This from WeberVST (more respected than the other Weber):
3. You might find that some vintage speakers, particularly JBL and
Jensens, were reverse-polarized. This means that a plus voltage
on the plus-indicated terminal of the speaker will actually cause
the speaker to move in rather than out.
You will want to make a note of this or relabel it for your convenience.
Another point to be made here is that if a person is accustomed to
thinking a plus on the plus-indicated terminal causes the speaker to
move in rather than out, it should be noted that this thinking is
also correct. Again, the speaker is an AC device. The purpose of
characterizing and marking them is for the convenience of the user to
ensure they will be connected for proper acoustic phasing.
I'm pretty sure WeberVST has probably had to deal with this issue due to speaker phasing in multi speaker amps. As is "I need one new speaker for my Super Reverb." I suppose it's possible then that some "batches" of vintage Jensen speakers left the factory with the sticker on the wrong lug? Though I've never heard of a multi speaker amp that had Jensens of differing polarity as I would expect if this were true.
P.S. Not EVERYTHING in the Gerald Weber books is wrong. He did (does?) work on a lot of old Fenders. Even if his actual tech knowledge is questionable I think his experience may be accurate. But to concede... His tech knowledge is pretty poor.
3. You might find that some vintage speakers, particularly JBL and
Jensens, were reverse-polarized. This means that a plus voltage
on the plus-indicated terminal of the speaker will actually cause
the speaker to move in rather than out.
You will want to make a note of this or relabel it for your convenience.
Another point to be made here is that if a person is accustomed to
thinking a plus on the plus-indicated terminal causes the speaker to
move in rather than out, it should be noted that this thinking is
also correct. Again, the speaker is an AC device. The purpose of
characterizing and marking them is for the convenience of the user to
ensure they will be connected for proper acoustic phasing.
I'm pretty sure WeberVST has probably had to deal with this issue due to speaker phasing in multi speaker amps. As is "I need one new speaker for my Super Reverb." I suppose it's possible then that some "batches" of vintage Jensen speakers left the factory with the sticker on the wrong lug? Though I've never heard of a multi speaker amp that had Jensens of differing polarity as I would expect if this were true.
P.S. Not EVERYTHING in the Gerald Weber books is wrong. He did (does?) work on a lot of old Fenders. Even if his actual tech knowledge is questionable I think his experience may be accurate. But to concede... His tech knowledge is pretty poor.
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