Members DTravz Posted February 7, 2007 Members Share Posted February 7, 2007 I want to plug my rack components, (which totals around 100 watts), into, say, an APC 300 watt UPS, (which costs around $50). Will this setup avoid the potential speaker-damaging 'THUMP' that occurs when the club's breaker trips, and the bartender resets the breaker without giving me time to properly switch off the gear? We all have to deal with inadequately wired clubs, but at times have to play them at the risk of our gear. I was hoping that this might buy a few precious minutes and save my speakers. Pros/cons? Sorry if this has been discussed to death. DT Link to comment Share on other sites More sharing options...
Members daklander Posted February 7, 2007 Members Share Posted February 7, 2007 There are no stupid questions, only stupid answers. Hope this ain't one of them. My thoughts, which could be out in left field..... Hmmm, I'm wondering, is that 100 watts the output power of your system?What is the total amperage draw of all pieces combined? That multiplied by the voltage will give you the wattage drawn. If your total amperage draw is, say 10 amps, you're looking at roughly 1200 watts, depending on the actual voltage supplied, so that power supply won't be any help much if at all.In any case, if the UPS is rated for the amperage you'll need to have a decent length of "hold time" to give you time to shut things down.I'm thinking you'll need to spend alot more than fifty bones to protect the system with an UPS. Link to comment Share on other sites More sharing options...
Members hammer744 Posted February 7, 2007 Members Share Posted February 7, 2007 As Daklander says, check the back of all your equipment - it should list the maximum power draw in either Amps, or Watts. $50 won't get you much capacity OR runtime. Price and weight increase in direct proportion with both of these factors. Depending on how long you've can expect before a circuit is reset is the minimum run-time you'll need to get the critical stuff shut down. There are cheaper UPS's than APC, but you can check www.apc.com to get an idea of capacity and run time provided by the different models and what price range and weight you're going to be dealing with. Link to comment Share on other sites More sharing options...
Members stvcmty Posted February 7, 2007 Members Share Posted February 7, 2007 If you mean putting everything that is not a power amp on UPS's, then that should avoid the thump. If all the gear that is not power amps never goes out, then when the amps come back on, there will be no thump from other equipment coming on. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted February 7, 2007 CMS Author Share Posted February 7, 2007 As long as the UPS is rated above the current draw of what you plug in, it will work. You will have a certain amount of time to power down depending upon the load on the UPS battery. You only plug in those devices that will "thump" on power loss, and plug the rest directly. It doesn't help if everything's running on UPS, and the UPS shuts down....then you get the thump through the amps as they power off, just like you had no UPS. You want the amps to cut out with the power failure, and keep the driveracks and other 'thumpy' gear running. They don't draw much, so the UPS will likely ride out a breaker trip easily. Link to comment Share on other sites More sharing options...
Members DTravz Posted February 7, 2007 Author Members Share Posted February 7, 2007 Yeah, I calc the total watts, without the power amps, will equal around 100 watts, per the manufacture's data. The APC unit is rated for 300 watts, giving you 4 minutes of ups at full load, which I should be well under. The power amps will be plugged into separate sources, and will not factor into the equation.This seems like such a simple solution, but I never see it discussed. I think it's worth the $50 piece of mind it would bring. Otherwise my nerves are always on edge at certain clubs, waiting for that moment that someone turns on a fan, or AC unit and POW!!! Then a few seconds of frozen bewilderment and the feared THUMP while I am scrambling for the rack switch. I'm going to try it. I've got too much invested to have that happen even once more. Thanks DT Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted February 7, 2007 CMS Author Share Posted February 7, 2007 Yeah, I calc the total watts, without the power amps, will equal around 100 watts, per the manufacture's data. The APC unit is rated for 300 watts, giving you 4 minutes of ups at full load, which I should be well under. The power amps will be plugged into separate sources, and will not factor into the equation.This seems like such a simple solution, but I never see it discussed. I think it's worth the $50 piece of mind it would bring. Otherwise my nerves are always on edge at certain clubs, waiting for that moment that someone turns on a fan, or AC unit and POW!!! Then a few seconds of frozen bewilderment and the feared THUMP while I am scrambling for the rack switch.I'm going to try it. I've got too much invested to have that happen even once more.ThanksDT Don't sweat it, this will work, and is not at all an unusual solution. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 7, 2007 Members Share Posted February 7, 2007 The real concern is the electronic noise the inverter generates that might couple into your audio via the audio unit's power transformers. Many budget UPS units are quite electrically noisy. Link to comment Share on other sites More sharing options...
Members Gregidon Posted February 7, 2007 Members Share Posted February 7, 2007 Agedhorse, are their any relay units that will do this? I imagine it would be somewhat trivial to make a unit that broke a relay when the power was cut.... Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 7, 2007 Members Share Posted February 7, 2007 Yes, a failsafe could be designed that mutes the audio lines out to the amps when power failed, but it would have to be pretty fast, and also delay the unmute function upon power-up. It's not an easy project though. Link to comment Share on other sites More sharing options...
Members Gregidon Posted February 7, 2007 Members Share Posted February 7, 2007 Yes, a failsafe could be designed that mutes the audio lines out to the amps when power failed, but it would have to be pretty fast, and also delay the unmute function upon power-up. It's not an easy project though. Is the thump caused when the breaker trips, or when the power is turned back on.... and why? I guess i'm somewhat confused about the cause of the thump. Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 7, 2007 Members Share Posted February 7, 2007 The cause of the thump is the signal processing circuits offsetting to DC, this offset spike then feeding the active power amps. Link to comment Share on other sites More sharing options...
CMS Author Craig Vecchione Posted February 7, 2007 CMS Author Share Posted February 7, 2007 The real concern is the electronic noise the inverter generates that might couple into your audio via the audio unit's power transformers. Many budget UPS units are quite electrically noisy. If he's talking about an APC Back-ups 300, I borrowed one to test with my dbx DRPA and it was quiet. I'll probably buy my own at some point. The output form factor is listed as "stepped sine wave", FWIW. The only annoyance is needing to power off the DRPA at the end of the gig to take the load off the UPS if you power off the rack supply, otherwise you get the battery alarm and will discharge the battery with the DRPA's load. I'd rather be able to nail the DRPA's power switch to "on" or eliminate it entirely. All things considered the DR260 would have been money better spent...... Link to comment Share on other sites More sharing options...
Members agedhorse Posted February 7, 2007 Members Share Posted February 7, 2007 It depends on each different UPS and each different audio piece on a case by case basis. Some will work fine and others not so fine. Link to comment Share on other sites More sharing options...
Members DTravz Posted February 8, 2007 Author Members Share Posted February 8, 2007 CraigV, yes the APC Back-UPS 300 is the puppy I was referring to. I'm glad you tried one. I may borrow one from work and try it this weekend. Thanks.And thanks Agedhorse for your input too. Link to comment Share on other sites More sharing options...
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