Marketing Math ?

Digital amp.

Here is an example.


If the amp has huge storage capacitors, you could have a very low continuous current pull from the wall, yet have huge reserves available for short burst which is what audio is. e.g., if your amp draws 100 watts for 10 seconds and you could output 1000 watts for 1 second, then wait for it to charge back up. Rinse and repeat. (of course assuming 100% efficiency, but that's another topic)

Better amps will have larger reserve capacity and therefore will seem to have lower power demands from the wall. It's still getting the same amount of power, but the demand can be spread over time. Cheaper amps with less reserve will pull from the wall when needed. This isn't about efficiency, it's about storage reserve.

Class D amplifiers are very efficient can theoretically approach 100% efficiency. Current amplifiers can be in the high 90's for efficiency. Class AB amplifiers run in the 50-75% efficiency range. Therefore, using a class D amplifier will allow you to get more power to your speaker from the same circuit instead of just converting the power to heat within the amplifier.
 
Our PA speakers can theoretically output (transients and peaks) at more than they draw being D class amps inside.

Tons of output. But if the AC draw was more than the output we would need another circuit for each one!!

Power Rating (Watts)1400 watts (4400 watts peak)
Max SPL (dB)133dB Peak (128dB Continuous)

Power Consumption (typ/max)2.4A/3.0A @ 120Vac

The 1400 watts output is Program, at continuous out is 700 watts. I suspect the Fender is similar, 3 dB headroom means 500 watts program output and 250 or so conitnuous.



 
Still marketing hype in my book. I get the capacitor instantaneously doing the power (measured in milliseconds probably). So now I wonder if the speaker is rated at 1000W ?
 
Don O said:
Still marketing hype in my book. I get the capacitor instantaneously doing the power (measured in milliseconds probably). So now I wonder if the speaker is rated at 1000W ?
Click to expand...
It had better be. 1000w on peaks. As I showed our PA tops are 1400 w program and total peaks (kick drum kinda thing) are 4400 somthe speakers have to be rated at 4400 peaks.
 
Don O said:
Watts is Watts.

P = I *E

AC or DC
Click to expand...
The fun of converting AC into DC, especially with Class D digital amplifiers, you can get a lot more "power" out of an amp than you appear to take in. Take an 80% efficiency rate you would need to take the 3 amps of input based on 350w max power in and provide 1000watts out of 2.4amps of power. With voltage multipliers and digital relay control of your voltage rails and outputs, you can get up to the 450VDC to give the 1000+wattts of power.

Bob Carver proved this theory back in the 70's but he couldn't make it work because of the processing and digital tracking it would require. He was successful in getting the design to work in the 90's when technology caught up. I read his white papers on them and studied them about 20+ years ago. I forgot most of the details but essentially, you get more "power" out than in, because you are actually calculating two circuits in two different ways.

Here's a quick tip:
1 amp at 1000Volts is 1000 watts.
100amps at 10volts is 1000 watts.

Current is a constant in that you can only get what your supply can handle. Voltage is a potential, so you can very easily manipulate this figure in a given circuit. Kind of why you can get 10million volts out of a stun gun from a 9volt battery.
 
Ghostman said:
The fun of converting AC into DC, especially with Class D digital amplifiers, you can get a lot more "power" out of an amp than you appear to take in. Take an 80% efficiency rate you would need to take the 3 amps of input based on 350w max power in and provide 1000watts out of 2.4amps of power. With voltage multipliers and digital relay control of your voltage rails and outputs, you can get up to the 450VDC to give the 1000+wattts of power.

Bob Carver proved this theory back in the 70's but he couldn't make it work because of the processing and digital tracking it would require. He was successful in getting the design to work in the 90's when technology caught up. I read his white papers on them and studied them about 20+ years ago. I forgot most of the details but essentially, you get more "power" out than in, because you are actually calculating two circuits in two different ways.

Here's a quick tip:
1 amp at 1000Volts is 1000 watts.
100amps at 10volts is 1000 watts.

Current is a constant in that you can only get what your supply can handle. Voltage is a potential, so you can very easily manipulate this figure in a given circuit. Kind of why you can get 10million volts out of a stun gun from a 9volt battery.
Click to expand...
Man, that sums it up well! Thanks Ghost
 
Ghostman said:
The fun of converting AC into DC, especially with Class D digital amplifiers, you can get a lot more "power" out of an amp than you appear to take in. Take an 80% efficiency rate you would need to take the 3 amps of input based on 350w max power in and provide 1000watts out of 2.4amps of power. With voltage multipliers and digital relay control of your voltage rails and outputs, you can get up to the 450VDC to give the 1000+wattts of power.

Bob Carver proved this theory back in the 70's but he couldn't make it work because of the processing and digital tracking it would require. He was successful in getting the design to work in the 90's when technology caught up. I read his white papers on them and studied them about 20+ years ago. I forgot most of the details but essentially, you get more "power" out than in, because you are actually calculating two circuits in two different ways.

Here's a quick tip:
1 amp at 1000Volts is 1000 watts.
100amps at 10volts is 1000 watts.

Current is a constant in that you can only get what your supply can handle. Voltage is a potential, so you can very easily manipulate this figure in a given circuit. Kind of why you can get 10million volts out of a stun gun from a 9volt battery.
Click to expand...
I get the PWM, the MOSFETs switching and capacitors storing energy. Class D amp are typically over 90% efficient. I guess my brain thinks in joules sometimes meaning if the amp draws 100w for 10 seconds it could output 1000w for 1 second. So basically the 1000w marketing claim is peak power (maybe 1000w for a millisecond) and not continuous RMS power (a 100W Marshall dimed). It’s all about the amount of work the amp can do over a period of TIME.

I’ll try and do some sound pressure level testing (I know the speaker will affect the test) between this and some other amps and report back.
 
You must log in or register to reply here.
Back
Top