radio's output (transformer). If you still hear crackling, then the trouble is in the radio (or the output transformer). Such causes could be: arcing output transformer, arcing tubes (especially in the output), microphonic tubes (especially if a tube has a partial short or bad connection inside), arcing capacitors (most likely in the output section), faulty resistors and other connections, and possibly a few other things.
:
:The radio should, with RF stating being the exception, produce clean and warm sound. It should be quite enjoyable with the wiring per factory specs (of course my negative feedback circuit can make it even better).
:
:T.

Terry: I wouldn't add negative feedback or make other modifications until you get your crackling problem troubleshot.

You can pull the 45s, one at a time, to see if that affects the problem. Also, wiggle various tubes and other components to see if you can pinpoint something causing the noise.
Doug

:I would like to have that negative feedback circuit. I did hook up a test speaker and the crackle is still present. I have a tube tester and all the tubes checked good. I hope the 45s are good for what I have seen on the price of them. I would really like to recap this radio but they are all in tar. I was going to replace the quality cap but it is in tar with the output transformer. These are really neat radios but are very hard to work on especially for a newbie but I am learning. Guess I am hooked now.
:Thank again, Terry.
::The sound quality in 1929 was excellent, though many radios lacked negative feedback, so they tended to have too much response in the mid-range. If you're curious about that one, I can give you a very simple little circuit that you can use in your radio. It'll make wonders happen.
::
::Regarding crackling, though, you may have loose connections, or a wire that's bumping something metal (be sure that all wires have sleeves of flexible cloth on them). You could have a problem in the radio. Disconnect the speaker's voice coil and connect another speaker to the radio's output (transformer). If you still hear crackling, then the trouble is in the radio (or the output transformer). Such causes could be: arcing output transformer, arcing tubes (especially in the output), microphonic tubes (especially if a tube has a partial short or bad connection inside), arcing capacitors (most likely in the output section), faulty resistors and other connections, and possibly a few other things.
::
::The radio should, with RF stating being the exception, produce clean and warm sound. It should be quite enjoyable with the wiring per factory specs (of course my negative feedback circuit can make it even better).
::
::T.

True that. You should definitely replace all original caps. Your crackling problem isn't due to the lack of negative feedback. It's due to a failing component. Your radio will sound pretty good as-is, once all capacitors are replaced.

Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.

T.

Hi Thomas, I cleaned all the tube pins and sockets and it sounds better. I stuck it back in the cabinet and I am enjoying listening to it a low volume it sounds pretty good. I have all the caps but I am afraid to try and tackle that job base on some of the feedback I got when I first got the radio. I would like to recap it and I actually made a replacement for the filter can on a PC board but then I was told there may be a choke or other components in there so I gave up. If I try and tackle this would you recommend melting the tar out of each component so I can see what’s in there and replace the caps and then what do you use in place of the tar? I don't want to ruin this radio but it does have the balloon type 45s I could always sell. Just kidding and any advice would be appreciated. Thanks, Terry N
:True that. You should definitely replace all original caps. Your crackling problem isn't due to the lack of negative feedback. It's due to a failing component. Your radio will sound pretty good as-is, once all capacitors are replaced.
:
:Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
:
:T.

I would suspect the "quality condenser" or audio output xfmr since they see high voltage, which increases with volume. You could temporarily haywire a substitute push-pull xfmr and "quality" cap to see if that makes the problem go away. If it does, then you've pinpointed the problem.

I have an AK 55 with all its original caps, including the power-supply filter caps - and it works fine. I know that the usual advice is to replace all caps, but with this particular set, if you can avoid this it would be nice. Once you start removing the tar, then it's easy to ruin the filter choke, etc.
Doug

:Hi Thomas, I cleaned all the tube pins and sockets and it sounds better. I stuck it back in the cabinet and I am enjoying listening to it a low volume it sounds pretty good. I have all the caps but I am afraid to try and tackle that job base on some of the feedback I got when I first got the radio. I would like to recap it and I actually made a replacement for the filter can on a PC board but then I was told there may be a choke or other components in there so I gave up. If I try and tackle this would you recommend melting the tar out of each component so I can see what’s in there and replace the caps and then what do you use in place of the tar? I don't want to ruin this radio but it does have the balloon type 45s I could always sell. Just kidding and any advice would be appreciated. Thanks, Terry N
::True that. You should definitely replace all original caps. Your crackling problem isn't due to the lack of negative feedback. It's due to a failing component. Your radio will sound pretty good as-is, once all capacitors are replaced.
::
::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
::
::T.

