Dangerous Music Convert-2 DAC Review - Stream of Consciousness

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by purr1n, Oct 26, 2018.

  1. purr1n

    purr1n Desire for betterer is endless.

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    I don't think turning up the volume on consumer amps is a realistic way to assess noise floor on pro-audio gear with hot outputs (high gain) into consumer gear. Just because consumer gear takes XLR inputs doesn't mean its input sensitivity is going to be matched with 22dBU outputs. It's also possible the outputs of the Convert-2 are padded with resistors so the source impedance is 150-600, which is typical for pro-audio gear.

    It's like what you said, you listen at 10, and noise is evident at 75 where max is 80. Just pretend your volume knob only goes to 50.
     
    Last edited: Oct 30, 2018
  2. Cspirou

    Cspirou They call me Sparky

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    Early on the pro gear was the audiophile gear. Consumer equipment was made to be cheap and had higher distortion while the studio gear didn't have the same budget restrictions.
     
  3. purr1n

    purr1n Desire for betterer is endless.

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    Analog section of board on Convert-2. Surprised to see opamps because the Convert-2 does not sound flat and dead. Probably has to do the high gain.

    IMG_20181030_093128.jpg


    AD1955 for D to A. BB OPA2134 for IV, followed by what appears to be the analog filter with OPA2134, and then THAT1646. The THAT1646 is interesting and seems purpose designed and made for this application, capable of 18Vrns into 600 ohms, and get this, floating balanced out! This might be fun to play with.
     
  4. Psalmanazar

    Psalmanazar Most improved member; A+

    Friend Slaytanic Cliff Clavin
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    Thanks for the board picture. All Dangerous gear seemingly shares the same basic analog stages developedt back in the early 2000s (or even late 90s at Sterling Sound).

    About outputs being suitable for gear too, I am convinced that your greatly worse bass experience (No one else, including me, experienced this with speakers) with Source compared to the Convert 2 was due to the hotter outputs (over +26 dbu ) being run into your transformer boxes being rated only for +20 and so forth onward. None of this gear truly designed for such a system (the transformer box recommendation is a "we're not liable for dumbasses frying the stuff we make. If you must hot plug, here's how" thing similar to the "If you must use Focal monitors, you may with some some ridiculous pads" stuff) but the Convert-2 has the FGPA (it seems to be there for the clock and routing options) able to perform some digital attenuation, making it much more suitable for typical hi-fi rigs with balanced inputs.

    Here's a gear dissection of Dbox:
    http://archive.is/Gdenx

    Source outputs:
    [​IMG]
     
  5. purr1n

    purr1n Desire for betterer is endless.

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    I'm convinced you are desperately trying to convince yourself that I screwed up on something so you can make yourself feel better. There is no hope. Don't even hope. Hoping that the Source is better than it really is like hoping for better quality health care at better prices, or taxing the shit out of rich people to pay for losers like us. Ain't gonna happen ever despite our rulers' best intentions.

    I believe that the Source comes from the factory with max outputs of +20dBu. To make it +26dBU, you have to pull two jumpers on the board. This makes sense because even +26dBU is kind of high in a pro-audio environment.

    While it's true that the Source shares familial traits with the Convert-2, it's absurd to think that it even comes close to the performance of the Convert-2, or that of the Gungnir MB A2, particularly when worthy downstream gear is used (which you do not have). The Source is one to two classes below these DACs. The Source does share the same THAT1646 output opamps as the Convert-2, but that's about it. We also need to take into consideration power supply, layout, and many other nuances (quality of parts, power supply bypassing, approaches to an analog filter, etc.).

    Here is a shot of the Source board. Unlike the layout of the Convert-2, the D to A chips are a mile away. There are two of them because the Source is a multi-function unit with x2 DACs. It looks like they followed by an OPA2134 buffer. There are switches / relays after the outputs. The BB1789 sucks from a spec point of view. Tone and timbre wise, and in this implementation, it sounds good. Everything else sucks. The BB1789 is voltage out and comes included with an analog filter. It's designed for lower-end applications (car audio, HT, DVD players, AV receivers, etc.) - it's basically for losers with veiled and unresolving gear. The TOTL AD1955 requires more work; but that allows someone like Chris Muth, or the guys at Bricasti to get the most out of it.

