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

[Sorenm]

Thanks @zoom777 and @Brijac! Makes good sense. As a relative novice, I am always trying to learn from the experience of others

 

[danny92]

Is there any alternatives to the recomended I/V stage opamps that are THT (DIP8)? The OPA627 is very expensive and the LM6171 seems to have higher distortion than the other opamps. Has anyone tried a AD811 based I/V stage with the AD1862, I think it needs a resistor between the current summing junction and the inverting input and a 2.2 nF feedback capacitor.

 

[Vunce]

As diyiggy would say…..

RTFT!!

There’s so much information in this thread from many members about different I/V options your head will spin, start reading😉

 

[danny92]

Ok, I think I'm just being lazy, I will try to dig some info about I/V stage opamps in the thread.

 

[EUVL]

People cannot do the reading for you.
One example :
https://www.diyaudio.com/community/...st-tht-i2s-input-nos-r-2r.354078/post-7264825


Patrick

 

[NIXIE62]

Is there any alternatives to the recomended I/V stage opamps that are THT (DIP8)? The OPA627 is very expensive and the LM6171 seems to have higher distortion than the other opamps. Has anyone tried a AD811 based I/V stage with the AD1862, I think it needs a resistor between the current summing junction and the inverting input and a 2.2 nF feedback capacitor.

I don't know about the AD1862, I just haven't made it yet, just like I haven't made the TDA1541 either.

For PCM63, Burson V6 Classic has performed best so far.

For AD1865 and PCM1702, Burson V5 (old model) and Sparkos SS3601 sound best to me.

Of all that, tubes are the best, whoever has the will and desire to use them.

 

[grunf]

Is there any alternatives to the recomended I/V stage opamps that are THT (DIP8)? The OPA627 is very expensive and the LM6171 seems to have higher distortion than the other opamps. Has anyone tried a AD811 based I/V stage with the AD1862, I think it needs a resistor between the current summing junction and the inverting input and a 2.2 nF feedback capacitor.

I'm glad you're considering an I/V conversion solution with the AD811. In my opinion, it is the best solution and at the same time the simplest, but it requires a top-quality power supply and a well-designed PCB since it is a video op-amp. No capacitor is needed at the output, and a sufficiently large current and low impedance of the AD811 can directly drive any amplifier.
Some useful information.

 

[crymen]

Is there any alternatives to the recomended I/V stage opamps that are THT (DIP8)? The OPA627 is very expensive and the LM6171 seems to have higher distortion than the other opamps. Has anyone tried a AD811 based I/V stage with the AD1862, I think it needs a resistor between the current summing junction and the inverting input and a 2.2 nF feedback capacitor.

I tried this OPA861 IV schematic by @Vunce with good result, you may take a look

https://www.diyaudio.com/community/...st-tht-i2s-input-nos-r-2r.354078/post-6286307

PCB manufacturing files here,

https://www.diyaudio.com/community/threads/dac-ad1862-almost-tht-i2s-input-nos-r-2r.354078/page-71#post-6516751

 

[zoom777]

@crymen he is specifically asking for DIP format, I think .

 

[crymen]

Yes, I think so as well. The original build mentioned above is a DIP compatible format. One good thing is it does not require a seperate power supply as it includes a power conversion from 12V to 5V

 

[NIXIE62]

Me again.
I need a link for the final version of AD1862 with JLS card. I have nothing but this picture.
And of course I got the PCB.

 

[zoom777]

https://www.diyaudio.com/community/...s-input-nos-r-2r.354078/page-128#post-6836289

 

[Brijac]

For pcm63, do not use caps on c43 c44, that literally kills the music 😅 Resolution, spaciousness, bass, everything is like hiding under a rock. Crazy how bad it influences..

 

[grunf]

True, those two capacitors on the Iout of the PCM63 are redundant but they could be used with passive I/V.

 

[Brijac]

I always doubt myself when it comes to this (psychoacoustics are a big factor), hence i always like to have someone else confirm or disagree with my observations. This was night and day difference, but i still had a listen with people i trust in. Confirmed. Then removed, and it literally was like going from slums to royal chambers.

 

[miro1360]

I don't use it either, that's why I put in "hints" so that people can try it without capacitors and verify my experience

 

[danny92]

@crymen
Thank you very much for the suggestion.
I already have a few AD811, so for now I will base the I/V stage on this CF opamp, I will keep that in mind and maybe in the future I will try the OPA861.

The I/V should be DIP8 compatible but not necessarily DIP.

 

[BRN]

I will have to removed C43 and C44 on my PCM63 and see if I can hear a difference.

I must have missed the hint about using them.

 

[crymen]

Me again.
I need a link for the final version of AD1862 with JLS card. I have nothing but this picture.
And of course I got the PCB.

A good landing page ,

https://electrodac.blogspot.com/p/dac-ad1862-almost-tht-i2s-input-nos-r.html

 

[zoom777]

@crymen , absolutely. I have always thought that Miro's blog is the place to go to for all his project information. Almost everything is there.