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harlon Location: USA Posts: 73	Posted - Mon Jun 09, 2003 10:02 pm  I HATE hardware units that don't have on/ off switches!! There - I said it. Just had to get that off my chest. I feel better now. _________________ Harlon www.harlonmoss.com
ozpeter Location: Australia Posts: 3200	Posted - Mon Jun 09, 2003 11:38 pm  I once toured some BBC Radio facilities in London and remarked to my guide that even in unoccupied studios, everything was left powered up. I was told that this actually improved the life of the equipment, the surges etc ocurring during power up/down being more damaging than the deterioration of components during steady running. This, however, was before the days when environmental considerations were thought about. The building was certainly uncomfortably warm. An afterthought - here in Australia you can get remote-control power points quite cheaply (ie a thing that plugs into the wall socket, and then you plug your equipment into that, via a distribution board if you like) - I use them for powering off/on switchless stuff connected to hard-to-reach sockets. - Ozpeter
Graeme Member Location: Spain Posts: 4663	Posted - Tue Jun 10, 2003 2:14 am  ozpeter wrote: I once toured some BBC Radio facilities in London and remarked to my guide that even in unoccupied studios, everything was left powered up. I was told that this actually improved the life of the equipment, the surges etc ocurring during power up/down being more damaging than the deterioration of components during steady running. I agree with this practice 100% - it's something which I have done for as long as I can remember. Apart from reducing the probability of breakdown, it also ensures that everything is running at a constant temperature and ready for instant use, with no warm-up drift, etc. ... and before anyone asks, no, I am not BBC trained - they don't have the sole right to good ideas and engineering practice. _________________ Graeme Don't forget to join the new CEP forum at audiomastersforum
SteveG Location: United Kingdom Posts: 6695	Posted - Tue Jun 10, 2003 3:22 am  This approach is fine if the manufacturer has designed the power supply so that it can cope with it! I've come across kit (especially rack-mounted and wall-wart powered) that really doesn't seem to be designed with this in mind - it just overheats and the power unit goes bang - even when you follow the manufacturer's ventilation recommendations. It's been my experience that any kit where the case, or a separate power supply, gets more than gently warm to the touch after 12hrs continuous running may have a potential problem in this area. But as a principle, I'd agree - equipment is far more likely to remain reliable if it is run continuously. _________________
zemlin Location: USA Posts: 1156	Posted - Tue Jun 10, 2003 8:19 am  I have wondered/worried about this with my monitors - Event 20/20bas. These suckers get HOT on the back side even just sitting idle. On the one hand, I hate to cycle power on and off as I'm sure there is a significant amount of thermal expansion and contraction action that could eventually result in failed internal connections. On the other hand, I hate to be heating my house for 23 hours a day (especially in summer) if I happen to be mixing for only an hour that day. I haven't decided how I'm going to live with that long-term. _________________ Karl Zemlin - www.cheap-tracks.com Host of the World Wide Cool Edit Collaboration Procedural Debate
Craig Jackman Location: Canada Posts: 909	Posted - Tue Jun 10, 2003 8:33 am  In "pro" installations where there is budget and income to cover power consumption, cooling for the additional heat, and money to fix things when they break ... by all means turn things on and leave them on. In "consumer" home installations where you have to pay for everything and the damn ship isn't running 23.5 hours a day, I'd turn things off when not in use. And I do. With that in mind, I also don't recommend turning things on and off 20 times a day. Turn it on and let it gently warm up before you use it, and turn things off at the end when you are done. Buy a rack mounted power bar or power conditioner so that you can turn everything on and off at once. Face it, with most digital boxes, once they've been in use for a couple of weeks, the first thing that would ususally break down is the mechanical switch that turns them on and off. _________________ Craig Jackman Production Supervisor CHEZ/CKBY/CIOX/CJET/CIWW Ottawa, Ontario, Canada
