(metal) FX w/ built-in xfrmr: safety-ground or not?

[goosonique]

Tried them all .... btw even with the power off (240V here) on the echo unit and having pluged into an amp powered on it still hums!! I find it weird !! The echo not powered and there is still hum on through amp.  

[Basstyra]

I finally grounded my pedal :


The ground wire is screwed between the two parts of the box.

I need a power cable such as for amplifiers or computers, it's big, bulky, but well, it's a need, isn't it ?

[puretube]

a great improvement

[Paul Perry (Frostwave)]

a great improvement

Good to know you will still be with us for a while yet, Basstyra!  :wink:

[Basstyra]

:lol:

[H.Manback]

Closely related, I want to ask you guys something about electrical isolation with a transformer (in amps in this case).

The way I understand, the old radios which did not use a isolation transformer, and which did not have a safety ground wire, are unsafe because there is a 50/50 chance of the chassis (ground) being directly connected to the phase wire of the outlet. Touch the chassis and you make a closed circuit with the earth, right?

Now when you have a transformer in between the outlet and your power supply, if you were to touch the chassis, it could not make a closed circuit using you (unless you were to touch the other end of the power supply).

The safety ground then only serves as a protection for when for example a filter cap has shorted (still important, don't get me wrong).

Is this understanding correct?

[H.Manback]

Sorry for the early kick, but I really want to know if I'm thinking on the right track here.