eggssell Posted November 25, 2009 Share Posted November 25, 2009 (last one for the day, its been a while so was making up for it... that or its my feeble attempt to get into the 1000 club in less than a month )anywho, i am getting an audible hum in my setup. being two st-150's, reloop iQ2, audio 8, my lappy, and an old technics mini system (no laffing it still goes hard, it's one of the last all built in japan models!)i thought it was the stantons as i thought i remembered reading something about it not having a ground wire etc, but cant find it now. but recently i was playing my ipod via the reloop's front panel aux plug and noticed the hum wasnt there. i then tested straight vinyl (not using the pass thru of traktor but just straight vinyl on tt to mixer) and there was no hum!so after some googling i realised it was my laptop.ive read a lot of conflicting suggestions so thought i would ask you learned lot who has experienced this, and what workarounds do you use. it would be extra great to hear from other audio 8 or audi 4 users.cheers!!!!EDIT: oh yeah the hum is in the master to the mini system, and the record out into the traktor (which then usb's to the lappy) Quote Link to comment Share on other sites More sharing options...
Tomy Posted November 25, 2009 Share Posted November 25, 2009 i dont use audio8 or 4 or traktor. But i had a similar problem with my zero korg4. i had unbalanced leads going to my speakers, changed over to balanced and there all good now. although mine noise wasn't a hum is was more of a hiss or loud noise floor sound. Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted November 25, 2009 Share Posted November 25, 2009 Welcome to the world of ground loop hums!"In short, ground loops are an unwanted current in an electrical circuit. They result from electrical devices not sharing the same earth or the same devices sometimes being at varying distances from a single earth. This current is a major source of noise (‘ground loop hum’) and interference (‘hum bars’) in audio and video systems. The easiest way to remove a ground loop hum is to ensure all the devices are on the same circuit (e.g. share the same power board). Another way is to break the loop by introducing an isolation transformer. A transformer is a way of transmitting an electrical signal such as audio or video without an actual physical connection."I have found that some laptops are more prone to GLH due to 'noisy' power supplies. Try unplugging your laptop power supply and see if the noise goes away. If so buy an isolation transformer and connect it into the signal path (say between mixer and amp):http://www.jaycar.com.au/productView.as ... rm=KEYWORDAnother way (only if your desperate) is to buy a travel adaptor that doesnt have an earth pin and connect it to your lappy. Of course you take your chances with getting zapped so try all other methods first.Let us know how you go? Quote Link to comment Share on other sites More sharing options...
eggssell Posted November 25, 2009 Author Share Posted November 25, 2009 cool cheers. yeah ill try to unplug the laptop to see if it is definitely this.in regards to the product you suggested, so i am plugging this between the mixer and the stereo (or mixer and back to audio 8 for recording). does that mean that all it is doing is filtering the hum? or does it actually cause the "grounding" to be fixed (if so curious to find out how, guess i could ask the jaycar folk).the zapping option is not preferred. i remember back in the day on the rental equip i stuck my hand under the road case and the other end of one of the cords just stuck out right thru the case, my hand hit it and i remember it was just an involuntary shaking of my hand. it was only lucky it hit the back of my hand, if it was the other way my hand probably would have automatically closed around it, and id be a goner! Quote Link to comment Share on other sites More sharing options...
tubby Posted November 25, 2009 Share Posted November 25, 2009 try plugging the laptop into a different outlet to the rest of the gear to it's not in the same loop. It might help. Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted November 26, 2009 Share Posted November 26, 2009 The ground loop is an unwanted current 'looping' somewhere in your system. Adding a isolator effectively cuts the loop by allowing the audio signal to pass but not the unwanted current. Try between mixer and amp/stereo first as you amp is anplifying the noise. If that doesnt work, try somewhere else in the signal path (mixer back to audio eight). Quote Link to comment Share on other sites More sharing options...
