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Thread: Interested in a USB Audio Amplifier?

  1. #31
    Fusion Brain Creator 2k1Toaster's Avatar
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    Unless your use of DAC means something other than digital-analogue-converter, then it is not a dac. It is a purely digital stream, no analogue conversion process anywhere.
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  2. #32
    Maximum Bitrate DaveDog's Avatar
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    Quote Originally Posted by 2k1Toaster View Post
    Unless your use of DAC means something other than digital-analogue-converter, then it is not a dac. It is a purely digital stream, no analogue conversion process anywhere.

    really, you're driving the speakers with a digital signal, guess my dog may be able to hear it...
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  3. #33
    Fusion Brain Creator 2k1Toaster's Avatar
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    Yes. That is what pulse width modulation is. It is a time based digital signal. If you want to get picky, there is no such thing as digital at all, just an analogue voltage with ideally two discrete points.

    Any Class D amplifier does the same thing. It is not driving it with a sine wave, but a series of timed pulses.
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  4. #34
    Maximum Bitrate DaveDog's Avatar
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    Quote Originally Posted by 2k1Toaster View Post
    Yes. That is what pulse width modulation is. It is a time based digital signal. If you want to get picky, there is no such thing as digital at all, just an analogue voltage with ideally two discrete points.

    Any Class D amplifier does the same thing. It is not driving it with a sine wave, but a series of timed pulses.
    didn't know that's how a class d worked, so am I correct that the times pulses are at different amplitude in the shape of a sine wave?
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  5. #35
    Fusion Brain Creator 2k1Toaster's Avatar
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    Quote Originally Posted by DaveDog View Post
    didn't know that's how a class d worked, so am I correct that the times pulses are at different amplitude in the shape of a sine wave?
    Nope. It is a single output voltage. Although the topology I am using will have a variable output stage for higher power. So if it cannot produce the power needed without clipping, it will step the voltage output higher to compensate and then bring it back down to save power.

    You can think of it as the longer the pulse is "on", the higher voltage the speaker sees. Not really, but it will work to try and imagine it.
    Fusion Brain Version 6 Released!
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    30 Digital Outputs -- Directly drive a relay
    15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
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  6. #36
    Maximum Bitrate DaveDog's Avatar
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    Quote Originally Posted by 2k1Toaster View Post
    Nope. It is a single output voltage. Although the topology I am using will have a variable output stage for higher power. So if it cannot produce the power needed without clipping, it will step the voltage output higher to compensate and then bring it back down to save power.

    You can think of it as the longer the pulse is "on", the higher voltage the speaker sees. Not really, but it will work to try and imagine it.
    a quick trip over to wikipedia got me squared away. Very interesting, it appears your design will eliminate a pair of digital to audio conversions that take place in current setups (if you are using a typical D class amp)

    Sounds good, we'll see what features shake out and I may just buy a couple, would work for my truck with line out pass thru (unfortunately a D to A conversion) and would work in my boat with the same and a manual volume control, would work in my car without either (my lowest powered system, no subs)
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  7. #37
    Fusion Brain Creator 2k1Toaster's Avatar
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    Exactly. Most designs go from a digital signal in a computer to a low level analogue output. Then transfers via a cable where the analogue signals picks up who knows what distortion and interference into an amplifier. If it is an analogue amp like A or AB, then it will amplify those errors too. If it is a class D, then you are taking that erroneous converted signal and converting it again before amplifying it and sending it out.
    Fusion Brain Version 6 Released!
    1.9in x 2.9in -- 47mm x 73mm
    30 Digital Outputs -- Directly drive a relay
    15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
    Buy now in the MP3Car.com Store

  8. #38
    Low Bitrate marci's Avatar
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    im interested too. If design and quality good, I see good chances within european market.

  9. #39
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    Quote Originally Posted by 2k1Toaster View Post
    I wasnt planning on making it DIN sized. I was figuring on making it look like an amp. But like I said, I have not laid it out yet.

    What type of footprint do you guys want? The limiting factor here is not component size (they are small), but heat dissipation. At high powers, this thing will get... toasty.
    As far as footprint goes, I think something that will fit underneath a seat, so in the same size range as the usual 4x50W amps would be about right.

    But, given we are computer geeks, why not try to make them a little more interesting? Rather than a box, make part of the shell a finned heatsink (I know, the normal amps use the shell as a heatsink, but I mean make it finned, give it some design!!!).

    But definitely count me in, I currently have a Sony 4x50W RMS amp, but I need to add a sub, and this would probably be the same price as me buying the monoblock amp for the sub.

    Just a question, if it is a USB audio device as well as the amp, would that mean it would support doing frequency splitting / crossovers? For instance, could I limit the output of certain frequencies to certain speakers?

    If it makes the design too expensive, then don't worry about it, but just not sure how that kind of thing would work! (Not an audio guy!).

    Also, as someone else requested, a hard wired volume knob would be really handy, because then I could ditch the stupid volume bar and buttons from out of centrafuse, and work on getting the most from screen real estate. Plus, a hardware knob would give you quick, easy, non touchscreen control on the sound. Hopefully it wouldn't add too much onto the price either?

  10. #40
    Fusion Brain Creator 2k1Toaster's Avatar
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    I am planning on this having much more power than 50w per channel. High power, extreme accuracy, extreme simplicity. The ultimate sound device.
    Fusion Brain Version 6 Released!
    1.9in x 2.9in -- 47mm x 73mm
    30 Digital Outputs -- Directly drive a relay
    15 Analogue Inputs -- Read sensors like temperature, light, distance, acceleration, and more
    Buy now in the MP3Car.com Store

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