Cable length after Cinemag XLR -> RCA Transformers

Discussion in 'Modifications and Tweaks' started by rhythmdevils, Dec 30, 2022.

  1. rhythmdevils

    rhythmdevils MOT: rhythmdevils audio

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    I emailed Dave at Cinemag to get a clear answer about this because there is a lot of different information communicated in the DIY balanced -> SE transformer thread. He was very kind and informative as always, and I thought this should be in it's own thread so it's accessible and visible for everyone, and not buried in that huge thread.

    My question was how long a cable length is ok to use after a CineMag Transformer before you loose sound quality or suffer signal degradation.

    The answer depends on whether you are using CMLI-600/600C or CMLI-15/15B. Not all DACs can drive the CMLI-600/600C, so be sure to check (can someone explain what it takes to drive the CMLI-600/600C in terms of specs and what to look for in your DAC and I will add it to this first post?)

    Here is Dave at Cinemag's answer

    Q:
    Can you tell me the max RCA cable length after the CMLI-600/600C before I start loosing sound quality in this chain?

    Yggdrasil A2 DAC -> 2 CMLI-600/600C -> 1 amplifier

    A:
    The acceptable length depends upon the total capacitance of the cable. For this application, I would keep it to less than 1000pF. Cables are rated at capacitance per foot.

    Q:
    What about the CMLI-15/15B?

    A:
    I would keep cable length to under 1 meter. Even shorter is better. This is to keep the total capacitance at a minimum. Low capacitance cable is good to have. Place the transformer at the input of the device that is being driven. This is because of the high impedance.

    Note: If you use a switcher before a CMLI-600/600C, then you are still using the chain mentioned above- DAC -> transformer -> 1 amplifier, because the DAC is only ever driving one amplifier. ​

    I created a thread collecting various low capacitance cables here. I am sure there are more on the market, but if you're using a CMLI-15/15B you definitely want one of these low capacitance cables and you also don't have enough cable length to use a switcher after a CMLI-15/15B. The cable needs to go from transformers into your amp in as short a cable length as possible, as Dave said, ideally right before the amplifier.
     

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