Passive Volume Control for DACs/Sources

Discussion in 'Digital: DACs, USB converters, decrapifiers' started by Madaboutaudio, Dec 20, 2015.

  1. Cspirou

    Cspirou They call me Sparky

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    4,401
    Dislikes Received:
    5
    Trophy Points:
    113
    Location:
    Northwest France
    Whoa, how did you make those panels? FPE?
     
  2. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    8,904
    Dislikes Received:
    3
    Trophy Points:
    113
    Location:
    On planet
    The red line applies to any value pot or stepped resistor attenuator. 6 dB attenuation is where the pot is halfway between two ends. The effect a 5K+5K divider, 6 dB attenuation, will have on frequency response may be seen in the blue lines for the 6 dB attenuation graphs found here . Short, low capacitance cables will introduce less than 0.2 dB roll-off at 20KHz, worst case. What is missing from this discussion is the combined effect of LC network formed by the AVC inductance and cable capacitance.
     
    frenchbat likes this.
  3. rlow

    rlow A happy woofer

    Friend
    Joined:
    Jul 18, 2017
    Likes Received:
    2,068
    Dislikes Received:
    3
    Trophy Points:
    93
    Location:
    Canada

    Does anyone else think that @bazelio is going for a Marty McFly on this?

    ED9FA2A9-2375-44EF-9561-BF1A60E6697B.jpeg


     
    Last edited: Mar 26, 2019
  4. frenchbat

    frenchbat BritishBat's arch enemy - Friend

    Friend
    Joined:
    Sep 26, 2015
    Likes Received:
    1,174
    Dislikes Received:
    3
    Trophy Points:
    93
    @atomicbob have you ever (or know a properly measured ref) measured same cable with different make for the plugs (rca or xlr) ?
     
  5. bazelio

    bazelio Friend

    Friend
    Joined:
    Nov 16, 2015
    Likes Received:
    3,203
    Dislikes Received:
    24
    Trophy Points:
    113
    Yeah I am at precisely -22.5 dB right now. This is a slightly loud listening volume most of the time. I expect that to increase slightly once I have finished off my room treatment. At the moment, I rarely go louder than -20 dB. EDIT: Speaking of which, GIK has 20% off Acoustic Art panels until the end of April. You can turn all or almost all their panels into art panels and provide your own image or vector files.

    Yup! FPE and a spreadsheet + high school math to calculate the coordinates and angles of all the tick marks. That was basically all manual inside FPE as the software isn't terribly feature rich. But it sure does give you an opportunity to create, and in the end, they ended up dead on. Every position of the AVC lands squarely on a tick mark.
     
    Last edited: Mar 26, 2019
    atomicbob, sfoclt and frenchbat like this.
  6. sfoclt

    sfoclt Friend

    Friend
    Joined:
    Nov 24, 2015
    Likes Received:
    802
    Dislikes Received:
    0
    Trophy Points:
    93
    Location:
    Online
    I don't have the db marks, but I'm basically at 10am to 1:30pm on mine as well. 2pm or above would be pretty damn loud in my system.
     
  7. atomicbob

    atomicbob dScope Yoda

    Friend BWC MZR
    Joined:
    Sep 27, 2015
    Likes Received:
    8,904
    Dislikes Received:
    3
    Trophy Points:
    113
    Location:
    On planet
    you have a PM.
     
  8. AdvanTech

    AdvanTech Friend

    Friend
    Joined:
    May 13, 2016
    Likes Received:
    383
    Dislikes Received:
    5
    Trophy Points:
    63
    Location:
    NYC
    GoodEnoughGear likes this.
  9. rlow

    rlow A happy woofer

    Friend
    Joined:
    Jul 18, 2017
    Likes Received:
    2,068
    Dislikes Received:
    3
    Trophy Points:
    93
    Location:
    Canada
  10. wormcycle

    wormcycle Friend

    Friend
    Joined:
    Aug 13, 2016
    Likes Received:
    387
    Dislikes Received:
    14
    Trophy Points:
    63
    Location:
    Toronto, ON, Canada
    Agree, it would be lovely if they could fill the gap: in general passive preamps come either at idiotic price points, or are inadequate.
     
    AdvanTech likes this.
  11. Thad E Ginathom

    Thad E Ginathom Friend

    Friend
    Joined:
    Sep 27, 2015
    Likes Received:
    5,261
    Dislikes Received:
    10
    Trophy Points:
    113
    Location:
    India
    My pre-amp was $1k, two decades ago. (bought by me just a few years ago for very much less). My one and only ever piece of Stereophile A-list kit!

