Digital VS. Class a (yes, this is for you Lars)
I happen to have heard a fairly wide selection of digi amps(including the zap pulse, now that you want to make this personally directed to your own products).
None of them impressed me. I may not have "golden ears", but i sure can tell good average from involving and amazing.
ICE is another example of fairly plain digi sound.
Magura
I happen to have heard a fairly wide selection of digi amps(including the zap pulse, now that you want to make this personally directed to your own products).
None of them impressed me. I may not have "golden ears", but i sure can tell good average from involving and amazing.
ICE is another example of fairly plain digi sound.
Magura
..I have to disagree a bit, we did a last-year project at school (wich didn`t work), where we modified a already buildt 100% digital amplifier (s/pdif input). The resolution in the unmodified version was around 12 bit, so when the volume was above 72dB, there was noticable noise (naturally since 1-bit equals 6 dB in dynamic range). But below this threshold the amplifier delivered the clearest sound I`ve ever heard in my life, and that with a pair of mid-end 2-way speakers and a computer cd-rom.
The unmodofied version consisted of a s/pdif interface, an interpolation circuit (B&B), and an older Altera FPGA wich did a 1st order noise filtering on a reduced 9-bit signal (differential pwm). Wich results in 12 bit resolution. (System clock=44100kHz*8*256=90.3168MHz).
In the modified one we used a bigger FPGA (flex-series if I remember correctly), and the noise filter was of 4th order (wich gives around 124-126 dB of dynamic range). Sadly, the thing didn`t work (probably) due to 30V in on the 3.3V Vcc. (Don`t ask me why, let`s just say that someone didn`t know how a lab power supply with a current limiter works...)
The unmodofied version consisted of a s/pdif interface, an interpolation circuit (B&B), and an older Altera FPGA wich did a 1st order noise filtering on a reduced 9-bit signal (differential pwm). Wich results in 12 bit resolution. (System clock=44100kHz*8*256=90.3168MHz).
In the modified one we used a bigger FPGA (flex-series if I remember correctly), and the noise filter was of 4th order (wich gives around 124-126 dB of dynamic range). Sadly, the thing didn`t work (probably) due to 30V in on the 3.3V Vcc. (Don`t ask me why, let`s just say that someone didn`t know how a lab power supply with a current limiter works...)
Hi Panzerlord!
Can you help me? I'm in doubt with digital amplifiers. I like to build an amplifier from TI chips which contains dsp.
I don't know how much the resulution of pwm the dsp is capable for, but I think the clolck is a limiting factor (200 MHz in this case). This i the tms320c6713. So the variations are:
1. Build an aplifier with DSP and TAS5015 PWM
2. Build an amplifier with DSP and analog PWM
3. Build an amplifier with DSP and other PWM technique.
My doubts are:
Only once time should be interpolation in the circuit. Option 1. shouldn't be used.
Short delay is needed between the dsp, the pwm output and the feedback ADC.
The DSD signal must be digitalised at the pwm frequency in order to avoid interpolation (why all of the dsd is for).
So my questions:
Are there any stable and accurate digital pwm technique ?
Should a feedback is be placed or not ?
What variation would you make ?
Thank you!
Gyula
Can you help me? I'm in doubt with digital amplifiers. I like to build an amplifier from TI chips which contains dsp.
I don't know how much the resulution of pwm the dsp is capable for, but I think the clolck is a limiting factor (200 MHz in this case). This i the tms320c6713. So the variations are:
1. Build an aplifier with DSP and TAS5015 PWM
2. Build an amplifier with DSP and analog PWM
3. Build an amplifier with DSP and other PWM technique.
My doubts are:
Only once time should be interpolation in the circuit. Option 1. shouldn't be used.
Short delay is needed between the dsp, the pwm output and the feedback ADC.
The DSD signal must be digitalised at the pwm frequency in order to avoid interpolation (why all of the dsd is for).
So my questions:
Are there any stable and accurate digital pwm technique ?
Should a feedback is be placed or not ?
What variation would you make ?
Thank you!
Gyula
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