hardtailstar Posted October 8, 2012 Posted October 8, 2012 Hi All, I dont know if this is the right forum but.... My school is after a new PA system or new amp to power the speakers etc. The speakers have the cables that look like guitar cables That is all I know if you need anymore info please do ask. Thanks in advance.
pcstru Posted October 8, 2012 Posted October 8, 2012 PA systems often have 5mm jacks (headphone style plugs) for speakers. If the speakers are OK, why not just buy a new AMP? I've used Berringer products as PA for a live band. It's relatively cheap but reasonable quality - or overall good value.
laserblazer Posted October 8, 2012 Posted October 8, 2012 What will it mainly be used for. How many microphones will you use. How big is the environment it will be used in? Remember, if you are planning to use the existing speakers with a new amp, you need to make sure they are the right impedance and will handle the power of the amp. Speakers usually have the ratings on a plate at the back. What's your budget?
mjs_mjs Posted October 8, 2012 Posted October 8, 2012 What will it mainly be used for. How many microphones will you use. How big is the environment it will be used in? Remember, if you are planning to use the existing speakers with a new amp, you need to make sure they are the right impedance and will handle the power of the amp. Speakers usually have the ratings on a plate at the back. What's your budget? What ^^ said, but also - what's your reason for buying something new - is it a new system or repairing an old one?
mjs_mjs Posted October 8, 2012 Posted October 8, 2012 FYI they're 6.3mm or 1/4inch jacks, or should be for speaker level signals.
hardtailstar Posted October 9, 2012 Author Posted October 9, 2012 Cheers all, it will be used for in the school hall and out on school field. The existing amp is dead pretty much, it works one minute and the next it doesnt. Ill find the info out and let you all know. if you can help?
sjatkn Posted October 9, 2012 Posted October 9, 2012 We had a similar problem. Eventually we got the cash for a Yamaha Stagepas 500. For us the advantage was the amp packs into a speaker and the cables into the other, that and a 'suitcase' on wheels. All in all a good investment and very easy to transport around the building.
robk Posted October 10, 2012 Posted October 10, 2012 The yamaha kits are very good for small stuff. Very easy to rig and pack. Seem good value for money.
laserblazer Posted October 10, 2012 Posted October 10, 2012 We've got one of these Kustom KPRO100 PA System 100w that we used to use in the hall until the PTA funded a bespoke system. We use the Kustom one for Sports Day etc., but with hindsight I'd get the 200W version. The speakers are wedge shaped and by connecting the "line in" to the "line out" of the hall system, they make great stage monitors, laid on their side.
januttall Posted October 10, 2012 Posted October 10, 2012 the amp should be above the power consumption of the speakers connected, but don't go way above you can blow speakers if its turned up to loud. so if you have 2 100W speakers you will can use a 200W amp. but a 250w or 300w would work just as well as long as its not turned up to far, and would allow for additional speakers. most amps are 2 channel (stereo) and don't worry to much about the connectors they are easy to change. and difrent amps will always have a different connector. normally input is a 6.5mm Jack or an XLR. and output to speakers is a spekon connector but it can be a 6.5mm jack the spekon is more stable and far less likely to fall out as it verry securely locks into place. pretty much any mixer will work just make sure that it has enough channels (microphone / CD /PC inputs) for you. and wiring from stage to mixer just use stage cable again check the length and number of cables in it normally these cables are very well shielded. i would put all of this on the same ring-main i have had issues where the amp and the mixer are on different mains supply's and the buzz from the equipment is unreal soon as its on the same ring nothing. ive even had the buzz running through the vga because a projector was on a different ring the PC was plugged in the amp and on the same ring but the difference between the projector and the amp via the pc still caused a massive buzz.
dhicks Posted October 10, 2012 Posted October 10, 2012 pretty much any mixer will work just make sure that it has enough channels (microphone / CD /PC inputs) for you. and wiring from stage to mixer just use stage cable again check the length and number of cables in it normally these cables are very well shielded. We're in a similar situation to the original poster, trying to figure out the best way to organise our audio kit so it's easy to transport between several different venues (assorted halls and churches that we use for various events). At the moment we have a large wheeled 19" case, about half a full-size rack in height, which is very sturdy but proving a bit much to transport aound. I'm thinking of splitting that up into sveral discreet comonents, with each one in its own flight case ready to be picked up and moved around. If I split up the amp and the mixing desk then I can place the mixing desk somewhere I can actually hear the sound being produced instead of having to sit near the speakers (i.e. I don't have to be stuck at the front, getting in the way). However, that does mean that any wired microphone has to be connected back to the mixing desk. Is that likly to be practical, having, say, four microphone cables and the mixing-desk-to-amp connecting cable all in a bunch running maybe 10 metres? Is there maybe a multiplexing option of some sort that lets me plug in a bunch of wired mics at the front of the stage and gets the signals back to the mixing desk for me?
pcstru Posted October 10, 2012 Posted October 10, 2012 Is there maybe a multiplexing option of some sort that lets me plug in a bunch of wired mics at the front of the stage and gets the signals back to the mixing desk for me? One of These.
dhicks Posted October 10, 2012 Posted October 10, 2012 One of These. Looks perfect, just the thing, thanks.