SteveG Location: United Kingdom Posts: 6695	Posted - Tue Jun 10, 2003 9:36 am  Here are a few examples of what happens here - not that this is particularly typical, but there are some reasons for why it's the way it is... The DAB tuner stays on 24/7, because it has a memory problem if I leave it off too long! It stays gently warm, so I think that's okay. The power amps go on in the morning and off at night. They don't get particularly hot unless they've been working hard - so on the law of averages, they get to cool down for a few hours each day. This has worked fine for years. The main switching preamp, OTOH, stays on permanently - because it can take an hour to warm up properly! All the network gear runs 24/7 - for half of it, it's an ISP requirement. The 'sacrificial' PC stays on unless it crashes. The DAW is treated like the power amps, because the drives get rather warm. Printers and Scanners have BG 'snooze' modes, so they can stay on. And three wall-warts have a fan blowing across them when they're on - reason as above. In the lab, the frequency standard runs forever - it has its own UPS. The voltage standard stays on all the time, but it did blow its power supply up once, and I wasn't too pleased - that cost a lot of money! The time standard - well, there's not much point in switching this off! (and it has a UPS). All other instrumentation gets a good warmup if used, but nothing else stays on permanently. SWMBO doesn't moan about the electricity bill, but in real terms, this lot doesn't really add up to much, so she has no real need to. But it can get a bit warm, because the insulation is too damned good. This is a problem that I will have to fix, I think. Just need a silent aircon - and I am supposed to be able to do that, apparently. But it's going to have to wait for the refit... _________________
SteveG Location: United Kingdom Posts: 6695	Posted - Tue Jun 10, 2003 9:43 am  zemlin wrote: I have wondered/worried about this with my monitors - Event 20/20bas. These suckers get HOT on the back side even just sitting idle. On the one hand, I hate to cycle power on and off as I'm sure there is a significant amount of thermal expansion and contraction action that could eventually result in failed internal connections. On the other hand, I hate to be heating my house for 23 hours a day (especially in summer) if I happen to be mixing for only an hour that day. I haven't decided how I'm going to live with that long-term. Perhaps if you turn them off when you go to sleep, and turn them on again when you wake (unless you're going to the day job)... If you don't think that the switches are rated for this, then you could consider a separate mains conditioning unit with switchable outlets - which may also help in other ways, depending upon the stability/noise of your house supply. _________________
VoodooRadio Location: USA Posts: 3971	Posted - Tue Jun 10, 2003 1:19 pm  My approach is; having separate racks for "like" units. (all pre's in one rack, all dynamic processor's in one rack, etc). I have 5 (6 space) racks and 2 (12 space). Each rack has it's on Power Conditioner, with all the racked gear plug into their own "dedicated" power conditioner. I have a 8 switch (rackmounted) power strip and each rack is plug into the switch strip. The Mackie board is also plugged into the switch strip. If I don't need a particular rack "powered up", then I just don't turn it on. Granted, most of the units that I own DO have on/off switches, which sometimes (but not often) get turned to the off position. Another plus is... a couple of my racks see occasional "road duty" and it's alot simpler to just put the covers on and go. It may seem excessive to some, but it's surely ergonomic!! _________________ I said Good Day! Voodoo
Havoc Posts: 735	Posted - Tue Jun 10, 2003 2:00 pm  Any electronics unit that changes it characteristics after 10 min is badly designed. So, I said it and feel better already. ]:} Well designed equipment should not care neither about being switched on, neither about being left on. And it should reach steady/stable state after a couple of minutes. If it doesn't there is a flaw in the design, as simple as that. I accept exceptions like the standards (that often include ovens for this reason and have thus very long time constants). But anything simple like preamps, convertors etc should be imune. When we designed a modem that needed a couple of minutes to reach optimal performance only after a couple of minutes on-time, we searched for the problem as to reach optimal performance directly after initialising. (and it was done with a layout change and different caps) As this lot is only used a couple of hours a day, I turn it off with a power bar. Certainly the stand-by stuff. It adds up to quite a lot of power. Most psu's are not very efficient in stand-by mode.
