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Topic: Odd Speaker Cable Question |
Rick Abbott
From:
Indiana, USA
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Posted 2 Dec 2019 6:12 pm |
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I say "odd" because I have spent hours using Google to search for an answer and must not be smart enough to ask the question in a way that will get ANY information. It's either that or no one has ever asked this question:
Can I use a 4-conductor wire to make a cord that is 2 mono quarter inch on one end and a single stereo quarter inch on the other by sending one hot to tip, and the other to the ring and tying the grounds into the sleeve? Like an insert cable, only a speaker cable instead.
I have a 2 channel tube power amp that I want to use to power a Blackface Bassman cabinet. I want to make it stereo, but don't want to drill another hole in it. So, I wondered if I could replace the jack with a stereo jack and run the above cable from the amp.
My gut tells me there will be an issue with the grounding because it's two independent signals, though the channels are earth-grounded on the same plug because they are in the same amp. I'm pretty dumb about this sort of thing. Thanks for any help.
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RICK ABBOTT
Sho~Bud D-10 Professional #7962
Remington T-8, Sehy #112
1975 Peavey Pacer 1963 Gibson Falcon |
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Brian Hollands
From:
Geneva, FL USA
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Posted 2 Dec 2019 6:40 pm
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You can't make a mono amp stereo. If its an old Bassman in question, it does have two seperate pre amps but those inputs are summed in the power amp. For the amp to be stereo it must have two seperate output transformers.
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'81 Sho-bud LDG, 2 EMCI's |
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Gabriel Edell
From:
Hamilton, Ontario
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Posted 2 Dec 2019 7:43 pm
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It sounds like you want to do the following:
-Wire a two-speaker cab so that the speakers are wired independently (not in series or parallel) and share a common stereo input jack with a common solder connection for one of each speaker's leads.
-Use a dual-mono to stereo (i.e. "Y cable") to feed each side of a stereo power amp to a speaker in the cab.
Is this correct? If so, no, you can't do that. Speakers can't share a common ground - they don't use a ground at all, just negative and positive voltage.
Your best bet would be to try to find a 4-conductor jack/plug combination so you can have independent connections for each of the four leads. But I don't know if you'd find one small enough to fit in the hole currently occupied by the cab's input jack. Since that's a vintage cab, it would probably be safer to buy a newer cab that's already wired for stereo.
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GFI S-10 P U, Moyo Volume, Fender Steel King, Fender 5F4 Super-Amp |
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Rick Abbott
From:
Indiana, USA
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Posted 3 Dec 2019 6:05 am
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| Gabriel Edell wrote: |
It sounds like you want to do the following:
-Wire a two-speaker cab so that the speakers are wired independently (not in series or parallel) and share a common stereo input jack with a common solder connection for one of each speaker's leads.
-Use a dual-mono to stereo (i.e. "Y cable") to feed each side of a stereo power amp to a speaker in the cab.
Is this correct? If so, no, you can't do that. Speakers can't share a common ground - they don't use a ground at all, just negative and positive voltage.
Your best bet would be to try to find a 4-conductor jack/plug combination so you can have independent connections for each of the four leads. But I don't know if you'd find one small enough to fit in the hole currently occupied by the cab's input jack. Since that's a vintage cab, it would probably be safer to buy a newer cab that's already wired for stereo. |
This is helpful. I thought speakers needed their own negative, or something, so my gut feeling was right.
Thank you very much!
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RICK ABBOTT
Sho~Bud D-10 Professional #7962
Remington T-8, Sehy #112
1975 Peavey Pacer 1963 Gibson Falcon |
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ajm
From:
Los Angeles
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Posted 3 Dec 2019 10:55 am
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| Brian Hollands: He is asking the question about a Bassman cabinet, not a Bassman amp/head. |
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Donny Hinson
From:
Glen Burnie, Md. U.S.A.
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Posted 8 Dec 2019 5:47 pm Re: Odd Speaker Cable Question
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| Rick Abbott wrote: |
Can I use a 4-conductor wire to make a cord that is 2 mono quarter inch on one end and a single stereo quarter inch on the other by sending one hot to tip, and the other to the ring and tying the grounds into the sleeve? Like an insert cable, only a speaker cable instead.
I have a 2 channel tube power amp that I want to use to power a Blackface Bassman cabinet. I want to make it stereo, but don't want to drill another hole in it. So, I wondered if I could replace the jack with a stereo jack and run the above cable from the amp.
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The short answer is "yes"...if the amp's speaker outputs have a common ground. (Most amps do.) Running two separate speakers with only 3 wires (for stereo) is something that's been done many times. The common ground would go to one of the terminals on each speaker, and the two "hots" would go to the two other open terminals, one on each speaker.
| Quote: |
| ...If so, no, you can't do that. Speakers can't share a common ground - they don't use a ground at all, just negative and positive voltage. |
That's simply not true. On almost all amps, one side of the speakers is common-grounded (through the standard 1/4", 2-conductor, jacks that are mounted in the chassis).
Last edited by Donny Hinson on 9 Dec 2019 7:07 pm; edited 1 time in total |
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Rick Abbott
From:
Indiana, USA
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Posted 9 Dec 2019 5:51 pm
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The amp is a TubeWorks 4250 ProValve. I'll have to take the top off of it and see what the grounding looks like. I've never had it open. I am about to put some new tubes in it and need to see how it is set up for biasing the output tubes anyway...so I'll check that out!
Thanks
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RICK ABBOTT
Sho~Bud D-10 Professional #7962
Remington T-8, Sehy #112
1975 Peavey Pacer 1963 Gibson Falcon |
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Bill Burch
From:
California, USA
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