I once saved everything I could find about the DSP-1 settings on a word file for future reference. The problem is I seem to have accidentally deleted it at some point :D I´ll do the research again and report back ASAP!
EDIT: found the document after all! Will be posting it here very soon...
EDIT 2: OK, here it goes!
First of all, check this url about what the individual switches change: http://currawong.net/head-fi/DSP_settings.html
Earlier versions of the DSP-1 use switches, while new DSP-1 uses jumpers (apparently due to sound quality reasons, Kingwa is not a fan of switches), but the settings order is the same on both versions.
None of what follows was written by me, I am just copypasting other posts from these forums from now on! These have been taken from various huge Audio-gd threads, no idea from where! I did A LOT of research and read almost everything posted about the REF7/DSP-1 when I was comtemplating placing an order. Glad to see some of that research will end up useful :-)
So let´s begin... *disclaimer* some of these posts talk about the same things, so there is double information inside all of this! Oh and don´t thank me, thank the people who did the testing :)
EDIT3: As this thread has turned into a general Audio-gd tweak/debate thread, I think this discussion is very suited here. I haven´t tried these settings yet, but will very soon I think :) Have fun experimenting! Oh and as you´ve already noticed from these settings, no the DSP-1 is not locked into any specific setting so if you want to almost turn it off and use the REF7 in NOS mode, feel free - Kingwa doesn´t restrict you. If you need jumpers, order something small from Audio-gd and ask for some. He included a small bag of jumpers as a gift on my CD7 box :)
Originally Posted by FauDrei
(answering to a question about NOS mode on REF7)
Turn off pin 7 for NOS.
IMO, the default settings are pretty good, possibly the best. I preferred playing with attenuation (ambiance, focus) and dithering (details) settings. NOS was dull compared to 8x OS.
YMMV. Try for yourself.
NOTE: before switching DSP-1 dip swithces - turn your DAC off.
Originally Posted by Newk Yuler
(answering to a question about his experience with DSP-1 settings on REF7)
This is the same image that Currawong originally posted for the Reference 1 and what Kingwa is emailing for anyone who asks about the settings. Vague at best and somewhat useless without further details. Can anyone give proper explanations to the functions?
Normally all switches are in the off position (which is an active configuration for some settings) except the one that puts the DSP in line, which is switch 7. According to Kingwa, if I interpreted him correctly, switching number 7 to off will bypass the DSP.
I'm going to stick my neck out and show my ignorance for the sake of someone correcting me and enlightening us all. I know some of you are a lot smarter than I am. (Hurt me! )
Switch 1. PLL. Active by default and normally best active. Signal buffering and jitter reduction.
Switches 2 and 3. Stopband Attenuation. This is a bandpass filter with selectable attenuation. Default on the highest possible setting. Anyone know the actual spec?
Switches 4 and 5. Oversampling. This is pretty straight forward. Default is 8x which is probably the best. Very curious about the 1x setting, though. It appears to provide no oversampling while allowing the benefits of running the signal through the DSP instead of a complete bypass (switch 7).
Switch 6. Data dithering. Active by default. Filtering quantization distortions. This might be one for experimenting depending on how you feed the DAC19DSP.
Switch 7. NOS. DSP bypass to the PCM1704UK. Actually eliminates DSP benefits instead of creating a simple NOS state.
Switch 9. Output format. PCM (Ref 1) and TDA1541 (Ref 2). What is "Ref 1" and "Ref 2"? PCM makes sense but what is TDA1541? Is that a reference to the Philips DAC chip?
Switches 11 and 12. Output bit. Preset to the spec of the PCM1704UK.
Now I'm looking at this written out it really appears the switches are already at optimal settings for normal use. Experimenting with the data dithering might be interesting. Switching oversampling to 1x would allow the benefits of all the other active settings while delivering NOS to the PCM1704UK. Unless I'm not really understanding 1x oversampling.
Some of you have said switching the DSP to NOS makes the DAC19DSP sound dull. Can you elaborate on that? The DSP is eliminating jitter from the input signal and switching to bypass would be allowing more jitter to pass to the PCM1704UK. If you aren't using a sure low jitter source (such as a Hiface by SPDIF) the extra jitter should be much more apparent with the DSP out of line. You also have to consider the jitter inherent to Kingwa's SPDIF circuit. Higher jitter causes the sound field to collapse and focus/definition to disappear. On the other hand, if you have a sure low jitter source, the affects shouldn't be as apparent. The USB input on the DAC19 is a weak adaptive interface and not the best way to feed it, likely producing a high jitter input signal and poor performance with the DSP bypassed.
Edited by vrln - 11/28/10 at 3:01am
Originally Posted by FauDrei
(answering the previous post)
You pretty much got it right. I'd just add a couple of comments:
Switches 2 and 3. Stopband Attenuation: how much "music energy" will slip out over stopband frequency. -130dB means almost nothing "gets away". OTOH, -90dB and -50dB are "letting some energy out" and in the process altering the balance of perceived audible focus and ambiance - lesser attenuations tend to have somewhat more "relaxed" sound. Worth experimenting.
Switches 4 and 5. Oversampling: it's about upper frequencies (treble). Lower the OS - greater the treble rolloff and lower treble definition (details). Some would argue less OS or no OS at all sound more natural. IMO "more natural" in majority of the cases is euphemism for "filtering in my DAC sucks so no filtering sounds better" (please do not shoot - it is just IMO). A-GD DACs tend to do OS and filtering right and having full OS (8x) means you are having detailed, crystal clear, not at all harsh treble. Thus my "dull NOS" comment - you are missing so called "treble sparkle" (or treble at all). Again, just IMO.
Switch 6. Data dithering: if you feed DSP-1 with 16 bit data and dithering is on, DSP-1 will "expand" 16 bits to 24 bits. This would be done not just by adding 8 zeroed bits, but 16 bit value will be relatively expanded to full 24 bit range. Dithering will be used to lower the relative error of such expansion. It should have no effect if DAC is fed with 24 bit data. Another setting worth experimenting with. Dithering slightly refines and "rounds" the sound, in certain cases no dithering can be perceived as more detailed. Try and decide for yourself.
Everything over dip 7 is DAC dependent and sets up DSP-1 module to work with it's host DAC.
FYI, Ref-1 is Reference One - first A-GD dac that had DSP-1 module. Ref-2 is Reference Two - discontinued twin brother of Ref-1 which used Philips TDA1541 DAC chips instead of PCM1704.
Hope this clarified DSP-1 a bit more.