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a.wayne 1st December 2009 10:30 PM

Dynamic Headroom
What part of an amplifier topology is important for dynamic headroom or is it a function of the Power supply size ?

wahab 2nd December 2009 08:49 PM

noise, wich is the floor, and output voltage (power) which is the ceiling...

destroyer X 2nd December 2009 10:05 PM

I would talk about this subject 3 hours long....
If i decide to write.... will be almost 40 pages....I know a lot about, but even with this knowledge i am sure there are others that knows 100 times more than i know,... in other words..i know half of nothing compared to some guys we have around.

I would like to see a Thread opened alike an interview about the subject...hard to explain (and i have doubts) that cheap supplies (weak) may provide even more dinamic Headroom.....sounds crazy?.... only talking several hours to explain and clarify what i mean... not possible here.

Also we enter the area of subjectiveness.... to me, the output power must be measured with maxinum 0.2% of distortion....because is my personnal threshold... and the maximum tollerable distortion will be 1 percent (to me, my own subjective values..what is tollerable to me).... so... the difference of power from 0.2% to 1 percent distortion is my personnal dinamic headroom.... others may measure into 10 percent of distortion...lovely big numbers this way..but the sound is alike an hidraulical hammer heating metalised pavement.

There are other ideas about... i do not know exactly the parameters.. i would like to know, but i know what happens into the hardware..for sure i know.

It is from supply, and also from circuit.. some amplifier can work with 2 ohms without distort too much, those use to be able to produce more dinamic with less distortion... there are valleys of impedance, drops of impedance that you will need special output and supply to face, also stages biasing is important... when you face a frequency where your speaker has low impedance, then your amplifier can behave better or not..this will produce a good dinamic headroom or not.... a peak power... a surge of power... a moment of power... a burst of power.

Not easy to words may be non sense to you my dear..but i ensure you they are not...but i would have to explain a lot of things in advance to make you understand what i mean.

This is not a simple question..... hard and complicated question.

We had interviews....but sadly they have not studied this important subject.

The most interesting is that small transformers and huge bank of electrolitic condensers produces interesting peaks of power..the transformer voltage drops and the enormous reserve of electrons, from the electrolitic condensers, the filter, discharge trying to keep the voltage almost equal the original and previous level... a small time peak appear and soon will have a decay... and soon the power will be the one that matches the power supply average power.... a huge supply does not produce the interesting effect.... this subject is wonderfull.... and NAD have explored that a lot.... and they made that a very clever way.

I hope some Doctor take to himself the task to teach us the stuff.



Ron E 2nd December 2009 10:55 PM

I have always believed that "Dynamic headroom" as a specification for bragging rights means the amp has enough (or nearly enough) devices for the larger power value, but not enough heatsink.

wg_ski 2nd December 2009 11:22 PM

"Dynamic headroom" used to be the spec (in dB) between the maximum burst-test output power for 20 mS and the sine wave output power. Higher number = a poor power supply and a hot running amplifier. An amp which puts out 100 watts sine wave and can put out 200 watts (RMS value) for a short burst has DH of 3dB. Such an amp is only really good for 100 watts in terms of subjective loudness, but has all of the voltage, current, and heat stresses typical of a 200W amp.

djk 6th December 2009 12:27 AM

Dynamic headroom is a way of bragging about poor power supply regulation.

Back in the day of monochrome monitors, amber had the best contrast but was more expensive. IBM bragged that theirs were green. They made more money, and peoples' eyes suffered. Brilliant marketing on their part.

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