1 bit CD players

Discussion in 'Audio Hardware' started by VinylSoul, Feb 5, 2011.

  1. VinylSoul

    VinylSoul Active Member

    Location:
    Lake Erie
    Why is this not the pursued path of digital perfection it was touted as? supposedly more analog like? Any owners still clinging to their 1bit players?
     
  2. kevinsinnott

    kevinsinnott Forum Coffeeologist

    Location:
    Chicago, IL USA
    Others more technically astute will weight in, but I thought the purpose in introducing 1 bit DACs was labor saving as they were self-adjusting.
     
  3. Hiro

    Hiro Well-Known Member

    Location:
    Poland
    The upcoming DSD DAW from Korg proves that 1bit technology is still, as you put it, the pursued path of perfection - pure 1bit signal, not 1bit audio downsampled to "CD quality".

    Definitely the highlight of the day was a demo given by Korg at the nearby W Hotel. There, they were showing off a beta version of a DSD (1-bit, 5.6 MHz) multitrack DAW application. Korg has long been a leader in 1-bit technology, but until now has confined it to stereo recorders. At the demo, the software’s developers were there, showing the astounding audio quality of the recordings using the software. The software, which hasn’t been named as of yet, looked like a fairly typical DAW (see photo below), but the sound was anything but. When I first arrived, they were playing acoustic jazz which sounded as rich and warm as if it had been recorded to analog tape, not digital. They then played some recordings of some Japanese flute music, and some live recordings from a surround mic captured on the floor of the AES show, which also sounded stunningly real. They also showed off its editing capabilities, which allowed for edits as small as 1 microsecond. There’s no timetable yet for when this will come to the market, this version was more of a “proof of concept.” It would be reasonable to surmise that this may very well be the future of audio, and it sounds amazing.

    http://blog.emusician.com/the_bus/2010/11/07/aes-day-2-highlights/
     
  4. MikeyH

    MikeyH Stamper King

    Location:
    Berkeley, CA
    It was a useful trade of computer speed used to increase performance. Since then we've got more accurate DACs (Strictly, programmed DSPs).

    I love my 1-bit Philips portable, it's the best sounding of my CD players (none of which get used much since listening from computer rip is much better) and the only one (including computer playing directly from CD) that can discern the 'jitter' difference on the deliberately wonky Stereophile test CD 2 track.
     
  5. kevinsinnott

    kevinsinnott Forum Coffeeologist

    Location:
    Chicago, IL USA
    Question: Is Bitstream the same thing as 1-bit? How about MASH?
     
  6. KT88

    KT88 Forum Resident

    Good topic and questions. Single bit systems are still in use but most CD player and DVD player, etc makers are using multi-bit DACs now. In fact, I can't think of any 1 bit players but for audio only units. It can sound very good, but like anything else audio, there are a lot of variables and simply putting one's faith in a single topology (or a single chip set for instance) is a sure recipe for overlooking some of the best designs out there as there are many other ways to achieve excellent sound quality. You hear a lot about how folks on various forums will say that a NOS DAC is the only way to go or this old arse chip set is the bee's knees and all others are just crap, yada, yada. That's very short sighted IMO.

    I liked the question because I used to have a 1 bit / 256 times OS player that I liked years ago and I used it for a while. It sounded better to me than the 16 bit 8x units that were more common. Of course a few years later, a 20 bit DAC was to replace that in my system. I now have 24 bit DACs which are also very fast and so have a smooth sound like the single bit and yet very high resolution.
    -Bill
     
  7. Hiro

    Hiro Well-Known Member

    Location:
    Poland
    From superaudiocenter.com:

    "Bitstream™ was based on high-speed sigma-delta modulation; however, the transport medium, CD in this case, used Pulse-Code Modulation (PCM)"

    http://www.superaudiocenter.com/DemRep.htm
     
  8. daglesj

    daglesj Forum Resident

    Location:
    Norfolk, UK
    MASH rocked. My first CD player was a Technics MASH player bought in 1990.

    Its still going strong at my parents house.

    Never heard a MASH player I didnt like.
     
  9. kevinsinnott

    kevinsinnott Forum Coffeeologist

    Location:
    Chicago, IL USA
    Thanks, Hiro.
     
  10. reb

    reb Long Live Rock

    Location:
    Long Island
    Burr Brown utilizes 1 Bit technology in it popular "Advanced Segment Dac Architecture" chips, such as the 1792 and 1794. These 24/192 chips are hybrids, utilizing both multi bit and 1 bit within the same chip.
     
  11. Black Elk

    Black Elk Music Lover

    Location:
    Bay Area, U.S.A.
    You never heard of SACD?

    Yes.

    No, but see below.

    What do you mean by multi-bit?

    ALL current audio ADCs and DACs are based on sigma-delta modulation. Bitstream and DSD/SACD are 1-bit systems. MASH was something like 2.5 bits (5-level). Some IC manufacturers use 1.5 bits (3 level), and designs vary up through the 5-bit dCS system to hybrid converters that combine a traditional PCM converter for the high-order bits with a sigma-delta modulator for the low-order bits (which can be 1-bit, 1.5-bit, etc.).

