DAC Bits for R/2R DACs

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1

Is there a processor power benefit to reducing the DAC bits down from 32 or 24 to 20?

I have couple of marginal cases where I cannot quite get a reliable performance due to chips go into throttling mode. I might give that a try (if of course I have not already tried it :face_with_hand_over_mouth:)

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Hi Michael,
I don’t know if there is any processor benefit, by all means check it out. I set it to 20 bits because that is what Jussi recommends for R2R ladder DACs. I’m not sure why! Sometimes I actually do as I’m told …

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3

Thanks for the reply and this one I do understand in relation to HQP :grin:

I have read of this setting before and assumed there was either a system benefit (DAC only uses 20 bits so it would otherwise be wasted) or less processor power required. When I move up to the man cave a little later I will see if it makes any difference to performance.

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4

No, but it removes non-linearity distortion from the output when combined with a suitable noise-shaper like LNS15 and high enough output rate (352.8k or higher), on Holo Audio R2R DACs. It is technically impossible to make R2R ladder that is accurate to 24-bits, not to even mention 32 (which exceeds what analog world can represent by several orders of magnitude)…

Correct setting depends on the DAC in question and requires some measurements to figure it out. Most other R2R DACs need lower values, 20 bits is a very very good result for R2R already.

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5

Thanks Jussi,
You refer to the limitations of R/2R architecture. Does this also apply to the SDM boards used by Holo Audio as distinct from the PCM R/2R boards or is bit depth irrelevant to SDM ?

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It seems that bit depth option is only available on PCM outputs. I had a little look last night, even though I don’t currently have an R/2R DAC.

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7

I got my Ares II set to 20bits, how does it works when I play 24bit PCM files? is there any challenges when “downsampling” from 24 to 20bits? what are the downsides if any @jussi_laako , thanks.

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It works fine as long as you use a proper dither. If you use noise-shaped dither like LNS15 or NS9 and high enough output rate (at least 352.8k, preferably 705.6/768k or more), you have more audio band dynamic range than what TPDF dithered 24-bit would have, and less distortion.

So no downsides, only positive sides.

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9

Great currently at 1536mhz max/adaptable, 20bit, LNS15, sounds amazing, thanks

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