Hi Doug,
I did wire in a quality cap and it did not help. I don't have xfmr to temp in but I do have a Eico 147A signal tracer that has test terminals labeled test amp can I use it?
Thanks, Terry N
:I would suspect the "quality condenser" or audio output xfmr since they see high voltage, which increases with volume. You could temporarily haywire a substitute push-pull xfmr and "quality" cap to see if that makes the problem go away. If it does, then you've pinpointed the problem.
:
:I have an AK 55 with all its original caps, including the power-supply filter caps - and it works fine. I know that the usual advice is to replace all caps, but with this particular set, if you can avoid this it would be nice. Once you start removing the tar, then it's easy to ruin the filter choke, etc.
:Doug
:
:
::Hi Thomas, I cleaned all the tube pins and sockets and it sounds better. I stuck it back in the cabinet and I am enjoying listening to it a low volume it sounds pretty good. I have all the caps but I am afraid to try and tackle that job base on some of the feedback I got when I first got the radio. I would like to recap it and I actually made a replacement for the filter can on a PC board but then I was told there may be a choke or other components in there so I gave up. If I try and tackle this would you recommend melting the tar out of each component so I can see what’s in there and replace the caps and then what do you use in place of the tar? I don't want to ruin this radio but it does have the balloon type 45s I could always sell. Just kidding and any advice would be appreciated. Thanks, Terry N
:::True that. You should definitely replace all original caps. Your crackling problem isn't due to the lack of negative feedback. It's due to a failing component. Your radio will sound pretty good as-is, once all capacitors are replaced.
:::
:::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
:::
:::T.

Did you disconnect the original "quality" cap or just shunt a new one across its terminals? The latter won't do it.

The Eico 147a, I think, isn't set up for push-pull outputs.
Doug

:Hi Doug,
:I did wire in a quality cap and it did not help. I don't have xfmr to temp in but I do have a Eico 147A signal tracer that has test terminals labeled test amp can I use it?
:Thanks, Terry N
::I would suspect the "quality condenser" or audio output xfmr since they see high voltage, which increases with volume. You could temporarily haywire a substitute push-pull xfmr and "quality" cap to see if that makes the problem go away. If it does, then you've pinpointed the problem.
::
::I have an AK 55 with all its original caps, including the power-supply filter caps - and it works fine. I know that the usual advice is to replace all caps, but with this particular set, if you can avoid this it would be nice. Once you start removing the tar, then it's easy to ruin the filter choke, etc.
::Doug
::
::
:::Hi Thomas, I cleaned all the tube pins and sockets and it sounds better. I stuck it back in the cabinet and I am enjoying listening to it a low volume it sounds pretty good. I have all the caps but I am afraid to try and tackle that job base on some of the feedback I got when I first got the radio. I would like to recap it and I actually made a replacement for the filter can on a PC board but then I was told there may be a choke or other components in there so I gave up. If I try and tackle this would you recommend melting the tar out of each component so I can see what’s in there and replace the caps and then what do you use in place of the tar? I don't want to ruin this radio but it does have the balloon type 45s I could always sell. Just kidding and any advice would be appreciated. Thanks, Terry N
::::True that. You should definitely replace all original caps. Your crackling problem isn't due to the lack of negative feedback. It's due to a failing component. Your radio will sound pretty good as-is, once all capacitors are replaced.
::::
::::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
::::
::::T.

Hi Doug,
Thats the problem the quality cap is in the can with the audio output xfmr so I did not disconnect it.
I thinking about trying to get the xfmr out of the can though.
Thanks again,
Terry N
:Did you disconnect the original "quality" cap or just shunt a new one across its terminals? The latter won't do it.
:
:The Eico 147a, I think, isn't set up for push-pull outputs.
:Doug
:
::Hi Doug,
::I did wire in a quality cap and it did not help. I don't have xfmr to temp in but I do have a Eico 147A signal tracer that has test terminals labeled test amp can I use it?
::Thanks, Terry N
:::I would suspect the "quality condenser" or audio output xfmr since they see high voltage, which increases with volume. You could temporarily haywire a substitute push-pull xfmr and "quality" cap to see if that makes the problem go away. If it does, then you've pinpointed the problem.
:::
:::I have an AK 55 with all its original caps, including the power-supply filter caps - and it works fine. I know that the usual advice is to replace all caps, but with this particular set, if you can avoid this it would be nice. Once you start removing the tar, then it's easy to ruin the filter choke, etc.
:::Doug
:::
:::
::::Hi Thomas, I cleaned all the tube pins and sockets and it sounds better. I stuck it back in the cabinet and I am enjoying listening to it a low volume it sounds pretty good. I have all the caps but I am afraid to try and tackle that job base on some of the feedback I got when I first got the radio. I would like to recap it and I actually made a replacement for the filter can on a PC board but then I was told there may be a choke or other components in there so I gave up. If I try and tackle this would you recommend melting the tar out of each component so I can see what’s in there and replace the caps and then what do you use in place of the tar? I don't want to ruin this radio but it does have the balloon type 45s I could always sell. Just kidding and any advice would be appreciated. Thanks, Terry N
:::::True that. You should definitely replace all original caps. Your crackling problem isn't due to the lack of negative feedback. It's due to a failing component. Your radio will sound pretty good as-is, once all capacitors are replaced.
:::::
:::::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
:::::
:::::T.

Agree w/Thomas - don't buy replacement tubes with the idea that'll solve your problem. Seldom does.

ST-shaped 45s are more economical, for sure. Even better, for pricey tubes, go with used, tested tubes.

::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
::
::T.

