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Since its inception ten years ago, the Harbeth User Group's ambition has been to create a lasting knowledge archive. Knowledge is based on facts and observations. Knowledge is timeless. Knowledge is human independent and replicatable. However, we live in new world where thanks to social media, 'facts' have become flexible and personal. HUG operates in that real world.

HUG has two approaches to contributor's Posts. If you have, like us, a scientific mind and are curious about how the ear works, how it can lead us to make the right - and wrong - decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual area of HUG is for you. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and can be easily understood and tried with negligible technical knowledge.

Alternatively, if you just like chatting about audio and subjectivity rules for you, then the Subjective Soundings sub-forum is you. If upon examination we think that Posts are better suited to one sub-forum than than the other, they will be redirected during Moderation, which is applied throughout the site.

Questions and Posts about, for example, 'does amplifier A sounds better than amplifier B' or 'which speaker stands or cables are best' are suitable for the Subjective Soundings area.

The Moderators' decision is final in all matters regarding what appears here. That said, very few Posts are rejected. HUG Moderation individually spell and layout checks Posts for clarity but due to the workload, Posts in the Subjective Soundings area, from Oct. 2016 will not be. We regret that but we are unable to accept Posts that present what we consider to be free advertising for products that Harbeth does not make.

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{Updated Nov. 2016A}
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Harbeth HL-P3ES2 specific

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  • #46
    Re: Building A New System Around Harbeth P3

    Thanks for the very useful info, Alan. The said CD player is the current Quad CDP-2 which can also control the volume via its remote control.

    Now my dealer offers me a Quad 67 Cd player which also sounds nice and way cheaper but here, I have to use a preamplifier like the Quad 34. However, your findings on the 34 clipping issue when the volume hits 13 worries me a bit as I like to listen to my music loud.

    I hate electronics, I find it much easier to choose which Harbeths I like because all of them sounds good :-)

    Comment


    • #47
      Re: Building A New System Around Harbeth P3

      Originally posted by SaifulAJ
      Thanks for the very useful info, Alan. The said CD player is the current Quad CDP-2 which can also control the volume via its remote control.

      Now my dealer offers me a Quad 67 Cd player which also sounds nice and way cheaper but here, I have to use a preamplifier like the Quad 34. However, your findings on the 34 clipping issue when the volume hits 13 worries me a bit as I like to listen to my music loud.

      I hate electronics, I find it much easier to choose which Harbeths I like because all of them sounds good :-)
      I am using Quad CDP-2, yes it controls the volume, but for me with 99 preamp sounds in a better way.

      Comment


      • #48
        Re: Building A New System Around Harbeth P3

        I know that the later QUAD remote units can control volume, but how about the tilt function. Is that remotely controllable? I assume that the tilt electronics is built into the QUAD preamp, so no peramp, no tilt. Is that correct?

        I was surprised at the clipping on the 34, but that's how I find it. Important point to bear in mind about (earlier) QUAD units like 33, 34, 44 preamps and QUAD 306, 405, 606 power amps ... they are designed as matched pairs. The implications of this are ...

        1. The preamp is phase inverting; the power amp is phase inverting. That means an inversion of an inversion = back to in phase with the input to the preamp for the signal to the speaker.

        2. The power amp's input sensitivity is, to my mind, extremely high. Just 0.5V rms will fully drive the power amplifier to maximum rated output. Anything more on the imput and the amp clips.

        3. A typical CD player will produce about 2.0V rms at peak recording level which is all too often the norm these days (four times that needed to clip the QUAD power amp) so it's essential to throttle down the CD signal if driven directly into the power amp. You have to throw away 3/4 (three quarters) of the signal coming from the CD player which implies that the in-line volume control will be operating near the bottom of its range where the inter-channel tracking of (mechanical) volume controls may not be very linear.

        It's a mystery why QUAD set the sensitivity so high at the power amps inputs. 1.0V or 2.0V would have been much safer, as indeed is the case with the professional QUAD 520, but that has other issues of load interdependence.
        Alan A. Shaw
        Designer, owner
        Harbeth Audio UK

        Comment


        • #49
          Re: Building A New System Around Harbeth P3

          Hi AS,

          I hv been using a passive preamp (oxymoron) made up of a resistive pot as a preamp feeding the 306 followed by the P3. The 'hot' output of the 306 is connected to the 'hot' input of the P3. Can you confirm that I need to swap the connection if I want to maintain absolute phase? And to think I hv been using it all these years (14 and counting) without realising it.....


          It is true the preamp is not really needed and the high gain of the 306 is more than adequate. The combo above drives my 16' x 24' room to more than adequate levels. However, my experience is that an active preamp (with gain) sounds better than a passive, resistive one. Solid or hollow state, it did not matter. What was most interesting was when my passive preamp was substituted with a transformer-based attenuator. That sounded very nice. There was just more details, and one could hear the decay of notes and 'soundstage'. Even my non-audiophile wife remarked she noticed a difference.
          Hmmm, there is more to it than meets the ear.

          YH

          Comment


          • #50
            Re: Building A New System Around Harbeth P3

            Interesting comments.

            Yes, in theory as the Q306 is phase inverting you could swap the hot/cold connections to both speakers but don't bother ... it will not give you the result you seek. Why:

            1. Can you be sure the CD player is not phase inverting? No, not without test equipment.

            2. Can you be sure that the entire recording chain, all the microphones, the mixing desk etc. etc. is not phase inverting? No.

            So - I wouldn't bother to make any changes.

