tygar2
Hello everyone
I have searched the forum but couldnt a topic that exactly addressed my problem so hope someone can help. I have a Hercules MK2 connected to my Denon DNX1500 for CD timecode use.
I am getting an electrical hum through my speakers. Even after disconnecting everything else apart from the Hercules and the laptop I still get the hum. I have however discovered that the hum stops when I run the laptop off battery. The hum starts the moment the the usb cable touches the port so I assume that is where it is coming from.
The hum has a 'computer' sound to it (cpu processing, hard drive spinning type of hum). If this is an electrical hum how do I isolate it as it is coming throughh via usb. Is this a common problem or is it a fault with my laptop?
Hope someone can help
I have searched the forum but couldnt a topic that exactly addressed my problem so hope someone can help. I have a Hercules MK2 connected to my Denon DNX1500 for CD timecode use.
I am getting an electrical hum through my speakers. Even after disconnecting everything else apart from the Hercules and the laptop I still get the hum. I have however discovered that the hum stops when I run the laptop off battery. The hum starts the moment the the usb cable touches the port so I assume that is where it is coming from.
The hum has a 'computer' sound to it (cpu processing, hard drive spinning type of hum). If this is an electrical hum how do I isolate it as it is coming throughh via usb. Is this a common problem or is it a fault with my laptop?
Hope someone can help
Posted Fri 02 May 08 @ 4:28 pm
Tim Bennett
You need a ground isolator, which you can pick up at any hardware store, very cheap fix.
Posted Fri 02 May 08 @ 4:36 pm
jimmy b
I sounds like to me that's it's a grounding problem.
You need a something like this
http://www.radioshack.com/sm-buy-the-ground-loop-isolator-on-http-wwwradioshackcom--pi-2062214.html
But what ever you do, DO NOT tamper with your equipments electrical plugs.
Posted Fri 02 May 08 @ 4:38 pm
Tear Em 'Up
jimmy b wrote :
But what ever you do, DO NOT tamper with your equipments electrical plugs.
Jimmy is correct..well done Jimmy.. ;-)
Posted Fri 02 May 08 @ 5:10 pm
tygar2
Thanks to all for the quick reponses.At the risk of sounding totally daft, can someone tell me how I will use this loop? Where do I plug it in? Do I need 2? one for each output channel? My mixer master out is XLR.
thanks for all you help.
thanks for all you help.
Posted Fri 02 May 08 @ 5:46 pm
Graomi
Tygar,
I had exactly the same problem, its usually caused by the fact that laptop power units dont have an earth in them just two pins.
The ground loop isolator pretty much eliminated the hum and they only cost a few quid on ebay. its one unit, a short barrell about an inch across and stereo jack in's and outs, just plug one end into the back of your hercules and attach your usual stereo cable between it and the mixing desk or amp.
simple as.
John
I had exactly the same problem, its usually caused by the fact that laptop power units dont have an earth in them just two pins.
The ground loop isolator pretty much eliminated the hum and they only cost a few quid on ebay. its one unit, a short barrell about an inch across and stereo jack in's and outs, just plug one end into the back of your hercules and attach your usual stereo cable between it and the mixing desk or amp.
simple as.
John
Posted Fri 02 May 08 @ 6:16 pm
Timmyg1978
tygar wrote :
Thanks to all for the quick reponses.At the risk of sounding totally daft, can someone tell me how I will use this loop? Where do I plug it in? Do I need 2? one for each output channel? My mixer master out is XLR.
thanks for all you help.
thanks for all you help.
If using an external mixer yes, you will need one isolator per stereo channel between the mk2 and your mixer. I have three as I'm using my internal for samples to a third channel;^]
Posted Fri 02 May 08 @ 6:42 pm
Marze.NZ
do you notice a difference in sound quality after putting these in? obviously it eliminates the hum but does it effect the output at all??
Posted Fri 02 May 08 @ 8:25 pm
tygar2
Thanks All. Will pop down to Maplins and 'borrow' (buy and return) 2 of their rather expensive units as I have my first virtual DJ gig tonight! Will search for cheaper ones online later. Naturally I will have CDs as backup in case I fluff up!
@DJ Marze
I will let you know if I notice any difference in sound quality once I try them out.
Thanks everyone!
@DJ Marze
I will let you know if I notice any difference in sound quality once I try them out.
Thanks everyone!
