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

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

  1. hifiandrun

    hifiandrun Almost "Made"

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    The DM2-2xx is the previous model number of PO-2xx. https://www.cs1.net/products/jensen_transformers/PO-2XX.htm
    The transformers in PO-2xx use thicker wire windings thus heavier and they don’t have shielding. The transformers in PI-2xx are much smaller and in cylinder shields. The PO-2xx spec is better on paper at zero ohm measurements, but worsen quickly at 150 ohm load or 300 ohm load (curves on Jensen website). Thus in common real world cases, PI-2xx would have better performance. But I don’t have EE background, could not explain the reasons.
     
    Last edited: Mar 21, 2021
  2. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Ha. I didn’t catch that. I guess if the buzz goes away I already have the best unit for my situation.

    are there any clues to the PO being an upgrade or just a name change?
     
  3. m17xr2b

    m17xr2b Friend

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    Last edited: Apr 15, 2021
  4. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    An update on my buzz issue.

    I confirmed the above ^ to be true with Cable solutions. They switched the model name but nothing else. They are the same units. In fact Jensen continues to ship units out with both model names. So either one is the same. Not an upgraded unit.

    I am guessing the buzz issue was an XLR cable that developed a loose connection at the solder joints in the connector. This particular cable gets curved pretty hard out of the iso max because it’s a stiff cable and my whole rig is against a wall with little space so it doesn’t have the room to curve out naturally. I am using it now with no buzz. I still have to identify the bad cable but I wish I thought of this before!

    I’ve been borrowing a PI-2XR from a friend and the first time I went from the PI to the PO I thought the PO sounded a bit better. The second time it just sounded a bit different tonally.

    I think it’s safe to buy either one and would probably recommend buying based on your cable lengths after the iso max. If they are short enough going with the standard PI is probably a better choice since it is much more widely used and Cable Solutions (probably wrongly but just in case) claims the PI sounds better. I doubt it but why not get the PI unless you have longer than 1m cable after the iso max.
     
  5. m17xr2b

    m17xr2b Friend

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    Two more boards almost ready to be sent out.

    One is with the Sowter 3575 PCB variant, 10K 1:1 with a slim profile as intended.
    [​IMG]

    [​IMG]

    Another board is for self installation of the Cinemag CMLI-15/15b threaded style, the middle connector is for solder and hassle free install since cinemag kindly pre strips the cables. Testing it out on one of my own transformers:
    [​IMG]

    Taller case but not unreasonable:
    [​IMG]
     
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  6. Walderstorn

    Walderstorn Friend

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    You make a very good converter, super pleased with mine.
     
  7. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Are these Cinemag converters considered better sounding then the Jensen units (PO-2XR/PI-2XR)?
     
  8. skem

    skem Friend

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    Yes they're better
     
  9. dankef

    dankef New

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    Has anyone had the opportunity to compare one of these converters with a Freya S? I'm having a look at the ampsandsound Black Box (https://ampsandsound.com/products/xlr-to-rca-converters), which I understand uses Cinemag transformers, versus a Freya S which I can still get from the local dealer. The amp will be a DNA Starlett.
     
  10. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    Have you considered the Jensen Pi-2XR? It might not sound quite as good I hear Cinemag transformers are the best but it's mcch less expensive.
     
  11. dankef

    dankef New

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    Thanks - it’s tricky because I’m in Australia so with shipping the ampsandsound box is almost the same price as the Freya S, and the Jensen is a bit cheaper but not that much. The preamp in the Freya S would be useful for a turntable in the future, but my main priority at the moment is the quality of the balanced to unbalanced conversion.
     
  12. Riotvan

    Riotvan Snoofer in the Woofer

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    Diy is an option too, can be even cheaper or more expensive depending on what parts you want in there. If you don't know how to solder this is also a good beginner project. I made something like this recently but with a selector for 3 outputs where one was hooked up to some transformers to step down to single ended.
     
  13. loadexfa

    loadexfa MOT: rhythmdevils audio

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    I haven’t heard the ampsandsound version but have the Freya S and the Jenson PI-2XR. The Freya does a great job, it’s hard to notice changes to the sound which is a good thing. Depending on your intended use, you may find the convenience of all the extra inputs and outputs worth the extra expense, I certainly do.
     
  14. dankef

    dankef New

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    Thanks - I assume you don’t notice a significant sound quality difference between the Freya and Jensen? I’m leaning towards the Freya for the extra functionality as you say, assuming the sound is pretty much the same.
     
  15. Taverius

    Taverius Smells like sausages

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    I don't mind the Freya S' conversion when it's directly running into speaker amps. That is how my Bifrost 2 gets converted to BAL for Vidar Monos.

    It only converts in its active modes, mind, and it's active stage does have a sound of its own, so I don't find it suited at all to being a preamp to a headphone amp.

    Get the trafos.
     
  16. batriq

    batriq Probably has made you smarter

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    I haven’t compared the Freya S with the Jensens, but I preferred the WE111C for balanced to SE conversion over the Freya S. For example, violin E string with Freya S conversion was etchy and sometimes unbearable.

    Edit: Posted more thoughts on the Freya S thread here.
     
    Last edited: Aug 28, 2021
  17. batriq

    batriq Probably has made you smarter

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    Finally built the converter with the Cinemag 15/15B. The case is a Hammond 1444-8. Below are some pics in case these are helpful for anyone building the same.

    Case with Neutrik connectors -- I like using these Hexseal screws which resist loosening:

    [​IMG]

    The transformers are mounted using the Cinemag hardware with thick Hillman nylon washers that I purchased separately. This ensures the screws go only 2mm into the transformer (datasheet specifies 3.8mm insertion clearance):

    [​IMG]

    Installed and soldered -- the wiring follows @purr1n 's schematic in #1:

    [​IMG]

    Final product:

    [​IMG]
     
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  18. batriq

    batriq Probably has made you smarter

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    The Cinemag 15/15B transformers seem to need time to break-in. They started out leaning lush and have become more neutral over the past few days, with more details in the music surfacing.
     
  19. RestoredSparda

    RestoredSparda Friend

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    Ok, so I'm about to build one of these but have a question (admittedly possibly a daft one). Is the volume level to an amp increased quite a bit compared to just using se output? Say, would the se output on the bifrost 2, and the xlr output (with the cinema conversion to se) be similar volume levels on the same amp, or would the xlr conversion create an se output at a higher gain?

    I don't want to end up not having enough play with my volume on the Bottlehead Mainline as it is already almost too loud with HD650.
     
  20. Erroneous

    Erroneous Friend

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    From Schitt's site:
    "Maximum Output: 2.0V RMS single-ended and 4.0V RMS balanced"

    Balanced will be louder than SE if you're using 1:1 transformers.
     

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