can amplifiers cause interference on each other?

[bal]

in my boot i have got 2 amplifiers. 1 is screwed to the back of the rear seats and the other is fixed to the side of my sub box.
the one on the side of the box is very close to the other one and it is at a right angle to it (so the 2 amps make an L shape) (ill get a photo)

so ive been talking to some poeple who think that the amps could be working against each other and maybe even causeing distortion in one another.

the reason for this has something to do with magnetic fields created by the amplifiers. and this is why amps are never positioned like this in professional installs.

is there any truth behind this?
should i locate the amplifiers far apart from each other at either side of the boot?

any help is greatly appreciated

 

[59 bhp is more than enough]

my amps were about 50mm apart and they never caused interferance. Mine were digitalt though so whether that has anything to do with it or not i dont know. are you getting any distortion or interferance through the speakers. i know plenty of pro jobs where the amps have bee put close together and they have been fine.

 

[micra man]

I think he is referring to the L-shape rather than them been close. Mine are close but have never caused me great problems although there has always been a very small amount of interference.

 

[bal]

yeah im more concerned about the L shape causing distortion, rather than them being close together

 

[NeX]

i don't think they generate any magnetic fields because they are sealed in metal boxes.

as for interferance, if they are grounded well with simmilar length and guage wire and they are connected together with good quality RCA Leads then you should have no problems.

the only problem i can think of is heat, you may get one heating the other etc...
but it's unlikely cos you have the whole boot open. but if it is an issue then install a fan

why not have the amps next to each other on the back of the seats?

would like to see how its looking, sounds cool

 

[Retepetsir]

my amps were about 50mm apart and they never caused interferance. Mine were digitalt though so whether that has anything to do with it or not i dont know. are you getting any distortion or interferance through the speakers. i know plenty of pro jobs where the amps have bee put close together and they have been fine.

Class-D does not mean digital amps . You've still got to send an analogue signal to the speakers.

bal, no it shouldnt really be a problem.

 

[59 bhp is more than enough]

what do you mean class D

 

[Retepetsir]

You said 'mine were digital'. What do you mean by that?

There are lots of classes of amplifier, including A, B, AB, etc, and D, which isnt digital!

 

[59 bhp is more than enough]

http://thebassbin.co.uk/shop/product/products_id/1303.html

not sure mate, this was what i had

 

[masterbiker]

How have you routed the cableing round your car? Because the power cables can create a lot of interference if they are placed near the phono leads. So put power cables down side of the car and the phono ones down the other.

 

[Ed]

Dont worry about it. The magnetic fields generated by an amp are the last things you need to worry about. BTW if you push a class D amp such as the kenwood ones you can actually see the digital stepping in the output waveform...

Ed

 

[bal]

thanks its good to know theres no problem with the L shape (i genuinely didnt think about the metal case :doh: )

i have installed my signal down one side and power down the other.

NEX - you said something that concerns me though, my earth wires are of a different guage and length.
why do they have to be the same?
(btw my amps are not the same power rating)

 

[NeX]

thanks its good to know theres no problem with the L shape (i genuinely didnt think about the metal case :doh: )

i have installed my signal down one side and power down the other.

NEX - you said something that concerns me though, my earth wires are of a different guage and length.
why do they have to be the same?
(btw my amps are not the same power rating)

well if you are not getting any interference then it doesn't matter. but the longer the wire, the higher the resistance. if the resistances are different then the Amp will try to reach ground through the RCAs instead of the earth wire and that will cause interferance. they have to be a thick enough gauge to handle the power but again the with of the cable governs its resistance (thicker being lower resistance) the main problem is a buzz from the Altinator, and then to fix this all you need is a ground loop isolator which isolates the two grounds and stops them going down the RCAs.

 

[bal]

nex
i do actually have a ground loop problem and im just about to buy an isolate, i think i will also sort some proper earth wires while im at it and see if it helps

thanks bud

 

[NeX]

nex
i do actually have a ground loop problem and im just about to buy an isolate, i think i will also sort some proper earth wires while im at it and see if it helps

thanks bud

no problem mate

let us know if it sorts it everything in the sound system that has power (amps, HU, PS2 etc) will need a really good ground to bare metal with the shortest wires you can make and thick wires (5~6mm diameter should be more than enough)

Good luck

 

[Ed]

Idealy you should use only 1 ground point for everything. This is common for alot of things, (audio, ecus, RF etc)

 

[NeX]

Idealy you should use only 1 ground point for everything. This is common for alot of things, (audio, ecus, RF etc)

really? i heard that common grounds can sometimes cause interferance.

but i suppose it makes sense. maybe it was, you are not ment to run all grounds to the battery directly.

 

[Ed]

Common ground is a FUNDEMENTAL aspect to reducing noise and ground loop/ isolation problems!! :grinning:

 

[Alienfish360]

Wouldn't recommend screwing an amp to a sub box though, unless the sub box has been reinforced. When your sub plays the box vibrates, and if it's not braced and reinforced for the amp, the vibration is gonna go straight through your amp, and over time it's gonna shakes it's more insides to bits

 

[Ed]

Not likely unless the box is made of 4mm mdf A sub box is not doing its job if it flexes or resonates at all.

 

[Alienfish360]

it'll flex and resonate when you drill holes in for screws

 

[Retepetsir]

18mm flexes with enough power

I love bracing!