nicholab Posted October 10, 2012 Posted October 10, 2012 Also the DXR series powered speakers form Yamaha looks amazing.
laserblazer Posted October 10, 2012 Posted October 10, 2012 I'm not sure I would agree with getting an amp that's rated higher than the speakers. The tendency is to turn the volume up to 11.
pcstru Posted October 10, 2012 Posted October 10, 2012 I'm not sure I would agree with getting an amp that's rated higher than the speakers. The tendency is to turn the volume up to 11. Generally that's OK. The real danger is from amplifiers that are underpowered for a speaker.
laserblazer Posted October 10, 2012 Posted October 10, 2012 Generally that's OK. The real danger is from amplifiers that are underpowered for a speaker. As I read it, the article says it's not a problem to underpower a speaker but it is a problem to overpower it. Which is how I've always understood it. Anyway, the long and the short is have a decent matched system. I suppose it would be ok to have a bigger amp if the speaker cables are fairly long. There's quite a lot of loss on a cable and a higher powered amp would compensate for the loss. Trouble is, someone will then use it with short cables and overdrive the speakers.
pcstru Posted October 10, 2012 Posted October 10, 2012 (edited) Sorry, yes it does. The thing with underpowered amps is they are more likely to clip before you hear distortion from the speaker, so when you turn it up to 11, it clips, the power doubles and your speakers very suddenly go bang. With an overpowered amp, you approach the limits of the speakers gradually and you can generally hear them start to distort (they tend to reach the limits of the cones excursion and make a fart like noise). It starts to sound very bad usually long before you actually damage the speaker. Edited October 10, 2012 by pcstru
dhicks Posted October 10, 2012 Posted October 10, 2012 The thing with underpowered amps is they are more likely to clip before you hear distortion from the speaker, so when you turn it up to 11, it clips, the power doubles and your speakers very suddenly go bang. What do you mean by "clip"? Do you mean that if I have an underpowered amp it might at some point suddenly stop powering one of the two speakers and put all of its power in to the one speaker, damaging it? I currently have our amp turned up as far as it will go, I generally then connect either one or two speakers before switching the whole thing on with the volume on the mixer board turned right down. I've not had a problem up until now, but is there the potential for me to forget to make sure the volume is right down on the mixer one day and blow the speakers? I think we have a properly matched amp and pair of speakers, by the way, so this might not be a problem for us.
pcstru Posted October 10, 2012 Posted October 10, 2012 Clip means that the signal peak is cut off - the output of the amp effectively changes from AC to DC and as a consequence of that, the power increases (twofold is about right). It doesn't put the power from one speaker to another, you can happily blow two speakers at a time :-)! When setting up, you should connect up the cables to the power amp before switching it on (inputs and outputs). I personally tend to set up with volume switches turned down. Occasionally I've had components in the chain go awry in peculiar ways and apart from anything else the results can be very horrible and very loud. It's nice to catch them before they cause hearing damage. 1
Andrew_C Posted October 10, 2012 Posted October 10, 2012 A more powerful amp is correct, but... You do need to set the gain structure correctly, or the speakers are toast. Less likely that with an over-driven, underpowered amp, but possible all the same.
laserblazer Posted October 10, 2012 Posted October 10, 2012 Sorry, yes it does. The thing with underpowered amps is they are more likely to clip before you hear distortion from the speaker, so when you turn it up to 11, it clips, the power doubles and your speakers very suddenly go bang. With an overpowered amp, you approach the limits of the speakers gradually and you can generally hear them start to distort (they tend to reach the limits of the cones excursion and make a fart like noise). It starts to sound very bad usually long before you actually damage the speaker. I see what you mean. A sensible person would back off the power when the speakers started to show signs of distress. There's just one problem with that. We don't tend to work with sensible people So, what we need are amps that have a lot of built in protection. I didn't know about the clipping effect. Thanks for that.
cpjitservices Posted October 18, 2012 Posted October 18, 2012 being a Hi-Fi enthusiast I advise to get an amp rated to match the power of the speakers, if you under-power your speakers you'll damage the amp as the amp has to work harder to power the speakers possibly even blowing caps if you don't have proper relay protection inside the amp circuitry, you also don't want to over power your speakers as you can blow them if you don't have speaker protection within the amp, some amps will detect what power speakers you have an add cut in protection if the speakers are being over powered if you've cranked the volume.
Oaktech Posted October 18, 2012 Posted October 18, 2012 We've got one of these Kustom KPRO100 PA System 100w that we used to use in the hall until the PTA funded a bespoke system. We use the Kustom one for Sports Day etc., but with hindsight I'd get the 200W version. The speakers are wedge shaped and by connecting the "line in" to the "line out" of the hall system, they make great stage monitors, laid on their side. Please don't do this... it sounds awful and is almost impossible to prevent feedback on. Any time you have a PA problem, rub some yamaha on it.
Andrew_C Posted October 18, 2012 Posted October 18, 2012 being a Hi-Fi enthusiast I advise to get an amp rated to match the power of the speakers, You might want to do that in your living room, that is not what we are discussing here. The correct thinking is that the amp should have a rated power higher than the speakers.
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