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Sujet: Amplifiers?

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well i always been using my only amp, a genimi x4 or something like that, now i want to buy a new one but i dont know alot about amps......what are ohms for whats the difference between 2,4,8 ohms....................what that about stereo? mono? bridge?.................what are some good brands of amplifiers?.......................one more question, is there a difference other than size and weight between having PA's or amp with speaker,which do you prefer?
 

Posté Thu 08 May 08 @ 4:56 pm
Scribe, when using my rig I have a powered mixer and two mackie 12" cabs. I am not hot on the powered speakers because they are so heavy. If you dont need the extra channels on a mixing desk then go for a rack mountabkle PA amp like a Peavey...in fact there are so many makes its hard to pick one out.

Ohms is the measure of resistance in the speaker cabinet, if you put two 8 ohm spekers in serial (ie connect the amp to one cab then from that cab to the next) then the resistanmce will go down to 4 ohms. The amp you buy will have a minimum ohm level on each channel and you should not go below this (your amp could blow) but if the ohm rating is too high on the speakers you will not get as much power to them.

Basically if you had an amp that delivers from 4 ohms per channel get either 4 or 8 ohm speakers if you are only having 1 pair on each channel or 8 or 16 ohm speakers if you are using 2 pairs such as a trop speaker and a bass bin on each channel.

I love the mackies they are reasonably priced and as hard wearing as....well as a hard wearing thing.

Mono on the amp sends the same signal to both left and right channels, stereo takes the 2 signals from a stereo cable and sends one to each side (left & right) Bridge uses both power channels through one output doubling the power but with the two sides of the stero mix channeld together. if you can stick to stereo.

Clear as mud?

John
 

thank you very much ☺
 

good name brand amps are Crown, QSC, Crest mackie... When looking for a Amp.. Look for one the can handle any where between 300 - 400 watts rms in 8 ohms. speakers are in 8 ohms and Most subwoofers are in 4 ohms...

Good speakers are JBL, carvin, Yamaha, mackie, qsc

Always look for what an amp can push in 8 ohms for the speakers..

If you have a pair of speakers that push 400 watts rms in 8 ohms... a good amp for that would be a crown ce 2000.
if you have a pair of subs that push 600 watts rms in 4 ohms, you can use another ce 2000 because this amp will push 660 in 4 ohms rms.
The lower the resistance, the more the amp can handle.

The amps that are lighter cost more and the heavier ones cost less
 

I use a QSC powerlight amp- and it's the best thing ever! It gives 600watt into each of my 8ohm speakers. (I've got a pair of EV Sx-200s).

I would say QSC and Crown are two makes that you definately can't go wrong with. There are plently of other decent ones but I think these two are kind of industry standards. (In nightclubs, concert halls, touring bands, etc.)

Your speakers should say on the back what power rating and how many ohms they are. If you post on here what they are, as well as the make and model, then I'm sure people will recommend some good amps for them.

If your budget doesn't stretch as far as QSC or crown, there's one other amp I would recommend...

Behringer (don't laugh!) EP2500. A man in the know told me that these are pretty much idental to a QSC model (so I assume they licensed it off QSC, or just stole the design maybe!)

http://www.behringer.com/EP2500/index.cfm?lang=ENG

It does 450 watts per channel into 8 ohms or 650 watts per channel into 4 ohms. The only downside is that is is quite heavy, but then it is great sounding, poweful and cheap, so you can't have everything!

If you're speakers are rated at less whats than 450w,8ohms or 650,4ohms, that's a good thing because you should always try to have an amp that's more powerful than your speakers. I can explain why if anybody's interested, but basically it goes something along the lines of: a low powered amp means you have to crank it up to maximum to get a decent volume, then every time there's an extra loud part of a song (like a drum roll or something) your amp distorts the sound because there's not enough power, and distorted output from the amp will kill your speakers sooner or later :-(

Hope that helps.

 

Look at what your speakers can handle in 8 ohms RMS........ Then look for an amp that can push at that level or a little higher.. in RMS ( 8 ohms )
 

behinger amps are surprisingly one of the only good things they make - the 2500 is perhaps the best value i have ever seen for 350. 2x and youve got a great system
 

so is it better to buy speakers with an amp in them or buy amp and speakers separately........what the difference?...............another thing is i want lots of bass ...............what are some good subwoofers and should they be the ones with an amp built in them or separately...............................................i was thinking of buying a pair of Mackie SA1532Z Dual 15" and some subwoofers either:Mackie SWA2801Z, Mackie SWA1801Z.............................what amp would go with a pair of Cerwin-Vega EL-36B Earthquakes?
 

I prefer powered/active speakers. The company already did all the math for you. Can you get a better sound the other way? Yes, but at a price. My stuff sounds great and weighs as much as regular speakers. So this is a matter of personal taste.