            As for you comments that introducing a transformer or an active preamp into the reproduction chain could enhance quality compared with a passive volume control - this is counter intuitive. All and every transformer ever made imparts a tiny bit of its own sonic signature on the signal passing through it, which is why of course, valve amps (which are built around output transformers) have a special tone that solid state amps can't mimic.
            Alan A. Shaw
            Designer, owner
            Harbeth Audio UK

            Comment


            • #51
              Re: Building A New System Around Harbeth P3

              Alan
              It is counter intuitive, that is why I found it interesting.

              The transformer attenuator in question has less than 0.05% distortion
              across the audio band with 2V input. The Quad 34 uses TLE2071 opamps
              with 0.02% distortion at 20kHz (Av=10, 2k load), not that far away.
              And if one adds the few stages together....
              Today's opamps are some 2 orders of magnitude better, cf LM4562.

              Even if one eschews the distortion induced by magnetic parts in
              transformers and even order harmonics of valve amps,
              I find a solid state preamp with resistive
              pot also sounds better to my ears than just a
              pure passive preamp - I do not know why.

              All,
              if you have the opportunity, try this out and hear for yourselves.

              cheers
              YH

              Comment


              • #52
                Re: Building A New System Around Harbeth P3

                I don't think its fair to compare distortions in such crude terms as total harmonic distortion %. What is the nature of the distortion? Second or third? Perhaps more revealing is the intermodulation and non-linear distortion performance.

                Take care not to sidestep the issue: what you may prefer is not necessarily what is technically distortion-free. That's legitimate of course and you are perfectly free to say so, but what you would be saying is 'I like some colourations'. Again, no crime in that but when a technical product that is much more complicated sounds superior to something extremely simple it does raise some serious questions that need to be addressed.

                It is, as I said, counter-intuitive and taken to its extreme, the goal in hifi would not be minimalism, but maximisation.

                In my experience, there is always an explanation for sound quality differences that are counter-intuitive but they are not obvious and take some detective work. The solution is intellectually satisfying though.
                Alan A. Shaw
                Designer, owner
                Harbeth Audio UK

                Comment


                • #53
                  QUAD 606 - wrong information

                  POST SCRIPT: I am wrong about QUAD 606.
                  =========

                  I have just found the sticker on my 606 where I wrote "This amp is Non-inverting".

                  If that is correct, it is unlike the 405 which I'm sure is inverting. I will double check this and report as soon as possible. It's very curious that QUAD have two opposite stances on this issue.
                  Alan A. Shaw
                  Designer, owner
                  Harbeth Audio UK

                  Comment


                  • #54
                    Re: Building A New System Around Harbeth P3

                    I do not disagree with you, Alan. Gross simplifications are necessary in a forum like this, and I am certainly not a fit antagonist to your genius and experience.

                    YH

                    Comment


                    • #55
                      Re: Building A New System Around Harbeth P3

                      No room for genii here! Experience - yes.

                      Remember - viewed from 25 or 50 years in the future, these will be seen as the Dark Ages of audio, as the biplane is now compared to the 787. That shouldn't prevent us from discussing and ruminating over our combined experience. My wish is that when our contribution to audio is scrutinised our part is seen as solid, pragmatic, credible and real knowledge-building - i.e. of some use to those who will follow us. What other reason is there for our combined efforts?
                      Alan A. Shaw
                      Designer, owner
                      Harbeth Audio UK

                      Comment


                      • #56
                        HL-P3's... solid state or tube?

                        Greetings to all,

                        I am new to the forum, but have owned several Harbeth loudspeakers over the years, finally settling on the venerable HL-P3 (first gen), because of its marvelous mid-range transparency.

                        Each pair of Harbeth?s I owned have been driven by solid state amplification of various wattage and brand, but I would like to hear from owners who are using tube equipment to drive theirs, and what brand/model it is.

                        I am contemplating the purchase of a pair of 50-watt per channel, Quicksilver Audio Mid-Mono?s to use with the HL-P3?s, but don?t want to rush into it if the general consensus is to stay with SS amplification.

                        Give me your reasons either way, as your opinions are very much welcomed. Thanks in advance to anyone who cares to share theirs.

                        Regards,

                        William

                        Comment


                        • #57
                          Re: HL-P3's... solid state or tube?

                          Silly me,

                          I see that my own question has been answered in one of the threads above. Sorry, I should have navigated the site more thoroughly before posting. Answer at your leisure.

                          William

                          Comment


                          • #58
                            Restoring The Finish On The HL-P3's

                            Hi,

                            The exterior veneer (walnut) on my HL-P3's is becoming somewhat dry. Do you have any recommendations on what I can use to restore the luster and shine to them once again? Should I use wax or sealer/refinisher? What is the best method? Thanks for any input.

                            Regards,

                            William

                            Comment


                            • #59
                              Re: Building A New System Around Harbeth P3

                              Just an update to this thread I started.

                              I finally end up with Quad 67, 34 and 606 for my P3s. What a combination! Thanks to my dealer (Tropical Audio of Malaysia) for giving excellent service and they really know Harbeth and Quad throughout. With dealer like this, I am sure more and more music fans will eventually convert to Harbeth in Malaysia.

                              Now I'm a very happy man. Maybe happier with 7ES-3 or SHL-5 in place but the P3s are really no slouch. Harbeth enriches my life and I really mean it. Thanks to Alan for such great magic!

                              Comment


                              • #60
                                Re: Building A New System Around Harbeth P3

                                Thanks for the feedback. In my experience, Sam Chan (Tropical Audio, Malaysia) has completely reliable and dependable judgment about what makes great music at home. He has a vast experience to draw on and many satisfied customers. We are all very pleased that you are happy.
                                Alan A. Shaw
                                Designer, owner
                                Harbeth Audio UK

                                Comment

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