eggssell Posted November 26, 2009 Author Share Posted November 26, 2009 okay mos def the laptop, plugged in hum, not plugged in no hum what so ever (i was a little taken a back because i have shitty caables from master to the mini system).And everything except the mini system is on one power board, but as above i still suspect the laptop.anywho, so i can go with the ground loop isolator from jaycar, but anyone have opinion/ experience on sound degradation? are thre different brand/ qualities or is that jaycar one the standard.other option is a direct box thingy. though my mixer only has one balanced output and two rca outputs, while all the DI's ive seen only have balanced inputs. which means it will only fix either recording or master but not both at the same time (hope that amkes sense)the other option I saw was the belkin home/ office laptop spare adaptor, which is like a universal adaptor for all laptops marketed so you only need to carry one power source. This adaptor has no ground (apparentally it deals with grounding som other way? or so i hope)so anyone have thoughts??cheers all and reps to all those who have helped Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted November 27, 2009 Share Posted November 27, 2009 A DI (direct input) box is usually used to connect a musical instrument (or mixer) to a professional PA system. They are designed to match the impedence of the instrument to that of the sound desk. Dont ask me to explain impedance cause I cant. Your correct in thinking that a DI has a 'ground lift' (ie isolation transformer built in) and will probably solve your problem. However, you will need to buy two DI boxes to accomodate both the left and right channels. If you have unbalanced outputs on the mixer thats OK as long as the cords are as short as possible. RCA to XLR connectors are also pretty common to buy.But...I think you should experiment with the cheapest option first (ie $20). From my experience the Jaycar transformer reduces the sound level slightly but doesnt affect the sound quality. Dont forget there are a number of other IT's on the market and they all vary in price and quality.The Belkin adaptor is probably a two pin power cord as opposed to the normal three and will act pretty much like the travel adaptor I mentioned (ie has no earth pin). Most lappies used be the same until recently. Quote Link to comment Share on other sites More sharing options...
pill Posted November 27, 2009 Share Posted November 27, 2009 I think you should experiment with the cheapest option first (ie $20). From my experience the Jaycar transformer reduces the sound level slightly but doesnt affect the sound quality. Dont forget there are a number of other IT's on the market and they all vary in price and quality..I don't suffer from hum due to using an isolater as mentioned above, but i suffer from the dreaded "hard drive in use" noise, its like a squelching noise and its fucking terrible. I have no way of getting rid of it, whenever I plug (either of my) laptops into something that is also plugged into the same power supply it comes out. I've tried GLIs...I also notice the same noise comes out of my pc when i plug my headphones directly into it.Man i wish that noise would die. Quote Link to comment Share on other sites More sharing options...
defanutley Posted November 27, 2009 Share Posted November 27, 2009 I know this might not be easy but try and plug your stereo equipment and computer into different wall power inputs let me know how you go Quote Link to comment Share on other sites More sharing options...
eggssell Posted November 27, 2009 Author Share Posted November 27, 2009 oh yeah? i thought i had read people saying keep them all on the one power bar, but hey its worth a try. ill do it over the w/e.anyone else have any experience with the other options (i.e. assuming others use lap tops in their setups) Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted November 30, 2009 Share Posted November 30, 2009 Plugging them into the same power board is the easiest thing to do to try and get rid of the earth loop. All your gear will then share the same earth and removes the chance of a difference in electrical potential between devices (ie no unwanted current in the system).But...If you cant get rid of the hum, sometimes you have to try and find a completely different electrical circuit for your computer or amp (ie not already connected to your system). This can sometimes mean running an extension cord from a different room. But...In my experience, some power supplies for laptops will generate a earth loop regardless of where you plug them in!! Back to the isolation transformer... Quote Link to comment Share on other sites More sharing options...
eggssell Posted December 3, 2009 Author Share Posted December 3, 2009 finally a chance to get on to this. been a longtime b/w drinks, other then trying to impress a 5 yr old w/ my laser scratches (enhanced w/ flanger effect) i havent had a bash for days..anywho yeah tried pluging it into my dining room outlet, the rest of the setup is in the lounge. may have imprved it by 2-5% but still pretty bad.in terms of the ground loop isolator, from what you've said that takes a way the unwanted voltage so having it on one point that should get rid of the hum on all outputs (i.e master, record and headphones). because right now im getting it on all outputs.my mate is gonna give me a surge adaptor that has a noise filter built in (from dick smith), to see i that helps. anyone use that??but if not ill hit the stores for a GLI on the weekend.cheers again sourceraver Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted December 4, 2009 Share Posted December 4, 2009 Just for the hell of it...An isolation transformer works by creating a physical barrier to unwanted current by placing a break in the circuit. But it still allows and audio signal to pass. The way I understand it, its a mass of copper wire on both sides of the transformer that are really tightly intermeshed...but not connected. The current is blocked but the audio signal 'jumps the gap' via some sort of electromagnetic property.Let us know how it goes! Quote Link to comment Share on other sites More sharing options...