Posted Sat 03 May 08 @ 12:45 am
tygar2
Timmyg1978 wrote :
If using an external mixer yes, you will need one isolator per stereo channel between the mk2 and your mixer. I have three as I'm using my internal for samples to a third channel;^]
If using an external mixer yes, you will need one isolator per stereo channel between the mk2 and your mixer. I have three as I'm using my internal for samples to a third channel;^]
I just realised that I may need 4 of these ground loops.
I use timecode CD but have split the output from my Denon DNS-3500 CD players in two resulting to two pairs of stereo out per deck. On each deck one pair goes into the Hercules Console and the other goes into the Denon DNX-1500 mixer I have. This means I have 4 channels (2 Denon and 2 Hercules) going into my mixer so I suspect each channel will probably need a ground loop as due to the signal splitting it all links back to the laptop.
The reason for this setup is because it allows me to easily switch from using virtual dj to playing ordinary CDs just by selecting a different chanel and replacing the timecode with an audio or mp3 CD.
I am still learning virtual dj so this is my backup in case I mess up, it crashes or I someone turns up with their 'special song' on CD and want it played immediately.
Just thought I'd share my 2 pence in case it helps someone else.
Posted Sat 03 May 08 @ 3:11 am
discobrian24
Couldnt you try 1 pair between the mixer and the amp instead of many of pairs??
Posted Sat 03 May 08 @ 4:23 am
Timmyg1978
tygar wrote :
I just realised that I may need 4 of these ground loops.
I use timecode CD but have split the output from my Denon DNS-3500 CD players in two resulting to two pairs of stereo out per deck. On each deck one pair goes into the Hercules Console and the other goes into the Denon DNX-1500 mixer I have. This means I have 4 channels (2 Denon and 2 Hercules) going into my mixer so I suspect each channel will probably need a ground loop as due to the signal splitting it all links back to the laptop.
The reason for this setup is because it allows me to easily switch from using virtual dj to playing ordinary CDs just by selecting a different chanel and replacing the timecode with an audio or mp3 CD.
I am still learning virtual dj so this is my backup in case I mess up, it crashes or I someone turns up with their 'special song' on CD and want it played immediately.
Just thought I'd share my 2 pence in case it helps someone else.
Timmyg1978 wrote :
If using an external mixer yes, you will need one isolator per stereo channel between the mk2 and your mixer. I have three as I'm using my internal for samples to a third channel;^]
If using an external mixer yes, you will need one isolator per stereo channel between the mk2 and your mixer. I have three as I'm using my internal for samples to a third channel;^]
I just realised that I may need 4 of these ground loops.
I use timecode CD but have split the output from my Denon DNS-3500 CD players in two resulting to two pairs of stereo out per deck. On each deck one pair goes into the Hercules Console and the other goes into the Denon DNX-1500 mixer I have. This means I have 4 channels (2 Denon and 2 Hercules) going into my mixer so I suspect each channel will probably need a ground loop as due to the signal splitting it all links back to the laptop.
The reason for this setup is because it allows me to easily switch from using virtual dj to playing ordinary CDs just by selecting a different chanel and replacing the timecode with an audio or mp3 CD.
I am still learning virtual dj so this is my backup in case I mess up, it crashes or I someone turns up with their 'special song' on CD and want it played immediately.
Just thought I'd share my 2 pence in case it helps someone else.
Actualy, if the outputs from your cd decks are split the way mine is, the second output isn't going into the soundcard so you shouldn't need a second set. However, if you're taking them straight to a gig it's good to have the extras just in case. I ordered mine on ebay from Hong Kong, about $15 for two of them.
@Discobrian, I've never been able to get them to work in any configuration except between the soundcard and mixer. Have you gotten them to work that way? I'm wondering if it's my setup or not;^]
Posted Sat 03 May 08 @ 7:48 am
TopHouse
The isolator is to stop the hum getting "in". If you put it 'after' the mixer (between mixer and amp) it has already got 'in' and is now combined with the audio, so it won't work that way.
To answer another question asked above, I have not had any noticable degradation in sound quality after using ground loop isolators.
To answer another question asked above, I have not had any noticable degradation in sound quality after using ground loop isolators.
Posted Sun 04 May 08 @ 3:32 am
smurf_slayer
Hi All,
Just thought I would throw an alternative possible source (for anyone that is reading this but the above does not solve the hum). I had a high frequency hum which was bloody annoying for over two years. I tried just about everything (unplugging, switching off, earthing, changing of cables... etc. etc.) but to no avail... UNTIL I turned my 19" TFT off! [silence]!
