Turn sub power off or not?

I

iabbott

Guest
Just bought myself an MJ Acoustics Pro50 to go with my Denon 1802 and KEF Q.35/85/95 setup. Really pleased, great sub.
Just wondering if I should turn the power off on the sub when I've finished using it.
Usually I just put the tv and amp on standby, but it's a bit of a pain having to reach round the back of the sub for the on/off switch everytime.
Any thoughts/experience?
Thanks
 

Jase

Distinguished Member
Always leave mine switched ON. Only switched OFF if its for long periods, holidays etc.
 
G

graham.myers

Guest
I turn mine off, but I've got easy access to it. I can here it humming and it gets on your t*t ends after a while

The light on the front goes from green to red when it cant see (hear!) a signal from the amp, but I wouldn't consider it standby

Mine is a Kef THX sub (TDM something)
 

dfield2000

Novice Member
I've had a MJ Acoustic Pro 50 for a couple of months now, and I've found that as soon as I switch the amp off it starts to buzz quite loudly. When you switch the amp back on it stops, even if the channel selected on the amp is not outputting any signal.

I'm using the crappy lead that came with the sub. Have you bought a new lead and if so which one and have you noticed a difference ?
 
I

iabbott

Guest
I've had no problems with buzzing/humming, when the amp is on or off. Might be a poor lead or a bad earth.
Salesman told me no leads were included, but managed to get a 5m black rhodium lead for £20. Haven't tried it with the standard "cheapo" lead.
 
J

juboy

Guest
As with most electronic equipment, it's probably best to leave your sub switched on. It seems to be amplifiers that benefit most from doing this and as the sub has it's own on-board amp I just tend to leave it on. Luckily I get no humming from mine, I dare say I'd turn it off if I did.
 

Hotblack

Banned
Originally posted by juboy
As with most electronic equipment, it's probably best to leave your sub switched on. It seems to be amplifiers that benefit most from doing this.....


Really? I've started to switch my amp off every night as my last one may have had an overheating problem. I say may because I told an engineer that the centre speaker had lost a lot of volume and he said that by leaving it on, it could over heat and dry out the solder joints (or something like that). Was he talking bollards then?

My amp is a Denon A10-SE (was Sony STR-DB940)
 

Reiner

Active Member
For safety reasons I would rather recommend to switch the sub completely off after use, i.e. disconnect it from the mains. Alternatively you could use a master-slave power socket.

Leaving an amplifier always on is common amongst audiophiles as they don't have to wait for the unit to warm up - something which mainly applies to tube amps.
As AV amplifiers are neither tube amps and most aren't that audiophile either I really don't see a point in leaving it on all the time, standby is IMHO totally sufficient. When I am not at home for a long period of time I disconnect everything.
 
J

juboy

Guest
Hotblack/Reiner - inefficiently designed valve, tube and class A amps can very often overheat and can also use a lot of electricity when turned on but not in use. For this reason, these amps are probably better turned off when not in use for more than two days at a time.

However, virtually all AV amps and onboard amps within subs will maintain a longer lifespan and sound slightly better if kept switched (unless going on holiday for 3 weeks etc.)

Unless faulty, your Denon A10-SE will not suffer from heat or being left on for long periods of time.

I do admit that leaving kit on stems from my hi fi days but have found the same applies to virtually all electronic kit. When I know I'm going to watch a DVD on a given evening, I will always turn the DVD player on and play the film through a few times with the TV off before using the player to actually watch the film later that day. I find it does give improvements, mainly to picture stability and the noise made by the actual DVD player itself. Suffice to say my AV amp is only turned off when I go on holiday.

The only times my hi fi pre and power amps are turned off is if my area suffers a power cut!
 
R

rob_w

Guest
I've always left my amps and subs on. I reckon that theres some truth in the " constant heating up/cooling from switching on/off can lessen the life of components" theory.......

Rob
 

Reiner

Active Member
Then I would argue the constant heat (as most amplifiers are always "amplifiying" when switched on, even there is no signal present) will shorten the lifespan.

Perhaps we should see it from an ecological point of view: safe the earth and yourself some money on the electricity bill - switch your gear OFF. ;)
 
J

juboy

Guest
Originally posted by Reiner
Then I would argue the constant heat (as most amplifiers are always "amplifiying" when switched on, even there is no signal present) will shorten the lifespan.

Does always being on shorten the lifespan of servers then?

The strain to all the components of electrical equipment when being turned on/off is far more wearing in the long term than the minimal disipation of energy involved in being left idle.
 

Reiner

Active Member
Does always being on shorten the lifespan of servers then?

a) I guess
b) Who knows?

