WARNING long story ....I am always amazed about the (mis)information about DACs.
The 'theory' is that the output level of a ladder DAC (Multibit) would be more accurate in absolute value compared to Delta Sigma
Delta Sigma exists in 2 basic forms.
A pure 1 bit version (DSD also is a pure 1 bit) and a 'multibit' version where a few bits are ladder type which are Delta Sigma modulated.
The theory most people 'follow' is that DS is bad (because it's incredibly cheap to make) and old fashioned 'multibit' is good (costs a LOT to make a good chip).
Driven on sentiment really.
Here is the thing that most people feel is the case. Assuming bit perfect playback.
Those using the volume control of the player/PC or DSP can already forget about bit-perfect....
It is important to realise what digital is.
An analog wave form is 'sampled' at a specific point in time and sampled again a fixed time period later.
At the point in time the signal is sampled the exact voltage at that time is 'held' for a short period and the value is converted in a value closest to a 'step size'.
The more bits the smaller the steps are, the more accurate the representation.
As we are talking about music the analog amplitude is changing constantly but 'sampled' at intervals.
The shorter the interval the higher the max frequency range will be.
Remember the sample is a point in time ... not a continuous held signal till the next sample is taken.
On playback we should thus have a point with the same value converted followed by 'nothing' till the next point-value comes along.
Of course this doesn't work in practice... it works on A-D conversion but NOT the other way around.
The first 'digital' signal was a 1 bit signal. BUT that took very fast swicthing and LOTS of datapoints (DSD) which wasn't feasable at that time.
So PCM was born which was 'easier' to make. Less points in time (so no high speeds needed) and the sample value was noted in 16 bits.
On playback the easiest way (because of speed) was to create a sample and hold D-A converter.
Such a converter sets its output (very fast) to the 'sample value' and holds that output voltage till the next sample value sets the output voltage to another value.
That value too is 'held' till the next sample arrives.
So recap.... on recording a single POINT in time is taken and on reproduction that 'value' which is a POINT is 'held' over a period of time to the same value.
Think the all familiar 'step graphs' you often see when digital is mentioned.
Well in MB DAC's those steps actually are there directly on the DAC CHIP output.
The question is how ACCURATE these steps can actually be.
This is determined by tolerances. The smallest step in a 16 bit signal 32768x smaller in value than the largest 'step'.
Something like that is very difficult to produce because the largest 'value' must be exactly 32768x bigger and must not be 327667 or 32769 x bigger.
Tolerances... very hard to do.
This is why those chips are expensive as they are laser trimmed or other trickery is used such as 'selection'.
Because of this the actual accuracy of 16 bit ladder DAC's often isn't much better than what could be achieved with 13 to 14 bit step sizes.
Back in the old days is was even less.
The newer '18 bit, 20 bit or 24bit' DAC's thus also do NOT reach their accuracy.
Those chips 'accept' 18, 20 or 24bit digital 'words' and TRY to convert that into an analog 'sample and hold' signal.
This doesn't LOOK anything like the original 'point' in time at all ... it is a 'stripe' over a certain time and NOT exactly the value it had.
So... NO MB DAC's do NOT represent the digital signal accurately despite what most 'assume'.
Except for some filterless NOS DAC's that some use because of their 'purist' beliefs NO other DAC in existence has 'stairsteps' as an output signal.
This is where the MB talk is much better talk already falls flat on its face.
The people claiming MB is more 'accurate' are not listening to 'stairsteps' NOR to single 'point in time' samples at all.
This is because of the 'brickwall or reconstruction' filter that MUST follow the DAC chip.
That filter must be 'steep and very complex' because we don't want the sample frequency (assume 44.1kHz) but we DO want the 20kHz signal.
The stairstep signal on playback thus is ONLY representing the 'original value' (as close as it can) just after the analog value appeared on the output of the chip.
Then it is 'held' there BUT on recording the signal was still changing in value.
The MB DAC chip does NOT change its value though UNTILL the next 'sample value' comes along.
