how do you build direct digital amp

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Direct Digital Amp??

I would say, watch out for "marketing hype". This stuff listed below seems to be a word play to me. Things like "eliminates the need for a DAC",..... and "Completely digital signal from source to speaker". That's kinda bogus.

If you feed your speaker with a binary bit-stream of 0's and 1's it won't make a sound, or if it does it will be a horrible hissing or buzzing sound. Your speaker needs an analog sound wave to play music.

So they've re-named the DAC to DDX. -Whatever. I think it's a poor way to explain what they are trying to do to reap benefits by making the conversion of digital to analog take place at the most ideal location in the signal chain.

Below is some information I found regarding your topic: http://www.apogeemems.com/ddx/PDFs/AN-14.pdf
[FONT=Arial,Bold][FONT=Arial,Bold]1.0 DDX Technology Overview[/FONT][/FONT][FONT=Arial,Bold]
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Direct Digital Amplification (DDX) is a patented, all-digital, high efficiency amplifier architecture developed to meet the needs of a wide range of audio applications, from PC multimedia to home audio systems to MP3 playback devices. Today’s entertainment systems, including those that claim to be digital, use analog amplifiers to boost analog signals produced by digital to analog converters (DACs). DDX technology eliminates the DAC by using a patented signal processing technique to digitally control a high efficiency power device. This approach directly connects to digital audio sources, eliminates analog signal corruption and increases amplifier efficiency by over a factor of three compared to analog designs. The technology enables manufacturers to produce truly digital audio products that provide pure digital sound reproduction from the source to the speaker.


In answer to your question, how to build one,.... I haven't got a clue, LOL
 
Hmm... Take digital bytes that represent the sampled voltages and write software for some processor that multiplies them by an amplification factor? Send the resulting byte stream to a D-to-A converter? Follow the DAC by a unity-gain high-power buffer amplifier that could put some high current with the DAC'd voltages, so they could drive low-impedance loads like speakers?
 
I think it's a neat idea to keep the signal in it's digital form, so it doesn't get dac'd until the last possible moment.

My cheapo receiver with some rather ordinary (nothing special) brown-burr dacs, sounds better to me when I connect it to cd player digitally, rather than using the analog rca from cd player.

I am currently thinking of how to combine a nice DAC with a B1-Buffer on the same chassis. I like this concept for pre-amp, so that immediately after signals are converted to analog, they can have the shortest path to the amp with fewest amount of other connections, thus hopefully minimizing analog signal loss.
 
TI have a selection of single chip class D amplifiers that accept a digital input. They also have multi-chip solutions that contain a digital input PWM driver that then drives specific output stages.

These typically contain advanced bi-quads too and are multi channel allowing one to create active loudspeakers fairly easily, providing the filtering required isn't tremendous.

I've used the TAS5706/B to do just this and think it sounds amazing for what amounts to one small chip doing all the hard work. You do need to be capable with micro's though to make all of this work.
 
my speakers i am going too build is open baffle with audio nirvana 15 alnico with no crossover just connect speaker caples direct in the audio nirvana and i am making a sub too elemental designs lt1300 with ciare 18" sw so that part is ready now i am just waiting for my wood man hehe
 
how do i build a direct digital amp and powersupply where can i buy some of the thing i need
some of the thing i want too use in the power supply is Factory Adjustable 0-25V
15A of Continuous Current
High current voltage regulation with high ripple rejection
65 ultra low ESR Organic Polymer capacitors
Mundorf Supreme MCap
V-cap CuTF and TFTF capacitors
6ns ultrafast rectifier
Oversized shielded transformer
Magnetic Grounding circuit Level 2Double the AC filter circuit
how i build the direct digital amp i dont no can any body help me
 
I think the problem people are having here is that the OP doesn't quite understand what making something like this entails. It is not a simple task and requires the marrying of several different system blocks together, to end up with a working product.

The information I provided about the chips from TI do what you've requested. A class D amplifier that takes a digital input and then turns it into a high voltage, high current output suitable for driving loudspeakers.

Obviously the chip(s) on its/their own isn't/aren't going to do much, it/they need(s) a micro controller and other supporting hardware. Core Audio technology get around a lot of the trouble that this could be by harnessing the power of a small PC inside the main case.

What you're basically doing here is building a small PC which can interface with wireless networks and all of the standard audio interfaces + USB. Then you take a digital output from this PC and feed it into a digital input class D amplifier.
 
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