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Watts; the worst measurement unit ever for amp output?
- Thread starter nukes_da_bass
- Start date
Many years ago I used a compressor to get more clean output power from my 150 Watt solid state amp.
Some tube preamp or DI-Boards may provide a similar/identical effect.
Depending on the usage of those effect boards the max. output power for one and the same amp may feel different.
So why not for different amps but same rated output power?
Some tube preamp or DI-Boards may provide a similar/identical effect.
Depending on the usage of those effect boards the max. output power for one and the same amp may feel different.
So why not for different amps but same rated output power?
Mr. Foxen
Commercial User
Backed up by the fact DC resistance is on the spec sheet of speakers, so you can see it is different from nominal impedance.
A watt, in regards to musical instrument amplifiers, does not refer to how loud the amp is. It refers to how much electrical power it will suck from a power outlet. An amplifier with a rating of 300 watts will use 300 watts of electricity. The power amp section may be rated at 200 watts, the pre-amp at 10 watts, the EQ may use 20 watts, and all the pretty lights might use 70 (for the sake of this argument).
So you have an amp that may sound the same as a bare bones, no features 200 watt amp, but it's rated at 300 watts because all the add-ons make it a 300 watt amp... because that's how much POWER it uses, not how much volume it makes.
So you have an amp that may sound the same as a bare bones, no features 200 watt amp, but it's rated at 300 watts because all the add-ons make it a 300 watt amp... because that's how much POWER it uses, not how much volume it makes.
A multi meter measures DC resistance, not impedance and that 5.73 Ohms reading is right about where it is when measuring DC resistance on a lot of 8 Ohm speakers/cabinets. The meter is probably fine but I would recommend that you re-test, making sure your meter is set to the X1 scale, not Auto or a higher scale, like X100, etc because some meters round up and remove significant digits.
If we can put a man on the moon, we can measure balls as an amplifier output measurement.
Amps should have balls.
All other amps will be known as Eunuch.
Amps should have balls.
All other amps will be known as Eunuch.
Balls!
THIS is a quantifiable (yet subjective) concept!
"We here at Excelsior Bass Amplification believe, although not quantifiable, that our bass amplifiers simply have enough BALLS engineered into our units to stop a buffalo stampede or, cut through a Keith Moon/John Bonham double drum solo!".
I mean, since they bend stats to the point of ridicule, why not?
Stats and specs are supposed to be useful, but they often aren't. Car and boat manufacturers do this, too. Some measure HP at the drive wheels and others at the crank. The one that shows 300HP at the drive wheels will exhibit more power in application and "seat of the pants" feel because there's no such think as a lossless drive train.
You know a ballsy bass rig when you feel it.
That power rating is on the sticker near the power cord or fuse, right? That's not the amp's output- you would be right in saying that it's the consumption but there's not an amp in the universe that outputs the same as it consumes because there's no such thing as a 100% efficient amplifier, or any other circuit, for that matter. If an amp generates ANY heat, it has wasted power. Wasted power can be measured and if you find out the BTU of generated heat, you can add that to the output to determine, very roughly, what its consumption is. Also, multiplying the fuse rating by the line voltage matters, too- if an amp is rated at a significantly higher output Wattage than the fuse rating x line voltage, someone is lying or using their own rating scale.
Power rating of an amplifier is never meant to state acoustical output.
Maybe a 'Clank' rating could be used (reference to brass balls).
The most useful information you could get at this point has to do with the amplifiers' designs, control specs and settings. If one amp has linear taper pots, the same settings won't cause the same increase/decrease in level. If the circuits associated with a particular control on each amp produce a different amount of gain, you'll hear a difference. If the boost control causes a 10dB increase, it demands a lot more from the output section. Will it produce more output? Sure, to a point, and this point depends on where the other controls are set. If the master volume and input controls are set lower, the amp won't distort when the boost is on but if the master and input level controls are jacked, it will turn to fuzz pretty fast. Add bass & mid boost and it demands even more from the amp. The one thing that limits output but serves the whole thing is the power supply and once that runs out of steam, the amp won't magically make more power. Adding load to the amp is like towing a trailer with a small car- it will do OK, to a point. Adding more weight or trying to tow the same load uphill will show that it can't do as well as it did on flat pavement.
My point exactly! My amp is a Hartke LH1000, which I run in bridge mode, so I have 2 power cores, each rated at 500 watts in standard configuration. Yet in bridge mode these 2 500 watt amps are rated at 1100 watts (heat generated by running one core into the other may account for the extra 100 watts of rated power). My power outlet supplies 240 volts (Australia) and the fuse in my amp is rated at 5 amps, so if my amp pulls more than 1200 watts of power, or voltage drops below 220 volts... boom, fuse gone!
By the way, I run the full 1100 watt monster into 800 watts (rated power handling) of speakers and haven't cooked a voice coil in the two years I've had this setup.
Absolutely nothing to do with how much noise the amp will make, it's all about power consumption. Try the maths yourself... as 1958Bassman said... fuse rating x line voltage should get you somewhere near (+/- 10%) the true rated power consumption of your amp. If it's rated way higher by the manufacturer... well, don't use the guy that came up with those figures as your tax accountant.
All you have to do is lift it.
