Electrical Switch Help

[jinx8402 10+ year member]

Hey Guys,

I'm looking for some help on determining which switch I need for my install. I want to have a switch that switches my dual 2ohm voice coil sub from series to parallel and vice versa. I have found this article on Instructables on how to go about this, which is fairly straight forward:

SIMPLE Parallel/Series Select Switch

The reason I would like to do this is I don't need all that power to my subwoofer on a daily driver, but would like the option of sending more to the subwoofer for competitions. With that being said, I need some help determining the switch I need.

1. The max power of the amp I am planning on running is 1500 rms x 1 at 1ohm. With a Peak output of 3000 x 1. I am assuming to determine the capacity of the switch, I multiply amps * volts (ex. 16a * 125vac = 2000 watts). Should I be looking for it to meet the Peak output, in this case 16a would not be large enough? Or as long as it can handle the rms at 1 ohm is that ok?

2. I noticed many switches have more than one "rating". For example this rocker from parts express: DPDT Rocker. It is listed as 16a/125vac and 10a/250vac. How do I know which one to go by? I've also seen some show both a resistive rating and an inductive rating. Which would a speaker be?

3. I also found this article which shows a similar method using relays and a switch to control the relay. Would this be a "safer" method? The only issue I have seen is that relays only come in 30a/12vac, which is only 360w. Is there a workaround for this issue?

Any insight would be helpful.

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[Kangaroux 5,000+ posts]

The AC voltage that goes to your speakers isn't usually over 40v. The rating on those switches would be for a typical wall socket. Your best bet may be to just use bolts on your box as terminals, and set it up in a way where you only have to move a couple wires coming from the amp to switch impedance.

 

[Kangaroux 5,000+ posts]

The AC voltage that goes to your speakers isn't usually over 40v. The rating on those switches would be for a typical wall socket. Your best bet may be to just use bolts on your box as terminals, and set it up in a way where you only have to move a couple wires coming from the amp to switch impedance.

 

[keep_hope_alive Premium Member]

When looking at relay contacts, look at voltage and current separate, do not combine for wattage.

You need a delay so that you fully disconnect before you make new connections. The switch should be done when the amp is off to prevent issues. I recommend separate relays for each configuration, and not to multi-purpose relays using both N.O and N.C.

If it is just for competitions, I would have bolted connections on the box accessible for manual wiring. Relays are not that reliable and will fail. When they fail you need to wire the system so that they fail safe and that no combination of failed relays results on a short. This means don't use the normally open and normally closed contacts to switch between.

Another option is actual switches and not relays. Switches would be faster than manual connections and more reliable than relays.

 

[keep_hope_alive Premium Member]

I have wired speakers with both relays and switches for speakers, but not subs. I use relay sockets so replacements are easy. With that much power and the desire to compete, you want to minimize all resistance in the signal path. Relay contacts will increase resistance.

 

[jinx8402 10+ year member]

I was originally going to go the switch route. However I'm scrapping that and going to go with just manual wire switching. Like you said, I don't want a failure, and I knew there was a chance of failure with either the relay option or switch option. Of course, I was intending on doing all switching with the system off (I'm not that stoopid, lol //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif)

I drew up a diagram of how it will work. I will basically use 3 sets of terminals. The first set is hooked up to the amp and to the neg and pos on opposite vc on the subwoofer. I will use the other two sets as jumpers that will only allow for it to either be in parrallel or series, with no way for it to fail.

If any one would like to see the diagram, or make suggestions if you notice something wrong, here it is:

In the diagram showing the subwoofer hooked up to the terminals, there is both a green line and blue line going from one pos to the terminal and the other neg to the terminal. Those are not separate wires, just did it for the diagram so I could follow along better //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif

 

[keep_hope_alive Premium Member]

I understand. Nice diagram.

As long as somone doesn't combine the wrong terminals and short the amp, you are good. Note that the terminals appear to be mirrored, keep yourself straight on that,

 

[jinx8402 10+ year member]

Yeah, I mirrored it on purpose. This way when looking at the diagram, it resembles what you would see from inside the box //content.invisioncic.com/y282845/emoticons/smile.gif.1ebc41e1811405b213edfc4622c41e27.gif