    IMG_20181030_122223.jpg

    I'm not a noob. Saturation with transformers happens very quickly and the effect is very noticeable. It's not linear and gradual like 0.05% to 0.10%. It's more like 0.5% to 50.00% THD in the span of a few dbU.

    Keep in mind that I can also pull out one of my balanced pro-audio amps (x2 Crest, x1 QSC) and use a modded HE-5. I didn't because this setup isn't as resolving as the others. I also have balanced Jot. Same thing.

    Nice try though. Good one.
     
    Last edited: Oct 30, 2018
  6. purr1n

    purr1n Desire for betterer is endless.

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    Do you have internal photos of the Bricasti, particularly from the AD-1955 to the outputs? Kind of curious because I agree that the Bricasti is more resolving and soundstages (speakers) better than the Convert-2.
     
  7. Priidik

    Priidik MOT: Estelon

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    A typical 'godly behaving' magnetic core with some airgap for audio application:
    It will go to saturation real sharply and it's bound to sound nasty at that point. ie: not suitable for guitar amp or effect block ;)
    [​IMG]
     
  8. Psalmanazar

    Psalmanazar Most improved member; A+

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    I never said it was better, only was pointing out potential flaws of testing that loudly advertises that it is no transformers in the analog signal path with a shit ton of transformers. Transformer affect sound even if not saturating. Transients tamed but exciting transformers can sound cool.

    Not everyone is buying Dangerous gear, which all exists to fulfill specific niches with little overlap, to get 3.1415% better performance on a perfectly cobbled together, deliberately colored to meet their preferred distortion and other playback preferences system. Most will buy it for playing back Starbucks music they don’t even like to impress dudes on the internet. If that sounds suspect, it’s because it is indeed very suspect

    Many people buying something that sounds great to meet their own specified needs as their system is already good, they’re happy with it, and don’t give a damn about making Daft Punk slam 3.14% harder. Source sounds good, is desktop, has preamp features, headphone outs that don’t suck. Converts rack mount and need rack space around it.

    Most people will buy this stuff to flex Spotify playlists. They already have...

    All would do better to just hunt down better masters of music they actually like or get better speakers or improve room if they already have actually gear rather than buy the latest, greatest, hyped piece of kit to impress nerds on the internet. Maybe Ted Somebody will run Convert 2 to Audeze and JBL for white people jazz. I would rather listen to Slayer off an iPhone or some guy banging on paint buckets than that bs

    Slayer ruled. Wimps, fetishists, annoying comedians, and whiny hipsters do not appreciate how sick tracks like Metal Storm: Face the Slayer truly are. They stand for all time. Deconstructing Slayer into wails, sick drumming, scarification, and cool riffs is impossible; Slayer are meant to be experienced until their worthwhile music is wholly internalized as excellence. For those who are mentally unprepared for Hanneman, King, Lombardo, and Araya? Hell Awaits.

    Schit is gear equivalent of World Painted Blood. All Dangerous stuff is Slayer singing about Satan back in the early to mid 80s. You can argue which is better but it’s all sick. Lavry and Prism type sheet is late 80s satan and serial killers Slayer. Benchmark are Slayer x Exodus poo poo platter. Mytek is that giant pot metal eagle that SlayerExodus tried to sell a few years ago. Lampizator is Vader, the Polish ersatz Slayer. Chinese bootleg transistor gear is the Slayer leprechaun shirt.
     
    Last edited: Oct 30, 2018
  9. Thenewerguy009

    Thenewerguy009 Friend

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    Doesn't the Crane Solaris have a transformer & it's supposed to sound even more transparent.
     
  10. purr1n

    purr1n Desire for betterer is endless.

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    Probably not on Solaris analog output. Likely there are transformers on the AES inputs - the Convert-2 has transformers on AES input. For ADCs, the "primo" pro-audio stuff might have transformers on the analog inputs. Sometimes for coloration*, sometimes for transparency and clarity. Sometimes for both**. There are transformers everywhere in the studio environment. Maybe fewer now than 40 years ago because opamps are cheap and effective, but they are still around.

    *We are not talking about warm poo or lush or bloom coloration. We are usually talking about big, or slammin', or spacious, etc.
    **There are sins of omission and sins of commision. They are not mutually exclusive. Transparency is a meaningless term without context.
     
  11. purr1n

    purr1n Desire for betterer is endless.

