Delta Sigma: An Inconvenient Truth

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by k4rstar, Jun 21, 2020.

  1. k4rstar

    k4rstar Britney fan club president

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    a small update, the creator of my DAC will be sending me two items: 1) a TDA1543 DAC that shares many design elements with his TDA1541 model I wrote about in post #161 2) a hybrid headphone amplifier based on the 6N6P triode and a germanium transistor output stage

    both of these items will be offered on loaner program here once I receive them, if there are interested participants. I estimate around 2 months for assembly and delivery from Ukraine, hopefully shorter, maybe longer.

    I have received a few PMs about the abbasaudio equipment and I think 2 people have already purchased a DAC from him. hopefully they will share their thoughts once ready. I have no commercial affiliation, I am just glad to open more doors to good sound for people.
     
  2. Azimuth

    Azimuth FKA rtaylor76, Friend

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    I have always considered the TDA1541 to be a decent DAC chip, I mean, from the very start. Yeah, it not super detailed and can be hazy in the top end, the low end can bloom due to the non-linearity, but I get it with this chip. There is a reason that it became the the standard for AKM D/S chips. I just feel after hearing more detail, I feel like l am losing something in that haze. TDA1543 have a similar sound, just don't have as much current drive. They were the low-cost multibit alternative when D/S started taking hold. I still have a couple of TDA1541 CD players and one TDA1543 CD player. You can still pickup these CD players pretty cheap like I did. They still remind me of a tape at 15 ips with all that low end bloom (R2R sounds like R2R, lol)

    This thread has also prompted me to get out my modded Denon DA-500 with dual PCM1702s. My first real foray into multibit about 4 or 5 years ago. Unmodded was a bit harsh on top, reminiscent of D/S, but still had this bottom end and depth. But with the op amp change outs sound kind of in-between my Modius and Bifrost MB. It still has a right pleasant sound and enough details. Top end at least more natural, but with 16x oversampling, things like cymbals can sound hissy/harsh. I won't go into all the op amps I tried, but it was a long road of trial an error trying to get the balance right. By the time I figured it out, I already went trough a Modi original, then Bifrost 4490, then upgraded to Bifrost MB.

    I have still yet to hear a PCM63 DAC and almost pulled the trigger on an Adcom GDA-600, but I am afraid that implementation is not going to do me anygood, just like this Denon implementation of the PCM1702 leaves much to be desired. Vintage DACs I have found it is less about the chip and more about the implementation around it. I still think there can be good and bad designs of both and can see the need and appeal of both.
     
  3. Azimuth

    Azimuth FKA rtaylor76, Friend

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    Fawk as Mike Moffat would say. I totally forgot about the multibit settling/warm up time. After a couple of days, I could listen to this mid-fi PCM1702 DAC for days.

    I will do my best to explain the sound. Wide and fast, with front to back depth, with this robust bottom end that is not overbearing. The top end and mid range smoothed out quite a bit, however, some might say there is to top end transients and peaks that might be too offensive to some, I find that it is the right amount of macro dynamics. It just has an open and effortless sound. Going back to the Bifrost MB sounds a bit muted and I am missing some details. I think Hands said something similar in his description of the BF2. I originally thought I had this other way round and I thought the Denon DA-500 was muted, until I went to unplug the Bifrost MB input and the sound went away.

    Going to Modius sounds colder and not nearly as much front to back detail. Nearly as wide though, and tonally similar, Modius just flatter soundstage. Even cymbals sound fairly natural. This is the balanced output with the stock power supply.
     
    Last edited: Jul 23, 2020
  4. k4rstar

    k4rstar Britney fan club president

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    it took a little longer than anticipated but the abbasaudio DAC0.1SE has arrived. this is a TDA1543 DAC available for $800 US on ebay. it uses germanium transistors for I/U conversion and a 6DJ8 output tube. there are only two microcircuits in the device, the TDA1543 DAC and a CS8412 S/PDIF receiver.

