Audio amplifier dynamic power explained with demonstration 

Very informative, thank you John.

For some of the more modern music with long sine waves in the bass region you need continuous power, the supply rails will be condtantly loaded and sagged. Something like acdc with a kick drum transient every second or so you benefit from dynamic power, between every kick drum the caps charge up to near idle voltage.

I remember when amplifiers were rated in RMS watts. That is what all the high end products (the only ones I looked at) were rated in. Also, all the pro sound studio monitor amps were rated in RMS also. Even today, I get studio reference amps for almost all my audio amp needs, and, at least Alesis (the brand I get because they make low power ones) is rated in RMS. I was looking for a consumer 30 watt per channel amp, in a case i was not concerned about top quality, and found many rated at 1000 and more watts that appeared to be around 30 watts channel. I could not find any that seemed to have a sensible power rating, and so just guessed based on the way it looked and the power it consumed. And so, I ended up getting a 1,200 watt amplifer, and indeed, it was 30 watts channel, just what I wanted. But the thing is, no matter how you test it, no matter what testing method one tests with, there is no way one could come up with 1,200 watts, and so IT IS A LIE!! Is false advertising legal these days? Based on my search for a 30 watt consumer amp, it must be legal to false advertise. Another great thing to check out, if one wants to find false advertising, check out home shop vacuums. I found them rated over Seven Horse Power, and yet they plug into a standard home outlet, aka Nema 5-15 outlet which are 15 amps. That motor would need a 230 volt 40 amp circuit. What I say about those products is that they are what everybody has been wanting, Over Unity!

You touched on the importance of the reservoir cap on the power supply, but it is most important for lower frequencies. With an inadequate reservoir cap on an amp pushed to it's power supplies continuous limit, the volume itself will audibly dip when low frequencies play, and then increase again dramatically when they stop. It sounds absolutely horrible but an easy thing for anyone to fix if they know what the problem sounds like.

Hi JohnAudioTech I love your channel 'cause I have learned a lot and still learning BTW can you do a video on a 2000Watt transistor amp, this will be of great help to me. Thank you.

oh maybe you could go into more about how a regulated supply interfaces with a power amp? im always looking to improve my setup.

Nice job on the videos, John. At 8:50, I was wondering: Doesn't your Rigol scope have vertical cursors that allow you to select a time point for the scope to read the waveform sample at? That's the cursor mode that I normally use on my Tek scope. I like the fast live FFT feature on your scope for finding the precise clipping point.

What does it look like with pink or white noise? Any easy way to measure for clipping with that?

Hi Dear Sir please make video How Wind your own Audio transformer or inductor For Audio Amplifier

my 12 inch sub is powered by 2 regulated 30V 5A (31.5V no load) power supplies, the amp is a TDA 7293 bass is solid even at very low volumes. I know im only getting about 85 watts RMS but man it sounds like 2 to 3 times that.

Home audio amplifiers were regulated, but car amplifiers weren't. A continuos sinewave is measured below 1% distortion for home amps. In fact some home amps are rated at .001 % distortion or somewhere in that neighborhood. The important thing is that 1% is were our ears can start to perceive distortion. Car amps on the other hand might be rated at something like 25 watts per channel at 10% distortion. That means it gets load and sound like shit doing it. There are other specs as well, and with most of them the lower number is the better except channel separation, signal to noise ratio, 100 or better is what to look for, frequency response, this should be a minimum of 20 hz to 20,000hz, the range of human hearing. 10hz to 100,000hz is much better, but the minimum requirement usually suffices. Anything less and you'll definitely miss part of the source material. I bought an Am that was rated from 40hz to 20,000hz. It lacked bass. It might have been made with a subwoofer output, but it still left a lot to be desired with the mains. And on the top end, dropping below 20,000hz to say 16,000hz will take away a lot of the transient response, say of a bass drum being kicked. That impact happens very fast and without a way to hear that attack the music will be lacking something. So keep these minimum specifications in mind when you boy any amp!

Hello friends. Such a question. I have 2 monoblock. The first mono pull out 5800 W RMS on static and 11000 W on dynamic test on 1 ohm, and the second 8000 W RMS on 1 Ohm static and the same 11000 W on dynamic 1 ohm test . The difference is only in the price of the amps Going to wire 2 subs 0.7 ohm with total 8000 W rated power.

1. One of the more well-known brands to specify dynamic power is NAD, who typically include a factor of 2 (3 dB). 2. 2000 µF caps are very skimpy for a 4 ohm capable amplifier - for a power bandwidth down to 20 Hz, you'd need about 8200 µF. Are your speakers that small? 3. It is not unusual to find a crest factor (peak / average ratio) of 6-10 dB in music. For kicks, I'd be tempted to use a rather wimpy transformer with rather highish (but still safe) voltages at idle plus a fairly massive amount of capacitance, like 2x 22000 µF or so or more, and see how that sounds. And no, large caps won't blow up your rectifier, the winding resistance of a smallish transformer makes for a good current limiter. Back in the late '70s, it actually was not unusual to find fairly big caps (10000-22000 µF), as transistors back then would also be limiting the maximum supplies you could run (SOA wasn't all that great). As the '80s rolled around, parts got better but things also started to be made more and more cheaply but in greater numbers, and build quality really suffered after about '82 or so, including skimping on electrolytics.

Can you make a class g type amplifier??

I watched a video of a new high power D-Class American amp chip. The CEO was proud to present this new amp and stated the power rating at 10 % distortion. Every PDF sheet I have looked at seems to try and hide the true performance of D-Class either concentrating on ridiculously low power figures or this stupid 10% figure depending on what parameter they are trying to fudge. Over half a century ago I built a pair of Mullard 20 W valve amps. Mullard were proud of 0.05 % RMS distortion into 15 Ohms. They quoted the max at 27 W, I can't remember the RMS value at that - certainly a lot less than an unusable 10%.

Late uploaded!!