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    Thought I should post from this from some PMs (and PMs that others have told me about) regarding some confusion that I am running a preamp into a solid state amp. This is only partially true - only for the signal under 350Hz, and there really isn't a preamp. I wanted to make this completely clear so people didn't think I was running "a tube preamp into a value solid-state amp into speakers" to justify their use of cheap self-powered studio monitors with these TOTL pro-audio DACs. If I had self-powered studio monitors, I'd just get a Modi 2U, or a used DM Source for $650 if balanced inputs were the only option.

    The tube "integrated" amp doesn't have that much power, just a few watts, therefore it can be used to power either efficient drivers or act as a line out. The horns are about 115db/W efficient. The tube amp directly powers the horns for 350Hz and up with only a single cap used as the passive HPF.

    The signal path between the tube amp and the Vidar can be cleaned up. I don't feel comfortable with the unnecessary AD-DA conversion from using the DCX2496, but it does sound better this way than with a passive 2nd order LPF on the woofers. I feel that woofers, particularly OB woofers, are best served with powerful SS rather than tubes. DCX also has a time delay since the woofers are in front of the Lowther drivers.

    Note that I forgot to draw the super-tweeter and associated HPF which runs in parallel with the horn. There is also a pad before the Vidar.
    System Diagram.png
     
    Last edited: Oct 31, 2018
  12. direstraitsfan98

    direstraitsfan98 D2Girls v2.0

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    Interesting setup Marv, thanks for sharing. At least people respect you enough to DM you to ask about your setup. I know people laugh at me because I bought “shitty pa speakers” but the truth of the matter is every setup is going to sound different in a different enviornment/room and at the end of the day it’s your system and unless others have heard it they should shut up.

    Your system isn’t even that overly complex considering the nature of your speakers. Seems like you know what you’re doing. As for using expensive pro audio source gear into active monitors, I really don’t know. I may have to dip my toes into it one day when (and if) I decide to get an M2.
     
  13. purr1n

    purr1n Desire for betterer is endless.

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    1. There are good active monitors. And there are some not so good ones.
    2. Shitty pa speakers are the best, they require more set up and aren't friendly to HGTV living rooms.
    3. The approach I took is a hybrid active / passive approach. It's based on this philosophy:
      1. There is no such thing as "fast" bass and "resolution" doesn't really exist in the lows, so we can get away with more "crap" in the signal path for the lows.
      2. Better to have tight articulate bass than muddy bass. This means a lot of power and low source Z, which means solid-state amps. Tube die-hards may disagree and say that tube bass is more immediate sounding, has superior microdynamics, despite higher distortion.
      3. 48 part crossovers (the components are ALL in the signal path - even the parts that are parallel to the driver) are bad, kill dynamics, and erase low-level information. For the critical region (~500Hz up more or less): keep the signal path as simple as possible from source to driver. Use a highly resolving driver. Use an efficient driver so that amplifiers with simple circuits can be used. Use quality passive components instead of active circuits.
      4. This approach can be used (to a partial extent) with any speaker that can be bi-amped.
     
    Last edited: Nov 1, 2018
  14. zerodeefex

    zerodeefex SBAF's Imelda Marcos

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    I stuffed the lx mini active analog 2 way crossover for ~350Hz with the cheap kit JFETs. Need to finish casework and send to Marv. I have a similar setup but the crossover outperforms the behringer for bass management for me.
     
  15. famish99

    famish99 Friend

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    Is this for protection or does it sound better when the driver isn't getting the full range signal?
     
  16. OJneg

    OJneg The Most Insufferable

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    Would be nice if you could split off the signal at the line level and run it directly into both low and high paths there! Would require volume control not to be in your amp though. Part of the reason I went to the trouble of building passive transformer/autoformer boxes!
     
  17. Cspirou

    Cspirou They call me Sparky

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    You should never run a tweeter without a capacitor.

    Secondary though is that the tweeter will have lower distortion when not dealing with low frequency energy it was not designed to handle.
     
  18. famish99

    famish99 Friend

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    But it's a widebander, aren't they generally rated to low frequencies anyways?

    Edit: getting a bit off topic, can move to PM if desired.
     
  19. Cspirou

    Cspirou They call me Sparky

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    I was referring to the Fostex horn tweeter he has. But @purr1n has said he's not a purist with fullrange drivers and applies passive EQ if it leads to improvements.
     
  20. OJneg

    OJneg The Most Insufferable

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    Moved
     

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