    I spent this entire day listening to the DAC in my speaker system using a cheap Philips CD player as a transport, listening to everything from Hendrix to Haydn. i'm not going to do a review, I am so over reviewing DACs, it's impossible to write more than 200 words without sounding like bullshit. I will put forth that this is an excellent example of a non-oversampling DAC done right and it comes close in performance to the more than twice as expensive DAC2.2SE which I mentioned earlier in this thread. any of the usual misconceptions about non-oversampling DACs such as sounding slow, rolled-off, dark, mushy, etc. do not apply here.

    I will listen for a few more days and then this DAC will be offered on a limited loaner tour here, assuming there is enough interest.

    IMG_1007.JPG
    IMG_1016.JPG
     
  5. k4rstar

    k4rstar Britney fan club president

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    P.S. delta-sigma still sucks balls and sounds like ass
     
  6. Azimuth

    Azimuth FKA rtaylor76, Friend

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    This is interesting.

    Why the two torrid transformers? Is one for the tube heaters? Or maybe a separate power supply. Where are the voltage regulators?

    So one germanium transistor connected to tube buffer?

    And what are those big white square things? The AC coupler MKP caps? If so, this can make a huge difference (to the good) on the final output over any electrolytic.
     
  7. k4rstar

    k4rstar Britney fan club president

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    separate mains transformer for the two microcircuits. voltage regulation is also done on germanium transistors.

    big white squares are output capacitors. siemens paper in oil.

    I should mention for anyone who is interested, there is a cheaper version of the DAC available: DAC Z which uses more economical parts. it is available assembled in a chassis or as a populated PCB.
     
    Last edited: Oct 31, 2020
  8. Jerry

    Jerry Friend

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    Thanks for sharing @k4rstar . Any comparison with Bifrost 2?
     
  9. k4rstar

    k4rstar Britney fan club president

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    I would have to have one on hand to tell you anything specific enough to be useful. I hope at least one person who joins the tour will have that DAC to compare.

    I will say for me, I would rather have this DAC than the Yggdrasil, let alone the Bifrost. a bold statement after just one day of listening, but it sounds so similar to the DAC2.2 I have already been enjoying for a year, there were really no surprises. in fact I have become so familiar with the non-oversampling Philips multibit sound that it is the oversampling DACs that sound off and peculiar to me.

    there are no amenities with this DAC. there is only one coaxial S/PIDF input, the signal from which directly feeds into the CS8412 receiver with no buffering or error correction schemes. the sound difference between transports becomes clear as day. to connect to a computer you will need a sound card or USB converter (I use the latter). it sounds best 5 minutes from power on. initial break in took about a day of running a signal through.

    the standout qualities of this DAC are explosive dynamics and an expressive, lively midrange quality. it is equally suited to classical, jazz and rock, but you could do better maybe for Yello and Infected Mushroom. the TDA1543 is a simplified version of TDA1541, it does not require so much care in feeding, there is no DEM clock to manage for instance, which makes it a good choice for an inexpensive converter.
     
  10. mitochondrium

    mitochondrium Friend

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    If i would not consider myself DAC deaf and live on the other side of the pond I would consider participating on the loaner tour if only to put the question of multibit/NOS/DS to rest forever.
    At the moment I count myself lucky to have the possibilty to slow down music enjoyment by listening to vinyl (get that record put it on the spinner, start the spinner, contemplate the record sleeve, while enjoying the music).

    Have fun
     
  11. Senorx12562

    Senorx12562 Case of the mondays

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    Thanks for not engaging in hyperbole.
     
  12. dllmsch

    dllmsch Friend

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    I was browsing some taobao Chi-fi recently for various knockoff amps and stumbled across this DAC DIY project.
    http://bbs.hifidiy.net/thread-718905-1-1.html
    Basically designed by Chinese DIYers and is pretty well received, granted that is a DIY forum and the subjective impressions circulate around individual DIYer's tweakings, I thought @k4rstar might be interested since your love to vintage Philips chip sound. This dude also sells dac based on PCM63 and PCM1704, seems interesting.
    Here are the equivalent aliexpress links but I think these sellers are just reselling taobao stuff.
    https://www.aliexpress.com/item/4000203310492.html
    https://www.aliexpress.com/item/4000203345950.html
    https://www.aliexpress.com/item/4000723766797.html

    On a side note, there's a general consensus in the Chinese DIY forum that different TDA1541 have different sound, goes like this: TDA1541A S2(with crown)>TDA1541A S1(with crown)>TDA1541A R1>TDA1541A>TDA1541. These refrences appeared as early as 2012 so before the price hike of the chip and fake ones flooded the market? Worth to experiment I think. I am personally happy with my bifrost 2.
     
