OL DAC: The People’s Filter

Understanding some customers’ want for customization, we placed an Easter egg in OL DAC  for you to filter the sound however you see fit!


If you wish to experiment with the sound signature of your OL DAC, we left pads for a 3-position DIP switch on the PCBs, Omron Part# A6SN-3104. Ask for it when ordering and we’ll be glad to pre-install.

Edit: AKM provides a summary of the available filters:

AK4490EQ Interpolation Filters [Source: AKM]
AK4490EQ Interpolation Filters [Source: AKM]

12 thoughts to “OL DAC: The People’s Filter”

    1. Hi Jay – You will need to solder the suggested DIP switches in place. Filters are configured using the 3 DIP switches. Please see above picture.

    1. Tom – Good question. The following S1 legend corresponds to the AK4490 datasheet:

      1 -> SLOW (off = Low)
      2 -> SD (off = High)
      3 -> SSLOW (off = Low)

      1. So if switch 2 is on with 1 and 3 off then you’d have the natural tone filter engaged? How the switch positions correspond to the specific filters isn’t clear to me looking at the datasheet, although having played with them I can hear slight differences large enough to identify a favorite.

        1. Seems we need to generate more diagrams! I’ll try to devote time to this ASAP.

          There is no concrete relationship between AKM’s summary graphic and the datasheet, but we can at least clarify the DIP positions in a table format.

        2. I have tested out with a very very ghetto setup the different filters and it seems like you’re correct, the middle one ON and the 2 others OFF is most likely the natural filter
          forgot to put legends and to take notes on the positions since I was just doing this for fun
          other positions seemed to always make the same graphs so I’m not sure exactly what it means

          1. Thanks for sharing! The filters also impact high frequency THD; this of course does not show up in freq. response measurements.

          2. Having the Slow or SSlow switches on always seems to make the sound a little warmer but kind of fuzzy and warbling sounding. It creates kind of an odd effect on the perceived soundstage too imo. I had no idea dacs could be engineered with different interpolation filters so this was a fun experiment for me. Having all the switches off is a decent sound but there’s still something a tad awkward about the soundstage like it feels when I close my eyes there’s not much sound coming from below. With dip switch 2 up and the other ones down the sound gets a little bit fuller and sound actually seems to come from all directions in a more balanced way. If that’s the default interpolation filter for your dacs then kudos for making the right choice imo.

            Before I got into this hobby I was fairly convinced by the objectivist argument but I’ve since then become something of a subjectivist with the caveat that a lot of supposed differences are way overblown by audiophiles. I’ve been comparing the EL dac to my schiit modi multibit and the differences between them are amusing and greater than I expected. Long story short, the EL dac compares favorably, sounds just as smooth and bass is tighter and more powerful than mb (usb straight out of comp is also much cleaner with EL than on mb imo when not using controversial usb scrubbers 😉 so you can save some money there if you believe in such things). Highs are more extended and overall the sound is more forward and present which makes it seem more detailed and vocals can ring out more brilliantly occasionally. The mb does have a more natural sound so to speak, it sounds much more relaxing to me with a fuller wider enveloping kind of sound, however it does sound hazy and looser compared to the EL dac. For much music I like the more smoky romantic sound from the mb (schiit’s filter bypassed by upsampling is how I prefer it, the DSP induced holographic effect is overrated imo), but for a lot of other stuff where I want more impact and presence and better bass with clarity to boot I prefer the EL dac. Just my two cents for anyone looking into JDS labs, differences aside nothing but quality engineering and excellent customer service here.

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