DAC AD1862: Almost THT, I2S input, NOS, R-2R

[diyiggy]

Thank you for sharing and the adress tip.



It would make a pair of months as I'm busy on a speaker project but I will send you by pm my personal review and what I've found about passive parts I'd liked best! I will have also to adapt tiny uf-l pads as my I2S source is from IanCanada, if the traces d the I2S through holes are big enough this would be not too much compicated...


My headphone is a Fostex, 70 ohms impedance iirc !

 

[miro1360]

The traces should be big enough for any I2S source.
easydac can drive 70 ohm impedance as well as 600 ohm because on the pcb is integrated TPA6120 headphone amplifier ... it can drive small speakers

 

[diyiggy]

you will laugh : an oap I use to like a lot for headphones was the JRC 4580DD if I remember, very neutral when care with the decoupling...quite old now vs newest designs...

 

[miro1360]

4580 was widely used, good sounding one

 

[diyiggy]

The DD version especially....When listening to my hifi musician friends say I'm not tottaly deaf yet! Maybe because the wine they drink here ! Lol !

 

[eziitis]

here is 4-layer PCB: easyDAC = NOS R-2R AD1862 DAC + Headphone Amp
you can omit some parts that you don't need
if there is more interest, I can create SMD version as well in the same way as this THT
But as diyiggi wrote, THT is trouble-free, the sound still be great

thanks, I will take a closer look.

 

[chi0001]

great, just downloaded the garber file.
i tried ad1862 with headphone amp, must try.

 

[miro1360]

Perfect Shing, then let us know, I hope for no errors on the PCB
C37 and C38 let unpopulated

 

[chi0001]

without rc filter means omit r10, r11, c37, c38 then solder the wire be jumper on r10 and r11?

 

[chi0001]

btw, the "ad1862 with headphone amp", the output stage i tried 3 different audio output transformers, one is from china, one is sowter 3575 and tamura tks-84, all of them excellent.
i think if that pcb output stage have 2 external pins for other passive output stage, thats perfect. ^^

 

[miro1360]

C37 and C38 is omitted for no RC filter
the R10 and R11 can stay on the PCB (or use a lower value, like 10R), without capacitor is has no effect
thanks for the info about output transformers

 

[chi0001]

how to adjust msb?

 

[miro1360]

read this thread:
DAC linearity test CD

 

[mllum]

Miro, any chance you could provide the pcb layout files from your cad software, so that we can vary the opamp i/v stage to a discrete stage?. It seems that there is plenty of space to fit 1/2 of a pass D1 i/v stage, if the opamp i/v is omitted. Perhaps you could post the files here. Thanks.

 

[miro1360]

you can easily route your own schematic, based on the original diagram, altough
I do not recommend routing custom I/V directly on the DAC board.
Until there is not known "the best final assembly", it will be better to build on interchangeable blocks.
Custom I/V often goes through significant customization and then it looks like a mess:

 

[diyiggy]

@Chi001 : Cool thing could be to remove caps or OT with a diamond buffer with pot nulling cross zero V circuit

 

[Vunce]

Hi All,

I’ve been poking around looking for a convenient solution for multiple inputs along with usb to I2S. Check these units out:

Amanero XMOS USB Digital Interface I2S / IIS to Coaxial Optical HDMI SPDIF AES 699906568846 | eBay

PCM2706 USB To I2S DAC Decoder For WINXP WIN7/8 WIN10 MAC OTG Replace Amanero | eBay

HIFI Combo384 USB to I2S Digital Interface Refer to Amanero USB IIS for Audio | eBay

 

[diyiggy]

Hi,



There are two excellent one developped here at diyaudio that is worthing more care from you :

Joro's one or Lucian's one : very good imho, ones of the best made for diy :

I2S over USB Audio - Home or Home : first maybe suit you better as we play with wires here for the I2S.
But Miro1360 has done an USB version iirc with the pcmxxxx chip ???

 

[Vunce]

Thanks for sharing the links.
Those are very nice I2S solutions.

 

[diyiggy]

The main is they sound good ! There is also an Ebay kit quite famous but I don't remmber the name : based on Crysteq xtal chip and Xmos chip as well, but those two gives better result imho because the Xtals are NDKs and basicly gives stock a better sounding results.


Most others uses more basic xtals most of the time. But it also depends of the pcb drawing, the Wave I/O is a good proven 4 layers ones, don't rememer for the JL sound, some prefer for the extra details clarity but it's also about the way you power supply such pcbs : very low noise reg chips or LiPoFe cells are advised. Having tried both solution : ultra low noise PS are enough and the diy pcb cheap.


But no doubt the front end matters a lot for the final sounding result, the luck is jitter is not a strong difficulty with such PCM chips but still matters !