My answer wasn't to be taken that seriously as I assume we are both assuming/guessing as I don't think anyone has ever conducted a study on that, let it be amplifiers or servers.
There is also quite a lot of electronic/electrical equipment which constantly switches but they also work for years, so I guess (again) in the end it might not be that obvious.

Well, I for myself rather not take the risk but reduce the power consumption by switching my stuff to stand-by or disconnecting it during my absence.
 

General Skanky

Well-known Member
'I turned mine on seven years ago and only turned it off to sell it earlier this year.'

It was only off for the span of the journey. It now sits on the whole time, just like the other one.:) I never turn my subs off unless on holiday etc. The manual actually tells you to leave it on anyway. I also have a hifi amp that is on the whole time too.

I just like burning electricity.:D
 
R

rob_w

Guest
I think it was more to do with repeated heating up and cooling of components, and the associated expansion/contraction of the metals etc involved - if you leave them on all the time they stay the same size sort of thing......

If you switch on/off/on/off etc the components expand/contract/expand/contract......

btw, the electricity consumed in standby is minimal, only class A amps burn current like theres no tomorrow.....

Rob
 
J

juboy

Guest
Originally posted by robwells
btw, the electricity consumed in standby is minimal, only class A amps burn current like theres no tomorrow.....

Exactly right. If it's energy conservation your after, you'd be better leaving your hi fi/ AV on all the time but doing your laundry by hand... have you ever seen what your electricity meter does during a washing machine fast spin cycle? Scary.
 

Reiner

Active Member
You mean idle, not standby!? When I switch to standby then there is a minimal current withdrawn for the IR receiver, when an amp is idle (switched on but no signal present) it still consumes more power than what you think.

Anyhow, I am familiar with the theory of switching on and off (and the associated heating/contracting etc) but I still think there is no such proof to support either opinion.
 

mandlebrot

Standard Member
I leave both my sub and amp on unless I go on holiday, this is not due to me being in any paticular camp, its purely because I'm a lazy git. I do turn my tv off though just before going to bed or when going out.

:D :D
 
J

juboy

Guest
Originally posted by Reiner
Anyhow, I am familiar with the theory of switching on and off (and the associated heating/contracting etc) but I still think there is no such proof to support either opinion.

From my experience, electrical equipment of all types seems more likely to fail when being switched on rather than whilst already having been on for some time.

Lightbulbs are a particularly common example of this.
 
M

MikeK

Guest
Yes, it's absolutely true!

Power supplies are far more likely to fail at startup than at any other time! (a bit like your light bulb example - if the average bulb life is 1000hrs, leave it on all the time and you may get 3-4000 out of it, whereas constant switching on and off, may mean only a few hundred)
You could probably over-engineer the unit to overcome this effect, but I doubt many do - all down to cost!
A few years ago, satellite receivers were so bad that people were afraid to unplug them, as often as not they wouldn't come on again afterwards :( (may still be that bad for all I know - don't have one any more)
 
G

greeny

Guest
Anyone with a remotely audiophile system will leave all their kit on all the time.

With my kit is is recognised that the sound changes for several weeks after first being turned on.

Ok so we are not talking audiophile quality generally with AV, but the same applies (to a lesser extent). I would leave the SUB on UNLESS you have a bad hum problem. This will increase the lifespan of most equipment. It's a bit like driving a car where all the wear is done in the first 5 minutes.

It will cost you a few quid a year (unless you have class A amps)and extend the life and enjoyment of your equipment.
 

Sinzer

Well-known Member
Tell that to the two HI-FI amps I blew up leaving them constantly on over a period of a year.

My current amp, which is 2 years old is fine and I switch it off after use. If they were designed to be left on, why include a power switch on them?

Depends on your preference, I prefer to lose a little quality than run the risk of components blowing out (eg resistors or PSU's) and sucking up electricity.
 
J

juboy

Guest
Originally posted by Sinzer
If they were designed to be left on, why include a power switch on them?

By that logic, my REL subwoofer has no power switch so therefore is designed to be left on.

My Cyrus pre and power amps have power switches, but located at the back... does that seem like encouragement to turn them off?

I can only imagine your problems were caused by power surges/spikes.
 
G

greeny

Guest
Tell that to the two HI-FI amps I blew up leaving them constantly on over a period of a year.

I'd buy from a diffrereny manufacturer if I were you. Either that or you have no/insufficient ventilation around them.

Indeed, as above some of my gear only has the power switch on the rear. Of course there are occations when you may need to turn on/off (plugging in new gear etc) so a power switch is required doesn't mean you should use it all the time though.

Seriously you have severe problems if your amp blows up just because it's left on.

There is an exception to the above. THUNDER STORMS. A lightning strike can induce a bad spike in the mains and damage equipment (typically things with a large transformer, like power amps) so I would unplug in this instance.
 

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