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Bi-wire, bi-amp connection problems

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  • Bi-wire, bi-amp connection problems

    Dear Alan:
    As far as i'm concerned,after the coming of 30 anniversary model,C7 3 & M40.1 have changed their connecting way,from bi-wiring to single terminal,what' the reason for that?
    Waiting for your reply.
    Thanks
    Zhangyu

  • #2
    Harbeth position on bi-wiring terminals ...

    I've covered this issue many times here before - for example here and here. The answer is twofold:

    a) Simplification. Bi-wire has confused some customers and led others down the path of fiddling about with different types of bi-wire links when they use the speaker in non-biwire (standard) mode. We don't believe that changing the standard expensively UK-made* gold plated brass links (supplied with the speakers) for any other connector will improve the sound.

    b) I have freely admitted here many times that we ourselves never use bi-wire connection, neither during the design nor at public exhibitions nor listening for pleasure. It was added for purely marketing reasons i.e. consumer choice.

    However, looking back over the twenty years or so since we applied bi-wiring terminals, it is seemingly a feature used by a very few customers that all customers must pay for. So speakers from the C7ES3 (that is, C7ES3, M40.1 and soon P3ESR) have reverted to the standard wiring pair. Any change in sound quality? None.

    * You cannot believe how expensive these brass links are to make here. The are punched one by one, de-burred by hand, cleaned by hand then sent to London to a jewellers who specialises in gold plating. So expensive is the gold plating process that the jeweller insists on immediate payment and even a small quantity of these links will involve us paying $1000. Despite all of this attention to detail, it's still not good enough for some users ...
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

    Comment


    • #3
      Harbeth position on bi-wiring terminals ...

      Alan
      Thanks for your detailed explaination.

      Comment


      • #4
        Terminals on old Harbeths .... biamping?

        Dear Alan:

        A friend of mine meets a problem--he has just bought a pair of Harbeths, HL Compact. During the period of enjoyment,he found that when he connected the speakers in bi-wiring way with 2 amps,not only the tweeters but also the woofers sounded so tiny that he almost could not hear.When he only connected the woofers with one amps,the circumstances didn't change any more,souned but tiny.He can be sure the amps are in all right.

        Were there any cases like this before?Because the speakers are second-handed ones,so he wants to know what the problem is,whether the speakers has been "editted" or it is the characteristic feature of design for the "old" HL Compact?
        Beg your instructions.
        Thanks

        Comment


        • #5
          Re: Terminals on old Harbeths .... biamping?

          Ah. I wondered if there was some problem underlying your original posting! OK. let's take this step by step. I'm thousands of miles away, and relying only on your posting I'm trying to imagine the situation that has befallen ni de pengyou.

          1. You say "HL Compact". You mean, the very original HL Compact with the black baffle, foam grille and bass unit with the long protruding plastic phase plug in the middle? That unit ended production about 15 years ago. So what has been the history of your friend's speaker these past years? How many people have owned and perhaps modified them inside? Or damaged them? If you email me with the serial number, I can look up our Log Books and find out when they were made.

          2. We do not recommend bi-amping. As I've said before, there are many things that can go wrong with bi-amping and it is possible that you can damage the amps and/or the speakers.

          Also, if your concept is to drive the woofer from one amp and the tweeter from another amp, how can you be sure that the gain of the amp is the same? You absolutely cannot be sure about the amp/speaker match unless you have electronic test equipment to measure the gain and the frequency response and the phase of the amp. Nobody has that equipment at home so we say, don't play with bi-amping.

          What I suggest is this: forget about bi-amping and bi-wiring. Ref-fit the bi-wire links between the tweeter (+) and bass (+) and tweeter (-) and bass (-) terminals on the back of the speakers and return the speakers to the original ex-factory condition. Then, find a standard, conventional hi-fi stereo amplifier and connect it to the 'normalised' speakers. Test and let me know what you find out. There must be a simple explanation for this. But we have to apply some Sherlock Holmes detective work to discover the real problem.
          Alan A. Shaw
          Designer, owner
          Harbeth Audio UK

          Comment


          • #6
            Connection problems to HL Compact?

            Alan
            A lot of thanks again,
            I like the sound of Harbeth so much that I post 2 threads named "I love Harbeth" at a Chinese Hi-Fi forum,so a lot of Harbeth lovers take me as a professional,as you see,because of the language barrier,many of them can't communicate with you directly,so when they have some questions ,they come to me ,I just want to try my best to help them.

            I hope we can build up a available way between the fans of Harbeth who can't speak to you in person and you, I do this without any economic benefits but want more and more people to know more about Harbeth.
            In addition, your Chinese is good,O(∩_∩)O~。
            张雨

            Comment


            • #7
              Connection problems to HL Compact?

