Posted January 31, 201213 yr I see people saying their rms "clamped" all the time, I'm curious to know what my Memphis is actually putting out. I have an amp probe and a dmm. How would I go about clamping my amp to see the power it is putting out?
January 31, 201213 yr things you will need.Power supply - this power supply should be able to hold a steady voltage for the entirety of your test and should be constantly monitored load - a bank of resistors is idealoscilloscope - something that can handle the amount of power the amp should maketwo multi-meter - a half decent one- one to monitor the A/c voltage and one to monitor the DC voltageclamp-meter - to monitor the amperage going the loadtone generator - to generate a clean tone or sine waveif you can follow me Dylan so far let me know and lets go from there!and what is an amp probe? link? picture?
January 31, 201213 yr I just screw it. Clamps can loosen.Your not using cheap plastic clamps are you? The metal ones with some loctite work wonders.
January 31, 201213 yr I just screw it. Clamps can loosen.Your not using cheap plastic clamps are you? The metal ones with some loctite work wonders.you guys are both wrong clamps blow and are ugly you should be using velcro!
January 31, 201213 yr Author things you will need.Power supply - this power supply should be able to hold a steady voltage for the entirety of your test and should be constantly monitored load - a bank of resistors is idealoscilloscope - something that can handle the amount of power the amp should maketwo multi-meter - a half decent one- one to monitor the A/c voltage and one to monitor the DC voltageclamp-meter - to monitor the amperage going the loadtone generator - to generate a clean tone or sine waveif you can follow me Dylan so far let me know and lets go from there!and what is an amp probe? link? picture?Car charger work for power supply?For the load wouldnt the subwoofer be the load?Don't have an oscope Fluke mmfluke clamp meterTest tone on a CD?amp probe is clamp meter - fluke 376 i think is the one I have
January 31, 201213 yr things you will need.Power supply - this power supply should be able to hold a steady voltage for the entirety of your test and should be constantly monitored load - a bank of resistors is idealoscilloscope - something that can handle the amount of power the amp should maketwo multi-meter - a half decent one- one to monitor the A/c voltage and one to monitor the DC voltageclamp-meter - to monitor the amperage going the loadtone generator - to generate a clean tone or sine waveif you can follow me Dylan so far let me know and lets go from there!and what is an amp probe? link? picture?Car charger work for power supply?For the load wouldnt the subwoofer be the load?Don't have an oscope Fluke mmfluke clamp meterTest tone on a CD?amp probe is clamp meter - fluke 376 i think is the one I haveI would use a battery that is being charged by a car charger over just the charger. For example if your amp is rated at 1500 get a battery that can support at least 1500watts! you would think that but resistors is what i say to use but in a pinch use a sub i guess lol! oscope is used to tell us when the amp is clipping so we know where and when max power output is reached, look into borrowing onetest tone on a cd is fine as long as it is accurate and isn't like +3db or something crazynow to clamp your amp simple:hook your cd into your amp to play the tone repeatedly (ipod or cd player with a 3mm to rca converter or a head unit if you got one laying around)hook the battery to the amp hook a dmm up the batteryhook your sub up free air hook your clamp meter on the positive lead going to the sub/loadhook your other dmm up to the output terminals on the amp to tell the A/C voltage then take your stolen oscope and hook it up in parellel to the load turn on the cd playeradjust gain until it starts to clipread the numbers off of your dmm and current meterdo some math, you have voltage and current so do something with those to find power! and report back and take lots of pictures lol! o and keep an eye on the battery voltage to make sure it stays constant! and if it drops record it! the only thing wrong with a sub is when it heats, or temp in the room heats up, or as you change frequencies the impedance of the sub will changes this will lead to inaccuracies but for a daily kind a guy who want to try something for kicks do it up! keeping in mind if you were profession the power supply and load would cost a lot of shinny pennies!o and I think your subs should be free air? not sure how the box will effect the test. we will see if anyone else chimes in on this!
January 31, 201213 yr Author So multiply the Amps going through the positive to the subwoofers by the AC volts going to the subwoofer?
January 31, 201213 yr Volts x Amps = Power! you are correct my man! and yes all on the output side of the amp!keeping in mind that the output of the amp is directly effected by the input voltage and load conditions! If your amp was rated at 14.4volt dc please try to keep 14.4 volts all test long!
January 31, 201213 yr Author Well 12.5 is what my charger can keep pretty solid. No idea what my amp was rated at, It's pretty old.
January 31, 201213 yr nice! well one of the key things to get to look into borrowing is an oscope as that will tell us how much power the amp is outputting before it sends out a clipped signal to the sub. I guess you could call it a clean signal? and 12.5vdc that is weak! lol
January 31, 201213 yr Author It's only meant to charge the battery! There's a 16v start switch on the charger but I'm not going to send 16v to my new truck. Truck started I can hold 14.2 Edited January 31, 201213 yr by djtomczak
January 31, 201213 yr Author Will do! Don't have free time until Thursday though. I'll see about a video and pictures of my new install as well.
February 1, 201213 yr nice! actually if you pop down to your local college and tell someone what you are doing I am sure they can help you out or even maybe want to she there class or whatever! either that or pop over to your local car audio and ask if they have one you could borrow for a few minutes, I know my local car audio shop has one! but they think it is gold and never lend it out lol!
February 1, 201213 yr Author My local shop believes in adjusting by ear, I watched them do it today and he did a pretty good job!
