[sdiy] Electrosmith Eurorack DSP platform

Mike Bryant mbryant at futurehorizons.com
Fri Jan 28 11:44:12 CET 2022

His THD isn't due to aliases, it's due to switching errors.   If you put two outputs in timesync with each other then you'd reduce noise by 3dB but the harmonic distortion would remain the same.  Offsetting one in time from the other means you have two smaller harmonic causing spikes of half the amplitude, which reduces the actual power in the harmonics ....  maybe :-)

-----Original Message-----
From: cheater cheater [mailto:cheater00social at gmail.com] 
Sent: 28 January 2022 10:38
To: Mike Bryant
Cc: Eric Brombaugh; synth-diy at synth-diy.org
Subject: Re: [sdiy] Electrosmith Eurorack DSP platform

The aliases would still be reflecting off the same sampling frequency
- how would that have the effect of a higher sampling rate? Am I missing something? Thanks

On Fri, Jan 28, 2022 at 10:45 AM Mike Bryant <mbryant at futurehorizons.com> wrote:
> On Thu, Jan 27, 2022 at 11:00 PM Eric Brombaugh via Synth-diy <synth-diy at synth-diy.org> wrote:
> >
> > I was seeing harmonics down slightly better than 80dB with all the 
> > mitigation measures active. Without it was more like 60-65dB. Not 
> > quite as good as even an inexpensive sigma-delta I2S audio DAC, but 
> > a few SMT passive parts beat that for cost & simplicity and I2S DACs 
> > don't support 12MHz sample rates.
> >
> > Eric
> Did you try running two systems in parallel with the second running half a sample behind and summing the pair ?   Might give a little bit performance as it would have the effect of an even higher sampling rate.

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