ChrisPointon 0 Posted November 22, 2004 Report Share Posted November 22, 2004 I don't recommend anybody disconnects the mains earth on any appliance http://www.dj-forum.co.uk/html/emoticons/excl.gif , over the years 100's of entertainers have lost their lives this way, since this is a procedure which could lead to electrocution if the power supply went faulty and the metal components became live. For less than £10 you can fix yourself up with a ground loop isolator which fits in line with the Audio output of your laptop and the input of your mixer and does exactly the same thing, without taking any of the risks. But disconnecting the mains earth should never be an option. Link to post Share on other sites
DJ Marky Marc 0 Posted November 22, 2004 Report Share Posted November 22, 2004 192 is the the slowest i would be happy to use http://www.dj-forum.co.uk/html/emoticons/sterb188.gif <a href="http://www.djassociates.org"><img src="http://www.djassociates.org/anims/compres_banner.gif" alt="Join the DJ Associates Disc Jockey Association" border="0" width="468" height="60"></a> Link to post Share on other sites
RobbieD 0 Posted November 22, 2004 Report Share Posted November 22, 2004 Like Chris says: NEVER DISCONNECT THE EARTH!!! http://www.dj-forum.co.uk/html/emoticons/nono.gif You may think that because the power supply and laptop both have plastic cases that ther is no electrocution risk. But if the power supply went faulty and the DC output became live, it could transfer through to your mixer via the PC's audio output. If the mixer is "double insulated" (ie no earth wire) or the earth in it fails as well, then its case would be live, and even your mike would become live!!! http://www.dj-forum.co.uk/html/emoticons/fear.gif Link to post Share on other sites
jonnygfm 0 Posted November 23, 2004 Report Share Posted November 23, 2004 I use good old Itunes and use 192kbps for best results Your Night, Your music, YOUR PARTY Link to post Share on other sites
Discodunc 0 Posted November 23, 2004 Report Share Posted November 23, 2004 Thanks for the advice and the concern! I was in no way advising anybody to do the same and on reflection, probably should not have mentioned it...... But the odd's of what you say may happen are........... well lets just say that i am more likely to win the lottery and be struck by lightning on my way to collect it. But no, anyone reading this thread don't do it. It is wrong,bad and dangerous. http://www.dj-forum.co.uk/html/emoticons/oops.gif Dunc. Link to post Share on other sites
brianmole 0 Posted November 23, 2004 Report Share Posted November 23, 2004 QUOTE But the odd's of what you say may happen are........... well lets just say that i am more likely to win the lottery and be struck by lightning on my way to collect it. The earth bond is a safety mechanism for when things go wrong, not an optional feature. How many times have you found screws fall out of mains plugs? http://www.dj-forum.co.uk/html/emoticons/fear.gif VBR - am I right in thinking that hardware MP3 players have a hard time decoding these? I was under the impression VBR is best avoided. One of SEDAs members did a presentation a few years ago where he researched which rate is best. He concluded that at 224, he could hear no difference between the original cd and the mp3, so he had a policy of ripping at the next highest rate of 256. I can't tell the difference at 192, but there is a difference at 160, and 128 is shockingly poor. Link to post Share on other sites
+Scooby+ 0 Posted November 23, 2004 Report Share Posted November 23, 2004 I’ve always ripped back at 192kb and I can’t audibly tell the difference between CD and MP3. I must say its surprising how many of you actually use a laptop that would worry me on an overheating basis. I use a tower with flatpanel monitor, a Soundblaster Audigy Card and a minimal install which I have never had any issues with. Obviously a laptop has its advantages as a great space saver but have you guys had any trouble with stability? Link to post Share on other sites
ChrisPointon 0 Posted November 23, 2004 Report Share Posted November 23, 2004 QUOTE Obviously a laptop has its advantages as a great space saver but have you guys had any trouble with stability? Non whatsoever. Not a glitch, not a crash, not a blue screen of death - ven after 6 hours of continuous running. If they were unreliable, people wouldn't use them http://www.dj-forum.co.uk/html/emoticons/smile.gif . In fact if you read another thread, you'll see a post I made, where I have stated that I personally have found a laptop to be more stable than some professional twin cd players that i've owned in the past!. Link to post Share on other sites