  13. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    People using these old Philips chips are shooting for a certain sound signature. I don't think that an opamp output stage is productive to achieve it.
     
  14. uncola

    uncola Friend

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  15. 7seven

    7seven Acquaintance

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    If anyone has a small amount of DIY ability or even wants to learn you could buy a cheap TDA1543 based board like this and mod it (or use as is).
    the TDA1543 and the roughly equivalent TDA1387 are like lego DAC chips, very simple (8 pins, DIP package), very cheap to replace and very flexible with implementation.

    The 8 pins:

    5V power
    ground
    left audio out
    right audio out
    voltage reference (this pin simply has a capacitor connected to ground)
    and 3 for I2S data (handled by the CS8412 SPDIF interface)

    That ebay board does not have the fancy output stage but you may not even need it or want it.
    It probably uses passive IV (current to voltage) conversion, which is a single resistor from the DAC output connected to ground. Higher resistor values results in a higher voltage.
    Even though it is so simple this kind of IV conversion is arguably the most transparent - zero active components and single passive one which isnt even in series with the signal.
    Obviously there is a catch, you can only get so much voltage from the DAC before it starts to distort.
    These particular TDA DACs happen to be very tolerant of passive IV conversion, you can get a few hundred millivolts output with no loss of quality and the loss is gradual beyond that.

    The question is how much voltage you actually need.
    For IEMs you could potentially use the maximum optimal resistor value for IV conversion and a headphone amp with no gain and still have deafening levels.
    For bigger headphones (HD6xx/8xx) you will still get decent levels if your amp has enough gain.

    These DAC chips are cheap with a nice signature and some of that multibit character but even at their best they really struggle with resolution. I wouldnt choose these over any half decent delta sigma DAC in a million years.
     
    Last edited: Nov 5, 2020
  16. je2a3

    je2a3 Almost "Made"

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    With all due respect, I beg to differ @7seven. I couldn't get a decent sound out of that TDA1543 + CS8412 DAC board. It doesn't even sound reminiscent of the TDA1543 equipped Philips/Magnavox CD players in my collection. Maybe I got a dud?

    The single chip'd TDA1543 DAC I liked was built on a slightly larger board fitted with a DIR 9001 receiver. I even DIY'ed a tube buffer for mine. Unfortunately, I haven't seen this version on eBay in over a year.
     
  17. 7seven

    7seven Acquaintance

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    Did you mod it?
    It would be surprising if it sounded good stock.

    That was just the first result on ebay to give an example of how cheap they can be and explain a few things about how they are very easy to build on and how even no output stage (1 resistor) can be the best output stage depending on your requirements, YMMV.
     
  18. je2a3

    je2a3 Almost "Made"

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    I replaced the electrolytic blocking caps with WIMAs, used a heavy wall wart with real iron in it, experimented with the I/V resistors, installed an 8-pin socket to make sure the TDA1543 was good. I made sure I gave it a fair hearing. All no go. :(

    The TDA1543/DIR9001 out of the padded envelope sounded much better!

    If you check the comment section, a reader confirmed my finding.
     
  19. 7seven

    7seven Acquaintance

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    Maybe it's the DIR9001? It is speced for 1/4 the jitter of C841X.
     
    Last edited: Nov 6, 2020
  20. je2a3

    je2a3 Almost "Made"

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    That's possible, and/or the CS8412 requires a more elaborate power supply to deliver its best while the DIR9001 performs adequately in a budget application.

    I have no issues with the CS8412 receiver inside my Adcom GDA600.
     

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