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. cameng318

    cameng318 Friend

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    I thought the A2 upgrade was able to drive as low as 600 ohms, but just double checked with Schiit's website. They said 600 ohms about Yggdrasil, but didn't mention it with Gungnir. It should handle 10k ohms just fine, as Ragnarok has 10k ohms. Your 3 amps adds up to 7k ohms, which isn't much lower, but seem low enough to upset Gungnir. I had thoughts about driving some special sauce loads with my Gungnir, guess it might not work so well after seeing this post.

    Another way to get around is to snug in a preamp right after the DAC. Most of them should handle low impedance just fine, and might even be strong enough to drive headphones. It's a great excuse for getting more gears.

    BTW, I might have missed it, does your Gungnir still distort now when driving only one amp?
     
  2. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I should have updated. After leaving it off for a week or so I turned it back on and after letting it warm up for two days tried it with just my SOHA1 connected and there’s no distortion now. So since the brain trust here as well as Schiit tech support blame daisy chaining that must be the culprit.

    I’m amazed that such a common practice is actually technically not ok to do. And even more amazed that the massdrop amps have pass jacks if it will fuck up the DAC attached. Amps designed by both Cavalli and Eddie Current (or at least endorsed by Eddie Current), probably my 2 favorite amp designers.

    better than a preamp is to just get one of these passive switchers. If they’re made right it shouldn’t degrade the signal at all and everyone will be happy. Plus you get to have fun toggling a knob. o_O
     
  3. Armaegis

    Armaegis Friend

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    Daisy chaining a couple amps with 50k input impedance probably isn't a big deal, but if you string together a few devices with 10k pots on their inputs, you start sinking into the iffy zone. I still suspect that there was a ground offset somewhere between the amps causing a current draw on the dac output stage. A little bit like forcing it into "class a" when it can't handle that much current.
     
  4. Hammy

    Hammy Friend

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    Is there a difference electrically between using an RCA splitter to connect to amps and using a pass-through connection to connect two amps?

    The Gungnir has two pairs of RCA jacks that I believe are wired as if they're on a splitter. Would it be better to connect two amps directly to the RCA jacks on the back of the Gungnir or would it be better to use only one pair of RCA jacks and do a pass-through to the second amp?

    I have a Gungnir MB A1. The two amps in question are a Liquid Fire and Liquid Glass. The Liquid Glass has a pass-through connection I could use.
     
  5. Armaegis

    Armaegis Friend

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    If the pass-through is passive, then there is no difference.

    Based on Schiit's response to rhythmdevil's original email, I would surmise that their three outputs are all separate active devices. If so, then it is definitely better to use each one separately instead of a splitter.
     
  6. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Yes Schiit specifically said it was best to use the 2 RCA and 1 XLR outputs instead of stringing amps from one output. I at first thought they were bullschiiting me but everything points towards them being correct.
     
  7. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    So does anyone have any thoughts about the two passive RCA switchers that were posted in this thread? I’ll repost the links for convenience.

    Someone else here bought this unit.

    https://www.amazon.com/TC-7240-Router-Switcher-Selector-Splitter/dp/B00KDQXITG

    here’s a pic of the inside.

    [​IMG]

    I’m no expert but it looks like this is done via circuit board and not point to point which isn’t ideal right?

    And this is the one I bought.

    https://www.amazon.com/Switch-Stereo-Switcher-Selector-Splitter/dp/B085W1PPHL

    I tried to open it up to take pictures of the guts but with the back panel unscrewed it’s attached to wires and won’t come off. I managed to find a square shaped bit and tried to unscrew the front panel screws but they don’t unscrew they just turn in an uncomfortable way. I have no idea how they put this thing together. I’d really like to know that it’s clean passive wiring and no weird shit.
     
  8. cameng318

    cameng318 Friend

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    I can't comment too much about how solder joints impact the sound, as I don't have much experience playing with it. There are people claiming they can hear solder joints (and even the brand of solder). The engineer me thinks they are BS, but the audiophile me puts them on pedestal. I'm pretty uncertain about this, so I don't want to comment subjectively here.

    Electrically the first switcher looks fine to me mostly. It has to use PCB to speed up the production. The trace layout is alright. I like it's using proper interconnect cables, but I dislike the flex cable in the middle, not sure if it's in the signal path though.

