For the faithful of the blog Ricable the concept of phase and out of phase will not be completely new. We have already dealt with it when we offered you a few tricksmost of the times free of charge, with which you can optimize the performance of the audio chain. In case of particularly detecting installations, to understand if they are in phase or in out of phase, the ear can be enough. The difficult thing is to "find out" which electronics are in phase and which are not. But let's start from the beginning, that is: what are phase and out of phase, and then we'll explain how you can carry out some tests to find the phase in your Hi-Fi system.
Phase and out of phase electronic audio
What does tuning the power supply mean? What powers our systems is the mains current, so a bad power supply can only lead to a less performing electronics, which will directly affect the sound. The current is 220 V in three contacts in our homes: earth (in the middle, and in this case we don't care), phase and neutral. In reality, an AC powered appliance will work in one direction or the other, especially if the electronics are not very delicate, like an oven or a fridge. In some cases it is important to insert the plug in the right way, and putting a Hi-Fi system in phase is just that. This is a problem not only for Hi-Fi, but also for other contexts, such as boilers. In any case, having just one device in out of phase will lead to having the whole system in out of phase. Not a small problem, if you consider that when the audio chain is all in phase there is a greater articulation of the low range, a sharper representation of the scene, a better focus and a more evident three-dimensionality. Two more premises: most of the devices have the phase in the right side; the first phase should be done with the mains distributor and the mains conditioner.
Find phase and out of phase in the wall socket
To find the phase and out of phase in the wall socket, you will need to take a screwdriver and insert it alternately into the side holes of the socket. We recommend that you take all necessary precautions before doing this operation.
You may also consider asking someone more experienced in this field to do it. When the phase finding screwdriver lights up, it means that we have touched the point through which the phase passes. Another more empirical solution is to open the socket; if our system is quite modern and made according to Italian standards, we will find three different colored cables: one blue (neutral), one yellow or green (ground) and a third of variable color (black, white, brown ...) which is precisely the phase. Now you can connect the power cable to the socket making sure that the two phases are corresponding.
Searching for phase and out of phase in the Hi-Fi system
How to find the phase of the amplifier in your Hi-Fi system, for example? A necessary condition is that each component must not be connected to the others by any kind of cable or connector, so only the power cable must be inserted. Once again, we invite you to carry out these operations with the utmost care, especially if your electric system is not equipped with a circuit breaker (on the contrary, if your electric system is not equipped with a circuit breaker, you should avoid to work on it!).
With the screwdriver
At this point, we can move on to the first useful method to find the phase in our electronics. First of all get a screwdriver phase finder, which costs a handful of euros. Connect only the power cord and turn on the device; use rubber insulating shoes to avoid grounding the phase finder reading, place the phase finder on a point of the chassis (for example a screw or a point not insulated by paint), being careful not to touch anything (otherwise you'll ground everything and it would be useless to make the measurement). Turn on the phase finder by placing a finger on the upper metal part. After that, notice the brightness of the phase detector. Now you have to turn the plug of the power cable and repeat the procedure, to see if the light intensity is lower or higher than the other side.
The appliance is in correct phase at the position on the plug where the light intensity of the phase finder is lower. Make a mark on the plug with a felt-tip pen or something else; the part of the plug just marked is the part that should be connected in phase with the wall socket. This measurement is subjective, as the brightness of the phase finder bulb depends on the electrical resistance of our body. For some people it might light up a lot, for others a little, for others still it might not light up at all. In the latter case you should switch to the second method to find the phase in your Hi-Fi system.
With the multimeter
As for the second method, the first thing you need to do is an electronic tester (we're talking about a little more than a ten euro expense). Connect the device as described in the first method. Set the tester's measurement value to mV AC. Place the test lead of the negative pole on a chassis screw not insulated by paint and the test lead of the positive pole on the hot pole of any RCA connector (preferably the output one) on the rear panel. Read the value on the tester and write it down. Then turn the plug over and repeat the measurement; the lower of the two values will correspond to the correct phase of the unit. Make a mark on the plug with a felt-tip pen or something else; the part of the plug just marked is the one that must be connected to the phase in the wall socket. This operation must be repeated on every appliance, provided it is always disconnected from the others.
The role of Hi-Fi power cables
All of the devices are now in phase, and you will only need to do this procedure again if you want to add new electronics to your audio chain. If you've done everything correctly, you'll notice that all the plugs of your devices will have the phase point that you've marked on the power strip. We would like to stress once again how an optimal power supply of your electronics can't help but contribute effectively to the restitution of a firm and transparent sound; to learn more, we refer you to to this article of ours. To have a solid and effective connection in your Hi-Fi system, instead, we suggest you to have a look at our power cables, handmade in Italy with first quality materials.