AD1865 / AD1862 / PCM63P NOS USB DAC (blast from the past)

[Mikorist]

pre 15 minuta, NIXIE reče

Vratio sam kondenzatore paralelno I/U otporniku. Stavio šta sam našao, 82pF keramičke. Zvuk je ostao isti tako da nije presudno za zvuk. Možda je trunku mekši zvuk na visokim ali više nisam siguran. I dalje mislim da je u kombinaciji sa ovim Zfoil najbolji match Burson V6C.  Sa Dale ne znam šta je najbolje, saznaću na svom primerku.

Ostaje da se probaju ova dva 1642 sa jfetovima kad mi stignu i to je to.

 

 

[NIXIE]

I 1655 ne zaboravi

[Mikorist]

pre 3 minuta, NIXIE reče

I 1655 ne zaboravi

Kad bude nabavljivo iz mousera

[NIXIE]

A sad kad se ugrejalo sve dobro, bolje zvuči na visokim sa onim kondenzatorima, nestalo je nekog metaliziranog prizvuka, Jes sitno i teško primetno, ali se ipak primeti ne nekim numerama da je veštački. U svakom slučaju isprobaću razne otpornike, i kondenzatore na Iout kojih sad nema.

Biće isto ko sa DDDAC, proći će godine dok izvučem maksimum iz ovoga. 

 

Izmenjeno Februar 11, 2023 od NIXIE

[Zen Mod]

pisah ja sta radi taj kond

seca li se ko?

ne stavlja se napamet, nego uz pomoc sinusa i osciloskopa

[NIXIE]

Mikin dak ide Miki, a moj će da služi za igranje, jerbo ja imam rezervnih dakova, a Mika nema (osim one motherboard).

Nabaviću kondenzatora tih sitnih pa ću već nešto namunjiti. Ima gi namestim da peva ki slavuj. 

 

A već sam naučio da nema gotovih recepata uvek, nekad se moraš pomučiti sa optimizacijom.

[zerowaf]

pre 3 časa, Zen Mod reče

pisah ja sta radi taj kond

seca li se ko?

ne stavlja se napamet, nego uz pomoc sinusa i osciloskopa

Ma buka, pa se ne cuje!  

[Mikorist]

pre 7 časa, Zen Mod reče

pisah ja sta radi taj kond

seca li se ko?

ne stavlja se napamet, nego uz pomoc sinusa i osciloskopa

Pa jest. Ali ja nemam osciloskop. A @NIXIE ima. Samo još da nacrtaš kako da izmeri .

Naravno da se ne stavlja napamet. Za sparkos MORA kondezator po uputsvu.

Preporučeno je od 22pF pa naviše -sve lepo piše u uputstvu. Samo treba pročitati.

Daklem nestaje HF nestabilnost sa njime u takvoj konfiguraciji. 

 

 

pre 8 časa, NIXIE reče

A sad kad se ugrejalo sve dobro, bolje zvuči na visokim sa onim kondenzatorima, nestalo je nekog metaliziranog prizvuka, Jes sitno i teško primetno, ali se ipak primeti ne nekim numerama da je veštački. U svakom slučaju isprobaću razne otpornike, i kondenzatore na Iout kojih sad nema.

Biće isto ko sa DDDAC, proći će godine dok izvučem maksimum iz ovoga. 

 

Ja ti rekoh da je samo do konda jebenog. Niti manjeg kondezatora niti večega tehničara 

 

[NIXIE]

Kondenzator je deo priče, a drugi deo je Zfoil koji proizvodi još svetliji zvuk. Znači meni se prva iteracija sa Dale+Sparkos mnogo bolje uklopila u sistem, a to je bilo i kod doktora na testu.

Ja sam odozdo inicijalno zalemio 33pF (1206SMD) na za to predviđeno mesto. To je neki minimum da ne osciluje bilo koji OPA. Odozgo dve žičice za isprobavanje otpornika i kondenzatora. Plus ću da probam dodavanje kondenzatora od Iout na GND, samo moram kupiti tih sitnijih vrednosti, 22, 33, 47, 68, 82pF itd. 

[VukJov]

Сада никада нећемо сазнати да ли је осциловао..

[Mikorist]

Pre sat vremena, NIXIE reče

Zfoil koji proizvodi još svetliji zvuk.

Zfoil ne proizvodi zvuk. Ne farba ništa - nema sa čim.

