Karaoke Forums

Usually I run a stereo set up , A & B channesl , seemed easy.
I want to try and run a MONO set up and thought I had it all set up right but then I read my AMP manual and got CONFUSED

Lets say first I switch the amp from STEREO TO MONO (BRIDGED )
On the amp (PEAVEY PV 1200)
I have the A & B input channels to the mixer ( 2 on each channel)
The mixer has Left and Right main outputs
And the amp has A & B (2 outputs each ) for speakers

I set up the following way: The 2 mains OUTPUTS from the mixer to the 2 inputs on the A channel of the AMP and the 2 channel A outputs on the amp to my two main speakers. IS THAT CORRECT ..I reade the manual last night and now I think I had it wrong!!! help

Whoa Trigger!!!!

Before you go & bridge, what are your speakers impedance rating (ohms). If they are 8 ohms each, you should be ok although this will heat your amp up a little more after a couple hours of use if pushed. If they are 4 ohms each, you CAN'T bridge without going below the minimum load rating for the amp. If that's the case, then you would just put both mixer outputs into one side of your amps inputs & plug both speakers into 1 channel. This will give the maximum output for that channel without going below the minimum rating.

In order to bridge, you would take the mixer outs (left & right) into channel A (paralell input) of the amp. Not sure if the 1200 has it's own bridged output of it's own, if not, you won't be using the actual speaker output jacks, you will need to get banana plugs on the end of your speaker cords for the amp. You can buy adapters if you don't feel comfortable with wiring. The banana plugs will go into "both" positives (red) on the binding posts. You will see which one is positive & which is negative. You will not be using the black binding posts at all. This is what bridging is, taking the power of both channels & summing them into 1. Make sure the banana plugs are facing the same way for the white & black wire. White is positive, black is negative on speaker wires.

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whoa>>>> Okay the speakers are 8ohms ( Peavey Sp5g's)
The amp has (2) 1/4" inputs and outputs per channel SO
I have to take the (2) mixer outs to CHANNEL A (2 inputs) and then the (2) amp outs (channel A) to each individual speaker ?
RIGHT

Thanks LON....AGAIN

You will take the mixer outs to channel A, this statement is correct.

You will NOT use the 1/4" speaker outputs. You will need to use the 2 "red" binding posts with banana plugs.
So you will need to pick up (2) 1/4" female jacks to banana plug adapter. Plug your speaker cords into the female 1/4" adapter. Plug the banana plug into the 2 "red" binding posts - white wire positive to channel A "red", black wire negative to channel B "red". You can piggyback the other banana plug on the first one - white wire positive. NOW you are bridged. You will not be using the black binding posts.

The way you described will work fine, but it is not bridging. What you are essentially doing is lowering the ohms on that channel, but you are not getting the full rated power of the amp that you would if you bridged. By connecting the speakers to just 1 side, you are going to be yielding 450 watts to your speakers, which your speakers are rated at 500 program. By true bridging you will yield 1200 watts to your speakers which is slightly more than double your program power handling, but you won't need to turn up the system as high to get the same listening level either, so you should be fine.

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If you plug both the left and right mixer outputs into channel A you are effectively shorting the mixer outputs together. While this ?probably? won?t hurt the mixer, it may be a good idea to verify this.

Bridging can provide more power if you need it but is not the best way to go if you only want a mono signal.

One way to run mono, but not bridged, would be to get a short ¼? jumper. Leave your system setup for stereo and plug the jumper between the two open jacks on A and B. You are now feeding the same signal to both channels. Again, you are shorting the mixer outputs.

You didn?t mention what type of mixer you are using but there may be a better way.

The general rule is that if your audience doesn?t have a good ?view? of both speakers run mono.

PS. I run a Peavey 1200 with TLS4?s.

That's what parallel inputs are for. It won't hurt the mixer at all.

Stereo for karaoke is nice but only if the room is set-up where EVERYBODY can have the benefit of the stereo imaging. If someone is sitting directly in front of a speaker, chances are they aren't going to hear the other speaker for the stereo effect so it becomes a moot point to try to run a stereo set-up. I know people do & swear by it, but most of the time, half the audience isn't hearing both sides of the music.
Also if you ARE going to run mono, there isn't any reason NOT to bridge your amp for the added power, as long as the load doesn't go below the minimum rating & your speakers will handle it - all this will do is add headroom & a cleaner sound at regular listening levels.

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If I may humbly disagree, the purpose of two parallel input jacks is to allow ?one to be used as a conventional input and, simultaneously, the other to be used as a ?line out? (Y-cord) to connect to another input jack on this amplifier or other amps or equipment?. This is a direct quote from the Peavey PV 1200 manual.

Further, I believe it is always a bad idea to connect two outputs directly together unless they were designed for such use.

To give one example why, consider the H bridge circuit. An example with a speaker is attached but this type of circuit is commonly used for many other purposes as well. To drive the speaker in one direction Q1 and Q4 would be turned on. Q2 and Q3 would be used for the other direction. Now consider two of these circuits were wired in parallel. When the two outputs (Left and Right) were driven with a strong signal 180 degrees out of phase then Q1 on one channel and Q2 of the other would both be on. The power supply is effectively shorted out through Q1 and Q2. Unless there is additional resistance in the path or special protection circuitry something will be damaged.

Many manufactures, including Peavey, recommend creating a Y cable with two 1 K ohm resistors in series with the two inputs.

I have connected outputs from CD players and other such devises using a simple Y cable with out problems. They, however, have high impedance outputs and use different circuitry which is tolerant to such abuse. Power amplifier outputs would be a definite no no. Mixers are a middle ground and I admit that I don?t know for sure. (notice that I waited until paragraph 5 before admitting this.)

Out of curiosity, I reviewed the manuals I have and searched the web to try and find some definitive answers. Other than Rane stating that headphone on their MOJO mixers must not be shorted, I couldn?t find anything else. So maybe I am totally wrong.

Finally, when in doubt contact the manufacture.

PS. No CD players or other electronic devices were injured or killed while writing this article.