February 1, 201213 yr Author I've always adjusted by ear, tried Dmm and turned out to be clipping still.I'm lucky, Two of the top twelve retailers by mobile electronics magazine are in my area!
February 1, 201213 yr I see people saying their rms "clamped" all the time, I'm curious to know what my Memphis is actually putting out. I have an amp probe and a dmm. How would I go about clamping my amp to see the power it is putting out?The first question is why you would want to "clamp" your amp to begin with? What are you hoping to find out and how will you use that information?"Clamping" an amp in the manor it is most commonly performed provides little relevant or useful information. The reason the measurements aren't accurate are many....for one, you don't know the accuracy of the measuring equipment. Second, measuring power into a reactive load (i.e. your subwoofer) is not a simple Volts x Amps calculation. Third, you are not measuring distortion (even with an o-scope you are not measuring distortion, only when the wave begins to clip). That's just to name a few.So all in all, the results of your measurement will be virtually useless and it will not tell you how much power your amplifier is "really" outputting. About the only way to do that reliably is with a professional level bench test measurement system, which isn't cheap.
February 1, 201213 yr Author I see people saying their rms "clamped" all the time, I'm curious to know what my Memphis is actually putting out. I have an amp probe and a dmm. How would I go about clamping my amp to see the power it is putting out?The first question is why you would want to "clamp" your amp? "Clamping" an amp in the manor it is most commonly performed provides little relevant or useful information. The reason the measurements aren't accurate are many....for one, you don't know the accuracy of the measuring equipment. Second, measuring power into a reactive load (i.e. your subwoofer) is not a simple Volts x Amps calculation. Third, you are not measuring distortion (even with an o-scope you are not measuring distortion, only when the wave begins to clip). That's just to name a few.So all in all, the results of your measurement will be virtually useless and it will not tell you how much power your amplifier is "really" outputting. About the only way to do that reliably is with a professional level bench test measurement system, which isn't cheap.Why do people do it if it doesn't really show any useful information? I don't need an exact number I just want a ball park to see if it's putting out what it's claiming.
February 1, 201213 yr Why do people do it if it doesn't really show any useful information?Monkey-see Monkey-DoHappens a lot in this hobby. I could go on a pretty long rant about all of the useless or senseless things people do in this hobby. I don't need an exact number I just want a ball park to see if it's putting out what it's claiming.In all honesty, it doesn't really matter. Even if the amp is over rated by 25% you're not going to hear a difference. As long as you're not running one of those extremely low end amps which rate everything at PMPO or ILS, generally real power output is going to be close enough to rated to not make an audible difference. It's often nice to know just from a manufacturer reputability aspect.....sure, I'll put a little more faith into the general build/design quality and respect for a company if their 500w amp really outputs 500w. But if it only does 400w, you're not going to hear a difference. Unless you are chasing #'s on a meter, it really doesn't make that big of a difference. But to actually measure the true output of an amplifier to the level of detail and accuracy required to compare it to the manufacturer's rated power is generally going to require a professional level measurement setup. A "clamp test" will do nothing of the sort.
February 1, 201213 yr Author Why do people do it if it doesn't really show any useful information?Monkey-see Monkey-DoHappens a lot in this hobby. I could go on a pretty long rant about all of the useless or senseless things people do in this hobby. I don't need an exact number I just want a ball park to see if it's putting out what it's claiming.In all honesty, it doesn't really matter. Even if the amp is over rated by 25% you're not going to hear a difference. As long as you're not running one of those extremely low end amps which rate everything at PMPO or ILS, generally real power output is going to be close enough to rated to not make an audible difference. It's often nice to know just from a manufacturer reputability aspect.....sure, I'll put a little more faith into the general build/design quality and respect for a company if their 500w amp really outputs 500w. But if it only does 400w, you're not going to hear a difference. Unless you are chasing #'s on a meter, it really doesn't make that big of a difference. But to actually measure the true output of an amplifier to the level of detail and accuracy required to compare it to the manufacturer's rated power is generally going to require a professional level measurement setup. A "clamp test" will do nothing of the sort.True^
February 1, 201213 yr P.S. this is the guy who talked me out of wasting my time and doing a silly clamp test also! he is good people with a ton of knowledge! Why do people do it if it doesn't really show any useful information?Monkey-see Monkey-DoHappens a lot in this hobby. I could go on a pretty long rant about all of the useless or senseless things people do in this hobby. I don't need an exact number I just want a ball park to see if it's putting out what it's claiming.In all honesty, it doesn't really matter. Even if the amp is over rated by 25% you're not going to hear a difference. As long as you're not running one of those extremely low end amps which rate everything at PMPO or ILS, generally real power output is going to be close enough to rated to not make an audible difference. It's often nice to know just from a manufacturer reputability aspect.....sure, I'll put a little more faith into the general build/design quality and respect for a company if their 500w amp really outputs 500w. But if it only does 400w, you're not going to hear a difference. Unless you are chasing #'s on a meter, it really doesn't make that big of a difference. But to actually measure the true output of an amplifier to the level of detail and accuracy required to compare it to the manufacturer's rated power is generally going to require a professional level measurement setup. A "clamp test" will do nothing of the sort.
February 2, 201213 yr Volts x amps = WATTS!......Volts x Amps = Power! you are correct my man! and yes all on the output side of the amp!keeping in mind that the output of the amp is directly effected by the input voltage and load conditions! If your amp was rated at 14.4volt dc please try to keep 14.4 volts all test long!
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