    Why use sigma-delta modulators? Because it is impossible to make conventional 'ladder-type' PCM converters with the required linearity. Just think of the tolerances that are required for a 24-bit converter where the MSB is nearly 8.5 million times the value of the LSB.

    As with most things in life, there are pros and cons to 1-bit, 1.5-bit, etc. and higher modulator orders, and designers take these into account when designing for a specific application. So, while 1-bit hasn't become the choice for ALL converters, sigma-delta in some form (including 1-bit) certainly has. Anyone using an SACD player for CD playback is likely hearing their music via a 1-bit converter, since the same converter is required for SACD.

    NOTE: I'm excluding current players based on ancient Philips multi-bit PCM chips!!
     
  12. jabbo5150

    jabbo5150 Active Member

    My Technics SL-PG350 is a 1-bit MASH player per the specs and I think it sounds good, especially for the price - I got it free! Nice player with some cool features. Probably way more than I'll ever use
     
  13. Black Elk

    Black Elk Music Lover

    Location:
    Bay Area, U.S.A.
    That is puzzling. MASH stands for Multi-Stage Noise Shaping. The goal of MASH is to achieve higher modulator orders through the use of multiple single-order modulators. The resulting system is stable unlike higher-order sigma-delta modulators (unless special actions are taken). However, the resulting output is an N-bit sequence, where N is the number of stages in the MASH design. To create a 1-bit MASH system, you would need a SINGLE stage, first- (or low-) order sigma-delta modulator. This would seem to defeat the purpose of MASH.

    I'm :confused:!
     
  14. MacGyver

    MacGyver Well-Known Member

  15. jabbo5150

    jabbo5150 Active Member

    You know way more about that than I do. I was just going by what my copy of the specs says (see attached)

    It shrunk it was down but it says MASH 1 bit for DA converter
     

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  16. JBStephens

    JBStephens I don't "drop needles" or "pull triggers".

    Location:
    Western NC
    What's puzzling is how they got MASH from "multi-stage noise shaping". Should be MSNS. Maybe Alan Alda was on the design team.

    But I did have one, and loved it.
     
    robertzombie likes this.
  17. jabbo5150

    jabbo5150 Active Member

    Good question. I like mine a lot. Some of the rest of the specs, for those interested are:

    Frequency response: 2-20,000 Hz, +/- 1 dB
    Output Voltage 2V at 0 dB
    Dynamic range 92 dB
    S/N 100 dB
    Total harmonic distortion 0.007% (1 KHz, 0 dB)
    Wow and flutter below measurable limit
    DA Converter MASH (1 bit)
    Output impedance approx 1 KΩ
    Load impedance More than 10KΩ
    Pickup Wavelength 780 nm

    Sounds good to my ears.
     
  18. jabbo5150

    jabbo5150 Active Member

  19. MacGyver

    MacGyver Well-Known Member


    Thanks! :)



    i thought MASH was a MATSUSHITA invention (by way of TECHNICS, of course)
     
  20. reb

    reb Long Live Rock

    Location:
    Long Island
    Multi-stAge noise SHaping

    FWIW, I was able to coax pretty good performance out of a Technics SL-P370 that I use in a 2nd system by "upgrading" some of the passive components. (RCA jacks, wire, capacitors, connections, power cord etc). Stock, the machine sounds rather rolled off on top with prominent bass and mediocre resolution.
    The chip is a Mash 4 DAC (MN6474 – MN6625)

    Lukasz Fikus has some nice things to say about MASH

    http://www.lampizator.eu/lampizator/REFERENCES/TECHNICS/SL-PS700/Technics SL-PS700.html
     
  21. JA Fant

    JA Fant New Member

    Agreed,

    I liked that MASH technology as well!!
     
  22. kevinsinnott

    kevinsinnott Forum Coffeeologist

    Location:
    Chicago, IL USA
    :righton: I like Lukasz Fikus.
     
  23. DrJ

    DrJ Forum Resident

    Location:
    Davis, CA, USA
    I once had an Audio Note DAC 2.1 Signature (tube) that employed the 1 bit approach. It was a nice sounding DAC but had reliability problems so I sold it. Never had a chance to head-to-head compare it against other good CD players.
     
  24. KT88

    KT88 Forum Resident

    I was just alluding to the sampling rates and the use of sigma-delta modulation as the standard actually. I'm no chip designer so I don't know all of the details about how each works and really have no idea what chips were in many of the old players that I have had over the years. The spec sheets would generally just list the resolution and sometimes sampling rates and frequencies. So today, we see lots of 24 bit resolution players. Whether they mostly use a 1 bit design and then apply sampling, I really don't know. I do see that many are using sigma-delta type arrangements. Most are not listed as Bitstream.
    -Bill
     
  25. kevinsinnott

    kevinsinnott Forum Coffeeologist

    Location:
    Chicago, IL USA
    Bill, here's a pretty extensive list of CD players and which DAC chips are used. There are other lists out there too, some which may also specify whether single or multibit designs are used. Like you, I'm no chip designer but it's nice to have some very knowledgeable people posting here.
     

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