Yup - the TFT was causing the noise (but the humming was heard through the speakers!). I tried changing from a DVI to a VGA cable, but still the noise. It was weird though, as the noise only came out when the pc image was actually displayed (i.e. if you turned off the pc, but leave the TFT on - the hum would stop!).
I've now changed (and took the opportunity to upgrade to a 22" widescreen!) the TFT and all is now as you would expect :)
...I hope this helps!
Cheers.
Just thought I would throw an alternative possible source (for anyone that is reading this but the above does not solve the hum). I had a high frequency hum which was bloody annoying for over two years. I tried just about everything (unplugging, switching off, earthing, changing of cables... etc. etc.) but to no avail... UNTIL I turned my 19" TFT off! [silence]!
Yup - the TFT was causing the noise (but the humming was heard through the speakers!). I tried changing from a DVI to a VGA cable, but still the noise. It was weird though, as the noise only came out when the pc image was actually displayed (i.e. if you turned off the pc, but leave the TFT on - the hum would stop!).
I've now changed (and took the opportunity to upgrade to a 22" widescreen!) the TFT and all is now as you would expect :)
...I hope this helps!
Cheers.
Posted Sun 04 May 08 @ 4:55 pm
TopHouse
possibly some sort of leakage from the video cable, possibly replacing it with a better quality one or adding a ferrite clamp may have cured it.
Posted Sun 04 May 08 @ 7:05 pm
Supacon
I've had a lot of problems with laptops causing really bad hum via the ground plug.
The fix is simple - break off the ground prong. Many laptops don't have one at all, so it's not going to be a big problem - but ideally, do this on the sort of power supply that has an interchangable cable so that you can run with the ground prong in other scenarios.
It sounds like a hack, but most of the time it works extremely well. If you still get ground loop problems, that can be due to the way equipment is plugged into different outlets which have different ground points. You can sometimes minimize this by plugging everythign in your audio setup to the same outlet, but sometimes (especially when running video) this is extremely difficult - in that case you will need ground isolators.
(BTW, I'm from Canada so we have different outlets than Europe, but other than their outlets being a higher voltage I believe the same principles would apply)
The fix is simple - break off the ground prong. Many laptops don't have one at all, so it's not going to be a big problem - but ideally, do this on the sort of power supply that has an interchangable cable so that you can run with the ground prong in other scenarios.
It sounds like a hack, but most of the time it works extremely well. If you still get ground loop problems, that can be due to the way equipment is plugged into different outlets which have different ground points. You can sometimes minimize this by plugging everythign in your audio setup to the same outlet, but sometimes (especially when running video) this is extremely difficult - in that case you will need ground isolators.
(BTW, I'm from Canada so we have different outlets than Europe, but other than their outlets being a higher voltage I believe the same principles would apply)
Posted Mon 05 May 08 @ 1:56 am
Timmyg1978
DO NOT, I repeat DO NOT attempt to modify your power plugs if you are not a trained & licensed electrician. This is extremly dangerous, if you need to plug a triple prong plug to a double prong outlet use the three to two prong adapter, if you have electric noise due to a ground loop use the isolators;^]
Posted Mon 05 May 08 @ 5:36 am
tygar2
Timmyg1978 wrote :
DO NOT, I repeat DO NOT attempt to modify your power plugs if you are not a trained & licensed electrician. This is extremly dangerous, if you need to plug a triple prong plug to a double prong outlet use the three to two prong adapter, if you have electric noise due to a ground loop use the isolators;^]
I agree. I purchased some ground loops after suggestions from users I asked in this forum and Im happy to say they worked. (Had other issues but thats another story). Would I be wrong in assuming that tampering with your plugs would invalidate your public liability insurance (uk). Im sure it does and seems more of a hassle than just plugging in some isolaters.
Posted Mon 05 May 08 @ 8:17 am
Timmyg1978
Exactly, plus it could even kill you in worst case scenerios. I know this isn't exactly a science forum, but this stuff should be common sense;^]
Posted Mon 05 May 08 @ 8:24 am
Tear Em 'Up
Common sense has become an oxymoron Timmy, its like hamburger steak, or calling a bald guy Curly...it is becoming more and more uncommon.
Posted Mon 05 May 08 @ 8:57 am
