DSP and Plugin Development • Alpha Juno DC offset

I wonder where the final DC offset on the Alpha Juno output comes from and how it is introduced. The image in the attachment shows the output with a simple saw.

In the schematics, it looks like there is already an HP filter after the DCO output (page 11) per voice that should already remove the offset before the filter and AMP envelope:

https://www.synthxl.com/wp-content/uplo ... -notes.pdf

When silent, the first notes envelope attack starts at zero. The ending is also at zero when you hold the note for a longer time or if the note has a long release time. But it's probably not at zero when the note is released after a short time.

The slow DC offset "jump" is there even when the HP with a frequency > 200 Hz is enabled which normally would remove the offset pretty fast within a few samples.

It also looks like the DC offset is not there at the start and the end of the note. It starts and ends at zero. This makes me think that it is probably introduced somewhere in the voice chip before the AMP envelope. But why doesn't the HP filter affect the behavior?

Any ideas are welcome. Thanks

Statistics: Posted by xhy3 — Wed Dec 27, 2023 2:24 pm — Replies 0 — Views 21

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