If it takes BOTH arms to lift it off the ground, it IS the best amp for metal.
Charlie Watts is the worst for measuring amp output. He just doesn't give a $hit about doing it right.
Mr. Foxen
Commercial User
No. Output rating in watts, is not the power consumption. Hence an SVT is 300w, not 1000w.
Did you read all of 1958's post?
Look on the back of your amp, near the mains cable/connector. That'll list the maximum draw of the amplifier, which you'll find to be a fair bit more than the output rating.
Most serious manufacturers give detailed specifications for the line socket current consumption which is measured at 1/8 and 1/3 output with Pink Noise.
The 1/8 output power method is very narrow to the real world for any PA amplifier. Whereas the 1/3 output power measurement is most of theoretical nature but not a really practical validity.
Sometimes manufacturers state an additional current consumption for full output power 1% THD. Those specifications are absolutely meaningless for max rms current consumption at the socket.
Ok, so lets calculate the current consumption at 1/8 Pink Noise output for an amp with 500 Watt sinus 1%THD output power by 50% Heating losses.
500 Watt : 8 = 62.5 Watt
62.5 Watt * 2 = 125 Watt Power consumption at the line socket.
The rms current consumption at 110V line socket calculates to appro 1 Ampere.
1/3 Pink Noise calculates to 3 Ampere current consumption.
Whereas full output power 1% THD calculates to appro 9 Ampere at the socket. But this specification is meaningless for all PA amplifiers in every real world applications.
The truth for maximum power consumption is probably somewhere in the range of 1/8 .. 1/3 Pink Noise.
But not knowing the nature of a given Audio program means in effect that it is not valid to state a max. possible consumption at the socket (or max. possible output power).
But it is valid to state the following point:
for any PA amplifier the rms current consumption calculates to significant lower values than it would be supposed at full output sinus 1% THD.
see consideration with Pink Noise 1/8 .. 1/3 vers. full sine output power.
GK states an average Power consumption at the socket for appro 1/3 of full power output.
In addition to this specification GK states as well the Power consumption for full output power (which is IMO absolutely obsolete).
This is copied and pasted straight from Hartke's owners manual:
Rated Output Power
LH500 500 watts @ 4 ohms, 350 watts @ 8 ohms
LH1000
Dual Parallel mode 2 x 225 watts @ 8 ohms , 2 x 320 watts @ 4 ohms, 2 x
545 watts @ 2 ohms
Bridge mode 1 x 750 watts @ 8 ohms , 1 x 1100 watts @ 4 ohm
Rated OUTPUT power, bridge mode 1100 watts @ 4 ohm. 240 volts x 5 amp fuse = 1200 watts. Still gives no indication of how loud it will be... just how much your electricity bill will be. In keeping with the OP's post, a watt is a terrible measurement when trying to decide on an amp, especially in the internet age, when more and more people are buying things online without actually trying them out, and relying on the advice of anonymous people in online forums. How many threads have I seen on here where people have bought a 300 watt head and a 2 x 10 cab because fellow bassists have told them it'll be great, and then wonder why they can't hear themselves over their drummer and guitarists. Doesn't really matter to me... I've got 1100 watts of rated OUTPUT power (1200 watts power consumption max.) and 8 x 10" speakers. I crank that baby and the drummer can't hear himself think!
I don't think that a Watt is a terrible measurement.
But I believe that is a hard way to keep together two different technical terms.
The term of Rated Output at sine 1%THD is very well known to most of us.
Whereas the term "Peak To RMS Ratio" describes the dynamics and/or a specific waveform.
Specific waveforms and dynamics are very essential for any sort of Audio programs.
Whereas a sine wave is a sine wave is all the time sine wave, every Audio program is very different to a sine wave and every Audio program is less or more different to the next one.
Talking about amplifiers means most of the time talking about a static sine wave. But talking about an Audio program (or an electric bass guitar signal) is a very different animal and very personal as well.
But I believe that is a hard way to keep together two different technical terms.
The term of Rated Output at sine 1%THD is very well known to most of us.
Whereas the term "Peak To RMS Ratio" describes the dynamics and/or a specific waveform.
Specific waveforms and dynamics are very essential for any sort of Audio programs.
Whereas a sine wave is a sine wave is all the time sine wave, every Audio program is very different to a sine wave and every Audio program is less or more different to the next one.
Talking about amplifiers means most of the time talking about a static sine wave. But talking about an Audio program (or an electric bass guitar signal) is a very different animal and very personal as well.
Calm down princess, you can spell OUTPUT, good for you, have a gold star.
As I said before, output power ≠ draw from wall, in your case you have a newer more efficient amplifier, hence the output isn't that much greater than the pull from the wall.
The output power for an amplifier is the maximum RMS output through the output jacks, generally at ~0.5% or so THD. It doesn't tell you much about your energy bill either, as you aren't going to be continually pulling 1200 watts from the wall.
It's a perfectly fine unit of measurement if you have an idea of the application in which you'll be using the amplifier, will you figure out the exact SPL using your exact instrument, amp settings and speaker setup? No, but then neither will an SPL measurement which isn't performed using exactly what you're going to be using.
PS - Drummers can't think, so you're not validating the loudness of your setup.