SteveG Location: United Kingdom Posts: 6695	Posted - Tue Jun 10, 2003 3:00 pm  Havoc wrote: Any electronics unit that changes it characteristics after 10 min is badly designed. So, I said it and feel better already. Most valve preamps take at least this long to stabilise - we used to reckon on rather longer than this back in the days of valved Image Orthicon cameras - more like 2 hours! And these were broadcast quality cameras - the best you could get at the time. Quote: Well designed equipment should not care neither about being switched on, neither about being left on. And it should reach steady/stable state after a couple of minutes. If it doesn't there is a flaw in the design, as simple as that. In the case of my preamp, it's a flaw in a couple of components, not the design. When I have time, I will fix it - until then, leaving it on is a viable option. Quote: I accept exceptions like the standards (that often include ovens for this reason and have thus very long time constants). But anything simple like preamps, convertors etc should be imune. When we designed a modem that needed a couple of minutes to reach optimal performance only after a couple of minutes on-time, we searched for the problem as to reach optimal performance directly after initialising. (and it was done with a layout change and different caps) As this lot is only used a couple of hours a day, I turn it off with a power bar. Certainly the stand-by stuff. It adds up to quite a lot of power. Most psu's are not very efficient in stand-by mode. The frequency and voltage standards are ovened - double-ovened in the case of the frequency standard. And the bugger still drifts... by a couple of parts in 10^12/month. But since it is externally locked to a caesium standard, who cares? Actually, I don't any more - it's thousands of times more accurate than I ever now need! Power amps usually take a little while to reach thermal equilibrium, and many would say that cartridges and speakers do as well - the compliance of their mountings can make a lot of difference to their electrical performance. So whilst I'd agree that anything purely digital should be okay pretty quickly after switch-on, some, especially older, analog stuff can be a little slippery. Quite often, some designs that people would give their eye teeth (ouch!) to get their hands on drift like hell - just look at the MiniMoog, for instance. It's not badly designed - it's just one of the things that people love about them! You might say it's a bad design - but thousands of satisfied users will say that you're very wrong - and that it's the little quirks in it that they regard as inspiring their creativity. More often than not, power supply design is done as an afterthought - often by junior engineers who are significantly unaware of some of the issues involved. And it is frequently the main source of many of the problems that people have with long-term running of equipment. People who know, like Bob Pease, have always said that you should only ever let experienced engineers do power supplies - and I think he's right on the money. And you should never let accountants design them! _________________
ozpeter Location: Australia Posts: 3200	Posted - Tue Jun 10, 2003 4:02 pm  I have a distant memory of reading something - perhaps in relation to "Quad" brand amps - that the harder certain amps work, the cooler they run, getting hottest when quiescent. Am I talking rubbish? - Ozpeter (preparing myself for a one-word answer...)
SteveG Location: United Kingdom Posts: 6695	Posted - Tue Jun 10, 2003 6:59 pm  ozpeter wrote: I have a distant memory of reading something - perhaps in relation to "Quad" brand amps - that the harder certain amps work, the cooler they run, getting hottest when quiescent. Am I talking rubbish? - Ozpeter (preparing myself for a one-word answer...) No, you get slightly more than one word... Duh??? That would virtually be class A inverted! I'm not aware of any amp class that could possibly achieve what you are suggesting. I mean, where do you draw the limit? 1kW and the amp freezes?. As far as I'm aware, no Quads, even the weird current dumper, can do this! Even a true class A amp won't - the current drawn by the output stage will be constant. The valves in a class A amp might actually be under a bit less of a voltage stress when being driven, but I don't think that they'll run any cooler, because this is determined by the heater current, which won't alter. And in any transistor amp, where the output devices are acting as any sort of current controlling mechanism, they will inevitably dissipate more power when working harder. _________________
ozpeter Location: Australia Posts: 3200	Posted - Tue Jun 10, 2003 8:55 pm  Thank you for you patient reply. Yes, it was the 'current dumper' I'm thinking of, now you mention it. I'm evidently seriously on the wrong track (again). - Ozpeter
post78 Location: USA Posts: 2887	Posted - Tue Jun 10, 2003 9:17 pm  Quote: Just need a silent aircon - and I am supposed to be able to do that, apparently. --SteveG :] _________________ Answer = 1. Probably.
Havoc Posts: 735	Posted - Wed Jun 11, 2003 3:51 am  Quote: Power amps usually take a little while to reach thermal equilibrium, This has nothing to do with its electrical operating point. Well, it should not anyway. Quote: In the case of my preamp, it's a flaw in a couple of components, As said, there is no need for it to be so. Component choise could be considered part of the design. Same goes for the minimoog part, it is that way, but there is no need for it to be the case. Valves, sorry, didn't thought about those. Not my worry.
