[LAU] Shielded electrical wiring for studio (or not)

[Glen MacArthur]

Len Ovens wrote:
> On Wed, 3 Jun 2015, David Christensen wrote:
>
>> On 06/02/2015 06:32 AM, Glen MacArthur wrote:
>>> ... I've received a few mic
>>> shocks to the lips over the years when I used to run a vintage amp
>>> without
>>> a ground (it only had a ground lift toggle switch)... It didn't take me
>>> long to upgrade the wiring to a fully grounded cord.. :)..
>>
>> I'm curious -- if an electric guitar amplifier has a two-conductor power
>> supply cord (with hot and neutral conductors only) and a "ground lift"
>> switch, what does the switch do?
>>
>>
>> Can you provide an example make and model that has a schematic available
>> on
>> the web?  For example:
>>
>>    http://www.thevintagesound.com/ffg/
>
> I don't know about ground switch, but some of them had a "hum" switch or
> something similar... flipped the ac lines. Sometimes the "neutral" was
> connected to chassis... which with no keying on the ac plug meant the
> chassis might just as easy be hot. Nobody has done that for a long time
> now. The idea was old and outdated 50 years ago. (probably before)
>
> --
> Len Ovens
> www.ovenwerks.net
>
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Len

Yes that's what it was, however the toggle switch itself said 'Ground' on
the back the amp chassis..

Both the bass player and I had vintage Traynor amps, he had a YBA-1 and I
had a YGM4 Studio Mate, If you google the model numbers you can find the
schematics, however a quick look didn't show me a schematic prior to 1973
but to my knowledge these amp models date back to the late 1960's. It
appears that the 1973 schematics show a chassis grounded plug..

In any case both of these amplifiers had ungrounded 2-prong molded plugs
and if the toggle was switched wrong with the wiring at whatever venue we
were playing at we would get shocks off of the microphones...lol

I heavily modified and sold mine to a nephew many years ago but Traynor
actually re-issued both of these amp models in recent years (with proper
electrical supplies). Had I known it was a classic... well hindsight is
always 20/20... To this day I still keep a respectable distance from
microphones when I sing...

Glen