              Alan,my friend's speakers' serial number is 3177,besides the certain parameters,he wants to know whether there are any differences in the design of frequency divider.

              Comment


              • #8
                Connection problems to HL Compact?

                Here is his speakers(they have been renovated on the surface and the screws).
                Attached Files

                Comment


                • #9
                  Connection problems to HL Compact?

                  As far as I can see, their is only one binding post. If you connect two amplifiers to this one binding post, you will short out both amplifiers, and possibly break them both. It would be wise if you would adhere to the advice Alan has given above.

                  Comment


                  • #10
                    Connection problems to HL Compact?

                    Originally posted by garmtz View Post
                    As far as I can see, their is only one binding post. If you connect two amplifiers to this one binding post, you will short out both amplifiers, and possibly break them both. It would be wise if you would adhere to the advice Alan has given above.
                    Thanks for your reminding,but I'm sure they are biwiring speakers.
                    Attached Files

                    Comment


                    • #11
                      Re: Connection problems to HL Compact?

                      OK, you have answered one question - these are indeed the original HL Compact (my first speaker design as the new owner of Harbeth company). They sold extremely well, especially in Japan and really created the foundation for the modern Harbeth company. I'm delighted that they are looking so fresh.

                      Back to the technical issues:

                      Yes, these are indeed bi-wireable (or bi-ampable). The top red/black terminals are wired to the tweeter crossover and the bottom two to the woofer crossover - see attached picture. To maximise my help you please need to follow the clear instructions I made in my previous posting, which I repeat again here:

                      "What I suggest is this: forget about bi-amping and bi-wiring. Ref-fit the bi-wire links between the tweeter (+) and bass (+) and tweeter (-) and bass (-) terminals on the back of the speakers and return the speakers to the original ex-factory condition. Then, find a standard, conventional hi-fi stereo amplifier and connect it to the 'normalised' speakers. Test and let me know what you find out...."

                      Please respond as I have requested. Problem solving by "remote control" at such great distance and across two languages must be conducted in a strictly logical way - please. Remember: many people are watching this thread and if we proceed in a logical way it may be of help to someone else in the future. That is the entire purpose of this Harbeth User Group - to build a knowledge archive for the future.

                      -----------------------------

                      P.S. I looked up the Log Book production records for these speakers. Your friends original HL Compact s/n 3177A-B were made on 31 Aug. 1990 and shipped to Hong Kong on 25 Sept. 1990. They are walnut. So, they are nearly 19 years old, and as we know, Harbeth speakers are built to last.

                      >
                      Attached Files
                      Alan A. Shaw
                      Designer, owner
                      Harbeth Audio UK

                      Comment


                      • #12
                        Bi-wiring connection problem

                        Alan
                        We are so lucky to make such a wise choice to choose Harbeth, not only for the reason of the fantastic sound, but also for the great technical backup from you.

                        My friend's HL Compact works well when connect it in the normal way. But when he took the wire jumpers away, linked the tweeters' terminals with one stereo amp, and the woofers' with another one, the problem that I mentioned before appears--both the tweeters and woofers sounds so tiny that he almost couldn't hear the music. And we don't know what the problem is.

                        Comment


                        • #13
                          Re: Bi-wiring connection problem

                          Pleased to try and be of service. I have very many friends in PRC and Hong Kong so I really would like to try and help you resolve this problem.

                          This is very interesting. First two basic tests ...

                          TEST No. 1
                          =========

                          Remove the bi-wire links and using the regular amplifier connect the speaker cable to only the top two (red/black) terminals. Can you hear a normal tweeter-only sound? You will not hear bass/middle, only high frequencies, but does it sound normal for listening with only the tweeter connected?

                          TEST No. 2
                          =========

                          Do not refit the bi-wire links
                          . Now remove the speaker wires from the top two red/black terminals and connect to the bottom two only. You should hear bass/mid sounds only, no high frequencies. Does that sound normal for listening with only the bass unit connected?

                          We may have to work through some more steps but I'd appreciate your reply to this.
                          Alan A. Shaw
                          Designer, owner
                          Harbeth Audio UK

                          Comment


                          • #14
                            Important!!

                            Whilst eating my lunch, mulling over your problem, I just realised that there is something strange about your photo of the terminals.

                            Can you confirm that the red terminals are on the left (as shown in your picture) or on the right side?
                            Alan A. Shaw
                            Designer, owner
                            Harbeth Audio UK

                            Comment


                            • #15
                              Re: Connection problems to HL Compact?

                              Originally posted by zhangyu.H View Post
                              Thanks for your reminding,but I'm sure they are biwiring speakers.
                              Sorry, couldn't see it from the earlier picture, my bad...!

                              Comment

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