Pročitaj pdf njegov. Nema kapacitet. Nema induktivnost. 

Čuješ PCM 100% kako jeste.

Slušaj dva tri dana  i usviraće se (mozak)

 

 

Sa brzim menjanjem otpornika ništa nećeš da postigneš . Nije moguće zbog audio memorije i centralnog nervnog sistema.

Nikad nećeš biti zadovoljan u kratkim intervalima.

Mora da stoji danima i nedeljama deo da bi čuo promenu. Ono što Zen kaže - treba mi dve nedelje da čujem i doživim promenu.

[Brijac]

Vise nije povoljno da se porucuje sa hificollective-a Al bi bilo valjano da se proba AMRG na riv poziciji ako je nekom do farbanja zvuka/balansiranja sistema. Najbitnija stvar kod zfoila je ne pomicanje statsa oscilacijom temperature, kao i out of the box uparivanje. 

[Mikorist]

Pa i da hoće da ofarba zvuk sa nekim ruskim otpornikom - mora da čeka tri dana. Ne može kao na traci da menja otpornike i čuje razliku.

Isto važi za bilo koji deo u bilo kojoj spravi. I u zvučniku takođe. Možda je vanzemaljac pa ima drugačije sinapse.

 

I sarma je bolja kad odstoji dva dana pa se podgreje. Prvi dan i nije nešto direkt iz vreloga lonca 

[Zen Mod]

2 hours ago, Mikorist said:

.......

Mora da stoji danima i nedeljama deo da bi čuo promenu. Ono što Zen kaže - treba mi dve nedelje da čujem i doživim promenu.

samo malo pojasnjenje 

cujem ja odmah ako se meni nesto ne svidja ...... ajd recimo - kad nije dobro, ili dovoljno dobro

a ako je dobro, onda sam skontao da ja bez 2 nedelje ne mogu da ocenim koliko je i kako je dobro

[Mikorist]

Pa to je to. Ovo sve što mi upoređujemo ne da je dobro - nego je odlično - ali oče čovek još bolje.

DDDAC vs PCM63P. 

I to samo promenom otpornika.

E pa kako će za 5 minuta to da oceni - to mi nije jasno. Ja to ne mogu. 

Ispada da ako promeni otpornike na DDDAC da će onda on bolje da svira.

Ali ako i ja donesem moj PC pa slušamo - još će bolje da svira moj.

Mora da promeni onda PC.

A ako promeni ribone još bolje. Ako ubaci fotelju još za nijansu.

Pa ako promeni parket u dnevnoj sobi...pa cipelarnik u predsoblju.

Nema kraja 

[Zen Mod]

@Mikorist

pa naravno da nema kraja ....... 

msm, kraj je tamo gde si zadovoljan , a to nema veze sa kvalitetom sprava nego sa glavom

ja se uvek setim primera onog tipa sa kofer gramofonom ispod jedne miske i 10 ploca ispod druge, rano jutro na trgu u NS

to da sebe setim i podsetim sta je najvaznije 

 

to da li cu ja uzivati u muzici nema nikakve veze sa najboljim komponentama na svetu, a jos manje sa tim da li komsija ima bolje sprave od mene

zato, msm da se ne zaboravi - PCM1702 rulez, svve to vase ostalo su igracke

 

 

[VukJov]

Неке промене могу да се чују за пет секунди ако су довољно драматичне, другима треба гатање од пар недеља..

Конкретно када сам забо неки фенси бурсон, мислим вивид, моментално ми се повраћало од шећера..

[Mikorist]

Delta Sigma vs Non-oversampling (NOS) R2R DAC Designs

A reflection on digital to analogue conversion concepts based on theory and practice

