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

very practical
could you please tell where did you connect trimmer to ad844 to null DC offset
Pin 2,3,4,5,6 and 7of all three op amp ICs are soldered together. Pin1 and 8 of the each ad844 are bent outwards, isolated from the stack. Then, I soldered just one of the AD844 ic pin 1 and 8 to each leg of the 25k trimmer. Centre pin of the trimmer is soldered to the pin 7 of the stack. Trims down to almost perfect 0dc when I set my meter range to 300mV and stayed this way even after a few hours of playing. Hence I didn't install any output caps.

Important, remove the civ and Riv on the board. Install civ and Riv between pin 5 and 3 (ground) instead. i used2.5k ad 470pf.
 
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Pin 2,3,4,5,6 and 7of all three op amp ICs are soldered together. Pin1 and 8 of the each ad844 are bent outwards, isolated from the stack. Then, I soldered just one of the AD844 ic pin 1 and 8 to each leg of the 25k trimmer. Centre pin of the trimmer is soldered to the pin 7 of the stack. Trims down to almost perfect 0dc when I set my meter range to 300mV and stayed this way even after a few hours of playing. Hence I didn't install any output caps.

Important, remove the civ and Riv on the board. Install civ and Riv between pin 5 and 3 (ground) instead. i used2.5k ad 470pf.
thank you very much for reply
appreciate very much
wish you luck Improving your setup even more when taking signal from unbuffered pin of ad844

BTW I found for my taste that Nichicon Muse KZ are some kind of unnatural compared to Panasonic FC, Nichicon ES bipolar, Elna Bipolar
 
thank you very much for reply
appreciate very much
wish you luck Improving your setup even more when taking signal from unbuffered pin of ad844

BTW I found for my taste that Nichicon Muse KZ are some kind of unnatural compared to Panasonic FC, Nichicon ES bipolar, Elna Bipolar
As a matter of fact, i do agree with you. But i went ahead to install them because they are leftovers from my previous project. I do think i want to change them out after i finalise the project. My aim is to quickly get the dac working for testing and try them out on different output stages.
 
Thanks! Did you already made all connectors in the back? Can you show us?
There is good space in the chassis for my adventure with output stages, psu etc. Yes connectors are at the back.
 

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@Vavilen Do you have a scope? Just to be sure if the voltage is clean without oscillation. But I think 270uF is fine, you can use it ;)
Be sure to use 2R2 resistors on the output power lines.
Hi Miro!
Do you mean this?
J1-J13: is 0R resistor, or a wire jumper for the PSU 1. Use 2R2 or 3R3 resistors for the PSU 2. Jumpers can be used as an alternative input for separate power supplies for each channel (no significant advantage with separate channels).
 

diyiggy

Member
2019-01-16 12:22 am
I duno...it is just a question as I have not tested...I find strange this oscilation thing and I suspect a 0.1 uF somewhere decoupling to be too much but where ? Before the ic reg input pin ...two 0.1 uf there on the power rails into 3 cm from the main reservour cap...too much odd? Or the output pin ? 2r2 should not arm but what a pity with such good reg ic... I am a noob and do not understand much but I like making experiment...I woyld have tried 100 uf output cap with 16V max rating to INCREASE the esr (adding resistance) instead putting a resistor...but yep...vias are so small I would not try too much desoldering caps there...
 
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Hi guys! I finished with burn-in of the Dac. Just yesterday I was listening my stereo. This is the best source compare to others my devices! I heard a very high resolution (same as Dodson:LOL:)with neutral and studio character. I'm shocked! My acoustic play a new colors! It seems a lot information pull out from records. Even the old records sound good!
I believe that replacement opamp will give the other sound but I don't buy them yet. I found a nice chassis and will be order at first.
By the way - the discrete opamps on last pages - are they also diy? Where I can get a gerber?
 
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diyiggy

Member
2019-01-16 12:22 am
Not sure it is the topic of this humble thread. I do not know but I believe it was made to easily find by yourself by experimentating. The final equilibrium also is whole hifi system dependant. So people have not focussed too much of ranking oaps, etc by intelectual honnesty. It is a NOS project without pre and post filtering, while filter exursion may happen. It is subjective as you say, the best conf and aops were discussed as tubes options.

It will be diificult to rate what is the best for each imho. Some like sot discrete with thermal issues, others like discrete expensive tower that distorss and how it sounds, some others a good oap, some round full tube sound, some other crystal tube sound made with another operating voltage, some humming DHT trade offs, etc.

I would test upsampling mode made by a streamer in digital domain in spite of an added ic hardware, some will prefer an ic....eventually different caps and power supply change the game...never ending story :) Make it KISS is what is smart here :)
Of course YMMV
 
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A request to all who write about subjective sound impressions: Could you please write what you are comparing? Are software or hardware filters involved? Upsampling or pure NOS operation...?
It's about hi-end Dac Dodson 217mk2d on PCM1704K. I was connected him by optical to PC and coaxial with my Akai CD79. Optical output gave a more musical sound with better resolution. Without upsampling. Maybe NOS also - I don't know. Better look at review or specifications.
 

Vunce

Member
Paid Member
2014-01-26 8:20 pm
LI, NY
Not sure it is the topic of this humble thread. I do not know but I believe it was made to easily find by yourself by experimentating. The final equilibrium also is whole hifi system dependant. So people have not focussed too much of ranking oaps, etc by intelectual honnesty. It is a NOS project without pre and post filtering, while filter exursion may happen. It is subjective as you say, the best conf and aops were discussed as tubes options.

It will be diificult to rate what is the best for each imho. Some like sot discrete with thermal issues, others like discrete expensive tower that distorss and how it sounds, some others a good oap, some round full tube sound, some other crystal tube sound made with another operating voltage, some humming DHT trade offs, etc.

I would test upsampling mode made by a streamer in digital domain in spite of an added ic hardware, some will prefer an ic....eventually different caps and power supply change the game...never ending story :) Make it KISS is what is smart here :)
Of course YMMV
Well said Iggy!
I like more than one I/V output stage option, that’s why I don’t think this dac will ever get a “permanent” home. ;)