Touching signal wires

[jared555]

Is there any risk of damage to the electronics of an amplifier when either the signal wire comes in contact with your skin or with something that is grounded? (and you get that oh so fun humming sound) or is it just a risk of blowing the speakers?

 

[highfigh]

The risk of damage depends on which circuit is touched and where it is in the circuit. Some, if grounded will do nothing more than shunt the signal to ground and make it disappear. Others, like at the speaker output terminals, will cause that circuit to pass infinite current (theoretically) and will kill that stage. In some amplifiers, it will take out even more than that. It's not a good idea to use any part of your body to touch the circuits directly. It can be relatively safe but under the right circumstances it can be lethal, like in a tube amp when you contact the plate circuitry which can carry well over 300VDC. At no time is it a good idea to touch any circuit with one hand and the chassis with any other part of your body, especially if it's on the other side of your body from that hand. Touching the live circuit with one hand and the chassis with the same arm can be bad if the voltage and current are high enough but the current isn't passing through your heart- it doesn't take much to stop a heart.

 

[jared555]

I am talking about the signal prong of an RCA jack when it comes in contact with your skin or anything grounded to earth.

I do know that the internal circuitry of components definitely is lethal, quite possibly even after it has been unplugged.

The reason I was asking is I was wondering if it is technically safe (other than static discharge) to hook up a dvd player, etc. when the system is turned on even with the amplifier at its lowest output.

 

[Rickster71]

The reason I was asking is I was wondering if it is technically safe (other than static discharge) to hook up a dvd player, etc. when the system is turned on even with the amplifier at its lowest output.

It's best to always shut off electronic equipment when hooking up or disconnecting.
RCA cables carry low voltage signals. Powering equipment down is save delicate internal electronics

 

[markw]

This cannot be emphasized enough.

It's best to always shut off electronic equipment when hooking up or disconnecting!!!

Aside from the annoying hum and possible damage, if you do this with speaker cables and they should happen to touch, even for an instant, it could result in a very expensive lesson.

 

[jared555]

Aside from the annoying hum and possible damage, if you do this with speaker cables and they should happen to touch, even for an instant, it could result in a very expensive lesson.

The only cables I typically connect when equipment is powered up is the signal wires and I try to hook up the input after the output so there is less of a chance of static discharge frying an audio input.

I never connect/disconnect live speaker outputs intentionally (1/4" speaker connectors seem designed for accidentally disconnecting)

Not sure but I think I have triggered protection circuitry plugging in headphones into the 1/4" jack on my onkyo receiver which is a little surprising.