How to run 2 amplifiers?

[notroubleclubber]

Ive got a large wedding coming up and i have a set of class D 15n subs with the associated 12" tops.
I find when using them together with my EP4000 amplifier they sound alot quieter at volume.

I also have a WA1300 amp and was wondering if i could use the 2 amps (one for tops, one for subs).

How would you recommend wiring these - what amps to use with what speakers?
Both amps can run mono.

Id prefer not to have to buy a seperate crossover if i have to as money is tight and its only next week.

Could i just use a phono lead splitter from the main output of my mixer to split the output to both amps and then one amp as mono(which on?)? Would this work just for this one gig?

[Shakermaker Promotions]

A Behringer Super X Crossover is cheap as chips (around £60.00) and does the job.
Sorry if I am not helping but I was in the same position. I got the Super X and sorted.

[notroubleclubber]

Thing is i got a holiday to pay and cant afford £60 at the mo!
When i get some money together i will get one.

[Shakermaker Promotions]

What mixer do you have?
If it has a Balanced XLR on it and also a Main Output or Booth then you can connect those up to each amp and have them running.

I was asked that if you use the XLR Balanced and also have a Phono Main Output, does using the XLR Balanced disable the Phono Main? I haven't tried it as I use the Crossover now but does anyone know? If it IS the case and you DO have a Booth output too, use that.

[notroubleclubber]

What mixer do you have?
If it has a Balanced XLR on it and also a Main Output or Booth then you can connect those up to each amp and have them running.

I was asked that if you use the XLR Balanced and also have a Phono Main Output, does using the XLR Balanced disable the Phono Main? I haven't tried it as I use the Crossover now but does anyone know? If it IS the case and you DO have a Booth output too, use that.


mmmm, didnt think of that.
Im using a numark cd mix2 as my main output mixer. I normally use a laptop with hercules rmx, output of that goes into my aux channel of the numark cdmix2 unit and then main output of that goes into the amp.
The numark does have XLR outputs as well as phono outputs so maybe this is an option? Can someone let me know as i dont have any XLR leads to try it and wouldnt want to buy some then find they dont work.

[Shakermaker Promotions]

Try it with a couple of Mic leads if you have them?

[notroubleclubber]

The only mics i use have jack plugs. I dont do alot of mix work ;)

[TonyB]

Yes you can use a splitter cable to feed both amps, i.e. master out from mixer to each channel input for each amp.

Each amp has two inputs, XLR and TRS jack. The usual way to do it is to daisy chain the amps, e.g. master out from mixer to input of one amp and then use the other input (they are connected in parallel internally) to run a cable to the input of the other amp.

I would use the berry for the bass bins and the WA1300 for the tops.

[notroubleclubber]

So just to clarify - i use either xlr or rca/phono to amp 1(which could be the ep4000 in bridged mode) then from the input of the ep4000 to the input to wa1300?

[TonyB]

I wouldn't run it in bridge mode. There is no need as it is powerful enough without and it could possibly overdrive the speakers, damaging them. If you connect two bins in bridge mode, each channel of the amp would be running at two ohms, which although the Berry states it can do, puts a lot of strain on the amp.

Just run a cable for each channel from the mixer to each channel input of one amp then link the inputs from that amp to the inputs of the other amp (if you are using the jack inputs get two jack TRS to male XLR patch cables or if you are using the XLR input get two TRS jack to jack cables)

[A1DL]

I find when using them together with my EP4000 amplifier they sound alot quieter at volume.

As one would expect. Putting it really simply, running an active system enables each of the amplifiers to concentrate on the frequencies they are "responsible" for.

You'll end up with a clearer, louder sound and (on a simple 2-way active system) the benefit of being able to adjust the LF/MHF+HF crossover point, to your preference.

If you can't afford to buy a crossover, the Behringer ones can be hired for £5-£10 per day, which also will enable you to try before you buy.

[notroubleclubber]

I noticed that the ep4000 has a lower filter switch. Is it worth turning this on when using this as the sub amp?

Also, so if i "daisy chain" one amp from the other i dont need to use a rca/phono splitter?

[A1DL]

if i "daisy chain" one amp from the other i dont need to use a rca/phono splitter?

Correct. If your amplifier/s don't have "link" XLRs per channel, they probably have an XLR and a TRS jack per channel, which serve the same purpose, i.e. use a short TRS to XLR jumper lead to come out of one amplifier into the next.

[TonyB]

I noticed that the ep4000 has a lower filter switch. Is it worth turning this on when using this as the sub amp?



Depends what frequency it cuts at. It will cut the lower frequencies. If it is around 30 or 40hz cut and the speakers can only go down to say 40hz then you may as well use it as it is pointless the amp using power to produce frequencies the speakers can't reproduce.

If it cuts them at a higher frequency e.g. 120hz/150hz then don't use it as it will cut out most of the bass.

[notroubleclubber]

Just checked and both my amps inputs are either or xlr or jack. So if i get a xlr to jack lead x2 then i can go xlr mixer out to xlr amp1 in then jack from amp1 input to jack amp2 input or something like that?

Reading up on balanced xlr outputs, if i use the xlr output on the numark cd mixer into xlr input amp1 then it would be louder than using jack/rca/phonos?

Also im guessing if i use xlr output from mixer to xlr input on the amp, if i then choose to go to another amp via either jack to jack or jack to xlr then it wont be balanced and hence quieter to the second amp?

