Running in and Warming Up
You’ve bought yourself a brand new car. You drive out the dealer gingerly, taking care not to over-rev it. Hey, it even says so in the manual, not that anyone except me ever reads them! Now everybody should know that cars need running in, this is to make sure the parts wear together evenly and smoothly. But do you know that audio equipment also needs running in?
Audio equipment consists of a range of items such as speakers, CD Players, amplifiers, pre-amps and more. Each has a different way of running in, some mechanically, others electrically or a combination. I am often asked how long something takes to run in. The answer isn’t always straightforward. Some items may run in faster than others and of course it can also depend on the level of quality and the level of complexity of the design.
CD, SACD and DVD players and the like are a mixture of mechanics and electronics. The mechanical parts of these units tend not to need much running in; laser sleds, laser lens focusing motors and disc spindle motors are all microprocessor controlled; any variations are corrected virtually instantaneously. For a turntable, this is often not the case. The belt will be a little tight to start with and cause some drag and since many motors are not microprocessor controlled, the speed variations (wow and flutter) will subside over time as the bearings, running gear and motor settle down.
The electronics will take some settling in as well. Capacitors probably take the longest to stabilise, some brands have been reported at taking many months to sound their best. Capacitors are used in the power supply for filtering noises and often in the signal path. The later are the most important as any problems here directly affect the signal, so they will have the biggest effect on the sound. Usually a few weeks will see them settle down as the chemical composition stabilises. Other electronic components can also take time but the differences are often not as great as with capacitors.
Amplifiers and Pre-Amps
These units generally have no moving parts so mechanically there is no issue. On the electronics side they are much the same as source units, however they may even be faster in running in due to the higher temperatures that amplifiers run at plus the circuitry in many cases is simpler so less parts need to run in.
Valve amplifiers, pre-amps and even valve CD players can take a while to run in. Firstly they almost always use large voltage capacitors to isolate the power from the signal and these can take longer than normal capacitors to run in. Valves themselves can also take some time to settle down, particularly new old stock (NOS) valves which are used as upgrades in some high-end brands. Valves probably need more warm up time when first switched on that any other type of equipment, so turn on the system about 1-2 hours beforehand.
Many people state that cables need run in periods as well. While I personally am undecided, there is a lot of anecdotal evidence that says they do, however I have yet to find a scientific explanation as to why. One hypothesis is that the metallic structure itself needs to settle down and stabilise, minute magnetic / electrostatic fields are formed in the cable structure. Either way, you can try it yourself when you next purchase a nice new set of cables.
These are probably the most important item that needs running in and I would say most people have certainly experienced it. From an electrical viewpoint, the crossover that divides up the high and low frequencies has capacitors and these, as in the other units mentioned before, will need some time to run in. The most crucial areas are the speaker drivers themselves. They are mostly mechanical and the suspension needs to loosen up. In woofers and many midranges, the suspension consists of the roll surround, the part you can often see around the edge which holds the outside of the cone in place and secondly the spider, the section underneath which holds the centre of the cone / voice coil in position. In tweeters these parts are either a lot smaller or non-existent, but they still have suspension, however it generally takes less time to run in than larger drivers. The materials used need to loosen, be they rubber, foam, paper or fabric.
How to Run-In Equipment
The easiest way is simply to find a piece of music that has a wide variety of styles and good dynamic range to work all the components well. (Make sure there are no high levels recorded that can damage or overload anything.) Put it on repat if possible and simply let it play. At first start at a low to medium volume level to as not to stress anything too early. After a few hours you can turn it up more and continue to do this gradually until normal listening levels or just above are reached. To run in loudspeakers faster some people place them facing each other, just a few centimetres apart. The theory is that the extra work the speakers have to do to “fight” against each other will speed up the process.
The first few hours will loosen up most items a reasonable amount; the next few days will probably do the majority. You will find that after this the improvements become smaller and smaller. It will vary with the type and brand of equipment; it really is impossible to say exactly how long. You will have to be the judge yourself.
Written by Leon Gross, originally published in Audio & Video Lifestyle magazine.
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