Which Power Amp

**Steve Williamson** · **11-22-06, 07:03 PM**

OK, narrowed down to a choice of two amps, I require 4 amps to power the 7 speakers leaving one channel free for future use.

Choice 1:

Behringer EP1500 - AU$460 each

Choice 2:

Biema W220i - AU$290 each

Anyone have personal experience with both amps

**Danny** · **11-23-06, 11:39 PM**

Just by looking at the specs (i haen't heard any of these amps) the Behringer looks like the better one

**Sonnie** · **11-24-06, 12:24 AM**

Same here... although I'm not sure how "unweighted" S/N Ratio compares to "a-weighted".

I wonder if the difference would be noticeable for the extra $170 per amp?

**eddthompson** · **12-09-06, 03:13 PM**

get the cheapest!

edd

**drf** · **12-18-06, 02:10 AM**

get the behringer, although I hear good things about biemma I have no first had experience with them.

The behringer can do 260Watts into 8ohms(I think?) and will drive a 2ohm load if needed, I can't see the biemma doing that (although you never know). Also I hear that the behringers are re-cased QSC RMX series amps.

http://www.qscaudio.com/products/amps/rmx/rmx.htm I believe the RMX 1450 is the same as the EP1500.

hope this helps.

dr f

**eddthompson** · **12-18-06, 07:40 AM**

the behringers are a backwards engineered clone of the qscs, considerbly lower quality i belive, but CHEAP!!

edd

**drf** · **01-03-07, 02:16 AM**

It wouldn't have to be backward engineered as the schematics are freely available. But I would assume you are correct and they would use significantly cheaper parts.

Steve: which one did you get? did you get one?

**Steve Williamson** · **01-03-07, 04:11 AM**

Our house should be finished building mid feb, I have a huge shopping list so it will be the Biema's for now, if they suck, I will ebay and go for the behringers.

I won't have the chance to test both out on the Jamo D6's so will have to settle with cost over spec for now. Already made the cabinet to house the four amps and have 4 double power points on their own circuits to run the AV gear.

**drf** · **01-04-07, 03:44 AM**

Cool, wil you be getting the biemmas' from altronics?
also, won't having 4 power points on seperate lines cause ground loop problems?

**Steve Williamson** · **01-04-07, 06:47 AM**

I was looking at getting them from Altronics, but selby on ebay has better pricing sometimes. not sure about the ground loop problem, I thought seperating the lines stopped any ground loop problems as no other equipment is on them.

**drf** · **01-04-07, 03:42 PM**

It doesn't actually seperate them though because the australian standard for house wiring is that the Neutral and Earth are connected together at the meter box, If the ground loop only goes as far as the power point then the voltage difference will be less than if the loop extands all the way back to the meter box.

this article Explains it better than me:

http://sound.westhost.com/earthing.htm

cheers
dr f

**Steve Williamson** · **01-05-07, 05:11 AM**

Why, I'm confused. What is the best way to power the 4 amps plus receiver and HTPC etc? Should I just use a power strip from the same power point to reduce the problem of unequal voltages over the earth and neutral then or something more elaborate like the power conditioners?

**drf** · **01-05-07, 05:50 AM**

you may actually be able to do that, whats the maximum current draw on those amps? The power fuse should tell you. A standard outlet can handle 10amps (15 if its the only one on the circuit) so add together all that you wish to run of the one outlet and see if it is too high.

As the wiring in your house is all new you may not notice ground loop hum anyway, but I can garrantee it will start as the connections and cabling deteriorate over time.

If it proves to be a problem the first thing i'd try is to run the reciever and htpc of one point, all the amps of another and anything that is double insulated (has no earth pin and the box in box logo) of the third point. Then you only have one, maybe two loops that could be an issue.

on the note of power conditioners, it has been my experiance that some of them are just snake oil, some do a little good but I have yet to use one that does what the box suggest it can do.

I wouldn't worry about ground loop issues untilt hey happen.

**Steve Williamson** · **01-05-07, 06:59 AM**

At 300w at half power times 4 that should be around 5 amps, maybe going to 10 amps at times

so I shouldn't have any probs running of one circuit for the amplifiers.

I agree about the conditioners, may look at whole house surge protection though.

Looking forward to writing up on the install and testing.

**Wayne A. Pflughaupt** · **01-05-07, 11:04 AM**

Quote:

Steve Williamson wrote:

Why, I'm confused. What is the best way to power the 4 amps plus receiver and HTPC etc? Should I just use a power strip from the same power point?

NO!! Never plug power amps into a power strip!! Especially not that many! And especially if you’re going to be driving them hard. If you ever took one of those things apart and saw how cheaply they’re made, it would scare you!

If you must use one, make sure it uses “real” electrical outlets – i.e., the same kind used in your house – and that the power cord uses 14 ga. cable. It’s hard to find any like that, though. Fortunately, it’s cheap and easy enough to make something yourself, using off-the-shelf parts from the electrical aisle at the hardware store.

Regards,
Wayne

**drf** · **01-05-07, 10:27 PM**

Quote:

Steve Williamson wrote:

At 300w at half power times 4 that should be around 5 amps, maybe going to 10 amps at times

so I shouldn't have any probs running of one circuit for the amplifiers.

I agree about the conditioners, may look at whole house surge protection though.

Looking forward to writing up on the install and testing.

I have seen sparkies wire up to ten outlets on the one circuit, the good thing about having 240 mains is that we draw half the current of 120V appliances. I agree with Wayne, stay away from powerstrips, use either an orange tradies box or comercial power board. Although 80% of the ones currently availiable would work, its not worth the risk.

**Danny** · **01-06-07, 11:59 PM**

You may be able to find a good quality Rack mountable power distro. Saw some that were rated to supply 15 Amps at 240Volts.

**Steve Williamson** · **01-07-07, 03:34 AM**

One quick question, using seperate power amps driven from the pre-outs from the receiver, does the receiver still control the volume? How is this possible if the pre-outs are line level? Am I stupid?

**drf** · **01-07-07, 04:40 AM**

yes it should depending on the reciever. All a power amp does is increase the signal enough so it will drive a speaker. basically the size of the input signal is directly proportional to the size of the ouput, therefore when the preamp increases or decrease the level of the signal it changes the level the power amp sees and thus the amount of amplification. Nearly all (exceptions being some guitar amps) effects or sound controls like tone, balance, volume, EQ and compression/expansion are added/manipulated at this preamp level.

hope this makes sense,
dr f

**intelonetwo** · **03-01-07, 08:52 PM**

Are these amplifier going to used to drive you front speakers?

**Steve Williamson** · **03-04-07, 03:56 AM**

Quote:

intelonetwo wrote:

Are these amplifier going to used to drive you front speakers?

All seven channels, only the subs are self powered.

**intelonetwo** · **03-04-07, 11:30 AM**

Typically these types of amplifier are not used to drive front speakers as they have typically have inferior specs than Hifi, or high end amplifiers. Now, I say typically because there are a few pro amps that have been used by audiophiles with great success. If these amps are those amplifiers I can't say but you should know.

**eddthompson** · **03-04-07, 01:46 PM**

I use the behringers, they were cheap, go loud, sound excellent to me (i must have plugged ears).

Given cost, id always be prepared to try a single amp, if its not to your likeing, ebay it.

edd

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