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

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surfparadise

Member
Joined 2016
diyiggy said:
The I2S direct hacked from the Rpi GPIO header is both noisy and not timing proof due to the Rpi architecture : you will have a great improvment by injecting a cleaner reclocked I2S with true crystals and not an I2S extrapolated from the poor standalone Rpi one that have timing issue and very noisy after passing through the embeded fgpa -dunno if right word for that- and the dna electric noise problems of the Rpi for that delicate task.


A good investment for all your futur diy I2S streaming project will profite from a the FifoPi hat for Rpi made here by IanCanada, also avaliable at Audiophonics - who I don't like especially due to the poor team I have had to talk services with- but reliable seller. the layer added basicly will get you a cleaner reclocked & fifoed I2S with noise isolation.
With NDK crystal it will mate pretty well with the AD1862 dac chip imho.


If you directly stream from USB a JLSounds lab USB to I2S is also good for less monney but will not have of course the versability streaming fro a Rpi based solution. If you stream for a computer or a NAS via USB, it's enough, the Fifo Rpi goes further though.


The In between is also the Kali reclocker Rpi hat from Allo for cheap enough : be just carefull of the frequency Xtal chosed related to the upsampling frequency of your music.
Click to expand...


I know that there are these hats for increase i2s riability, but for this project... it’s start to be a little expensive....
In the future I want build an ‘honey badger’ with the integration of arylic board —> Kali reckloker —> DAC -> power amplifier (with arduino for manage analog/digital sources and volume).

For the moment I’m learning, I’m experimenting a bit to do a background knowledge .... but everything start cheap and end to be really expensive... at this point I’m start to think... could be this diy product better than a commercial one with the same money investment? Of course it’s more funny but....

And you guys are fantastic.... I’m learning a lot... alone could be really difficult ... maybe impossible
 
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diyiggy

diyiggy

Disabled Account
Joined 2019
All is about the sound targett or the click management in what you said if a penny is a penny.


If I try to scale your needs here accoording my experience... then go for the Kali, save monney from fancy LDOs boards and go the inexpensive ferroboard diy for them and usual old proof designs for the analog or inexpensive ldo for the digital side.I think in your trade offs you will have the best result with this scenatio. You will think about multiple PS traffo later.
 
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surfparadise

Member
Joined 2016
diyiggy said:
All is about the sound targett or the click management in what you said if a penny is a penny.


If I try to scale your needs here accoording my experience... then go for the Kali, save monney from fancy LDOs boards and go the inexpensive ferroboard diy for them and usual old proof designs for the analog or inexpensive ldo for the digital side.I think in your trade offs you will have the best result with this scenatio. You will think about multiple PS traffo later.
Click to expand...

This type of stuff are to avoid or I can save some bucks?

Let's shop together on AliExpress with new user coupons
Your € 0,92 in coupons are here!
Lusya SUQIYA Sigma79 Series LDO Low Noise Step Down Linear Regulated Power Supply Module T0703|Amplifier| - AliExpress
 
diyiggy

diyiggy

Disabled Account
Joined 2019
surfparadise said:
... at this point I’m start to think... could be this diy product better than a commercial one with the same money investment? Of course it’s more funny but....
Click to expand...


You have to focus or one is tempted to try all the appealing designs.


The one you pointed above seems a little all in one and too complex imho to be sure for the road you are drawing, at least from my experience with close targets if not worst than yours on the monney side.


Nothing bad with such good chips : TDA1541A, AD1862/PCM63; PCM1704, PCM56K, AD1865... I focussed on the two first. AK chips in the modern designs are maybe good enough though certainly more difficult to salt & pepper on the digital side due to theitr own needs.


So focusiing is mandatory in your quest : two opposit targets relative to the monney : learning and get rapidly a good sound... nothing new under the sun I learn you nothing there. From my experience this project is good enough if you have the AD1862 chips. If you have tda1541A chip I can advise you in PM but here it's off topic. I think this project is very sympathetic and disearve your care and attention.
 
diyiggy

diyiggy

Disabled Account
Joined 2019
good LM317 is certainly enough for the analog side.
And the board showed for the digital side will benefice from a rectfied voltage so needs some pennies before it : rectifiers, main cap + a decoupling one before the 78/79xx family board shown haven't... so a good fase idea but if you have the parts already. Anyway I will not putt tis for tha analog side : a simple LM317 famil reg will do, it's less than 1 euro on local shops... or hack it from old boards like 78/79xxx reg : they are everywhere and will do with some care for the analog side waiting futur improvments but having good music in between :)
 