Terry, the 147A can be used to trace that noise/crackle. Do you have the user manual? It has a good explaination of how to use it.The caps-in-cans are usually in a high temp wax (they didn't use tar) and can be melted out. After re-stuffing can you can use silicone chaulking to hold componenets in place you do not have to refill.From your original post it appears that you were placing the voice coil across the B+ and may have been arc welding those wires together temporarily, then they would fail again.
pl

:Agree w/Thomas - don't buy replacement tubes with the idea that'll solve your problem. Seldom does.
:
:ST-shaped 45s are more economical, for sure. Even better, for pricey tubes, go with used, tested tubes.
:
:::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
:::
:::T.

I do have the manual and will do that. I already built a filter cap assembly on a PC board and was going to take the cap can out of the brown box and just put that in place of it but was told there are more components in the can than just the caps?
Thanks, Terry N
: Terry, the 147A can be used to trace that noise/crackle. Do you have the user manual? It has a good explaination of how to use it.The caps-in-cans are usually in a high temp wax (they didn't use tar) and can be melted out. After re-stuffing can you can use silicone chaulking to hold componenets in place you do not have to refill.From your original post it appears that you were placing the voice coil across the B+ and may have been arc welding those wires together temporarily, then they would fail again.
:pl
:
:
:
::Agree w/Thomas - don't buy replacement tubes with the idea that'll solve your problem. Seldom does.
::
::ST-shaped 45s are more economical, for sure. Even better, for pricey tubes, go with used, tested tubes.
::
::::Type 45 tubes in the ST version aren't that expensive. You can find them all the time on eBay. Going for the globe type gets pricy. If your 45s work well otherwise, you can find out if they are causing trouble by tapping and bumping them. If there's a short or loose connection inside, you'll hear it (could also be a bad socket connection). More likely a capacitor or resistor is arcing when you turn the radio up high. Loud singals create large voltage fluctuations, which can cause arcing, if a component is failing.
::::
::::T.

As Doug said, you can't parallel the old cap with a new one to see if the old one is failing. Obtain a push-pull transformer designed for 45 tubes, and wire the new cap to that. Disconnect the old transformer and cap assembly and test the amplifier with the new one.

As Planigan also suggested, there is a device for testing the radio. You might try testing each stage to locate the trouble. One other method would be to take a signal generator and test the radio at high volume, each stage at a time. As each stage is checked, it is then disconnected, as you move on to the next stage. When you get to the audio stages, use your CD player through some .05 MFD caps. I kind of feel that the trouble is in the audio section, though. It only seems logical, especially since it only happens at high volumes.

Tar can be removed by soaking in gasoline or mineral spirits. I don't recommend soaking cans containing transformers in gasoline or mineral spirits, though supposedly you can with good results. I have cleaned motors before using those solvents. They usually don't affect enamel. If there is a way to suspend everything without the tar, I recommend not filling the cans with anything at all. That will make future repairs easier. However, there are some cases where the tar acts as a support for terminals and things. I've never owned an AK radio, so I don't know about those.

T.

Hi Thomas,
The only push pull audio transformer I can find is at Radio Daze. They have several universal ones but I do not know which one to pick. They do not list one for the 45 tubes? How do I choose which one I need?
Thanks again, Terry N
:As Doug said, you can't parallel the old cap with a new one to see if the old one is failing. Obtain a push-pull transformer designed for 45 tubes, and wire the new cap to that. Disconnect the old transformer and cap assembly and test the amplifier with the new one.
:
:As Planigan also suggested, there is a device for testing the radio. You might try testing each stage to locate the trouble. One other method would be to take a signal generator and test the radio at high volume, each stage at a time. As each stage is checked, it is then disconnected, as you move on to the next stage. When you get to the audio stages, use your CD player through some .05 MFD caps. I kind of feel that the trouble is in the audio section, though. It only seems logical, especially since it only happens at high volumes.
:
:Tar can be removed by soaking in gasoline or mineral spirits. I don't recommend soaking cans containing transformers in gasoline or mineral spirits, though supposedly you can with good results. I have cleaned motors before using those solvents. They usually don't affect enamel. If there is a way to suspend everything without the tar, I recommend not filling the cans with anything at all. That will make future repairs easier. However, there are some cases where the tar acts as a support for terminals and things. I've never owned an AK radio, so I don't know about those.
:
:
:
:T.

An AC impedance around 4,000 ohms will be fine. That should be 4,000 ohms per tube, not across the entire winding. AES also sells push-pull transformers. Your universal transformers should work well. Even one with 2,500 ohm impedances would work alright.

T.

Not sure what speaker you're going to be using - but I'd go with something inexpensive, say Hammond HX-125J, $17.60 from RadioDaze. You'll have some different taps on the xfmr to play with and see which sound the best.

For push-pull output, the output xfmr needs to have a center tap. No sense getting a xfmr with "ultra-linear" taps, which you don't need.
Doug

:Hi Thomas,
:The only push pull audio transformer I can find is at Radio Daze. They have several universal ones but I do not know which one to pick. They do not list one for the 45 tubes? How do I choose which one I need?
:Thanks again, Terry N