Mixing and Matching

[Shaundy]

Hey Guys,

I', just chasing some info on incorporating a sub into my stereo based on the components I already have. I know that most will think that I'd be better off going out and buying matching gear from the start but I'm poor and I want to use the stuff that I have collected.

This is what I have

- 1 x Alpine Type - R 12" sub (SWR 1240D)
- 1 x US Audio amp - USA502ZA - 350w max power
- 1 x Fusion fr4-1000x amp - Reactor series, 4 channel, 1000 watt, 2 ohm stable, electronic cross over.
- approx. 5 metres 8 gauge cable with fuse
- approx. 5 metres 4 gauge cable

Basically, what can I do with these components? How do I wire them up? I would particularly know about wiring the sub as I've noticed that it has two sets of pos and neg terminals.

Any help would be greatly appreciated

Shaundy.

[HCVP]

Ok, so you have a 4 channel amplifier, here are it's true specs, as found.-
4 x 125 watts RMS @ 4 ohm.
2 x 250 watts RMS @ 4 ohm when bridged.
It states it is 2 ohm stable, but does not give any power figures for it (that i could find)

You also have a 2 channel amp, with the only info i could find on that being that is is a 2 channel amp, producing 50 watts RMS per channel.

Finally, you have a dual 4 ohm subwoofer, rated at approx 4-500 watts RMS.

As far as uses go, i'd bin the US audio amp. At a measley 50 watts per channel, it's not going to be of much use for anything, unless you were completely keen on using it to drive a set of rear speakers.

The Fusion amp, has 3 possible uses.
1, Would be to power 4 speakers.
2, Would be to bridge it, and power a single pair of speakers, ideal when you have a fairly good set of front speakers, and want the most performance out of them.
3, Would be to power a single pair of speakers off 2 channels, and bridge the remaining 2 channels to drive a sub.It would mean less than ideal power going to a sub, but none the less, it would work.This would apply to your current sub, you would just have to make sure that you wire the voice coils correctly to bring your impedance load down to 2 ohm.

Your 4 guage wiring would be ideal for connecting your 4 channel amplifier, however you are still going to need 4 RCA's, a trigger wire, some speaker wire, (assuming you don't already have some) and some earth wire.You could snip a bit off the power wire if you had enough left over for an earth wire.But by the time you purchase the individual items, it is in most cases cheaper just to buy a wiring kit.

As far as the 8 guage goes, if the US audio amp was used for the rear application, then this could be used to power that, But again, cheaper to buy the full wiring kit. 8 guage power cable does make for a bad ass speaker cable though but you won't have enough.Beside's that it's unnessacary, and i haven't seen anyone doing it excepct for myself, or maybe Chuck Norris.

Don't forget you will need an aftermarket head unit to support these additions.

[holdenboy]

Alrighty, firstly thank you for posting up specs....makes it so much easier to give you an informed response

The Alpine Type R sub is dual voice coil, 4 ohm. Which basically means its like two normal single voice coil (one set of speaker terminals) subwoofers. So my advice would be to power it off the Fusion 4ch. amplifier. You can bridge that amp so it produces 250wrms x 2. So all you do is connect a pair of speaker wires to each pair of speaker terminals, then run these to the amp. Now the amp will have front and rear channels. If you dont know how to do this then here's a quick explanation:
What you do to "bridge" the amp is take one positive and one negative from the front pair of speaker terminals and connect your speaker wires to these, it should be marked on the amp like this: (notice the diagram on the right hand side of the terminals).


Use the 4AWG power cable to run this Fusion amplifier.


If you want to use the US Audio amp then you can power speakers off it, preferably some front speakers (6-6.5").


Dont worry about not matching amps to speakers / subwoofers......i dont think ive ever owned a system with less than 3 different brands of components

BIG EDIT - Oops, VP beat me to it and im old and slow, haha.

[Shaundy]

Thanks guys that was awesome. Still have a couple of questions but I'll get to those later. First though, how do I wire up the two sets of terminals on the sub. Do I wire them so one set has wires running from and to the amp and the other set just has a wire running between them, or do I run a wire from the amp to the positive on one set and then the wire to them amp from the negative on the other set, with a wire joining the two sets?

[Shaundy]

Oh, and by the way I am running a Pioneer DEH-2050MP (or MPG, can't remember) headunit and it has two RCA sockets (not two sets, just two).