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lasercut

Member
Joined 2017
surfparadise said:
And the other negative missing?
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the bib board come with one spare positive board. not useful for this project but it makes sense, the 2 positive boards have often been useful when only positive supplies were needed for a project, each channel could have a seperate regulator and this improved channel seperation.

about this DIY project vs a commercial one...
If R2R is a requirement for you then you will not find a commercial product with anywhere close to this level of price to performance IF done right
 
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miro1360

Member
Joined 2010
surfparadise said:
... or I can save some bucks?
...
Click to expand...
You can save huge money. This DAC can compare (and beat some :D) with the most expensive DACs on the market. You can build it for a few bucks.

If you buy 7812/7912 7805/7905 regulators, I highly recommend the OnSemi brand. Do not use too much filtration after the regulators, rather increase the filtration before regulators (the filtration between diode bridge and regulators). It is the cheapest (and still enough) solution for this DAC.

If you want something cheap for I2S, simply start with USB to I2S based on PCM2706. It is total cheap from china, as a plug and play device (purple PCB, cost about 6 usd with shipping). R-2R DAC is not so much sensitive to jitter, so you will be fine with this low cost. An xmos based I2S can be tried later.
I bet that the sound will be better as with the most expensive delta-sigma, which you, or your friend find at home :D

Just start cheap and then you can try to upgrade. After an upgrade carefully listen to a change in the music :)
 
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Robin De Wolf

Member
Joined 2019
Great thread by the way! I am getting really tempted to start this new project. I have a set of ultrabibs, so 12v power supply covered. I am wondering if I could use my neurochrome buffer, which I currently use in the dddac for the I/V conversion. Any thoughts or suggestions would be welcome.

More a question in general: why is it that in this thread people tend to recommend opamps as a good option to pair with this dac, while in others (dddac) passive iv conversion combined with either trafo's or tubes is standard and far preferable? Or am I heading into dangerous territory now? [emoji6]
 
diyiggy

diyiggy

Disabled Account
Joined 2019
I'm not sure an i/v stage and a buffer stage share the same goals...


In this order I believe from my very limted but long experience enough while biased from ears while also buffered by musicians friends and good mates here : buffer is about what the next stage can see in relation to its impedance inputt. The real challenge is to design the best i/v for such a chips with a low impedance and if possible not local feedback... while nothing print in the marble, be confident to your ears and own system, limitations can be eslwhere as well - aka : don't look at "the fly when you have a Rhino in your room" 's concept.
 
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Joseph K

Member
Joined 2004
Hm. I'm possessing my much tweaked faithful ol' PCM63 dac with extra careful clocking, bypassing, low feedback high speed discrete power supplies.
Passive I/V, + much tweaked 12B4 tube buffer.
Sounds gorgeous.
Also an AK4499, dual mono, extra care in clocking, and in general.
OPA1656 as I/V stage. Guess which sounds convincingly better..

So much for group beleifs. The PCM dac is using an old fashioned NPC5842APT (best sounding chip for a long time) oversampler, though. That thing sounds much better than it should.. But still no contest against HQP in dsd256..

Ciao, George
 
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miro1360

Member
Joined 2010
Robin De Wolf said:
More a question in general: why is it that in this thread people tend to recommend opamps as a good option to pair with this dac, while in others (dddac) passive iv conversion combined with either trafo's or tubes is standard and far preferable? Or am I heading into dangerous territory now? [emoji6]
Click to expand...

I recommend start with opamps because it is cheap, fast plug&play solution :D In a hour you can test a few of them. And then you can easily switch for another I/V solution like audio transformer, or I/V from DDDAC if you configure it for single ended aplication (if dddac is balanced). What matters most is how you like the sound, Maybe a well designed I/V with tubes will be the best.
 
diyiggy

diyiggy

Disabled Account
Joined 2019
miro1360 said:
I recommend start with opamps because it is cheap, fast plug&play solution :D In a hour you can test a few of them. And then you can easily switch for another I/V solution like audio transformer, or I/V from DDDAC if you configure it for single ended aplication (if dddac is balanced). What matters most is how you like the sound, Maybe a well designed I/V with tubes will be the best.
Click to expand...


I believe it's the way to go and glue to the starting spirit of this thread and its share bt Miro1360 :) 'thanks guy for the cool project, very more casual that manies.
 
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