Vintage DACs

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Luckbad, Apr 26, 2016.

  1. Enigmatic

    Enigmatic Friend

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    You lucky guy (with the AES). :p
    I'm stuck with coax since I couldn't get my unit to pcX to replace the toslink to AES.

    The SFD1 is really enjoyable to listen to.
     
  2. Clemmaster

    Clemmaster Friend

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    Does it have an ST input as well?
     
  3. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Yep. ST-Fiber, Coax, and AES.
     
  4. Azimuth

    Azimuth FKA rtaylor76, Friend

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    I picked up a Denon DA-500 with two PCM1702s on a popular auction site for $50 - a steal! It hands down ate my Modi for lunch.

    I had to get a dedicated USB to S/PDIF conveter, but it was well worth it. I picked up a used Peachtree X1.

    The high end can be somewhat sibilant at times, but a very true sound. I've been reading up on mods for this guy and a popular mod is of course switching op amps and changing or removing the output coupling caps.

    It also has a polarity invert switch. All I can tell is that there is more impact and a narrower soundstage with it flipped, so I usually leave it off or in polarity.

    Praise be the antique Multibit DACs! Although I also picked up a vintage Magnaox CD changer for cheap with a TDA1543, and somehow it can best the DA-500 narrowly. Something very transient happening with those TDA1541/1543 chips.
     
  5. rikkitik

    rikkitik New

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    To the best of my knowledge, the earlier release SFD's have the AES input. I'm pretty sure the AES is "as delivered". The black faced unit I still have has the toslink, I think SF made changes "on the fly". The units they (PCx) modify look a bit "cobbled". The one I kept, but have never listened to.....:(, also has a completely different setup on the output caps.
     
  6. rikkitik

    rikkitik New

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    Then again, looking at the SF manuals online, even the original SFD1 (non mkII) literature says Toslink not AES.

    edit; Dummy me....I just noticed the selector switch on the front has a Toslink, not AES position.....oops :confused:
     
    Last edited: May 19, 2016
  7. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Looking inside, it seems to be stock apart from the AES input as far as I can tell from pictures of other units.

    They sure didn't make it easy to replace the tubes... something like 20 screws.
     
  8. rikkitik

    rikkitik New

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    And.....iirc, you can put it on backwards, all but two holes on the sides will line up. Make sure they all line up before spinning any of them in.....don't ask how I know, lol.
     
  9. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Talked to Parts ConneXion. AES was a factory option in the middle of the product life cycle. This unit has no mods. I'm going to get the maxed out mods, which costs $800.
    • Bang for the buck upgrade for $499.95 USD installed: output jacks, output wire, output series resistors, output coupling caps, tubes
    • Comprehensive for $799.95 USD installed: add in PS caps, PS diodes, EAR compliant feet, chassis dampening, tube sockets, etc..)
     
  10. SpaceLaser

    SpaceLaser Friend

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    I picked up a Theta DSPro Prime locally for shits and giggles today. Gonna do some more listening tonight, but first impressions are pretty pleasant with decent staging compared to my other D/S DACs.
     
  11. Mr.Sneis

    Mr.Sneis Friend

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    Performed the CS8412 wildmonkeysects loop filter mod on a Parasound d/ac 1600 last night. I don't know what everyone was talking about it making a significant difference in bass, blackground, etc. but it seems to be a nice subtle difference overall to me with the most gain in the details department which is slightly better.

    The mod is decently documented around the web and universally praised but to add what it is for future reference since it may once again be relevant thanks to the newfound popularity of old ass dacs. I suspect it can even be performed on CS8414 not that any off the shelf DACs came with the 8414.

    As it relates to the 1600, the CS8412 chip has a stock from the datasheet implementation like this...
    Pin 20 goes to R106 -- a 1K resistor and C144 -- a .047uf polyester film capacitor which then goes to ground
    Pin 21 goes to ground

    The mod...
    Adds a 3300pf SMD film cap across pins 20+21
    Swaps 1k resistor for 470R
    Swaps .047uf film cap for a 220nf MKS film cap
     
  12. Hrodulf

    Hrodulf Prohibited from acting as an MOT until year 2050

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    Good job, Sneis!
     
  13. haywood

    haywood Friend

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    You might be interested in this, I remembered someone posting it in the old head-fi thread pre-changstar (or at least pre- my knowing about it anyway).

    http://www.stereophile.com/content/theta-ds-pro-prime-da-processor
     
  14. SpaceLaser

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    I gave it a few looks over before I picked it up, thanks for posting. I'm still gathering my thoughts about the it.
     