[acarmody]

I'm pretty sure this is the wiring configuration that Holdenboy is referring too, and I know thats not your sub but I needed a picture and that was the first I could find, but the basics will be the same.


Also are there too low pass filters (LPF) on the fusion amp? If not then that isn't going to work.

[Shaundy]

Thanks for that acarmody, that's exactly what I wanted! The Fusion amp has a LPF section with separate Low controls for front and rear. I would also like to know which sockets should I be hooking my RCAs up to. I bought a couple of RCA splitters today as my H/U only has two sockets as mentioned and the amp has four. The four inputs are labelled as 1CH, 2CH, 3 CH and 4 CH. Just out of interest, the amp also has two output RCA sockets. What are these for?

[holdenboy]

Connect the splitters to the RCA cable at the amp end. Then connect one of the left channels to "CH 1" and the other left channel to "CH 3". The right channels go to CH 2 and 4.

The amp has RCA outputs to allow you to "daisy chain" amplifiers together without splitting RCAs etc. Not often used these days.

When tuning the amp, make sure the GAIN and LPF controls are the same for the front and rear channels, this is so each voice coil receives the same signals.

[Shaundy]

Thanks Holdenboy...once again that is exactly the info I needed!...Another question, this time relating to cables and probly a bit stupid...I will be using the 4ga cable to power the amp...does the ground also have to be 4 gauge or can I get away with using the 8ga? or possibly using two lengths of 8ga side by side in the same socket to increase the thickness. Just asking as I don't know how much 4ga if any will be left over and don't really want to buy a heap of cable just to make a 40cm earth cable...

[Shaundy]

Heres something else to think about: I went into WOW sight and sound today to ask about wiring and was told that the best way to wire the sub was this: (I'm gonna lable the terminals in post #6 A,B,C,D,E,F,G,H in a clockwise direction to explain myself) :
E + F to the pos and neg terminals on one side of the sub,
G + H to the pos and neg terminal of the other side,
A,B,C,D to a set of speakers.

What are your thoughts on this?

[acarmody]

Basically that will only give you 250wrms going into the sub instead of the 500wrms the above diagram will give you. Essentially its exactly the same thing except your only using half of the amp and freeing up the other half to power some speakers.

[Shaundy]

Thanks acarmody. I will be definitely going with your configuration. What are your thoughts on my ground cable theories?

[acarmody]

Ground cable MUST be the same (or bigger) as the power cable. Last time I checked some decent 4 gauge wire cost only a few dollars a metre, nearly any car audio store will sell by the metre. I wouldn't try the dual 8 gauge option as I don't think you will have much luck getting a nice solid connection of both wire in the amp.

[Shaundy]

Ok thats fair enough. Will have to go out and get my self some 4ga (or maybe even 2ga) cable for an earth. Thanks again!

[VZ-Rob]

Ok,........
You also have a 2 channel amp, with the only info i could find on that being that is is a 2 channel amp, producing 50 watts RMS per channel.........
As far as uses go, i'd bin the US audio amp. At a measley 50 watts per channel, it's not going to be of much use for anything, .........

That's perfect for running your front splits tweeters only
leaving the 4 channel for the mid's and sub
You'll get a cleaner sound without the bass distorting the tweeters

[HCVP]

That's perfect for running your front splits tweeters only
leaving the 4 channel for the mid's and sub
You'll get a cleaner sound without the bass distorting the tweeters

What would be the point in messing around tying to run 6 channels off a single pre-out, to use a second amp, of less power, to run your front stage?

[Shaundy]

Well I've discovered that a capacitor has come loose in the Fusion amp so until I break out the soldering iron, that ones on the back-burner. What I did today was connect up a rough system using the sub and the US Audio amp. I used the 8ga cable for the power and the 4 ga cable for the earth, mostly because I didn't want to cut up any cables yet. I ran power to the sub from the two channels on the amp using the layout that the WOW guy gave me, i.e. one channel to one set of sub terminals, the other channel to the other set. Lo and behold the sub works and puts out a reasonable sound...it definitely has a lot of cone movement anyway. Its got a bad vibration noise but I believe that this is due to the rubber ring around the cone coming loose.

So it appears that the small amp is working at this stage, but before I go bolting anything in, are there any negatives to using it, such as things burning out and such?