Speaker wiring

[InflamedMonkey]

Ok so I have a question about speaker wiring.
I Have four 4 ohm speakers wired at 16 ohms that I want at 4, It's a Behringer 4x12 cab, It has a mono/stereo selector switch on the back plate with a circut board attached to that, the board has 4 wires coming off it, 2 go to the left and 2 to the right, the speakers are in sets of 2 top/bottom on the left and right, I don't know if any of that helps but anyway... I want to wire it to 4 ohms, I havent found a site that helps yet because none of them have anything like the board I have to deal with it seems.
Also, can you use a normal switch craft 1/4 jack to wire a cab or do I need some special one?
Thats only if I cant figure out how to do this with the board thats in it now.... I have no real use for stereo. Thanx for your help.

[fett]

Re: Speaker wiring

The smaller the guage the bigger the wire. The addage goes The bigger the wire the more sound gets to the speakers. ohms, at this point, are krishnas. [img]/images/graemlins/smile.gif[/img]

[nonamemx]

Re: Speaker wiring

Here is a very good site.
http://www.slightlyaltered.com/id34.htm

Scroll down until you reach "Series/Parallel" wiring, which is what you will need, and a standard 1/4" mono jack will work just fine if you arent going to use Stereo.

Just wire the 4 (4 ohm) speakers in the Series/Parallel wiring, and it will end up with a end result of 4 ohms, and wire it directly to the input jack.

I dont think you need the circuit board, I think it just holds all the stereo/mono switching stuff, just wire it directly to the input jack, with the + going to the Tip of the jack, and the - going to the ground (shaft).

[mm2002]

Re: Speaker wiring

To make it a 4 ohm cab just wire all four speakers in parallel to a mono jack. The switchcraft is good. Put simply, that means that the two wires coming from the mono jack will go the the first speaker, wire those two to the second speaker, and so on.

[MountainDog]

Re: Speaker wiring

nonamex is correct: four 4ohm speakers in series/parallel will give you a net of 4ohms (just like the link he posted said). The first set of two speakers in series is 8ohms (4+4), the second set of two in series is the same 8ohm (4+4). Then those two sets of speakers wired in parallel gives you 4ohms (8x8 divided by 8+8 = 4). Wire them up to the switchcraft 1/4" mono jack just like the diagram in the link.

mm2002, sorry, but four 4ohm speakers wired all in parallel ends up being 1ohm. You might be thinking of four 16ohm speakers (the normal impedance in most 4x12 marshalls) being wired in parallel giving you 4ohms.

FYI, you should make sure your amp will safely drive a 4ohm load before you do all this!!! I assume you have a tube amp with a 4 or 8 or 16ohm impedance switch on the back??? Make sure you set it to 4ohm.

2nd FYI, your Behringer cabinet with the mono/stereo switch is wired up thru that circuit board, so that when you insert just one 1/4" phone plug into the mono jack, it is effectively sending the signal to the four speakers in series, giving you 16ohm load you mention. When plugging in a 2nd phone jack to the 2nd jack and selecting stereo, it is splitting the cab into a right and left, with each set of two speakers being wired in series giving you 8ohm load per side.

oh, fyi, I work for a speaker company...

[InflamedMonkey]

Re: Speaker wiring

Cool deal, I have it to well almost 4 lol, 4.something that bounces around a little.
Also I am going to use a Randall RG100 ES with this cab, so I figured I would get the most wattage I could out of it... plus I was bored [img]/images/graemlins/tongue.gif[/img]

[MountainDog]

Re: Speaker wiring

Are you checking it with a meter? Impedance is actually a measure of when the speaker is under a load from an amp, a static measurement with an ohm meter is called DCR or DC Resistance, which is pretty close, and works for this purpose. So as long as the meter is hovering around 4ohms +/- a few tenths you'll be ok.

The Randall is solid state, and should handle the 4 ohm load ok. I have one. If you're going to crank it up, I'd recommend getting a 8" clamp-on fan and clip it to the back of the amp & point it towards the heat sink to help keep it cool and happy.

[mm2002]

Re: Speaker wiring

[ QUOTE ]
mm2002, sorry, but four 4ohm speakers wired all in parallel ends up being 1ohm. You might be thinking of four 16ohm speakers (the normal impedance in most 4x12 marshalls) being wired in parallel giving you 4ohms.

[/ QUOTE ]

Good call Mountandog, yup I missed the part about him having 4 ohm speakers. I need to learn how to read instead of assume! LOL

[InflamedMonkey]

Re: Speaker wiring

[ QUOTE ]
Are you checking it with a meter? Impedance is actually a measure of when the speaker is under a load from an amp, a static measurement with an ohm meter is called DCR or DC Resistance, which is pretty close, and works for this purpose. So as long as the meter is hovering around 4ohms +/- a few tenths you'll be ok.

The Randall is solid state, and should handle the 4 ohm load ok. I have one. If you're going to crank it up, I'd recommend getting a 8" clamp-on fan and clip it to the back of the amp & point it towards the heat sink to help keep it cool and happy.

[/ QUOTE ]

so the cheap kind you can get at any store? I plan on cranking it up around 5-7, I have no clue how loud these things are.
Also, will the fan add any extra noise, I don't want to fry the head by overheating it or anything.

[MountainDog]

Re: Speaker wiring

Yes, a cheap $10 fan. Fan won't add any noise to your amp and you can mount it on the clips that you use to store the power cord. Point it so it sends the air into the vent in the back, see pic:

Oh, on the back of the amp you'll see two speaker speaker jacks saying 8ohm, and above it you'll see the note "120 Watts RMS 4ohm". This means the amp will handle the 4ohm load no problem. (The two 8ohm jacks mean you can plug in two 8 ohm cabinets. Two 8 ohm cabs plugged in the back of the amp gives a 4 ohm load to the amp, similar to the same math done with speaker impedance).
[image][/image]

[InflamedMonkey]

Re: Speaker wiring

Well off to Big Lots for a fan, too bad computer fans wont work, I have millions of them.

[InflamedMonkey]

Re: Speaker wiring

I have seen alot of stuff on the web for people who used computer fans to cool tube amps internally but none for solidstate.

[InflamedMonkey]

Re: Speaker wiring

[ QUOTE ]
Oh, on the back of the amp you'll see two speaker speaker jacks saying 8ohm, and above it you'll see the note "120 Watts RMS 4ohm". This means the amp will handle the 4ohm load no problem. (The two 8ohm jacks mean you can plug in two 8 ohm cabinets. Two 8 ohm cabs plugged in the back of the amp gives a 4 ohm load to the amp, similar to the same math done with speaker impedance)

[/ QUOTE ]

I got the manual and it says "Less than 8 ohm load impedence not recommended".... I need 8 ohm speakers damn it lol, then I wont worry about frying it or having a stupid ohm rated cab. 8 is the norm it seems.

[InflamedMonkey]

Re: Speaker wiring

Ok now I have a new question.... After wiring it to 4 ohms my cab lost some bass and is brighter now... Is this normal? or is something wrong somewhere?

[nonamemx]

Re: Speaker wiring

Well, to my knowledge the Ohms dont make a difference tonally if the amp is set to the correct impedence.

Maybe you have them "out of phase", check and see.