Amp and speaker hiss - do I go back an AVR? Jul 11, 2017 18:51:26 GMT -5
Post by alucard on Jul 11, 2017 18:51:26 GMT -5
Jul 11, 2017 9:35:53 GMT -5 @texzick said:Sorry I could not get back yesterday.
Our intent is to check the wall plug you are using for power.
Everything in the system is referenced to 0 volts- circuit ground in electronics- and need to know if there is voltage floating on that reference to chassis ground.
1) check neutral to ground with equipment plugged in, but "off"
2) Then unplug everything, take neutral to ground readings again
3) plug in everything, turn "on" and check a third time.
Pls use a low setting on your meter, using 200vac setting may not show what we are looking for.
As I said on page 1, if there is voltage between the neutral- ground, there is a wiring problem. In a perfect world that reading should be 0 volts, but in reality, sometime there will be a small voltage there. The question is how much voltage. If there is 2-2.5 volts or more, you need a new line run because you can not find any tap offs someone may have added after the circuit was installed, or the wire gauge is undersized for the load it carries. If we are using that circuit to run a light or power tool, it's not a problem, but with electronics it's a big deal.
If you think about it, digital is 0 volts off, 5 volts on, a floating voltage of 2.5 volts or more on the reference will drive the processor nuts, causing intermittent problems.
In audio, a floating voltage on reference can be audible noise.
After I got the XPA-5, I installed a new 20 amp breaker & 12 gauge 3-wire to the plug because I also run a rear projection tv monitor off it.
The last thing I want is a supply line voltage fluctuating due to high current draw.
That line is called an "isolated line" because nothing is tapped off and only goes to one service outlet. In the business world that circuit will have an orange plug.
A dedicate line is one that has a dedicated hot (breaker) but the neutral-ground is shared with another circuit.
Most houses have all shared lines, meaning there is up to 3 outlets using one breaker & wires.
Usually shared lines are not an issue until there is high current draw or something with inductive load is spiking the line as the coil field collapses & re-energizes.
Busy day today, but I'll check back
@texzick , my results are below
Plugged in/off: 0.096v
Amp/Pre On: 0.244v