SteveG Location: United Kingdom Posts: 6695	Posted - Wed Jun 11, 2003 4:31 am  Havoc wrote: Quote: Power amps usually take a little while to reach thermal equilibrium, This has nothing to do with its electrical operating point. Well, it should not anyway. Ah, but it does... Quote: Quote: In the case of my preamp, it's a flaw in a couple of components, As said, there is no need for it to be so. Component choise could be considered part of the design. Same goes for the minimoog part, it is that way, but there is no need for it to be the case. Valves, sorry, didn't thought about those. Not my worry. So nothing's ever allowed to fail gradually, is it? Sounds like a bit of a tall order to me! Sounds also like you only ever desgn from a digital point of view. Analog design has always been about compromise, and it always will be. There is no such thing as thermal perfection, and the time that devices take to get to their designed operating temperature has as much to do with their thermal mass as anything, and there's nothing you can do about that. Even a cursory understanding of the operational mechanism of a transistor will show you that it is thermally dependant, and if you operate it in a linear mode, then you cannot avoid the consequences of this - the best you can try to do is compensate for them. Bob Moog can design perfectly stable oscillators - but they sound bland. People actually want the sound that he gets from his older-style oscillators, so he has to find ways to stabilise them the best he can. He uses ovening techniques within chips to do this, as you would expect, but to get this stuff to stabilise across three oscillators and have them all track each other still requires a major setup operation on the production line. I counted 19-20 presets on the new Voyager analog board, which has well over 800 separate parts on it. That it works as well as it does, considering that virtually every paramenter is voltage-controlled is little short of amazing. I would respectfully suggest that if you can't come up with something as good as this, then you shouldn't knock it. And I think that you'd be pretty hard put to get anywhere even vaguely close until you have learned and applied the subtle art of compromise... _________________
Havoc Posts: 735	Posted - Wed Jun 11, 2003 12:57 pm  Quote: There is no such thing as thermal perfection, and the time that devices take to get to their designed operating temperature has as much to do with their thermal mass as anything, and there's nothing you can do about that. Right. But you can and should take into account the variations resulting and compensate/eliminate/minimise as far as possible. This may not be an excuse for something like a wandering offset on a power amp. (yes, I know it will wander a bit, some mV's, but not V's) Quote: Even a cursory understanding of the operational mechanism of a transistor will show you that it is thermally dependant, and if you operate it in a linear mode, then you cannot avoid the consequences of this - the best you can try to do is compensate for them. You say so yourself: you have to compensate. Feedback also plays a role in this, as well as component choices and topologies (and pcb layout). I don't knock on it, but designing an amp that has no wandering bias point and so on when the temp changes (okay, within limits, no picobells and femtobells for me neither) isn't exactly black art. If you depend on the final temp reached by a semiconductor to set operation points, then you are taking risks to say the least. The minimoog may be a bad example. It is something creative, while preamps etc for me are tools, they should be "exact". What is the use of a 24bit convertor when it drifts several lsb's after 10 minutes? Quote: So nothing's ever allowed to fail gradually, is it? Depends. When my piano gets out of tune, I have it tuned. When the paint on the wall fades, I can stand it for a couple of years.
SteveG Location: United Kingdom Posts: 6695	Posted - Wed Jun 11, 2003 1:01 pm  Havoc wrote: Quote: So nothing's ever allowed to fail gradually, is it? Depends. When my piano gets out of tune, I have it tuned. When the paint on the wall fades, I can stand it for a couple of years. My preamp is like your paint... Quote: If you depend on the final temp reached by a semiconductor to set operation points, then you are taking risks to say the least. When you design log converters, that's exactly what you have to do - you don't have a choice. This is why Bob Moog has all the problems - he has to use these techniques to get the correct control law. Hence the ovened components. _________________
twright Location: USA Posts: 230	Posted - Fri Jun 27, 2003 11:25 am  i guess that it's my turn to vent...i'm tired of everyone having to put on headphones when one person is recording vocals, just because i live in a 1 bedroom apt. i need a control room or something where i can listen through the monitors while someone is recording their vocals. guess it's time to move into a house, huh? that's all i need, more responsibility.
MusicConductor Location: USA Posts: 1524	Posted - Fri Jun 27, 2003 12:27 pm  Got a closet full of clothes with a door?
twright Location: USA Posts: 230	Posted - Fri Jun 27, 2003 2:32 pm  MusicConductor wrote: Got a closet full of clothes with a door? looks like i have some cleaning to do
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