Nashville 112 - No Ground Switch?

Richard Sinkler · From: aka: Rusty Strings -- Missoula, Montana

My NV 400 has a ground switch, but the NV 112 doesn't. If I was to be singing into a mic while touching my guitar, I assume I could potentially get shocked. Why would they not put a ground switch on the 112?
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Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting.

Larry Dering · From: Missouri, USA

Richard, I have seen very few amps with the polarity switch especially on most modern amps. I don't know the answer because like you I have been hit with the shock on older tube Twins. I quickly learned to use a socket tester and confirm polarity at the outlets.

Bill A. Moore · From: Silver City, New Mexico, USA

All "modern" amps have to be properly grounded, so there is no need for a "ground" switch.

Ricky Davis · From: Bertram, Texas USA

Yes just like Bill said; the Amps are fine. It is the other areas not grounded that will haunt you. Like the power strip may not have a Ground Prong; or extension cord is not grounded or old wiring in club/house/...etc that is not grounded...etc.
So check all that..ha...LOL.
Ricky
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Ricky Davis
Email Ricky: sshawaiian2362@gmail.com

Jerry Overstreet · From: Louisville Ky

The 400 to which Richard refers has a 3 position polarity switch + - or o. [pos, neg, or neutral]. So how does this differ from a ground switch or a ground lift switch? Just asking for my own information.

Bill A. Moore · From: Silver City, New Mexico, USA

Peavey did the same as the 70's Fender amps, either leg, (+ -) shorted to ground through a capacitor, or open (0).
It may have been a transition thing as folks were used to flipping switches, or rotating plugs in the 60's two wire amps.

Richard Sinkler · From: aka: Rusty Strings -- Missoula, Montana

Interesting stuff. Thanks.
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Carter D10 8p/8k, Dekley S10 3p/4k C6 setup,Regal RD40 Dobro, Recording King Professional Dobro, NV400, NV112,Ibanez Gio guitar, Epiphone SG Special (open D slide guitar) . Playing for 54 years and still counting.

David Ball · From: North Carolina High Country

Pat Chong · From: New Mexico, USA

Hi Richard,

"rotating plugs" as Bill had brought out, was done with old style (60's) wiring.

Plugs today are "polarized" in that they fit only one way, or with the grounded plug, which again, will fit only one way. That way the wiring (to the amplifier) is correct and a polar switch is not needed, because you can't rotate the plug.

That the NV400 still has it may have been a "transition thing" (or to compensate for bad wiring???)

Pat.

Jerry Overstreet · From: Louisville Ky

Guess I'm just slow at grasping this thing. All NV400 and earlier Peavey amps all used 3 prong grounded lug plugs.

It sounds as though you guys are saying the switch has no function, but in fact it does. If you had hum at one position, swithcing to another selection would cure it.

I don't have a huge understanding of electronics, I admit, I'd just like to understand from a layman's point of view the function of the 3 way switch on devices with 3 prong grounded plugs.

Also, a lot of my gear has a ground lift switch, so how does that work to keep the gear grounded safely? Just trying to wrap my head around this stuff. I'm really more familiar with DC voltage v. AC, but I do have some understanding of that also as I've done a little house plug wiring. The hot, neutral and bare wire ground.

I'm familiar with switching blades on the old 2 blade plugs. I understand how that reverses polarity, I think.

Bill A. Moore · From: Silver City, New Mexico, USA

The switch adds a capacitor to ground between the "hot", "neutral", or neither. I suspect an attempt to filter the power to some extent. Does it work?
With modern wiring the dedicated ground ensures that if the "hot" leg ever shorts to the chassis, the potential is never going to energize your instrument. I have a DI box with a "ground lift" that opens the "shield" wire on the XLR. My Amp is still grounded, as well at the mixer or whatever the destination equipment is, but sometimes it's necessary to keep hum down.

Ron Pruter · From: Arizona, USA

I know a couple famous people from the 60's got killed that way. One was one of the Yardbirds.. Can't remember the second. RP
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Emmons SKH Le Grande, '73 Fender P/J bass, Tick tack bass, Regal high strung, USA Nashville 112.

Richard Sinkler · From: aka: Rusty Strings -- Missoula, Montana

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