240volts and ground hum problems.

[Paul Maddox]

Batz,


>The thing is that this
>gear was technically speaking, double insulated. IE: has only the 2 pins.
>Neutral and Active. Now from my understanding, this is illegal. If it's a
>metal chassis then it must be earthed.
>

errr, nope....
Double insulated just means there is no way a current could get from 
live/neutral to chasis.. the test, is to apply 3KV to the earth pin and test 
for leakage on the case.

>this happened on all the AKAI gear we owned at the time. From an X7000 thru
>S950. I don't remember if the apedgiator thing we had also did it. I got so
>sick of getting a boot off of the X7000 that I replaced the proprietary
>AKAI 2 pin mains connector for an IEC one. Connecting the Earth pin to the
>Chassis. It did not create a hum loop but did stop us getting a kick off it
>every time we tried to play it.
>

Thanks, I just got given a S700, I'll make sure I earth the chassis.

>It beats me how they could get away with stuff like that?
>

different regs....

>One could be forgiven for thinking that it was relying on the rack for
>earth but I know this is also illegal under Australian wiring rules. In
>fact you are supposed to have a separate ground wire to every separate
>metal part or the chassis. You are not supposed to rely on the fact that
>they are bolted together to form an earth.
>

This makes sense, think baout it.. JO bloggs the guitarist with his home 
made leads could have a nice 0v at the bottom of the rack and 200Vac at the 
top, kapow!


Just my twopenneth worth...
ALL my stuff the 0v of the supply is connected to the gound of th mains 
inlet.. ALL sockets have their own 0v connection to the circuit. I dont have 
a problem with mains hum :-)

Paul



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