There is a never-ending debate on the topic of what is better: Delta Sigma (DS) or R2R (R/2R or
resistor ladder) DAC designs. First of all, it makes little sense to prove what is better in theory
because there infinte number of variables of implementation in designing and building a DAC. The
analogy would be to prove that all apples are better than pears. In order to substantiate any
claim, one needs to compare a typical sound of a DS DAC design with a well designed NOS (non-
oversampling or digital filterless) R2R DAC design. Those who tried a decent digital filterless R2R
design such as the popular NOS TDA1543, know its naturally musical sound character.  Having said
that, let us  also not forget that it is not just about a type of a DAC chip. What surrounds it is
equally if not more important such as power supplies, I/V conversion stage, SPDIF receiver (if
there is one) and an output stage. Also in practice, there is so much more to it. The design of the
circuit and the choice and combination of components round the DAC chip, last but not least is the
digital transport (its role is as at least as crucial as a DAC) – all these factors can make a huge
difference. The R2R DAC design with special emphasis on non-oversampling (without digital signal
filter or manipulation of any kind) sounds completely different to the same DAC but with digital
filtering  or noise-shaping Delta Sigma, digital signal processing (DSP) type (also in form of
FPGA) of digital circuit. In the right design, a great R2R DAC in non-oversampling mode presents
music in way more deeper, more organic and natural way than any DS type of DAC. The analogy is akin
to comparison of pictures taken with a) a camera equipped with proper optical lens (non-
oversampling R2R DAC) and b) with a camera taken with a digital zoom and a lot of DSP post-
processing, done by the software and hardware of a camera (DS DAC). Pictures taken with a) have
sense of depth, are more natural in their textures and are smoother in their transients. There is
no post-processing and all original data is presented more or less as captured. Pictures taken with
b) are flatter, textures are more synthetic and are edgier in the transients as post-processing was
applied to interpolate the missing data and all results heavily depends on post-processing
algorithm chosen. The same pretty much applies to the sonic presentation. There is obviously more
to it than whether the DAC is DS or R2R type but overall it is a valid analogy as long all other
variables are kept equal. It is true, the specs of Delta Sigma (DS) chips may look better on paper.
In practice, however, they are incomparable to R2R. The stated accuracy numbers of DS DACs are post
modulation (after digital filtering has been applied) and are not always attainable in practice for
a number of reasons (such as quality of power supplies and imperfections of components & materials,
which apply to both R2R and DS) even if your recording comes in the HD PCM or DSD format (which is
a modulated 1bit pink noise). One must admit that oversampling, demodulation and noise shaping (
read more about it here) is a clever concept to manipulate the digital signal carrying musical
information. Yet in practice there is no free lunch-  all digital signal manipulation comes at a
cost – musicality that is. Since part of the Delta Sigma conversion process (similar to switched
power supplies) is a high frequency pink noise, it requires a lot of digital filtering or
oversampling and noise-shaping. Essentially, oversampling is a corrective process, which needs to
sort the digital data in the signal and come up with bits that are not are not a part of the
original data stream. These bits is a missing information we do not have (not part of the
recording), so they need to be invented (process called interpolation) and then noise-shape
filtered. Noise-shaping and overs-sampling process are essentially adding artificial information (
artifacts) not present in the original samples. All that noise (the reason why it is called noise
shaping) with additional artifact samples (which are not part of the original recording) are
filtered with a demodulator which relies on the reduced original data by means of a negative
feedback loop. The claimed resolution of a DS DAC is of its demodulator after all the digital
filtering and not of the data stream itself (which is nothing but noise, please refer to the
picture below). In a nutshell, all DS DACs produce filtered noise (which requires demodulation),
which we perceive as a sound after a corrective digital filtering (in over-sampling) is applied.
Now that sound could be characterized as clear with a lot of perceived details, however at the same
time music tend to sound synthetic & flat without coherence and precision without exception
regardless which interpolation algorithm is used. Music however is more than just a collection of
noise reconstructed sounds. The concept of negative feedback loop and its devastating effect on
music can be found here. Music is defined by a strict relationship between signal and time. If the
musical signal is altered  relative to its time domain then one hardly can call the resulting sound
“music” by the definition. Any shift in relationship between signal and its time domain is called
phase (time) /signal amplitude distortion (or jitter in digital domain). The main cause for phase
distortion is the deliberate use of digital filtering, higher order filters and by negative
feedback loop manipulation in order to achieve better linearity. In terms of distortion, Delta
Sigma (DS) DAC designs distort musical information at all times unlike with NOS R2R. That type of
distortion (measurable or not) is made up by the noise and artifacts as DS DAC produces completely
new samples (not a part of the original recording) by the means of oversampling and the negative
feedback applied to demodulate (noise shaping and filtering) an over sampled signal. The effect of
phase to amplitude distortion is evident if one compared class- A amplification with a negative
feedback (NFB) and without. The sound is more linear with NFB applied and everything sounds sort of
nice but in the same time it all sounds the same, lacks natural coherence, harmonics and dynamics,
effectively fails to involve one emotionally. And that is the area where Delta Sigma DACs designs
fail, really. All (regardless of type) D to A converters are far from perfect. In theory and in
practice, digital conversion can only approximate analogue sine waves with stated theoretical
accuracies. However, that does not mean that we should give up on the concept of digital. In
practice, both R2R and Delta Sigma designs have larger actual quantization errors than stated in
their data sheets. Theoretically, errors of R2R converter are larger on average because of the
apparent bit depth limitation, ceteris paribus. In practice though, DS DACs have higher
quantization noise and therefore it is perfectly possible that a properly implemented R2R chip
could be less erroneous than a decently implemented Delta Sigma chip (a topic for electronic
engineers). However, let us not get confused here with different concepts. One of the key factors
for the natural sound is the lack of any manipulation in the digital domain, i.e. absence of
digital filtering or having a non-oversampled design is a good starting point. There may be a small
difference in terms between oversampling R2R and non oversampling, digital filter-less (NOS) R2R
designs, however there is a huge difference between those designs in terms of how music sounds. One
can have R2R design with oversampling and that design is not much better than Delta Sigma because
of the digital filtering involved and is a sort of the worst of both worlds. As matter of fact most
commercially available TDA154X CD players came with oversampling, usually with a SAA7322 chip (that
is perhaps the reason why most people think that those old R2Rs are obsolete).