MadGutts 0 Posted November 23, 2004 Report Share Posted November 23, 2004 (edited) I now rip at 192... But when i started, i used 128... Only when i'm playing with a 10K rig can you tell the difference - but that is only if your ears a trained to what should, and shouldn't be coming from the speakers. Most people cant tell the difference when its played, so there is no real problem with either bitrate. I would recomend 192, purely because it seems to be the standard setting with the majority of encoders. I too use a pc instead of a laptop. Not for stability reasons though... A laptop should be as stable as any pc. But with a desktop style pc, you can add other benefits that are not available to a laptop. e.g. RAID - i have a mirrored pair of drives, if 1 dies, the other keeps the machine running. 2 Graphics cards - I use the visualisations from OtsDJ, and when i'm running presentations. So the second card runs the digital projector. Better cooling - Laptops can get very hot - mainly AMD processors and also the PSU can get very hot on a Laptop. Whereas i have extra fans and a fan speed controller so the pc runs quietly and never gets warm. Some laptop psu's will generate "audible noise" but that is due to there construction. They are what is know as Double insullated. Basically there is no way the earth or power from one side of the psu can get to the other. They have a "Chopping transformer" which is why they cause noise. I have never had this problem with any of my sound systems and my notebook. But when i used someone elses sound system there was an awful amout of noise. But this was down to the whole system being setup wrong. All the grounds were lifted, but the cables were run too close the the main power so the noise was induced via the cables. Edited November 23, 2004 by MadGutts The only UK number 1 record to contain in its lyrics the title of the song which knocked it off number 1 was... Bohemian Rhapsody by Queen (lyric: "Mamma Mia")! The Forums Computer Nutter and expert! Discos, Lighting and Sound Reinforcement in and around Oxfordshire, Wiltshire, Gloustershire and Buckinghamshire etc... Special FX Entertainment Services Link to post Share on other sites
RobbieD 0 Posted November 23, 2004 Report Share Posted November 23, 2004 QUOTE (Discodunc @ Nov 23 2004, 06:56 AM) But the odd's of what you say may happen are........... well lets just say that i am more likely to win the lottery and be struck by lightning on my way to collect it. Sorry to contradict you but if you disconnect the earth on a piece of equipment, you are many times more likely to be electrocuted, than win the lottery! But however small the risk is, it should never be taken - especially as we are working in public places. What if a guest was electrocuted, and it was found that you had put a switch in the earth connection? (I don’t think your PLI would cover you for that claim!!) NEVER DISCONNECT THE EARTH Link to post Share on other sites
ChrisPointon 0 Posted November 23, 2004 Report Share Posted November 23, 2004 So why the interference and why the safety hazard??. Most PSU's nowadays are switch mode, this means that there is no heavy transformer, making it lightweight and more efficient. However... As already mentioned the switching at 50 times a second (50hz) of the mains frequency through a poorly suppressed PSU can create mains noise, which feeds down the mains wire and more especially affecting any floating non voltage carrying wire such as the mains earth. However this can be safely prevented by fitting a ground loop isolator. It also means that unlike the fairly high isolation (Seperate coils of wire) offered by a conventional wound transformer most of the components inside the Switch Mode PSU are at mains potential, which means they are either already carrying high mains voltages, or if they or the circuit was to fail, then they would become live http://www.dj-forum.co.uk/html/emoticons/scared.gif . Thus any component such as a regulator or transistor which is screwed onto a metal heatsink, can break down internally and fail causing the live mains voltage to appear on the component and also the metal heatsink. Equally most switch mode designs boost the mains voltage to 300v+ DC in parts of the circuit. DC voltages are lethal since it wont cause your muscles to 'throw you' away from the live source like AC can. So touching a live DC voltage will cause your muscles to contract and to grip the item tighter rather than throwing you across the room!. High DC Voltages can also flash over to other metal parts which is probably why close metal objects inside the PSU are earthed in the first place. Also bear in mind that some in circuit interference supression also relies on a mains earth to work properly, so by disconnecting it, not only are you defeating its CE approval but also could be unknowingly feeding spikes and surges into your laptop via the power lead- which may cause damage if a surge was to appear on the mains. In other words, a Switch Mode PSU is a more likely candidate to fail and become a hazard than most other electrical items. Link to post Share on other sites
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