Ibasso Discrete portable DAC with R2R D16
Jan 23, 2024 at 11:03 AM Thread Starter Post #1 of 459

Whitigir

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Not sure where is to have a good sub forum for this one. However, since it is considered a Digital to Analog as a source of converter. This may be a good one to have a dedicated thread for it.

It has powerful phones out with FPG and Stepped attenuator

D16productpage-1.jpg
 
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Jan 23, 2024 at 11:15 AM Post #2 of 459
Since it is a DAC/amp it should probably be in the Portable Headphone Amps sub-forum. The advertising refers to it as a DAC but it’s also a Class A amp, and they even show it being used for the amp with a DAP.

This looks like an interesting product. $1500 for a portable DAC/amp is a lot but I might have to get it…
 
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Jan 23, 2024 at 10:36 PM Post #5 of 459
So we did get confirmation of iBasso's FPGA 2 timing the 32 level outputs per phase clock cycle by cycle for construction of the audio waveform.

Screenshot 2024-01-24 at 11.36.17 AM.png


Indeed if we see it as a 128 element DAC (32x4) and the corresponding 128 resistors, then we are looking at a low-pass Resistor-Capacitor filter together with the 16 capacitors in the circuit to pass on the decoded analog.

Screenshot 2024-01-24 at 11.33.42 AM.png
 
Jan 23, 2024 at 11:01 PM Post #6 of 459
So we did get confirmation of iBasso's FPGA 2 timing the 32 level outputs per phase clock cycle by cycle for construction of the audio waveform.

Screenshot 2024-01-24 at 11.36.17 AM.png

Indeed if we see it as a 128 element DAC (32x4) and the corresponding 128 resistors, then we are looking at a low-pass Resistor-Capacitor filter together with the 16 capacitors in the circuit to pass on the decoded analog.

Screenshot 2024-01-24 at 11.33.42 AM.png
By chances, do you know the specific Fir elements from Cayin N7 ? Just out of curiosity for people who may want similar innovation but a complete solution of a DAP
 
Jan 23, 2024 at 11:16 PM Post #7 of 459
Cayin also build with 128 resistors, but I don't want to speculate on how many FIR elements N7 employs. It's unlikely to be 128 elements, that's for sure.

What we see below is the DSP chip that D16 employs supplementary to its FPGA – and that's another key differentiation to N7, its oversampling operation.

Screenshot 2024-01-24 at 12.16.00 PM.png
 
Jan 23, 2024 at 11:19 PM Post #8 of 459
Cayin also build with 128 resistors, but I don't want to speculate on how many FIR elements N7 employs. It's unlikely to be 128 elements, that's for sure.

What we see below is the DSP chip that D16 employs supplementary to its FPGA – and that's another key differentiation to N7, its oversampling operation.

Look to be OS 4X if I am not mistaken. I wonder if NOS is achievable
 
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Jan 23, 2024 at 11:56 PM Post #9 of 459
As a 1-bit or delta-sigma DAC, the oversampling would be fundamental to operation – for instance, R8II's NOS filter is in-fact an oversampling filter but mimicking NOS on an impulse, 1-tap level.

I'm also a big advocate on upsampling DSD64. With its very high noise floor, it's just not a viable high-res file and needs at least to double in rate to become a high-performance format.
 
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Jan 24, 2024 at 8:27 AM Post #10 of 459
As a 1-bit or delta-sigma DAC, the oversampling would be fundamental to operation – for instance, R8II's NOS filter is in-fact an oversampling filter but mimicking NOS on an impulse, 1-tap level.

I'm also a big advocate on upsampling DSD64. With its very high noise floor, it's just not a viable high-res file and needs at least to double in rate to become a high-performance format.
Agreed with everything ! A +NOS would be nice to have as an option. I like the way it is designed this way !

1/ all chips interfaces are dedicatedly separated such as DSP then FPGA then Filters with Analog stage! Separate them out and being dedicated is the right way to do thing, even AM4499EX is doing similar

2/ All of this is running off pure DC batteries and discretely designed in house. There is no other messy voltages of references, just one pure direct voltage of 3.5V straight out from battery. Usually DAC chips has different voltages of operation as optional and their final analog filters is integrated, so usually it runs off higher voltages than 3.5V. But in reality, a DAC doesn’t need higher voltage, except for analog signal amplifications

3/ With it being dedicated this ways, everything is within the maker controls, in this case, Ibasso! I have faith in Ibasso tuning ability and firmware relating to sound performances. I have enjoyed Ibasso since Dx300Max and had no desires to tinker around. Not to mention that Ibasso has the fastest upgrades on firmwares when something need fixing

4/ R2R ladder only down at final stages (I adore this topology much better than R2R at the digital DSP stages) which is immune to Jitters and noises or being effected possibly changed by interferences or any other outcomes such as precision tolerances is amazing ! It almost taking out the limits of resistors tolerances out of the pictures . I would love to see Ibasso moving forward with a limited releases of Top Tier resistor values 0.005% film foils! These are amazingly expensive but definitely the top of the summit being in components. It is totally within the design limitations but impossible to be also budget friendly. However, I respect what China can make. China has the resources, the will, and the work ethics to pull off almost anything.

It is simple to see that Ibasso did design it correctly with everything in minds. This is how we are having such low noise floors of THD and amazing crosstalk in values.
 
Jan 25, 2024 at 2:47 AM Post #11 of 459
Is there any information about the battery type? I wonder if the battery is user-replaceable (e.g. 18650 or 21700).
 
Jan 25, 2024 at 7:20 AM Post #13 of 459
Jan 25, 2024 at 8:28 AM Post #14 of 459
I need to try this for myself. First impression of mainland user of prerelease unit suggested that D16 was rather underpowered, and Ibasso is really designed it for usage with their AMP.
 
Jan 25, 2024 at 9:10 AM Post #15 of 459
I need to try this for myself. First impression of mainland user of prerelease unit suggested that D16 was rather underpowered, and Ibasso is really designed it for usage with their AMP.
The PB5 Amplifier is looking good for sure . The designs language being similar, the releases of it in the same date . That spell, use us both!!
 

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