Passive Volume Control for DACs/Sources

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

  1. gixxerwimp

    gixxerwimp Professional tricycle rider

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    Is this it?
    https://jdslabs.com/product/ol-switcher/

    2-in/2-out with passive attenuation is exactly what I need right now. Maybe I should have gotten this instead of the Chi-fi switcher. The pot can't be as nice as the one one the NanoPatch though.
     
  2. bixby

    bixby Friend

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    @gixxerwimp

    Yes that is it, pot is decent but does have some imbalance down at about 7pm or so. Made nicely and you know they will stand by it if any issues.

    Reviews on the nanopatch seem mixed, but I am sure most users are much more hard on that product since it is used in "pro" audio.
     
  3. gixxerwimp

    gixxerwimp Professional tricycle rider

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    It's too bad that OL Switcher has 3.5mm for it's 2nd in/output. Mostly nervosa, but I'd prefer independent RCAs and a point-to-point switch with separate grounds. I guess if I got another Chi-fi switch and put it at the output of the nanopatch, I'd have what I need to isolate the amps rather than daisy-chaining them. I can't hear any difference between isolated and daisied, so I'll leave a 2-in/2-out passive preamp/switcher as a final tweak for when all the dust has settled.
     
  4. Merrick

    Merrick A lidless ear

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    Looks like the JBL Nano Patch is now discontinued, at least according to all the retail outlets I'm seeing. Are the other balanced passives under $100 even worth looking at?
     
  5. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Hell yes I am. I love it. It’s so well thought out, he even has a dim button on the remote so you can adjust the brightness of the LED’s. I’m going to be using this for the long haul. Maybe someday to power dual mono amps for Maggies.
     
  6. bixby

    bixby Friend

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    EDIT: I did not see the balanced part so disregard the reference below. But if it is that good with unbalanced RCA there has to be good balanced stuff for not much $ out there.

    yup. I am using a JDS Labs passive and it is quite decent. I think key to the good sound is a good and very short 1.5 ft. cable from the passive to the amp.
     
  7. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    unless it’s a balanced passive pre right? I’ve got my Khozmo balanced running straight to 2 powered monitors. So the cables are about 6-8 feet. But XLR

    I bet a lot of people run unbalanced (RCA) passive preamps to powered monitors, with long RCA cable runs. I used to.
     
  8. bilboda

    bilboda Florida boomer

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  9. skem

    skem Friend

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    I'm not sure I would advise this. As I understand it, there are two reasons to avoid long cable runs on a passive pre.
    1. The primary reason is that the long cable run creates a LRC circuit with the passive pre that begins to attenuate high frequencies and transients.
    2. A secondary reason has nothing to do with passive preamps, but is that long cable runs are generally bad because they pickup noise.

    The balanced cable will help with #2, but it will not fix #1 because the cable capacitance will affect the absolute amplitude of the signal identically for both the negative or positive phases, so the unbalancing circuit cannot remove that type of degradation. In other words, balanced cables are not a fix for passive preamps.
     
  10. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Are you sure? This would mean my monitors have been taking a hit for years. I need to find a powered preamp now? A number of smart people advised a passive preamp for powered monitors im surprised none of them mentioned this.
     
  11. Cspirou

    Cspirou They call me Sparky

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    6-8ft is not a long cable run in my opinion. Especially for XLR cables. You should be fine.

    some of this also depends on the input impedance of the amp/monitors.
     
  12. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Now I have to buy a Freya + to see if it sounds better. Bleh
     
  13. Cspirou

    Cspirou They call me Sparky

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    the great thing about Freya is that you can switch between active and passive and see how much of a difference it makes
     
  14. batriq

    batriq Probably has made you smarter

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    There's a SAGA OG up for sale for $170. You can turn on the tube buffer or use it as passive.
     
  15. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I have really nice XLR cables so I’d like to use a balanced preamp. Moar stuff to buy!
     
  16. batriq

    batriq Probably has made you smarter

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    I have this project in mind to take my Saga OG, add XLR connectors to it and two Cinemag transformers for balanced to SE conversion

    |{
     
  17. lehmanhill

    lehmanhill Almost "Made"

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    +1 on the Freya + Relay stepped attenuators sound great and where else are you going to find a circlotron tube stage?

    If I didn't already love my Relaixed2 preamp, I would be chasing a Freya +.
     
  18. Merrick

    Merrick A lidless ear

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  19. bixby

    bixby Friend

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    @skem is correct. Capacitance in the cable is the big bugaboo with a passive. My good friend has built a number of high quality passives and said even a 3 foot cable can audibly sound worse than a 1 foot cable all else being the same. I have only compared my very good 1.5 foot cable to a 6 foot cheaper cable and the difference was "large" (audibly apparent :)).

    It was the typical stuff of lower fidelity, weaker transients, less soundstage, clarity etc.

    While the longer cables will pass the signal just fine and sound okay, it might be best to toss in a short cable of low capacitance to hear what it does. Even my not super revealing setup can present the difference.

    May do some listening tests soon with some 3 footers that I have to build, but they will not be as good as the Grimm TPR short cables.
     
    Last edited: Apr 26, 2021
  20. bixby

    bixby Friend

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    @ merrick

    Here is a thought. I assume you have balanced from dac to passive.
    If you want to do some critical listening, why not use your speaker XLRs hooked directly to the dac and reduce the gain on the monitors (level match) to do a comparison to the current setup. And if you have to trim a few db off the signal you can do it in your player software and not through away any audible bits with many modern implementations like Jriver and Roon.
     

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