Cupe Posted December 4, 2009 Share Posted December 4, 2009 SourceRaverYou are a legend +rep Quote Link to comment Share on other sites More sharing options...
eggssell Posted December 11, 2009 Author Share Posted December 11, 2009 only got my hand on the noise filter line adaptor yest http://www.dse.com.au/cgi-bin/dse.storefront/4b2190d6031b8e5e273fc0a87e01067c/Product/View/M7800didnt work. by coniky dink i ran into the crest/ monster cable rep at harvey norman and he said it wouldn't work because the "noise" that is being filtered is from electro magnetic interference which can affect tv reception or high end audiophile stereo systems, it won't filter out currents which is the problem in the ground loop. he then suggested why don't i buy a crest "figure 8 2 pin" cable to replace my mixers power cable (??) but they didnt have any stock! ha ha ...i went around to harvey, jb and dick smith looking for ground loop isolators but no one had one. seems to be mainly used in car setups so jaycar or radio shack.jb did have the belkin laptop adaptor http://www.belkin.com/au/IWCatProductPa ... _Id=418433apparentally because the 2 pins are insulated and the transformer has a built in surge protector, there is no risk of grounding to myself, and that the reason laptops have the ground pin was not to protect the person rather the laptop components because the charge is too small to badly hurt someone. So the built in surge protector is meant to protect grounding through the laptop components so much that they guarantee it. however they don't guarantee anything else i.e. my setup!! so i think i am physically safe with this option the question is whether everything else is, and also other then one person on djforum (or maybe dj techtools) i cant find anyone else that took this option. so i might run around today trying to locate a ground loop isolator because it is just $20, but an audiophile friend is telling me that should be worse case scenario. i guess he doesnt realise i only have a 10 yr old mini system.heh!! Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted December 14, 2009 Share Posted December 14, 2009 http://www.behringer.de/EN/Products/HD400.aspxhttp://shop.ebay.com.au/i.html?_nkw=gro ... &_osacat=0Your audiophile friemd would probably die if he walked into a nightclub. A lot of them are operating on a mono sound reinforcement system (ie not stereo) and the emphisis is on LOUD not quality. Quote Link to comment Share on other sites More sharing options...
eggssell Posted December 16, 2009 Author Share Posted December 16, 2009 hey man thanks again. i might go the hum destroyer... i just need to get trs to rca adapters or cords. is it better just to get cords? or are adapters fine? Quote Link to comment Share on other sites More sharing options...
SourceRaver Posted December 16, 2009 Share Posted December 16, 2009 Adaptors are fine. Quote Link to comment Share on other sites More sharing options...
eggssell Posted December 29, 2009 Author Share Posted December 29, 2009 finally got the hum destroyer!!!tried before xmas everyone was sold out. works a treat. id give ya more rep sourceraver but anymore love from me would be more inappropriate!yeah works a treat. hooked it on the master and clear as on all outputs.just digitised my super seal vinyl and sounds perfect!thanks everyone who chipped in! Quote Link to comment Share on other sites More sharing options...
Skank Posted December 29, 2009 Share Posted December 29, 2009 now explain the matrix to me please Quote Link to comment Share on other sites More sharing options...
FabDJ Posted April 10, 2010 Share Posted April 10, 2010 I have the same problem with negative loop on my laptop when it is connected to a power supplyThe easiest way to remove hum is to cut the earth off a double adaptor to power the laptop. I write PC only on the double adaptor and use it only with the PC Minimum chance of being zapped as its only 13 Volts input.FabDJ Quote Link to comment Share on other sites More sharing options...
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