In contrast to the all digitally filtered designs (regardless whether Delta Sigma or R2R), all of
the SW1X Audio Design™s are NOS (without digital filter) R2R- a completely different approach. A
NOS R2R DAC design sounds much more natural and more musically alive than any DS DAC with digital
filters and a corrective feedback loop inherited by its design. However, it must be admitted that
there is no DAC design without weakness and even NOS R2R designs have their own weaknesses. One of
them is the perceived lack of resolution. That weakness can be actually turned into strength with
carefully selected, low distortion, audio capacitors and optimised PCB and properly designed I/V
conversion. SW1X Audio Designs™ only employs finest capacitors & resistors around the NOS DAC chips
which brings out their true resolution to the maximum. This way, the NOS R2R is in no way inferior
to Delta Sigma and one could say quite on contrary. We would even go as far as saying that our NOS
R2R designs could easily outperform any modern Delta Sigma design even with the ones with the
claimed 32 bit resolution (of the demoldulator, after noise shaping and interpolation). The other
weakness is monotonous and predictable character, which true for all DAC chips. Those weaknesses
are curable with high quality voltage regulation, rectification and careful SPDIF receiver IC
tuning. Last but not least is the lack of energy and perceived dynamics. That issue is partly due
to choice of materials and components, I/V conversion technique and the choice of an output stage.
The later part is plagued by impedance mismatch in almost all mainstream designs with a few
exceptions. The issue of impedance mismatch is critical in 2 places of a DAC design: A) Between the
current out of DAC chip after the current to voltage (I/V or I/U) conversion and B) Between the
first amplification output stage and the preamp/power amp input. Most common approach in the
current out (best possible quality output of an R2R chip, which is impossible with Delta Sigma
chips) DAC implementation is to use a passive shunt resistor as I/V converter. This approach works
fine but has some drawbacks: the shunt resistor worsens the impedance mismatch further and it takes
energy away, therefore some of the dynamics are irreversibly lost and all subsequent stage are
lacking the drive. We, at SW1X Audio Design™ on the other hand, addressing the point A) by using a
single transistor that does the job of I/V conversion, lowers the output impedance after the I/V
stage (the DAC chip sees only 10 Ohm input impedance) and preserves the dynamics. Plus this
approach allows us to use a simple but elegant class A, zero feedback valve output stage with low
output impedance, which addresses impedance mismatch issue in the point B). On top of that the
circuit remains elegant and simple and makes the music come alive with incredible dynamics and
extreme analogue smoothness. So, the question is what is really better? A) NOS R2R DAC
characterised by brute force, real time, true resolution resistive voltage divider network
conversion with all the imperfections of the original data and conversion errors  or B) Delta Sigma
chip producing accurately filtered 1bit (or more bits) pink noise manipulated by a clever algorithm
with all the corresponding artifacts and phase /signal amplitude distortion? The answer to that
question could only be answered after an in depth critical evaluation based on real world examples.
It would also depend on whether one would like to listen to music or to sounds. In our book, music
is a time continuum from start to end which when broken is irreparably damaged and no amount of
clever digital manipulation can restore it to its original time / frequency / amplitude duration or
relationship. Some people would consider the classic Philips TDA1543 or the TDA1541 (and many other
older resistor network (R2R) based DACs) as old fashion and obsolete. That may be justified given
its age however the R2R DAC is far from obsolete. Zero oversampling R2R DACs can never be out of
date if they sound great. It would be a mistake to write off the R2R DAC just because it is not the
most modern technology. The non-oversampling DAC is very musical and analogue sounding in nature (a
feature that stands out among all modern Delta Sigma type of DACs) even with sub-optimal choice of
components and circuit design. However, the DAC itself is just a starting point as the rest of the
circuit can either “make it shine or break it”. The circuit implementation is even more critical
than the DAC on its own. The main reason for the prejudgement is that  many people have not heard
the non-oversampled (zero digital filtering) implementation at its full glory: with discrete shunt
regulated Germanium transistor power supply and a discrete and active I/U with a single ended,
class A, zero feedback valve output stage. If DACs were cars and one considered our circuit design
and the materials we employ together, the DACs that we offer would resemble something like an old
timers– to me they are classy ones. It is very interesting to see how an old timer (DAC that is
based on established and optimized technologies) compares to the latest most modern & cost-saving
technologies like bit-stream, aka Delta Sigma and DSD based DACs, which rely on digital filters (
that also remove the soul from the music). There is a huge difference how both technologies present
spatial information, dynamics & harmonics. Timbres sound much more natural and more accurate on non-
oversampled (no digital filtering) designs, while everything sound homogenized and flat on
oversampling DACs. That is one of the reasons why Delta Sigma technology is not a part of our
designs. When a true 16 bit resolution, non-oversampled R2R DAC sounds vinyl or reel to reel tape
alike in terms of perceived resolution than I would say we have not progressed much in audio
particularly in the last 30 years. I would go further to say there has not been much of a progress
in sound since the technologies (valves and transistors) were invented. It may sound provocative
but I leave to our customers to decide.   

