Although I am a DAC builder, I strongly not recommend anyone who are love to hear the music with their equipment trying to heat up their soldering iron and start to build one. Because making a working DAC is simple but making a good sound quality DAC is far difficult than you might think.
Thankfully, without any trouble to built a vintage multibit DAC for your own, Schiit audio already make a DAC named Bifrost 2. It is considerably an affordable modern multibit DAC that having the sound signature of the vintage multibit DAC. It sound pretty good indeed. I have review it and compare to my DAC built here and I wish you visit it again.
So in this post, let's see what components that Schiit audio use on their Bifrost 2 DAC.
Actually the Schiit audio official websites already put the photos of their Biforst 2 DAC internal, but I think it is not detail yet. So I disassembly mine to see more detail components that they are using in it.
The Bifrost 2 using semi-modular PCB design. The main board is consist of power supply section, SPDIF & Toslink circuitry, logic control for input selector and 2 socket for modular PCB on top of it. The secondary board is for USB receiver and the third board is for the DAC and analog stages.
I start from the power supply section first.
AC line filter 6EEJP rating 6 amp.
MCI 4-05-4626, 30 VA transformer secondary 26 volt x2.
317T & 337T On-semi voltage regulator.
7805 (unknown) voltage regulator.
Here are the digital receiver and logic control components on the main board.
AKM AK4113VE digital receiver.
Analog Device ADSP21478 DSP controller and input selector.
Microchip PIC32MM digital interface.
MXIC MX25L4006EPI NOR flash IC.
Finished with the main board components, then I exploring to the second board which is the USB receiver. Schiit audio using their own proprietary Unison USB interface which actually their own programing for this USB to I2s conversion.
PIC MZ0512EFE 32 bit MCU
12 Mhz crystal oscillator
Wurth 7490100110A high speed digital transformer
Silicon Labs Si8640BB
The third board is the main components for DAC function. This Bifrost 2 is a modular design DAC and this DAC board is a replaceable board ready as long as the Schiit audio provide the specific board for the future upgrade.
Analog Device AD5781 voltage output 18 bit DAC. This is a two match DAC section in one die. One is 6 MSB's of 18 bit data word are decode to drive 63 switches (probably Delta Sigma architecture) and the other is 12 bit R2R DAC.
Analog Device AD8676 dual op-amps.
Analog Device AD8512A dual op-amps.
TI LME49724 dual op-amps for differential circuit, probably for balanced to single ended conversion.
A3901 dual full bridge driver (for DAC power supply).
TI REF 5010K precision voltage reference.
Micro programable IC SN1920
Quite interesting that this DAC using the newer DAC technology from Analog Device that I guess it is not fully a R2R multibit DAC structure. This is because the present of the first 6 MSB's segment are probably the Delta Sigma architecture before the next 12 bit R2R DAC as describe on the datasheet.
The output from the DAC IC are balanced, as expected from the present of 2 pieces of AD5781 DAC, then going to the analog stages that consist of several op-amps. Specifically for the balanced to single ended converter circuit is provided using TI LME49724 op-amp.
I think that's all for the Schiit Bifrost 2 DAC tear down, an interesting internals layout that using many high quality components.
Disclaimer: Any statement and photos in this article are not allowed to copy or publish without written permission from the writer. Any injury or loss from following tips in this article is not under writer responsibility.
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