A true balanced audio system

May 20, 2021
 by Paul McGowan

16 comments on “A true balanced audio system”

  1. With the exception of Quad, who implemented a proprietary balanced connection over 25 years ago, and the cable costs $20, this is a good argument to keep the signal digital for as long as possible, and use as few analogue cables as possible. This seems to be the trend. Some systems never convert the signal to analogue at all. The one I use allegedly has an analogue signal path about 2 inches long from the DAC to the speaker cables. I assume this is why they are so quiet and revealing.

  2. There is a problem on the input side of my Jolida JD-1000P tube amp, that I want to correct.
    I have both RCA and balanced LXR inputs on that amp.
    But here is the problem with the XLR jacks.
    If you have three pens, one is ground and as for the other two which one is out of faze with the other, then why fuse those two together with a jumper?
    The input cerkets can except either balanced or unbalanced signals.
    But the way the XLR jacks are wired up, I don’t see how you would be able to put a balanced signal threw that.
    Am I misunderstanding something here about this amp?

    1. JP,
      It may not be truly balanced.
      Some designers will include XLR inputs’s even though their amps are
      not actually designed with true balanced circuitry…sad but true!

      1. Hey Fat Rat!
        For once, you may be on to something here.
        The input cerkets to the amp, looks like it can take both signal types.
        But on the XLR jacks, I want to rewire them so that I can put balanced signals in to them.
        But, I’m not quite sure of how one would go about doing that.
        Should I put transformers on those, or should I just do something else with them?

        1. JP,
          I’m always onto something; not just “once”.
          I only comment if:
          a) I’m talking from experience, or
          b) I’m being obtuse or humorous.
          Some of the stuff that you post quite often makes me laugh,
          but I’m not sure if that is your intention.
          Oh well, thanks for the chuckles 🙂

  3. I have nothing against Chinese products, many of which are excellent, but these kind of unbalanced XLR connections are relatively common. I guess they are put in for convenience so you can use a wider range of interconnects but it should be made clear they are not actually true balanced connections which are, of course, more expensive to implement.

    1. I also have nothing against Chinese products, per se.
      It is the fact that when we buy Chinese Hi-Fi gear that
      we are funding the CCP; that’s where I have a problem.
      Since the CCP has unleashed CoViD-19 on the world I am
      taking a proactive stance & NOT buying anything made in
      China ‘until further notice’.

      1. Well Fat Rat, it’s like this.
        On a real serious note, I bought that amp, almost 4 years ago.
        But it was reasontly as last year that I opened it up to clean dust out of it.
        Because it was acting up on me.
        It would shut itself down, without even a warning.
        I checked the bias on all 8 of the KT88 tubes, but they were ok.
        But when I took a closer look at the inside of the amp, that’s when I discovered the jumpers that are soldered across pens 2 and 3.
        But it’s like I told you all yesterday, the cerkets look like they can receive both types of signals.
        That is both balanced and unbalanced.
        But how do you get one of those cerkets connected properly to the XLR jacks?
        Should I put in line transformers, or should I do something else with those jacks?
        I went all the way threw the manual, but it makes no mention of those jacks.
        It just tells you, how to bias the tubes, using the built in easy biasing system.
        I choose to use a multimeter instead.
        I’m old fashion, that easy biasing system doesn’t work for me.
        How can you be sure that you biased the tubes correctly by looking at those little red lights?
        I think you have to set your multimeter to DC and watch it as you’re biasing the tubes.
        Just so you’ll know, that you biased the tubes to the correct voltage and currant.
        Don’t you agree?

        1. JP,
          Depending on the topology (design) of your particular amp, you can really only go by what your product manual tells you.
          I would suggest that you search ‘the net’ for your amplifier’s make & model & discuss your concerns with those who are familiar with what you’ve got, or find an on-line site that deals specifically with tube amps as it has been decades since I ‘messed’ with tube amps & even when I did, they were all single-ended, not truly balanced ones.
          Best of luck!

          1. Hey Fat Rat!
            To answer the question you posed, this amp started out in life, as an EL34 tube amp.
            I had Jolida to modify it to run 6550/KT88 tubes for me.
            But it is in deed a push pull tube amp.
            The highest power output, is 150watts per channel in to 4 8 and 16ohms.
            I don’t quite get how the preamp tubes are sat up, but Micle Allen told me, “the 12AX7 and 12AT7 tubes work in this configuration.
            The 12AX7 tubes, are high voltage, the 12AT7 tubes, are high currant.”
            He also told me that one tube per channel, are sat up to receive both balanced and unbalanced signals.
            The power supply board looks like it can do that too.
            I just don’t get the jumpers across pens 2 and 3 on the XLR jacks.
            If this amp can take balanced signals, I want to take advantage of that.
            I’m thinking about hooking a Mcintosh C22 all tube preamp up to itt.
            If you know anything about Mcintosh tube equipment, they do balanced signals right.
            I want to hear that.

            1. JP,
              Huh?!
              What question I posed?
              I didn’t pose any question.
              What the hell are you smoking over there sunshine?
              (That’s the only question that I’m posing)

  4. Hi Paul, love all your videos, very educational, inspirational and quite entertaining, learn something new and interesting every time, never missed one, thank you very much for your tremendous effort, and kindness of sharing your knowledge, experience and wisdom with us, audiophiles community!
    Have a question about your true balanced system video. You mentioned it goes all away through the system INCLUDING from amp to speakers.
    Please clarify that, because all amps and speakers I’ve seen so far (and besides being a lifelong audiophile, I have an old friend owner of a small Hi End Audio store, so I’ve seen a lot), all of amps had RCA speaker terminals, and all of speakers had RCA input terminals, never seen any other types of connectors. So, how the path between amp and speakers could be true balanced?
    Thanks again,
    hifi4evr

    1. Thanks but I am probably not understanding your question properly. I have never seen a speaker with RCA inputs. Maybe it is terminology.

      Speakers have binding posts that speaker cables connect to and amps have the same binding posts.

      If a power amp is balanced connected through XLR on its input, and that amp is balanced output, like many of our amps, then the system is true balanced from in to out.

      1. Good morning Paul!
        If you look back to midway to the end of the 1950’s and the beginning of the 1960’s, there were both integrated amps and speakers that used RCA jacks to connect to each other.
        But however, those systems were relatively small systems that people either sat up in their bed rooms, or systems that some people took to work with them.
        Just so that they could listen to music while they worked in their offices.
        But as reasontly as 20 years ago, I saw a Carry Audio system that used quarter inch jacks to connect their speakers to their amplifiers.
        Now I’m yoost to seeing that kind of connection with pro audio equipment, but that was the first time I’ve ever seen that with high end home audio.

  5. Good Morning Paul,

    regarding the question from the Young Man about balanced signal. can you get a balance signal from an integrated Amp?

    regards

    Bob

    1. There’s technically no reason you cannot get a balanced signal from an integrated amp though in practice it is rare. I suspect that is true because integrated are typically cost conscious.

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