24 Bit DAC for Teensy

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Rolfdegen

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I tested different 24bit DACs on my Teensy 4.1.


1. PT8211 16-bit DAC
2. PCM5102A 32-bit DAC Burr Brown
3. ES9032P 24Bit DAC HIFIberry Board

Here are spectrum analysis from DACs. The sample rate for PT8211 to 44.1KHz and and the others are 88.2KHz.

I measured the frequency spectrum of the DAC converter with a measuring Sine tone of 440 Hz from Teensy.

PT8211 shows large distortions in the overtones. PCM5102A and ES9032 are very good and have very little noise.



PT8211
Samplerate: 44.1KHz (PT8211 Teensy driver)
PT8211-Spek-88-2-KHz.jpg


PCM5102A
Samplerate: 88.2KHz (I2S1 Teensy driver)
PCM5102-A-Spek-88-2-KHz.jpg


ES9023P
Samplerate: 88.2KHz (I2S1 Teensy driver)
ES9023-P-Spek-88-2-KHz.jpg



PT8211
Unbenannt.png


PCM5102A
20210418-165103.jpg


ES9023P
20210418-165119.jpg




Gruß Rolf
 
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Interesting to see, but a bit of apples to oranges. We expect different results when measured at double sampling frequency. Doesn't really show that they are better at the same sampling frequency.
 
I also measured at 44.1KHz and found no harmonic distortion with PCM5102A and ES9023P. Only harmonic distortion with PT8211.

Increasing the sample rate to 88.2KHz with the PT8211 was no improvement.
 
Hallo Rolf,
Just curious: what measurement program did you use and what ADC?

Danke,
Paul
 
I use 32Bit DAC PCM5102A and Audacity.

The 440Hz sines wave is generated by AudioSynthWaveform from Teensy 4.1 and LCK 44.1KHz, BCK 2.857MHz.
 
Hallo Rolf,
Thanks for your reply. I was wondering what A/D-converter you were using for your measurements. Some USB audio device?

Paul
 
The PT8211 datasheet shows the distortion performance is about 9 or 10 bits equivalent with 0.1 to 0.3%
being quoted (around -60..-50dB) depending on how close to the full-scale you venture. Its key feature
is monotonicity to 16 bits, thus the claim for good dynamic range. Monotonicity and linearity are fairly
independent metrics for ADC/DAC performance.
 
Thanks all for the information.

The PCM5102A (right) has very good values for harmonic distortion. I think I using this DAC in my Synth. :)

PCM5102-A-FFT-Plot.jpg
 
You all might want to kill me, but personally i find the PT8211s sounds quite nice if you are into gritty sounds. Remember, many famous Synthesizers and Samplers had awful D/A (pre 1000 Akais, PPG Wave and especdially Prophet VS come to my mind) yet these added Harmonics are part of their iconic sound. Besides the perpetual disussion about digital filters D/As that are too "slick" are part of the problem Emulations never sound as the original.
 
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