von bovist » 1. Sep 2012, 10:06
Hi all,
some people complained about kind of digitizing noise when using the leslie sim. I'm working on this issue which will occur particularly if leslie volume is set to very low levels. To prevent it (until next upgrade of FPGA configuration), set leslie volume always to an undistorted minimum at least, not lower (may be about 0.7 to 1V on leslie volume control input). Leslie volume pot is not intended as an overall volume control (for now), as noise increases with lower input signals.
This is due to 16 bit implementation of the leslie sim which limits dynamics of the 122 amp circuit (uses 4 valid bits solely for tube overdrive, so there are only 12 bits remaining for audio). I will switch to 24 bit in near future.
For now, AVR firmware version 3.05 tries to fix it by limiting the control range of the leslie volume pot.
Hi all,
some people complained about kind of digitizing noise when using the leslie sim. I'm working on this issue which will occur particularly if leslie volume is set to very low levels. To prevent it (until next upgrade of FPGA configuration), set leslie volume always to an undistorted minimum at least, not lower (may be about 0.7 to 1V on leslie volume control input). Leslie volume pot is not intended as an overall volume control (for now), as noise increases with lower input signals.
This is due to 16 bit implementation of the leslie sim which limits dynamics of the 122 amp circuit (uses 4 valid bits solely for tube overdrive, so there are only 12 bits remaining for audio). I will switch to 24 bit in near future.
For now, AVR firmware version 3.05 tries to fix it by limiting the control range of the leslie volume pot.