  15. Azimuth

    Azimuth FKA rtaylor76, Friend

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    Just picked up an Adcom GCD-575 with the remote on a popular auction site. I got a deal because the Play button on the unit does not work, but it does on the remote. (Something I will have to look into later)

    Anyway, this has the legendary Phillips TDA1541A chip with the CXD1088Q receiver and Sony KSS-150A transport. It also has a better more thought out output section with an Adcom 6A for I/V and filter, however, the Adcom 6A is nothing more than an LT1056.

    This one is stock and in great condition except for the play button. And I can say about the SQ is HOLY CRAP! It is very natural sounding, no strain at all, and maybe just a touch clinical that I cannot tell if it is the oversampling or the output chip. It has more separation and layers than my Denon DA-500 with dual PCM1702s that is also unmodded. The Adcom is very clear, concise, with better soundstage, layers, and a more robust sound than the Denon. It has the typical big but loose lows of the TDA1541, but somehow I think the 4x oversampling gives it that touch of digital sheen. The 8x oversampling Denon has that same sheen and can sound kind of 1-bitish at times, but overall the Adcom does sound a touch less focused and a touch less detail than the Denon.

    I am still planning out my mods for these. Mostly op amp swaps, but also some cap changes/additions.
     
  16. Mr.Sneis

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    I really don't/shouldn't care but outside of the transport thread Marv posted up a while back... are you vintage guys finding that the transport quality (read spend more $$$$) is making a significant and meaningful difference? I've bare-bonsed myself such that my best USB based transport remaining is a lowly HiFace 1. Again I know I should not be caring about this lalalala !!!!
     
  17. AustinValentine

    AustinValentine Friend

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    The Denon DA-500 also could really use a master clock bipass, beyond caps and opamps. These links should get you started here and here if you decide to go through with it. Just crazy jitter otherwise.

    The transport made a pretty significant difference with my old Thetas, Transdacs, and Adcoms. The move up from a Peachtree X1 to Gustard U12 to Jkenny Ciunas wasn't subtle. (I haven't tried out any of the Mutecs or the CI Audio Transient yet, I would imagine that those would be a step up even from the ones that I tried with my prior vintage units).
     
  18. Azimuth

    Azimuth FKA rtaylor76, Friend

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    Thanks for those links. I think I found a couple, but it is good to have them for quick reference. That Yamaha YM3623B is kind of known for it's jitter. I read somewhere that MB DACs have less artifacts than 1-bit DACs, however, I am sure jitter reduction certainly helps any DAC. But maybe 1-bit DACs are just more susceptible to jitter. I fell kind of scared to do this as I have never done stuff with the digital end, only the analog end of things. Also, when I got this DAC there were issues with it locking onto the input. Sometimes it would not say it was locked (sample rate light flashing), but I heard clear audio, and then cycling power it would lock, but the right channel would be some quiet garbled distortion. Then cycling power and signal again might lock. It was intermittent, but it took a second sometimes to lock on. So screwing with the clock might not be the best thing. Not sure. This unit would be better with a different input chip, but you cannot do that without a serious redesign.

    Most of what I read is that the filter, Mitsubishi M5218A, and IV and output, NEC PC4570, are older designs and can greatly benefit with faster and lower noise op amps. And of course replacing that high pass electrolytic capacitor with an MKP.


    Noted. And thanks for that suggestion. That Gustard U12 seems pretty nice. The Peachtree X1 replaced my Fiio X3 II that was serving as a USB to SPDIF converter and wanting something more permanent in my work setup. I do pair it with a Wyrd. It is funny that the Fiio X3 II also has and XMOS processor. I did to tests and found that the X1 sounded better and sounded about equal with the X3 II when using optical on the X1.

    I have no doubt that the Gustard or the other devices are better than the X1. There s no doubt in my mind. For my work setup, it works well for now, but worthy of an upgrade at some point. Just as the Wyrd could also be upgraded to the Regen or other USB decrapifier device. I wish there was a better way to get a good digital audio stream out of a Windows machine.
     
  19. haywood

    haywood Friend

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    The new cutting edge best thing ever apparently is using pro audio lan based transports (e.g. Focusrite Rednet). They're even more expensive than the Mutec but would probably hold their value longer.
     
  20. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    Rednet will likely lose value, as the tech is still being adopted and prices haven't settled down yet. I'm waiting until those get cheaper to try them out.
     

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