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matching amplifiers phase


BMS

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So i have 2 prv ad8000.1 amps and the each run one voice coil in each of my subs. So basically they are not strap-able im just using both to power my subs. so obviously i want to make sure the amps are in phase with each other it is easy to match the phase except for that the amps don't have a potentiometer (dial) to adjust my phase so i can mach them. Can I add something on the rca (input) like lets say a crossover that has a phase dial Because i can't find one that has that. they all just have phase swap 0 to 180. I don't have an oscilloscope to check if im out of phase but via a different method (swapping the polarity so the coils fight each other) i am rather sure i am out of phase or maybe im wrong while potentiometers can have slightly different values which would be the reason amps with a phase adjustment will likely be out of phase with each other if my amps don't maybe they are in phase.

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You shouldn't need anything special to get your amps in phase.  Just make sure both the phase switches are set the same.  

If you want to make sure you wire them up right, hook up one amp and play like a 20 hz size wave a low power.  Notice how much the cone moves.  Hook the other amp up so they are both playing and play the same 20 hz sine wave.  If the cone moves more than before you are good to go, if it moves less swap the output wires on one amp. 

 

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1 hour ago, BMS said:

well if one amps phase was 180 degrees and the other was 100 degrees the cone would move more when you plug the second amp in but that wouldn't be the most efficient way to run the system.

Like poorfish88 said, having one amp 100 degrees out of phase isn't going to happen.  They are either going to be completely in phase or completely out of phase.  

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10 minutes ago, Triticum Agricolam said:

Like poorfish88 said, having one amp 100 degrees out of phase isn't going to happen.  They are either going to be completely in phase or completely out of phase.  

Not necessarily true.    This video might be worth watching.  Shows a different approach to gain matching,  subwoofer wiring, and also shows 2 identical amps with the phase out of alignment on the scope.

 

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Being a person who has ran multiple sets of brazilian amps with no phase dial or button, they have always been perfectly in phase. I did the whole low power trick with reversing the leads on 1 coil and it was dead still.

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1 hour ago, Draggin dually said:

Not necessarily true.    This video might be worth watching.  Shows a different approach to gain matching,  subwoofer wiring, and also shows 2 identical amps with the phase out of alignment on the scope.

 

The amps in that video has adjustable phase knobs, not 0-or-180 phase switches like the OPs amps.  With the OPs amps what was shown in the video isn't going to happen. 

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"Making bass is easy, making music is the hard part."

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I'm in agreement with you as far as the op amps are concerned.  I mostly posted the video to show that 0 doesnt always equal 0 and 180 isnt always 180 on every single amp.  I'll be honest,  ive been doing audio since the early 90's and it never, ever crossed my mind that if i had 2 identical amps with the potentiometers both set to zero that they could be behaving differently.  And im sure im not the only person with that mindset.    Which brings up this question.......why do the majority of manufacturers use potentiometers for phase adjustment as opposed to a sliding phase inversion switch ?   What are the benefits of the potentiometer ?   There has to be something right ?  I would assume it is a more expensive part than a simple inversion switch,  maybe only pennies but with the race to zero every penny counts.

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a switch only gives you 2 options though. That is helpful if your subs are exactly 180 degrees out of phase with the rest of your speakers. But if your subs are anything between 0 and 180 degrees out of phase with the rest of your speakers then you need to be able to adjust the phase in between those as well.

 

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