Dr. Slawa Roschkow, 11. 2015

https://sw1xad.co.uk/technology_post/delta-sigma-vs-non-oversampling-r2r-dac-designs/

 

[Zen Mod]

nadji uljeza. msm bullshit:

Quote

.......with discrete shunt regulated Germanium transistor power supply and a discrete and active I/U with a single ended, class A, zero feedback valve output stage..........

 

verovatno toga ima vise, ali posle ovoga necu ni da gledam

ne kazem da nije dobro poceo, slazem se sa osnovnom idejom ( sa generalnog stanovista, daleko od toga da mogu i da prismrdim u bilo kakvom dizajnu).... al uvek ima neka ebena agenda

[vladd]

Taj raspricljivi rad, isproglasavali sta je egzotika pa trendseterisu...a najbolje kada nagomilaju tu nabrojenu kao ezoteriju i to je tada najnapricaniji kvalitet

Taman kao plasticna devojka najprirodnijeg izgleda...pa nabrajaj bitne detalje zainteresovanima...

 

P.S.

Skoro je bilo u NATURE, da je AI napravila naucni rad koji su neki progutali i dobro ocenili, imao je more tih karakteristicnih reci i izraza...

Tako da diskretni -sant - germanijum u dubokoj a klasi ali single ended apsolutno toliko prirodno bez dodatnoh oversemplinga i kontrolom nonjiter kloka ...kako bolje od toga

Izmenjeno Februar 12, 2023 od vladd

[Mikorist]

Pa nije jedini. Cela Ruska škola zvuka radi te DAC na Germanijumu. Imaju zalihe tih tranzistora za 100 godina. Valjda mu je jeftino delove da ubaci te. 

Ja sam generalno za američku školu zvuka. Preko Analog Devices LDO za napajanja - do Texas instruments OPA. Fairchild traniztora itd....

[Zen Mod]

dobro, zakopao sam malo po sajtu im, pa je logicno - imaju pricu i prodaju je

ceve i to - to mu dodje filozofija, put do zeljenog cilja po pitanju prirode zvuka

pa onda ciljna grupa

al msm Ge tranzistor u Shunt regu ........ nicim ne moze da se opravda 

cilj shunt rega je da bude apsolutno idealna konstrukcija ....... a upotrebom manje dobrog elementa samo se udaljavas od idealnog

zakljucak