Tagged: Electronics Restoration
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April 1, 2021 at 6:19 pm #16516
Doug Parker
CVRS MemberCannot know for sure on my Viking 48-74v – Is the speaker positive or negative lead connected to the frame ground?
I would assume it is the negative lead but not certain. Any help would be appreciated I have included the schematic.Attachments:
April 2, 2021 at 5:47 am #16518Alistair Thomson
Forum ParticipantI don’t really understand the question 🙂 unless you’ve dis-assembled the speaker drive unit. The schematic seems to indicate that the plug/socket has one thick connector and one thin one so the correct polarity is already guaranteed. If you have dis-assembled the drive unit then the way the speaker voice coil is connected is unimportant. It looks like the speaker chassis is grounded using the thick plug pin so if you connect the speaker with the radio switched off you should get continuity from the speaker chassis to the radio ground.
April 2, 2021 at 10:13 am #16519Doug Parker
CVRS MemberThe speaker wires were previously spliced and changed before I got the radio and that is why the larger and smaller diameter leads on the chassis that go to the speaker could be right or wrong. I am asking whether the speaker polarity lead running from the chassis frame grounded lead of the audio output transformer is the positive speaker lead or the negative? The speaker positive or negative polarity are almost never listed on the schematics on antique radio schematics like they are on modern amps so I want to be sure before I reinstall the speaker into the cabinet. At this point I would rather not assume. Thank you.
April 2, 2021 at 10:49 am #16520Alistair Thomson
Forum ParticipantIf you think about the voice coil, the polarity of the connection is irrelevant in a mono setup. IT’s just a oil and the audio will drive it just fine no matter what way round you connect it. It’s only of you have two or more speakers reproducing the same sounds that it matters, because you want both speakers moving in phase, but with one speaker it makes absolutely no difference.
April 2, 2021 at 7:39 pm #16522Doug Parker
CVRS MemberI had the radio playing and with clip leads I switched the speaker wires one way and then reversed them. There was a notable difference to the clarity and bass amount. I will just hook up the leads for the best sound. Thank you for your help.
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