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In Reply to: Any major audio improvement in Denon's 3930 over 3910? posted by The Sound Guy on February 7, 2007 at 01:49:33:
3910 DACs are the same as in 3930, both operating in differential mode. In my experience, bypassing the AL24 processor brings better sonics.The real problem is that (just as every universal or SACD player) the PCM is being attenuated (truncated) in order to equalize with the lower level of DSD (SACD). This is one of the reasons why CD performance is not that great on most universal or SACD players compared to dedicated CD players.
What really makes the 3930 performance superior compared to 3910 is the new linear power supply for DAC/Analog stages. 3910 is entirely supplied by a noisy switching power supply.
Follow Ups:
Thanks for your insights. Can AL24 processing be disabled by the user (via menu or buttons) or is it by altering the board?
Why is DSD often at a lower level compared to PCM? I think in many players the SACD & PCM levels are quite different.
You can't disable the AL24 processing with setup. It has to be disabled physically.DSD is usually 6db lower level than PCM due to its processing. This is the reason PCM attenuation is needed. Most universal and SACD players CD resolution is 15 bit because of that. There are other solutions achieving full 16 bit resolution using other techniques. One is DSD to PCM conversion or PCM to DSD conversion. Some players change the gain in the analog domain after the DACs.
Denon players attenuate PCM in the digital domain. This can also be disabled. :-)
DSD is usually 6db lower level than PCM due to its processing. This is the reason PCM attenuation is needed. Most universal and SACD players CD resolution is 15 bit because of that.Must we continue perpetuating this rumor? If what you say were true of most SACD players, then it would be impossible to measure LSB dither, a -90 dB sine wave, or the correct noise floor. Yet Stereophile and others continue to measure these things, and I've yet to see one single measurement of a SACD player that didn't indicate proper 16-bit CD performance.
Can the AL24 processing & PCM attenuation be disabled by a fairly technically competent user by opening the cover or does it need the skill of a person like you?Is the LSB attenuated or is it the MSB or is this via DSP/AL24? I don’t think DACs generally have a way to truncate bits! Also will this not result in distortion?
Is the LSB attenuated or is it the MSB or is this via DSP/AL24? I don’t think DACs generally have a way to truncate bits! Also will this not result in distortion?If an implementation did truncate bits, yes you would measure quantization distortion - as if dithering had not been applied. Since every multi-format DSD/PCM DAC handles 24-bit PCM data, it would be simple to implement the attenuation via bit shifting in the digital filter or DSP. Even simpler, use the digital attenuation feature built into most DACs.
Dave,The digital attenuation in the Denon is done in the DACs digital filter. I have no idea what bits are shifted and how loss-less the attenuation is, but disabling the attenuation brings up 6dB and it sounds appreciably better. Go figure....
Also, in the SACD1000, if you look at the data stream with CD you can clearly see 24 bits, but the level was still attenuated with 6dB. Format is I2S. However, certain manufacturer was changing the NV-RAM software for the PCM decoder in order to get rid of the attenuation which resulted in much better sonics. The CS4396 DACs in the Philips do not have digital attenuation so it had to be done in the DSP.
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