Balanced to single-ended converter (XLR to RCA / BAL to SE)

Discussion in 'DIY' started by purr1n, Jun 27, 2020.

  1. dematted

    dematted Almost "Made"

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    Thank you very much, that helps me a lot! I'll make sure to do the -3 dB digital attenuation through Roon. And I think I know better understand what all these numbers mean...
     
  2. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    I have a 1:1 iso transformer I believe the one that is recommended here.

    [​IMG]

    I’ve read that the RCA ca LE on the output needs to be short.

    I’m wondering how short exactly? And if it runs to a switcher with a 1.5 foot RCA cable can I then use a longer RCA cable out of the switcher without SQ loss or does it still add onto the length of RCA out from the iso converter?

    Thanks for any insights
     
  3. Tommy

    Tommy Rando

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    I recall reading in this thread that it’s the dac side that should be as short as possible, but maybe that was specific to the Cinemag setup. About to start work so aren’t able to search, but I’m pretty sure it was in the earlier pages.
     
  4. crenca

    crenca Friend

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    I use this unit (the 1:1 PI-2XR for those who do not know) to transform XLR out of Gun MB A2 to SE inputs of a Saga (which then run SE to my amps). There is nothing unique to this product that requires specially short SE runs. I think what you guys are reading is general best practice around SE RCA, which with a relatively weak signal and no inherent noise rejection like the XLR side, means it is smart to keep runs as short as possible and as far away from usual EMI noise sources (switchers, computers, etc.) as possible.

    EDIT: see below, Jensen recommends < 1m cable for purpose of keeping capacitance below 200pF
     
    Last edited: Feb 18, 2021
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  5. loadexfa

    loadexfa Friend

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    I have one of these as well, here is the manual for it:
    https://www.cs1.net/pic/jensen_transformers/PC-2XR_user_guide.pdf

    It indicates to keep the SE portion under 10 feet and they explicitly say do not route this to a patch bay. I don’t know if that is due to concerns around total cable length or other issues could be introduced. I’m using it right before the amp.
     
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  6. crenca

    crenca Friend

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    That is the manual for the 4:1 model (PC-2XR), not the 1:1 model (PI-2XR) that @rhythmdevils has, not that their recommendations would be substantively different I would think.

    Edit:

    Here is what I found:

    https://www.cs1.net/products/jensen_transformers/PI-2XX.htm

    This is relevant:

    "FYI: The capacitance of the cables on the output side of the PI-2XX need to present a load of less than 200 pF, so that generally means that the cable can be no longer than 1 meter. The input of the equipment connected on that side must have a minimum impedance of 10k Ohms. There is no cable length restriction on the input side of the PI-2XX..."
     
    Last edited: Feb 18, 2021
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  7. loadexfa

    loadexfa Friend

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    Ahh, thanks for the correction, I was confused for a moment because there is still a slight difference in the model number, mine (and the one rhythmdevils has) has SE outs. I do have the PI model (PI-2XR) so the output is also 1:1 and the manual you linked is the correct one. The correct manual also has a warning about not connecting the outputs to a patch bay.
     
  8. Scott Kramer

    Scott Kramer Friend

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  9. crenca

    crenca Friend

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    I have been curious about this unit (PO-2XR) since you posted it 2 years ago now. I just placed an order with Cable Solutions. They warned me that with Covid related supply chain issues Jensen might say it will be long delayed but no matter. I will do a direct comparo review to the PI-2XR when I get it.
     
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  10. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    I’ve had a buzz in my amp for the past few weeks. I thought it was a dying tube. But I just switched DACs from my Gungnir to my RDAC and the buzz is gone. I’m praying it’s not the Gungnir.

    I will test the SE outs but that still won’t be conclusive as it could be the balanced out only.

    Could my ISO MAX be responsible?

    [​IMG]

    Interestingly the buzz goes down in volume when the Gungnir switches (clicks) after music is paused or stops.

    gah I can’t believe I have a new noise issue.
     
  11. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    ive isolated the buzz to the iso max. My Gungnir has no buzz from the RCA output and when I plug the balanced out straight into my 789 with no iso max it has no buzz.

    is anyone here interested in having a look at it and trying to fix it? I could pay of course. Shame to toss it when it’s maybe fixable.
     
  12. m17xr2b

    m17xr2b Friend

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    Doesn't it have configurable pins at the back? Sounds like a ground loop, try to enable disable anything related to ground.
     
  13. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    I have no idea what I’m doing here.

    This is a picture of the back. Thank you!

    [​IMG]
     
    Last edited: Feb 23, 2021 at 5:39 AM
  14. Baten

    Baten Friend

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    The ISO-MAX I've owned (don't have it anymore) could also buzz but it highly depended on which source was plugged into it. Sources with most optimal grounding planes seemed to not be affected.
     
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  15. rhythmdevils

    rhythmdevils Best SBAF member of all time

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    It’s strange because it was fine and I unplugged it to reorganize things and plugged it back in and it’s buzzing now. Didn’t drop it or anything.
     
  16. m17xr2b

    m17xr2b Friend

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    What about the bottom? Should be like this:
    [​IMG]

    Now, does it buzz in one channel or both? Number 2 and number 6 should be OFF in the down position. Try switching a few times in case the switch is sticky. If that doesn't work try changing pin 1 and 5. Could be you unintentionally changed one when moving or such. Transformers don't just get noisy.
    [​IMG]
     
    Last edited: Feb 23, 2021 at 6:30 AM
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  17. crenca

    crenca Friend

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    PO-2XR came in yesterday. This is the Jensen ISO-MAX product that like the PI-2XR is a 1:1 XLR > SE converter, but has larger and heaver (it weighs at least twice as much in hand) Nickle transformers, and unlike the PI model is not 'faraday cage' but can drive longer cable runs, the transformers are slightly more robust in distortion specs, etc.:

    https://www.jensen-transformers.com/product/po-2xx/

    https://www.jensen-transformers.com/product/pi-2xx/#section-3

    My application is XLR conversion from Gungnir MB A2 to SE input of Saga OG, then on to DNA Starlett powering Utopia HP's.

    I have had the PI-2XR for a year or two now. So how does the PO-2XR sound in comparison?

    No difference! LOL!! Seriously, I might be hearing a smidgeon more "air", and perhaps a touch less transformer "wet" coloration, but I am not confident it is beyond placebo range. So in my application, with very short SE cable runs, decent EMI environment, etc. the audible differences between these two are very small to my ears.
     
    Last edited: Feb 25, 2021 at 10:19 AM
  18. Baten

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    Refreshingly honest at least. Appreciate the no bullshit review, Lol :) I did expect you to tell us it'd sound better.
     
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