Is it important or not to unplug hi-fi elements from the mains after switching off?
If the switch fully disconnects the power between the mains cable going into the back of the unit and the step-down transformer inside the unit (as it does in my amplifier) there is very little point in unplugging it, unless e.g. you are very paranoid that your house might be hit by lightning and somehow blow up anything left plugged in.
If the switch leaves the equipment in a standby state it is better to unplug it or switch off at wall, to help save the environment by wasting less power. Often the standby state is not so obvious for hifi equipment compared with TVs. But generally power is always being used by anything that will switch on with the remote or by pushing a button like the open/close button.
Thank you! That makes the situation clearer.
Agree with TedR, I'm no doubt a bit paranoid but there is always a miniscule risk of a transformer or component burning out when it is permanently powered up and although of course we have to leave much electrical equipment, 'fridges, timers etc permanently "on" I don't like to leave equipment on standby overnight or if I'm out for a longish period. The same goes for the mains plug mounted power supplies which give a low voltage output. There have been cases of these being subject to safety recalls due to overheating etc.
I don't think it's just lightning that can mess up your gear. If you live in a rural area hits on the power lines can be a problem. I was assured by people who know much more about it than me, that once you were fully switched off (i.e. not in standby mode) all was well. Where I live, power isn't that clean to begin with (surges, brown-outs etc.) and during storms we'll often get trees on the line or rockfall cutting it, causing power blips and complete outages. Coincidence or not, I've had amp, cd player, speaker and woofer breakdowns after these storms, once three pieces of equipment going at the same time.
I was also told, categorically by somebody who ought to know, that electrostatic speakers should be left charged at all times. Maybe, but when they're charged they're potentially attracting particles in the air and probably drying out the dust membrane, resulting in tiny tears or pinholes. Bottom line is, sooner rather than later you find yourself in for a serious repair bill.
When all's said and done the theorists are probably right, in theory, but it's you that's footing the bill if practice and theory don't match. I unplug everything or at least mains-protect it. Electronics repairs don't come cheap these days.
It is an extremely rare occurrence, but not totally unknown, for power line faults to deliver two live phases rather than a single phase plus a neutral. In the UK that would mean instead of a nominal 230 - 240 volts a subscriber would get around 400 - 420 volts which would blow all domestic equipment. There have been legal disputes with electricity supply companies over compensation when this has occurred (there is probably some small print hidden away somewhere in one's electricity supply contract about responsibilities for such occurrences).
We has exactly this happen in our office last month, a failure in the building 3 phase supply blew the lighting, the aircon and power supplies to VOIP phones and computers.
Interestingly, there was almost no other damage to computer equipment (or phones) and new power supplies repaired everything with no loss of data.
I have always left my Hi fi units on as I have read from a number of sources that equipment sounds better when warm. Also, some manufacturers of which Quad is a prime example i.e the 606 amp, locate on/off switches on the back which can be difficult to reach, say in equipment racks. I even have a Chord integrated amp with no on/off switch at all, only a standby button. Can anyone tell me whether any damage can be caused to equipment if it is left switched on with the supply being controlled at the socket? Can this give rise to a surge in the supply when the power is switched on?
It is extremely unlikey that you will get "phase" issues in the UK as domestic properties are only connected to one phase.