Im just wondering if i can get away with just going from rca/phono on the mixer out then splitting it as ive already got rca splitters then one going to each amp (2 channels per amp) then that will do for this particular gig? Will i hear much difference than daisy chaining the amps?

[TonyB]

If you already have a splitter that will split the output from the mixer to feed both inputs of the amps then it should be fine to use it.

The jacks are TRS (Tip Ring Sleeve) - like the jacks on a pair of stereo headphones which are balanced. You can use TR jacks (Tip Ring) but it just means that it won't be balanced.

In practice, you probably won't hear much difference in the volume and if there was, just adjust the gain control on the amps to compensate. Just make sure you don't let the amps clip (even mild clipping).

Rather than spend money on additional cables, save the money and put it towards a Crossover when you can afford one :)

[notroubleclubber]

I think im going to split the signal with the spliiters i have for that one gig and then save for a crossover. Im watching some on the bay as we talk!

[DJMaxG]

The idea of running one output from the Master and one from the booth does work, however you may be without an output VU for the booth. I have ran my system that way before.

I would use a digital driverack ideally though, or an active (powered) external crossover, if budget is lower.

[notroubleclubber]

I believe ive only got one master output, the only other output is the headphones.

[A1DL]

The problem with just splitting the master LR signal, is you will be sending both amplifiers a full range signal, as opposed to the LF and MHF+HF signals they want. This will result in the LF amplifier feeding the subs with program that they cannot reproduce and the tops running as full range cabs. I doubt the sound would be as good as passively linking the boxes as described in the OP.

As Max states above, you really need a crossover to do the job properly.

[TonyB]

We are going round in circles here! It has been explained that the best option would be to use a Crossover or other LMS but the op doesn't have one and at this stage doesn't intend getting one for a one of gig.

He has a splitter that will do the job for now so why keep harping on about something the OP doesn't want to do at the moment when he can get away with what he has got?

[A1DL]

We are going round in circles here! It has been explained that the best option would be to use a Crossover or other LMS but the op doesn't have one and at this stage doesn't intend getting one for a one of gig.

He has a splitter that will do the job for now so why keep harping on about something the OP doesn't want to do at the moment when he can get away with what he has got?

No one is "harping on". The detrimental effect of sending full range signals to both amplifiers was not mentioned until my last post, and the OP may not have understood this, hence why I mentioned it. I think Max was simply summarising what the options were and for the sake of ~£5 day hire there's no excuse not to do the job properly.

Whether two amplifiers with a common signal will "do the job" any better than his current passive single amplifier setup is of course debatable and what may sound acceptable to your ears could sound pants to mine.

[Excalibur]

A Behringer Super X Crossover is cheap as chips (around £60.00) and does the job.
Sorry if I am not helping but I was in the same position. I got the Super X and sorted.
Agreed.

Yes you can use a splitter cable to feed both amps, i.e. master out from mixer to each channel input for each amp.

Each amp has two inputs, XLR and TRS jack. The usual way to do it is to daisy chain the amps, e.g. master out from mixer to input of one amp and then use the other input (they are connected in parallel internally) to run a cable to the input of the other amp.

I would use the berry for the bass bins and the WA1300 for the tops.
That would work.


Just checked and both my amps inputs are either or xlr or jack. So if i get a xlr to jack lead x2 then i can go xlr mixer out to xlr amp1 in then jack from amp1 input to jack amp2 input or something like that?

Reading up on balanced xlr outputs, if i use the xlr output on the numark cd mixer into xlr input amp1 then it would be louder than using jack/rca/phonos?
Also im guessing if i use xlr output from mixer to xlr input on the amp, if i then choose to go to another amp via either jack to jack or jack to xlr then it wont be balanced and hence quieter to the second amp?
Im just wondering if i can get away with just going from rca/phono on the mixer out then splitting it as ive already got rca splitters then one going to each amp (2 channels per amp) then that will do for this particular gig? Will i hear much difference than daisy chaining the amps?
Don't think the difference will be apparent unless you split unbalanced signals more than once.
As stated, if you use cables XLR male to Stereo Jack ( three segments, as opposed to two )
Bad move.


The problem with just splitting the master LR signal, is you will be sending both amplifiers a full range signal, as opposed to the LF and MHF+HF signals they want. This will result in the LF amplifier feeding the subs with program that they cannot reproduce and the tops running as full range cabs. I doubt the sound would be as good as passively linking the boxes as described in the OP.

As Max states above, you really need a crossover to do the job properly.
Specsavers. I just read Tony agreeing with Max. :eek: :eek: Perhaps I should cu down on my drinking? :confused:

No one is "harping on". The detrimental effect of sending full range signals to both amplifiers was not mentioned until my last post, and the OP may not have understood this, hence why I mentioned it. I think Max was simply summarising what the options were and for the sake of ~£5 day hire there's no excuse not to do the job properly.

Whether two amplifiers with a common signal will "do the job" any better than his current passive single amplifier setup is of course debatable and what may sound acceptable to your ears could sound pants to mine.

Agreed.Some folk prefer to run subs from one amp, and tops as full range. To each his own. I'm a crossover/frequency split man myself.

There is also what is possibly a simpler way. I'd expect both amps to be able to run mono both sides, ie the left channel only is fed with a signal, but it goes to both amp channels. Feed one amp with one xlr cable from mixer left out, and run subs, t'other amp right hand mixer out and run tops. No extra cables, no splitters. Simples.