    Have a refurbishment plan. But I find that even non-audiophool gold-plated phono sockets are INR300 and it needs 22. For starters.

    And the scratchy pot? eek. But my magic repair man (who was working on another of Koth Ganesh's boxes when I saw him 2 days back) says he can spray some magic liquid into that.
     
  12. trung225

    trung225 Almost "Made"

    Joined:
    Oct 22, 2015
    Likes Received:
    129
    Dislikes Received:
    6
    Trophy Points:
    43
    Unless Schiit can outsource good AVCs/TVCs from China, where the salary is much lower than US or European, I don't think you can expect the good AVC/TVC passive preamp for less than 1.5K. The high quality core is not cheap, the good winding technique is mandatory, and the salary for professional winders in US/Europe is also not cheap too. Adding the cost for case, wiring,... and profit for manufacturer, the price will go up. And trust me, unlike the pot volume (Alps) or relay stepped attenuator (like in Schiit preamp), the low cost TVC/AVC with inadequate winding technique or low quality core is unbearable
     
    msommers, rlow and GoodEnoughGear like this.
  13. OJneg

    OJneg The Most Insufferable

    Friend BWC
    Joined:
    Sep 25, 2015
    Likes Received:
    3,544
    Dislikes Received:
    13
    Trophy Points:
    113
    Location:
    Grand Rapids
    I would buy this.

    Make it so Bazzy
     
    bazelio, sfoclt and AdvanTech like this.
  14. ogodei

    ogodei Friend

    Friend
    Joined:
    Feb 9, 2016
    Likes Received:
    368
    Dislikes Received:
    3
    Trophy Points:
    63
    Location:
    Chicago
    That's a very pretty display screen. Tempted, wonder what the final price will be.

    Is use of Apple remote for higher-end audio gear common these days? Guess it makes sense, the user can purchase it cheaper than it would cost Nord to OEM it.
     
  15. mitochondrium

    mitochondrium Friend

    Friend
    Joined:
    Sep 1, 2017
    Likes Received:
    351
    Dislikes Received:
    0
    Trophy Points:
    63
    Location:
    A Cell
    Whole heartedly agree with you. I know my music first audio TVC is not cheap, yet I do not think it is overpriced given the BOM and the time a skilled person needs to put everything together.

    A cheaper option with good quality might be:

    http://www.promitheusaudio.com/referencetvc/ref.htm

    Never heard it myself and did not consider it due to lack of European warranty.
     
  16. mitochondrium

    mitochondrium Friend

    Friend
    Joined:
    Sep 1, 2017
    Likes Received:
    351
    Dislikes Received:
    0
    Trophy Points:
    63
    Location:
    A Cell
    What I cannot get my head around is why anybody would add a remote function, which introduces an active electric circuit to the passive amp, even if it is not in the path of the audio signal. Beats me. But hey the more (choices) the merrier.
     
  17. ogodei

    ogodei Friend

    Friend
    Joined:
    Feb 9, 2016
    Likes Received:
    368
    Dislikes Received:
    3
    Trophy Points:
    63
    Location:
    Chicago
    When your gear is in an audio closet.
     
  18. rlow

    rlow A happy woofer

    Friend
    Joined:
    Jul 18, 2017
    Likes Received:
    2,068
    Dislikes Received:
    3
    Trophy Points:
    93
    Location:
    Canada
    Time for your gear to come out of the closet man, it’s almost 2020 already! :p
     
    Last edited: Apr 4, 2019
  19. ogodei

    ogodei Friend

    Friend
    Joined:
    Feb 9, 2016
    Likes Received:
    368
    Dislikes Received:
    3
    Trophy Points:
    63
    Location:
    Chicago
    I've seen Promitheus mentioned around here but has anyone actually ordered one of their products? Are they still in business and making these things? Looks like that last external reference they list is from Stereophile in 2007.
     
  20. bazelio

    bazelio Friend

    Friend
    Joined:
    Nov 16, 2015
    Likes Received:
    3,203
    Dislikes Received:
    24
    Trophy Points:
    113
    If that's the tranny from Bangkok, @MrTeaRex played with it and it gave him herpes. He can expound.
     
    Last edited: Apr 4, 2019

Share This Page