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

[jimk04]

Just finishing populating my 2nd build....v1.3PPY.
R10 and 11 silkscreen shows 0 - 100. The schematic shows 100r.
What is the function of this resistor and what does varying the R from 0 to 100 actually do?
Thanks

 

[Paddy Garcia]

I'm not exactly sure of the purpose but found that the AD844 op amp required a resistor there. 6171 and others didn't seem to care.

 

[miro1360]

It is termination resistor for testing purposes (someone might notice the difference between the values, I didn't notice)

 

[jimk04]

Thanks guys

 

[woodturner-fran]

I think I asked this before, but can't find or remember the answer if anyone had it.

Some DAC chips are fussy about having VCC and VDD present at the same time - for example the 1794 will melt fairly spectacularly if you supply one without the other.

So what is the story with the AD1862 on this? If you had a power supply failure etc and only had +12V and no -12V, or had +5V but only -2V, would the chip be damaged?

Fran

 

[jimk04]

Hi Fran. When I first built my Miro dac I had a small issue....sounded bad.. realised one rail became disconnected. Can't remember if pos or neg or on the analogue or digital side. But no damage done

 

[miro1360]

Hi Fran, this chip is quite durable. It can be damaged under reversed polarity as any other device. It survives a disconnected rail or any timing in connection as long as the voltages are in the range - it can be damaged when the voltages are over +-15V (even though +-13.2V is the maximum in the datasheet).

 

[woodturner-fran]

This is great information, thank you all.

It's nice to know that the chip won't be damaged if something should go wrong

 

[Traktorist3d]

Hello everyone, I see Kammrada reportedly there are strains about buying high-quality power stabilizers. Once upon a time, I did draw scarves in Sprint-layout for my needs based on the so-called "Behemoth" stub, from the audio perfection site.


If anyone is interested, I can throw off the gerberas, for the manufacture of the stabilizer, the components are all readily available. Perhaps there is something to correct in this board drawn by me. There is also a drawn version of the bipolar stabilizer (just for our needs).

According to the author's measurements and the simulation, the stabilizer is very good, I recommend it. I use them myself with a DAC from Pavel Pogodin DSC-1

There are also drawn shawls of the so-called "Nazar Stabilizer", you need to try both of them, perhaps it will be better than microcircuits from manufacturers, in any case there are no problems with the purchase of components, all are readily available.

 

[platon.rado]

Hi everybody
The sound is amazing. Better than Holo Audio Spring R2R DAC.
The DAC with AD1862 has more details and tireless sound.
Used IO AD797

Thanks Miro

 

[Paddy Garcia]

Nice work, done quickly!

 

[BRN]

I know that the AD1862 is a 20bit DAC, so what file resolutions can be used with it? I have mostly redbook, but a do have a number of 24bit with various sampling frequencies. Would I need to set the resolution on the USB-I2S board I use, or in the server software?

 

[miro1360]

@BRN you can play all recordings, 16 or 24bit, resolution from 44.1 up to 192kHz ... from 24bit recording only 20bits will be played (most significant bits, the rest is ignored)...
You can set the resolution on control driver for the USB-I2S board

 

[TJF]

I know that the AD1862 is a 20bit DAC, so what file resolutions can be used with it? I have mostly redbook, but a do have a number of 24bit with various sampling frequencies. Would I need to set the resolution on the USB-I2S board I use, or in the server software?

If you want to play real (!) 24 bit files bit-exactly, you have to wait for miros PCM1704 project...

 

[diyiggy]

Pcm 1704 has no interrest VS the AD1862.
Numbers are not all.

 

[BRN]

Thanks. Understand that the number of bits is not everything.

 

[Traktorist3d]

Dear Miro, there is a possibility that you will modify the version of the DAC on the AD1865 with two microcircuits (dual mono), for complete separation by channels, I heard that in this version the DAC on the AD1685 is clearly more interesting in terms of the scene.

 

[miro1360]

PCM1704 is unavailable. It is available for purchase on ebay, however, it will be a recycled component. It is SMD so they used an uncontrollable hotair to pull out from the PCB - they have certainly degraded it. I would avoid this component from ebay

@Traktorist3d
Maybe sometime in the future. The output (I/V) stage is very critical part for dual mono, not as simple as in single connection - the most challenging part.
The basic connection is simple. You can create a prototype from 2 single boards. Invert Data to the second board (with SN74HCT14N). Left current output on the first board and Left current output on the second board is dual mono left channel, similiar for the right channel

 

[TJF]

I am giving away 4 pieces of new AD1862 that I no longer need. Unused and original packaging from Rochester (via Paddy).

I also have 2 x 5 pieces (each original shrink-wrapped from JLCPCB) of miro-boards left: diyAudio_AD1862_DAC_v1.3_pad_PPY3_2021-01-14

If you are interested please PM.

 

[TJF]

PCM1704 is unavailable. It is available for purchase on ebay, however, it will be a recycled component. It is SMD so they used an uncontrollable hotair to pull out from the PCB - they have certainly degraded it. I would avoid this component from ebay

This is the only alternative I can think of to the AD1862 if someone really needs 24 bits. But as diyiggy says, not everyone needs that...

Here for example some are marked as new. Whether that is true...?