Advice On Amp

[StageStar 0]

Hi, I have read the pinned article on buying amps and speakers but am still a little confused.

At present I have 2 x Peavey Messenger Pro 12's 250w rms 9 (rated 4 ohms) run from a phonic power pod 740 plus mixer amp 220w per channel at 4ohms. I wish to add 2 x Peavey Pro Sub MK2 subwoofers 300w at 4 ohms. Because my power pod is also my mixer I am fairly sure I will need to run my subwoofers from a different amp (via line out from the mixer/amp). What power amount would be suitable for these subwoofers? 200w at 4 ohms or maybe 250w at 4ohms per channel or would I need to go the whole hog to get the most from these and get an 300rms per channel amplifier?

 

Thanks for taking the time to read and any advice greatly appreciated.

[vokf 0]

Personally, I'd get at least a 300WRMS Amp, and ideally see if it will drive 2Ohm loads.

 

The Sub has a built-in crossover, so if your "top" amp failed, you could come out of the subs and drive the tops - it just gives you a few options and some redundancy if an amp does fail. If you did this, the speakers would be in Series, giving a 2Ohm load on the amp - some amps do not like this, so if you see one that lists this, then its worth considering.

 

 

In an ideal world you would filter the signals before it gets to the amps, and this would give the best quality, an active crossover would get the best out of the system - your sub amp will only be amplifiying "sub sounds", and the amps for the tops would also be only covering the range they function under.

Just an idea - and possibly worth borrowing/hiring one.

 

[TonyB 0]

I have Peavey Pro Bass bins and I run them from a T Amp 1050 that gives 525w per channel at 4 ohms. Gain is set to 12 O'clock which is half way.

 

Edit. The Peavey bass bins have a crossover in them that is designed so that if you link 4 Ohm tops to them, the total impedance would still be 4 Ohms.

 

An active crossover would be a good idea if you didn't have a powered mixer but as you have, the easiest way would be to use the master outs to the amp.

Edited July 31, 2009 by TonyB

[superstardeejay 0]

TonyB is right about the speakers, the amp wont mind as it'll still be a 4ohm load..however the power output from the amp will now be split across both tops and bins..meaning you wont gain any extra power output.

 

I'd say get a slave amp for the bins, but keep the powerpod for the main mixer and the tops. If the bass amp fails, well you can still manage a gig without them...as you are doing at the moment!!

 

Choose a slave amp of at least 300W and preferably a little more to ensure it isnt always running flat out. Any 4 ohm load will make an amp run hotter than 8 and so factor this in especially if you have them in a nice warm case. As the slave amp will be handling bass, get a quality one with a high 'damping factor'...look for something over 300 and the higher the better. If this figure isn't mentioned in the spec, it may be because it's poor. Damping factor contributes enormously to the tightness of the bass response.

 

 

Edited July 31, 2009 by superstardeejay

[StageStar 0]

TonyB is right about the speakers, the amp wont mind as it'll still be a 4ohm load..however the power output from the amp will now be split across both tops and bins..meaning you wont gain any extra power output.

 

I'd say get a slave amp for the bins, but keep the powerpod for the main mixer and the tops. If the bass amp fails, well you can still manage a gig without them...as you are doing at the moment!!

 

Choose a slave amp of at least 300W and preferably a little more to ensure it isnt always running flat out. Any 4 ohm load will make an amp run hotter than 8 and so factor this in especially if you have them in a nice warm case. As the slave amp will be handling bass, get a quality one with a high 'damping factor'...look for something over 300 and the higher the better. If this figure isn't mentioned in the spec, it may be because it's poor. Damping factor contributes enormously to the tightness of the bass response.

 

Thanks everyone for the advice. I think this is possibly the way to go - had never heard of 'damping factor' so this particularly useful. Will start searching for a suitable amp but on a budget so may need to go second-hand.

 

[gadget 0]

Hmmn both Amps I have have no damping factor figure quoted :/

 

I think I'll also be looking for a better amp to power my pair of peavey pro 15's. Both are underrated for the speakers anyway (one is 250w RMS 4ohm and the other is 275w RMS 4Ohm).

 

 

[superstardeejay 0]

damping factor pdf

 

Click the above for further reading on Damping Factor, this is a paper from Crown.

 

Most DJ amps damping factors average around the 200-250 mark eg CMark, Thomann, Kam, Numark etc.

 

The big Crown Macrotechs (all 3 grand of it) had a figure of 5000!!

 

 

 

 

[spinner 0]

The Thomann T.Amp 2400 Mk. X has a damping factor of 500:1/1kHz/8Ohm.

 

That sounds good although I'm not sure if the way it is expressed is slanted to make it appear better than it is.

[norty303 0]

Don't get too hung up on damping factor as a spec - once it's above a certain value you can pretty much ignore it, and it also varies with frequency and is often embellished as another spec to sell product.

 

Any halfway decent amp will have enough for your use. It's only really applicable for bass use and even then, you'd only really need to start looking closely at it if running long cables and low impedances.

 

I would also seriously discourage running an amp at 2R if possible. Only really good amps (read: expensive) do it well, and it seriously reduces the mean time before failure. Handy as a get out of trouble scenario if an amp goes down on a gig but not recommended for everyday use.