Those Mackies will not need a sub for crowds of under 150-200. Those 15" speakers carry a huge amount of bottom punch. If you plan to do larger crowds then you can alway rent a sub. Do more than 5-10 a year then purchase.
 

We use QSC Amps for our three way system. (2) QSC RMX-1450's for highs and mids and (1) QSC 5050 (5,000 Watt) for the bottoms. We run the 5050 with the JBL bottoms 18 inch speakers (4 ohm,) in bridged mono for maximum punch. This is all we we can handle and still be portable.

As far as what is best this is like the Chevy, Ford, Lexus question, which is better may be what you can afford. There was a time we used Peavey and were as pleased as our budget could allow us to be.

http://home.comcast.net/~thirdrock/All1.jpg
 

Mackie powered subs and speakers are bad ass. They are not cheap, but they sound great, you dont have to mess with seperate amps and speakers. If you dont know much about amps and ohms and all that stuff, I suggest you buy powered subs and speakers. It will be easier for you and as said above the math is already done for you.
 

My problem with powered speakers is simple. You have all your eggs in one basket, if it goes down "most" won't have a back up powered speaker. We carry backup amps and speakers than can be replaced on the spot, call me paranoid. :^)
 

djrenee wrote :
My problem with powered speakers is simple. You have all your eggs in one basket, if it goes down "most" won't have a back up powered speaker. We carry backup amps and speakers than can be replaced on the spot, call me paranoid. :^)



Well said Renee...I have been using my Mackies for five years now..no failure..ever...also the same could be said if an amp blows or a speaker that are not powered.....with the powered speakers at least you always have one running......that might not be the case if you are not carrying a spare amp around...just a thought
 

Thank for helping me out with all my questions I'm going to go with some Pa speakers and some subs.............any advice with some subs.................How is cerwin vega are their pa speakers & subwoofers good?......................what amp would go with a pair of Cerwin-Vega EL-36B Earthquakes?..................any other good subs?
 

are Cerwin Vega amps capable of amplifying their Cerwin Vega subs?
 

HI mate

I have been DJing in the UK since the age of 13 (now 39). If you are like me you enjoy playing the gig and not the humping and dumping of the equipment (one of the many reasons for using VDJ instead of carting cds around). I would suggest that you base what you buy on what you need to get the job done but build in flexibility to expand if required. Rule of thumb The bigger the venue the bigger the system. I know this sounds obvious but the same rule works in reverse. Dont take a 100000watt rig to a house party(I know some guys that do).

Powered speakers are fine but they dont provide the flexibility a separate amp and speaker setup provides.

I am now a firm fan of QSC's PLX2 series amps they are very light (the most powerful one is less than 10 kilos), relyable and the range of models provides something for everyone.

JBL have a range of speakers for almost everyones budget and even the cheapest are well built and relyable.

For connecting speakers it works like this:-

Speakers are rated in Ohms and Watts. Ohms is a mesurement of resistence to electriacal current flow and is used to match an amplifier to a speaker in order to ensure the maximum available power transfer between them. Watts is simply a mesurement of how much power an amp will produce or a speaker will handle. You can connect speakers together in 2 different ways SERIES and PARALLEL. Parallel is the normal way and the thing to remember is that 2 8Ohm speakers connected in parallel is seen the same way by the amplifier as one 4 Ohm speaker.

Most power amps will drive 2 8Ohm speakers daisycahained (correct term is connected in parallel) or 1 4Ohm on each channel.

The 2 8Ohm speakers will equaly share the power from the amplifier. this is a good way to run your system as the individual speakers only recieve half of the amps output so if you have say a 500W per channel amp you can run 4 250W 8Ohm speakers with no fear of damage. If you are doing a smaller gig where just use two speakers as the 8 Ohm speakers will still only see 250W.

The single 4Ohm speaker setup is usefull for running bass cabs where the amp is required to deliver all of its power into one pair of bins.

BTW Some of the QSC amps will drive a pair of 4 Ohm speakers in parallel on each channel ( the 2Ohm output you mentioned in your first question)


DAZ
 

I WAS a user of Vegas subs, muy first pro setup had 4 sl-36B subs... they punch, but they wasnt deep and clean. After 2 years of use, I sell them and bought DAS speakers... man! incredible sound for their price. All of them powered with Crest Audio CA's series amps.

My AMPs Rack


The rear of the amp rack


To power this (only one side in the pic. Picture was taken during instalation)

 

 

Other than the speaker size whats the difference between the Mackie SA1232Z Dual 12" and the Mackie SA1532Z Dual 15"?
 

Power output....if you are not going to purchase a sub I would go with the 15" ones...they will naturally have more bottom end.
 



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