Switchers - How to properly connect multiple amps to one DAC output

Discussion in 'Headphone Amplifiers and Combo (DAC/Amp) Units' started by rhythmdevils, Nov 7, 2020.

  1. purr1n

    purr1n Burned out

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    I have 50lbs of that stuff. I guess I better use it.
     
  2. dBel84

    dBel84 Friend

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    i see some zoom community braiding parties in your future
     
  3. Armaegis

    Armaegis Friend

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    Rhythm had snuck in an edit, because at first he wrote "single crystal carbon" and I was wondering if he got duped into some crazy expensive graphite or "diamond" cable. :cool:

    I spent 15 years in post-graduate studies in metallurgy, with most of that sitting behind an electron microscope. I try to stay away from forums of people discussing materials like they even know what a grain boundary or edge dislocation means o_O
     
  4. purr1n

    purr1n Burned out

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    It's all voodoo bullshit anyway. Like those speaker cables that consist of three different gauges of cables, one for the lows, one for the mids, and one for the highs. I'm pretty sure electrons are not that selective. Some of them fancy cables sound pretty good, but I wouldn't bet more than $10 that I could pass a blind test.
     
  5. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Sometimes I call them Single Crystal Nano Carbon. Anything with the word Nano in it sounds 5x better.
     
  6. gixxerwimp

    gixxerwimp Professional tricycle rider

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    So it would seem I'm the first to buy one of these. I needed a way to switch between my newly acquired SFD-1 Mk2 SE+ and trusty BF2, so the Chi-fi RCA switcher seemed the best option for me. Had to wait for them to get back from Chinese New Year holidays, but I got it ordered and shipped by SF Express to Taiwan in about a week (arranged via messaging after order was placed, faster and cheaper than the available shipping options on the order page, shipping cost COD, not sure if they can do this for other countries).

    The box looks well made and solid. The knob is about as big as the Shvonce on @rhythmdevils' new balls out unit.

    234266.jpg

    The knurls look similar, but it's hard to tell from photos. This one feels really rough on the fingers. I might wrap a layer of photographers tape on it so it doesn't feel so harsh to the touch. Font is big and somewhat goofy, but you don't have to look at INPUT/OUTPUT all the time so it's not too bad.

    234267.jpg

    The switch doesn't have a PCB like the one on the more expensive wood version, and I don't think the RCAs are the same fancy CNC ones.
    I went all out and spent the extra $3.20 for a pre-assembled unit. The soldering looks OK and everything is connected as it should be, so I'm glad I did. They probably did a better job than I would have.

    234268.jpg
    234269.jpg


    Switching between sources sounds clean, and it's transparent to my ears. The length is just a bit too long to sit comfortably on the BF2, with the feet just fitting on the flat area of the BF2's chassis.

    234285.jpg

    Overall, I'm happy with the purchase.
     
  7. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Looking at the switch on the wood and metal versions, it seems that they use the same basic unit, but the wood version uses a PCB to break out the pins and (possibly) make it easier to solder.

    https://www.aliexpress.com/item/32991454826.html
    [​IMG]

    Wait, I just realized my metal version is supposed to have the "break-out" PCB. But I got it for $62.55, and it's currently selling for $69.50 assembled. I guess they saved a buck fifty or so by soldering directly to the pins on the switch on my unit.

    https://www.aliexpress.com/item/1005001672509476.html
    [​IMG]


    Here's the switch alone, w/ and w/o PCB.
    https://www.aliexpress.com/item/4000451156524.html
     
  8. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I emailed Goldpoint and got an answer: Yes & No

    Hopefully they'll do a "1 In / 2 Out" version next time round. More likely if everyone emails them asking about it! |\/|
     
  9. Thad E Ginathom

    Thad E Ginathom Friend

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    I like a company that can talk like that about its products. :)
     
  10. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Maybe you’re better off without the pcb. Here’s a picture of the (partially finished) wiring of mine. No pcb. Hopefully Don doesn’t mind. The red and black is the crystal Nano fiber wiring and the pink is unknown I think it’s ground.

    [​IMG]
     
  11. dBel84

    dBel84 Friend

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    the pink is just OFC copper for ground wiring , mostly better to hard wire - fewer connections to go wrong but using a PCB for complex routing would make good sense
     
  12. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Yes, I agree a direct connection is better. I'm not sure if they soldered the wires to the pins directly or used a sleeve. The PCB must mainly be for the convenience of those doing it DIY.

    I guess someone who knew what they were doing could figure out the required circuit to rewire the SA2 for 1-in/2-out. It's not rocket science, but I wouldn't feel comfortable coming up with it. I think someone priced out the retail BOM of a Goldpoint box and found their pricing quite reasonable. But doing it DIY instead of customizing the SA2 would be more cost effective.

    I have my SW51 and Laconic NBM daisy chained, and I can't hear any difference compared to when they're isolated, but a switch box with attenuator would eliminate nervosa and be tidier than adding a switch after my NanoPatch.


    Edit: I just realized a custom 2-in/2-out with attenuator would also take the Chi-fi switcher out of the picture and be even tidier. Guess that would be @rhythmdevils' balls-out unit with a pot. When I finally get @Zampotech's hard rock adapter for the NBM and decide if I'm going to keep it, that will be my next project.
     
    Last edited: Mar 2, 2021
  13. Metro

    Metro Friend

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    This would be simple to check. With a continuity tester, see if the two sets of RCA outputs are connected to each other.
     
  14. bboris77

    bboris77 Friend

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    Could you please check if the grounds are separated or all joined together? In an ideal situation (for me), there should only be continuity between the ground of one channel of the selected input and its output. My switcher has them all joined together which can cause very annoying ground loops and antenna effects.
     
  15. dBel84

    dBel84 Friend

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    If you are referring to RDs build, each input option is isolated from the rest at input and output
     
  16. bboris77

    bboris77 Friend

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    I was actually asking @gixxerwimp about his Aliexpress unit.
     
  17. gixxerwimp

    gixxerwimp Professional tricycle rider

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    I thought they were, but now I'm pretty sure they aren't. I can check when I get home, but the photos of the PCB show that all the grounds are tied together. And there would have to be at least 16 pins for point-to-point, but there are only 12.

    https://www.aliexpress.com/item/4000451156524.html

    [​IMG]

    [​IMG]
     
  18. dBel84

    dBel84 Friend

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    yes - the PCB shows the center pin connected across all the input and output connectors - this means that the ground wire is not switched but is continuous
     
  19. Noodlz

    Noodlz Almost "Made"

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  20. fastfwd

    fastfwd Friend

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    If you don't need the multiple inputs/outputs, the Rolls MB15b does a lot more for around the same price: RCA-to-XLR and XLR-to-RCA conversion, pro/consumer level conversion in both directions, adjustable levels, can be used as an XLR-to-XLR level control by simply jumpering across the RCA sockets, has a 3.5mm phono input, etc: https://www.amazon.com/dp/B0002IL4B4
     

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