1935 GE Model A-53 AM/SW Tombstone Radio

[Electronic M]

You could try bypassing the bucking coil or reversing the leads and see if hum improves.

[vortalexfan]

Originally Posted by Electronic M

You could try bypassing the bucking coil or reversing the leads and see if hum improves.

How would I do that? Which wires go to the hum bucking coil? I'm asking because I don't want to accidentally cut the wrong wires.

[vortalexfan]

I'm guessing the hum bucking coil is the black and white wires coming out of the coil on the back of the speaker shown in the picture below?

[vortalexfan]

OK, so a little update, I removed the original speaker from the cabinet and replaced the original speaker plug with the one from my parts unit, and hooked the original speaker up to the radio with it outside the cabinet and no hum! So was it maybe something weird with the old speaker plug and something weird with the cabinet?

[Kevin Kuehn]

[QUOTE=vortalexfan;3238193]I'm guessing the hum bucking coil is the black and white wires coming out of the coil on the back of the speaker shown in the picture below?[/Q

I'm not familiar with that radio, but I'd guess the black and white wires are L16( the speaker field). The humbucking coil is a separate coil(likely sandwiched to one end of L16), that is wired in series with the voice coil. Reversing the field could have the same result as reversing the hum bucking coil, resulting in more hum. The way to figure that out is to try reversing it. Whichever way produces less hum is correct.

[vortalexfan]

[QUOTE=Kevin Kuehn;3238202]

Originally Posted by vortalexfan

I'm guessing the hum bucking coil is the black and white wires coming out of the coil on the back of the speaker shown in the picture below?[/Q

I'm not familiar with that radio, but I'd guess the black and white wires are L16( the speaker field). The humbucking coil is a separate coil(likely sandwiched to one end of L16), that is wired in series with the voice coil. Reversing the field could have the same result as reversing the hum bucking coil, resulting in more hum. The way to figure that out is to try reversing it. Whichever way produces less hum is correct.

Ok, so I'm not sure what would be different between the speaker being in the cabinet and out of the cabinet but with the speaker out of the cabinet the hum is non-existent, and I'm not sure if this would of affected it or not but I did replace the old broken speaker plug.

[Kevin Kuehn]

Partially because having the speaker on a baffle board allows it to reproduce the 60 hz frequency more efficiently. Without the cabinet the wave coming off the back of the cone partially cancels the wave off the front.

[vortalexfan]

Originally Posted by Kevin Kuehn

Partially because having the speaker on a baffle board allows it to reproduce the 60 hz frequency more efficiently. Without the cabinet the wave coming off the back of the cone partially cancels the wave off the front.

OK, well I'm going to try putting the speaker back into the cabinet and hook it up to the radio again and see if it still hums.

[vortalexfan]

OK, so a little update, it was definitely the original speaker that was bad (bad humbucking coil) because I installed the speaker from the parts radio like this one, and it for sure was not humming whereas the original speaker that came with this radio did hum, in fact when I looked at the parts radio speaker and the original speaker for this radio, it actually looks like the original speaker was maybe missing its humbucking coil (it only had two wires coming out of the field coil whereas the parts speaker had 4 wires coming out of the field coil.)

So now I can officially say that this radio is fixed, unfortunately though the parts radio's speaker was slightly smaller than the original speaker was, so I had to modify it slightly to make it fit in the cabinet.