SO .. NOT as accurate as they believe.
The reconstruction filter's steepness smoothes over/connects in a 'sliding' way over time between the AVERAGE values of the 'held' signals. Thereby creating an analog value that is NEVER the exact same value as the original sample was at that point.
Instead it 'glides' past that value at some point in time between the original samples.
So much for 'the MB DAC has the exact values' ... it's nonsense.
Therefore the MB DAC is NOT an exact repersentation of the digital value at all which is what 'believers' like to believe.
They believe it is more accurate and thus they HEAR it as more accurate/real whatever as well. (Mindset)
Now Delta Sigma works different.
What the reconstruction filter behind the MD DAC does the DS does as well but 'creates' many sample values inbetween the 'known' values.
It is quite complicated but the 'average' value of those 'invented inbetween' samples (upsampling) is based on sample values before and after the current sample value (that would have been 'held' by the MB DAC output) and as the next value differs and the previous value differs many small 'average values' are spaced very closely together.
Many of those average values BETWEEN the original samples thus.
Those small steps can be 'post filtered' by a very simple and nNOT 'steep and complex' filter.
So the average voltage between those original values are mathmatically generated values that VERY closely approximate the values as they (probably) had been when the original analog signal was sampled.
The fun part is that those 'approximations' are actually even MORE accurate than the analog representations the MB ladder DAC can put out because of tolerances and the sample point NOT being a sample 'period of time'.
The 'probable' continuous value of the original analog signal is thus also 'estimated' because of the steep reconstruction filter in MB DACs as well as the value is 'estimated' but digitally in the DS DAC.
So BOTH values are inaccurate representations and the MB is actually WORSE in accuracy than the MB ladder DAC ... because of physics (tolerances) and the effect of the reconstruction filters.
Of course we see 32 bit SD DAC's around which doesn't mean it can make actual steps that small.
It can't ... the chip just accepts 32 bit 'words' but also 16, 18, 20 or 24 or whatever you throw at it.
It is converted to a higher sample rate anyway.
So there you have it ... the Multibit hype is just what it is.. a hype driven by demand.
MB is NOT more accurate in fact it is less accurate.
The inaccuracies of both MB and DS are smaller than anyone can detect though.
You need to BLAST music at 130dB SPL (deafening) in order to be able to detect the smallest 'deviations' which are so soft that at night in a quiet room you could faintly hear 'something' while the actual music signal would vary between 100dB SPL and 130dB SPL (IF your speakers can reach it and your amp can deliver the power).
So take the hype for what it is... a hype .. driven by demand and websites 'discussing what they hear'.
IF I had to choose between the Bifrost with AK4490 (VERY accurate MB-DS) which can probably resolve 18 bits, maybe even 20 bits ? and a much more expensive multibit version with a 16 bit ladder DAC that can resolve to about 13.5 bits than for me the choice would be simple.
The AK4490 please ... MUCH more accurate and closer to the original.
But WAIT everyone keeps saying the MB sounds so much better... well to them HP A sounds better than headphone B and those differences are HUGE and very measurable.
You may prefer B over A.
So in the end you should choose what you 'think/feel/believe' is THE best and perhaps have to trust other peoples ears.
Then there is the analog stage, the power supplly, the PCB layout, the used chips, the chosen algorithms, the signal handling, the actual output voltage level and what not that can actually measurably change the output signal.
I think that those 'differences' there are GREATER than the difference in output voltage accuracy between those different conversion methods.
In short.... the DS is more accurate and cheaper.
The MB is more expensive and less accurate BUT you have something most don't have.
To me the choice is obvious based on technical merits.
I would choose a DAC over functionality and looks rather than 2 different types of conversion chips and hype trains.
Others may prefer the hype or having something 'different'.
When someone hears substantial differences between those DACS then they should choose what they believe or heard to be the best.
I am DAC deaf (I can hear differences between poorly designed and properly designed ones though) so every competently designed DAC sounds exactly the same when level matched AND when not aware WHAT I am listening at.