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

not sure, that dullness have often more to see in the midrange upper band till the beginning of treble territorry "only" I have found. If it is dull some things can be improved in the mid filter pass band according the cut offs... that mgth differ according each loudspeakers filter cut offs perhaps. An illlustration : at iso spll curve I have quite different results in the cymbals or trumpets "reality rendition" if the serie attenuation resistors are Mox, or Wirewound M Supreme, or cement wirewound (R matched till 1% each time and very low value : 4R9)

Wanted to ask : all that copper certainly between the dac chip current output and the I/V add a lot of inductance and a little of capacitance as well. Is it a problem or just a trade off design ?

People talked a lot of traffo (step up transformer) to lift up the current as a passive "solution", but many gave up too as it has linearity problems. How about alll that inductors.
How one should choose the slope, ChebyChev, etc. It is not easy to wonder if one should choose from an enthusiast point of view like mine : maximum flat, Bessel (best timming), over damped. Does this low pass sum with the natural ears low pass ? (stupid question here I assume)
 
Thanks for the clarification. So, neither addresses the hf roll-off, right?
My filter does, I ring up the response by about 2dB at the filter cut-off frequency. Don't know about the Zanden.

A couple of dbs @20kHz may not sound like a big deal, but the roll-off is already measurable at 10kHz, so covers a significant range and may easily be audible.

Yes, its about 0.75dB down at 10kHz.
 
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DAC8811 tested with the same result: Not suitable for audio use 😕 (releases digital interference into audio portion, sound is nothing special - far from good dac).
I am not sure who on the web came to this recommendation, but this is not good DAC for audio. But there was something very positive on this experience: I wasted money and time so you don't have to 🤣

Anyway, we found the best candidates for R-2R DACs without filters, AD1862, AD1865 (and I recommend to try my TDA1540 - which still can be found in a good price, really good DAC).
My next focus for future will be on different design only with AD1862 or AD1865.
There are just not better filterless DACs with basic attributes:
  • price affordable and highly modifyable
  • even very simple design can do jaw drop
  • can compete with the most expensive audio devices :hphones:
 
@jimk04 got the CEN boards working fine, they are very good indeed. Immediate improvement on the op-amps, Cheers mate, also to @woodturner-fran for the help. Good lads 👍

Here they are hooked up to the PCM63 DAC, more Whack than DAC right now but it sounds very good.

IMG_0785.JPG
 
OK, should be in bed but can't turn this thing off. Possibly the best I have heard and certainly built.

@miro1360, the PCM63 mate. Very nice my friend. I get it now. Thank you. The Abbado 2 is very good, this set up is better (at many times the price), coming from a Chinese ESS9038 DAC, the NOS sound is certainly very engaging, suits a mosfet amp.

It clearly needs some work to get the best, the output stage is obviously crucial. I'm sure there is a perfect op-amp out there, but the CEN IV is proving to be very special for this DAC. Will see if Abraxalito's Dark IV is better. Still want to try your OPA627 boards, got the parts to match.
 
wonder about AMR CD66 (TDA1541A and tubes by T Loesch) that have FGPA filter selections and NOS option which one sounds the best. Never heard the Zanden, their flagship with TDA1541A is a legend too.
I think you mean the AMR CD-77.

I may have said before that the versions of the TDA 1541A chip sound quite different, the S1 gives a small boost to HF and to me seems to have a slightly more open sound. The S2 and the Taiwan chips are similar to each other, I'd say very different to the base A's. It's almost a different thing entirely with a more "detailed" sound, a bit more dry, but still very musical and in no way tiring. (All to my ears).

The different sampling settings on the AMR give changes to the sound profile in a similar way, (as do valve and output cap changes too) I leave it set on factory setting dig master 2.

"Digital Master I does without digital or analogue filtering, to ensure the highest possible frequency fidelity.
Digital Master II – with a simple analogue smoothing filter that compensates for the slight rolloff at higher frequencies inherent in (according to the AMR developers) Digital Master I. Therefore, Digital Master I is useful for bright recordings. However, to maintain the same, the developers, recommend Master II as the standard for enjoying music.
Other options: 2 times or 4 times Oversampling and Up sampling (oversampling frequency of 96 or 192 kHz) can also be used if you want to make the sound more detailed and dynamic which also gives rise to a harder, "digital" sound."

Just like with op amp swaps on other players, the impact on sound profile can be dramatic. In many ways they are like different players. I never cease to be amazed at how the sound can be shaped/changed by so few components. (I have also found this to be the case with the BB 1702 as in the Kenwood DP-7090). Obviously base design is most important, but just a few simple well chosen changes can have big effects.
 
@jimk04 got the CEN boards working fine, they are very good indeed. Immediate improvement on the op-amps, Cheers mate, also to @woodturner-fran for the help. Good lads 👍
Well done Rich they certainly got the better of me. And you're welcome.
Do you want to sell them back now you've honed them to perfection!😆

I'm digging out the Dark IV for you today.