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Apparently, if you decide to run your amp in bridged mode, it will double the distortion.


I am, however, amused at the idea of bridging my pair of Crown XLS 202Ds so I can feed 600 watts into my fronts. But the possibility of higher distortion worries me.


Is bridging really going to damage the sound?
 

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Bridging is sweet. All my amps are bridged. Double clipping headroom.
 

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This is actually the first time I have ever heard this. Bridging is simply taking the out put of two amps and feeding it to one speaker. I haven't done it in a while, but I think you take the + terminal from both amps and connect one to the + on the speaker and one to the - . The THD shouldn't change but you are feeding it double the power.
 

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Well the THD doesn't really change, it is just accumulative(sp?) of the two channels.


Each channel is .02 THD the bridged result will be .04 THD....



There is, or at least can be, a spike in IMD though beyond what the THD numbers will show, this is what most of the more purists gripe about when they say not to do it.
 

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Hey John, I am trying to figure out why two amps with .02 THD when bridged have .04. Shouldn't the increased head room keep the THD the same?
 

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Well you do better at the same output level, if that is what you mean.


Remember THD number are at full output. So at full out put bridged, the effect is accumlative since both amp sections are producing the full output of the bridged circuit.


IMD comes about by running multiple frequencies through the same wire or component. I'm not sure why exactly it is much worse when using a bridged setup, but many people in the know have assured me it happens and I believe them.
 

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Uhhhh No destruction, that is exactly how you wire it up....


There is no connections put on the - from either amp/side of the bridged output.


+ from one side of the bridge goes to + on the speaker and + on the other side of the bridge goes to the - on the speaker.
 

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Keep in mind that you should follow manufacturers recommended method of bridging

their amp as there may be slight difference between manufacturers. Check the input {RCA}

and output connection {speaker terminals} requirements.
 

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I did not mis-read it.


I just assumed he was speaking of one single amp, that could run either stereo 2 channel or mono-bridged, yet referring to each channel as separate amps. In other words I really think he meant both sides, not both amps as in separate amps here. I tried hard to make sure I was clear about this being each side.



If you had the right amps, I suppose, maybe you could connect the two negatives of the two amps together and run the positives, but I am not so brave, I would have to have the manufacturer list that setup in the manual or tell me it would be OK.
 

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Quote:
I did not mis-read it.

He suggested connecting each amp output in parallel, and you agreed that this is how bridging works.

Quote:
In other words I really think he meant both sides, not both amps as in separate amps here.

Both "sides" of a stereo amp, are seperate amplifiers.

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If you had the right amps, I suppose, maybe you could connect the two negatives of the two amps together and run the positives,

What would this accomplish? It's not bridging.

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If the OP is talking about taking two individual amps and bridging them togther I am out of my league.

That would just be dumb. To bridge an amplifier, they must have a common ground, and must have 'identical' properties.
 

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Here is an explaination from an EE on amp bridging. An amp that is bridged has to be designed for it. First the input signal is split into 2 opposite phases, then one phase is applied to one amp, and the 180 deg out of phase signal is applied to the other amp. each amp acts as one side of the output signal giving you double voltage swing across the speakers, hence almost double the power. But the output impedance seen by the amp is now one half. Example 8 ohm speaker now looks like a 4 ohm load for the amp. In most amps the speaker is now connected across both + terminals. The amps have to be balanced and the power supply has to be designed for this condition. Most Pro amps are designed this way. We used to call this bootstrapping in the old days.



Mike
 

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In order to bridge one of the amps I have, it IS necessary to place a jumper wire between the amplifier's two "-" terminals. Then, the "+" terminal of whichever channel is running inverted becomes the terminal that you connect to the speaker's "-" terminal. There is also some jumpering of pins at the balanced inputs in order to bridge it as well as the aforementioned output terminals. This amp I speak of is a true dual-mono, fully balanced (not just balanced input stage) amp.


As mentioned previously, many amps, the newer Crowns included, are much simpler to bridge. Merely flipping a switch and connecting properly to the output terminals is all that's required. Many also have the bridged configuration setup silkscreened right on the back panel.


And yes, it's true, in bridged mode the channels are essentially in series so not only does the power become additive to the tune of 2x the 4 ohm rating (assuming bridged into 8 ohms, that is), the distortion of both channels is added together. Also, since the output impedance of both channels is in series, the damping factor is cut in half.


Whether or not the downsides outweigh the power increase is hard to say. Even with the distortion of both channels summed, the typical amount is still very small.
 

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OK, I think noiseman explained this pretty well. I am sitting here with the owners manual of one of my crown xls 402 amps. To bridge it, you need a custom Y cable that will split the signal and invert the polarity for channel 2 and connect it between the source and the amp inputs 1 and 2. You then connect the speaker in one of two ways. Either wire the speaker across the two red binding posts of each channel (the positives) or use the top Speakon connector. It actually says DO NOT USE THE BLACK BINDING POSTS IN BRIDGE MODE.

Targus, is this satisfactory?
 

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Quote:
Originally Posted by Megalith /forum/post/0


Apparently, if you decide to run your amp in bridged mode, it will double the distortion.


I am, however, amused at the idea of bridging my pair of Crown XLS 202Ds so I can feed 600 watts into my fronts. But the possibility of higher distortion worries me.


Is bridging really going to damage the sound?

The best way is to compare the bridged 202Ds vs a standard 600 WPC setup and go with what sounds better.


Bridge the amp correctly and you should have some fun deciding for yourself.


- Steve O.
 

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Quote:
Originally Posted by Targus /forum/post/0


He suggested connecting each amp output in parallel, and you agreed that this is how bridging works..

it's accomplishing the same thing more or less, but will typically create more heat as wiring in parallel is wiring two speakers into one terminal to create more power with a lower ohm load. bridging is running one/two speakers over two seperate amps or terminals to create more power without necessarily reducing the load, this option is typically more stable if your amp supports it


Both "sides" of a stereo amp, are seperate amplifiers.



Quote:
Originally Posted by Targus /forum/post/0


What would this accomplish? It's not bridging..

well it may not be bridging as not all bridging effectively cuts the ohm load in half, but it's running the wires in parellel which would normally close to double the power, granted it would put more strain on the amplifier, but if your amp can handel 4 ohm loads, connecting two speakers into the same terminal with 8 ohm loads will work out with it. I prefer not to run my amps hotter than necessary, and just buy a more powerful amplifier, but it's an easy way to gain power if your amp is stable doing so

Quote:
Originally Posted by Targus /forum/post/0


That would just be dumb. To bridge an amplifier, they must have a common ground, and must have 'identical' properties.

Yeah, another thing that I wouldn't recommend exactly..but if you have a speaker with dual terminals that you could use to double the power off of..that would be a typically cheaper option that would make sense in that case..but I doubt that is what this person's scenario is
 

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Quote:
Originally Posted by Targus /forum/post/0


He suggested connecting each amp output in parallel, and you agreed that this is how bridging works.




Both "sides" of a stereo amp, are seperate amplifiers.




What would this accomplish? It's not bridging.




That would just be dumb. To bridge an amplifier, they must have a common ground, and must have 'identical' properties.



I still agree with it and have re-read it several times....


He said take the + from both amps / sides and connect one to the speaker + and one to the speaker -, this is the common method of bridging.


beyond that I have no idea what your talking about. I have seven amps running just this way as per the manufacture.



Your sure apouting off a lot of what seems like garbage, how much do you know about amp design again? I do have a degree in electronics, old degree for sure, but I did do professional studio and live sound engineering work for 20 years.


Everything I stated is fact.
 
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