    For the second switcher that you brought is likely to be similar. I think the quality of the connectors matters more than the joints, but it's hard to tell based on pictures. A loose connection obviously destroies the sound.

    To be honest, don't stress too much if you are only connecting the Massdrop amps to it. There are already solder joints, relays and protection circuits in the signal chain when they are used in daisy chain. I'm pretty one relay in the signal chain affect the sound more than feets of cable, even just based on the datasheet.
     
  9. bilboda

    bilboda Florida boomer

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    Where these are likely to fail you is in the switch itself. I had a decent passive pre amp with 4 inputs and 2 outputs and the switch failed, just fell apart internally. I purchased an elma switch from hificollective and just wired it for a switch, no volume control, all point to point wiring and I use it 2 in 4 out. ZDS, SW51+, HP1 and Adcom for my Hifiman, easy to A/B, not that I do that much
     
  10. Jer925

    Jer925 Rando

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    I have used both the Monoprice 887 (Drop 789) and liquid platinum, both behave the same when I use the RCA "output" to my AV receiver. Which, distortion is very audible in the headphone amp output (sounds like FM) and I guess in the speakers as well but less obvious there. With the receiver turned on the distortion almost go away. The source is a Yamaha CD player.

    So I bought a preamp that has fixed and variable output, used the variable out for the liquid platinum, fixed to the receiver, still the same problem, maybe less obvious.

    I also used a SYS to disconnect the pathway to the receiver. I felt because the ground is still connected I think perhaps it was still affecting the sound quality of my headphones. Perhaps in theory it's not possible, but If there is an output switch that can switch both negative and positive I would gladly buy it.

    I am glad I found this post and the explanation of overdriving the source. It seems things can be better or worse by simply just being CONNECTED together.. I actually tried 3 different receivers , they all sound is distorted when receiver is off, to various degrees.

    The best solution I found is the use the headphone output of the liquid platinum with a 3.5mm to RCA cables to the receiver, and only plug it in when I want to use speakers. Which for me is not very frequent. The sounds fantastic (isn't an audiophile speakers setup) But it really does sound best that way.

    I just feel when you split something at least some sound quality is lost and with high quality headphones very easy to tell.
     
  11. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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  12. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    So I can hear music playing faintly while headphones are plugged into an amp that is not selected with the switcher I bought. I have my Andromeda plugged into output 1 and I can hear faint music while 2,3 and 4 are selected.

    https://www.amazon.com/Switch-Stereo-Switcher-Selector-Splitter/dp/B085W1PPHL

    [​IMG]

    [​IMG]

    This means I should take it out back and beat it with a baseball bat right? (Or return it and get the other unit posted here?)


    [​IMG]
     
    Last edited: Nov 12, 2020
  13. Erroneous

    Erroneous Friend

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    Yep, I don't have that problem with the one I posted.
    I tried a different one though ("Five Input Source Tabletop Control Switch Box Internal Pc Board Design Metal Case", also from Amazon and a much lower price), and it had the same problem you're experiencing. I definitely don't recommend that one.
    Very happy with the TC-7240 though.
     
  14. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    So much for “go hifi!” Kind of made me smile seeing that. I always picture two super dorks wearing headphones doing high fives.
     
  15. Mr.Sneis

    Mr.Sneis Friend

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    If this daisy chain thing is true, and it makes total sense given different load impedance of each device, it should be distorting right away not over time?
     
  16. Armaegis

    Armaegis Friend

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    Could be crosstalk or coupling in the switcher, or something is leaking to ground somewhere.
     
  17. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    what’s the “mp3/IPod” mini jack on the front panel? I’d be wiring this backwards 2 in 4 out.
     
  18. Erroneous

    Erroneous Friend

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    Ipod input replaces input 4 if a 3.5mm is plugged in. I've never used that, only the RCAs.
     
  19. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    what would that make it do if I’m running it backwards? 2 in 4 out? A mini output jack that replaces output 4 if plugged in? Will this mess with the SQ of output 4? I think this is the only thing I don’t like about this unit.

    are there other options outside amazon? Surely there must be more RCA switchers on the market.
     
  20. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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