4 Channel vs 2 Channel Amp

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tristan20
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4 Channel vs 2 Channel Amp

Post by tristan20 »

Hi guys, I have this friend that keeps arguing with me that a 4 channel is better than a 2 channel for his mids. He said all other installers told him that.

I told him thats bull, once the impedence matches it will all be fine, you just loose fader. But not sq or power as the other installers told him.

I asked him to ask the installers what makes a 4 channel better than a 2 channel. They told him that the 2 channel will give him problems in the future. Hehe

What do you guys think? Is a 4 channel better than a 2 channel, same overall power, same overall frequency range. He has 4 speakers. (he doesnt care for fader control)
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bdubs767
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Post by bdubs767 »

nothign he says makes sense.

But 4 channel is in theory better....bridge is and you have a seperate power supply for each speakers, so basically a dual mono amps design. There are some problems with some older amps that arise with bridging w/ noise coming into play, but now a days they shouldnt have those problems. Most of the guys that are the heavy hitters in the SQ lanes all calm that the 4 channel bridged > 2 Channel thats not Dual Mono.
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Eric D
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Post by Eric D »

4-channel amps only have one power supply (unless it is a special amp), so a bridged 4-channel is not dual mono at all. As a rule of thumb, the quantity of transformers equals the quantity of power supplies. This is of course not true in all cases, some amps have multiple secondary windings off of the main transformer, which would make them pseudo dual mono. And, I have even seen dual transformers which come together to a single pair of voltage rails, so it would not be a dual mono amp at all.

I personally prefer a bridged 4-channel simply because all the excess power adds up to a heck of a lot more control over the driver.

Now, at one point I ran a pair of ZX450s for my stereo. I had one bridged into a component and a sub for the right channel, and the other bridged into a component and a sub for the left. This gave me true dual mono as far as separation was concerned, but since the ZX450 has only one power supply, the loading was still shared between the sub and the component on each amp.
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bdubs767
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Post by bdubs767 »

Eric D wrote:4-channel amps only have one power supply (unless it is a special amp), so a bridged 4-channel is not dual mono at all. As a rule of thumb, the quantity of transformers equals the quantity of power supplies. This is of course not true in all cases, some amps have multiple secondary windings off of the main transformer, which would make them pseudo dual mono. And, I have even seen dual transformers which come together to a single pair of voltage rails, so it would not be a dual mono amp at all.

I personally prefer a bridged 4-channel simply because all the excess power adds up to a heck of a lot more control over the driver.

Now, at one point I ran a pair of ZX450s for my stereo. I had one bridged into a component and a sub for the right channel, and the other bridged into a component and a sub for the left. This gave me true dual mono as far as separation was concerned, but since the ZX450 has only one power supply, the loading was still shared between the sub and the component on each amp.
hmm I stand corrected as I take a look at the boards of channel amps. There has to be something to this as audionutz, werewolf and a few other if memory serves me right were talking about this. Ill see if I can find it
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Eric D
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Post by Eric D »

For any others reading this, here are some photos to compare. All of these amps posted have only one set of rectifiers, thus they physically only have one pair of voltage rails, a positive and a negative, and consequently, only one power supply.

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bdubs767
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Post by bdubs767 »

im not arguing w/ you doc...your def right here.
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Post by RATIFIED »

What old school RF amps are those? I had a Power 500m and a Power 250X2 back in the day. I kick myself everytime for getting rid of them. *wanders off to kick self
444 FED
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Post by 444 FED »

For sound quality running 4 speakers I would use a 4 channel amp. The 4 ohm impedance on an amplifier will have greater control over the speaker, and run cooler, making that control last longer over a listening session.
As the impedance drops the control over the speaker is lessened, due to the slew rate lowering at lower impedances.
A smaller and lighter cone, smaller voice coil etc, or a single unit of these will also have greater ability to be controled by a single channel, as compared to running two speakers off the same channel, even worse when those speakers are not exactly the same (size, model, brand, etc).
The 4ch will run cooler, or at least each set of outputs will, since they are not being pushed as hard, effcetivly helping the life span of the amp.

The above is also why I would prefer to buy a larger 2 ch amp to run a pair of speakers than a smaller 4 ch, where the final power output would be equal, the amp running at the hogher impedance will generally have better SQ in the end.
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Eric D
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Post by Eric D »

bdubs767 wrote:im not arguing w/ you doc...your def right here.
I know, I just want people who look at this thread and might not understand what we are talking about to have a means to see what is going on.
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