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"This Harbeth User Group (HUG) is the Manufacturer's own managed forum dedicated to natural sound from microphone to ear, achievable by recognising and controlling the numerous confounding variables that exist along the audio chain. The Harbeth designer's objective is to make loudspeakers that contribute little of themselves to the music passing through them.

Identifying system components for their sonic neutrality should logically proceed from the interpretation and analysis of their technical, objective performance. Deviations from a flat frequency response at any point along the signal chain from microphone to ear is likely to give an audible sonic personality to the system at your ear; this includes the significant contribution of the listening room itself. To accurately reproduce the recorded sound as Harbeth speakers are designed to do, you would be best advised to select system components (sources, electronics, cables and so on) that do not color the sound before it reaches the speakers.

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HUG specialises in making complex technical matters simple to understand, getting at the repeatable facts in a post-truth environment where objectivity is increasingly ridiculed. With our heritage of natural sound and pragmatic design, HUG is not the best place to discuss non-Harbeth audio components selected, knowingly or not, to introduce a significantly personalised system sound. For that you should do your own research and above all, make the effort to visit an Authorised Dealer and listen to your music at your loudness on your loudspeakers through the various offerings there. There is really no on-line substitute for time invested in a dealer's showroom because 'tuning' your system to taste is such a highly personal matter. Our overall objective here is to empower readers to make the factually best procurement decisions in the interests of lifelike music at home.

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Feb. 2018
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Ultimate Integrated Amp For Compact 7ES-3 and SHL-5

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  • #61
    Re: Amplifiers .... distortion thresholds

    I'm sorry but I don't know who "J.F." is. And I certainly don't use "J.F's" amplifiers!

    About 'amplifier accuracy' etc. - the amp that you have at home right now may well be as 'accurate' as it needs to be.

    However, there is a standard below which one definitely shouldn't go. I bought a 5.1 channel AV amp from a British brand of well respected middle-audiophile electronics - amp made in the Far East. Looks nice. Lot's of features. Rows of connectors. Good handset. BUT, there is so much digital processing crammed into the full-rack case that it produces a roar of digital hash over the speakers if the volume is turned up just above normal. At a normal setting I can't hear the hash, but I know that it's there and that's psychologically biased me against the amp, and even the brand.

    Compared to designing a simple basic stereo amplifier, it must require electronic design skills of the very highest order (as you'd expect to find in the Japanese corporations) to design really good AV amps where the digital and analogue circuitry are adjacent to each other without RF or PSU break-through. Ditto mobile phone design where radio signals and audio signals are millimetres apart on the same PCB. Incredible. Those guys have have really moved the frontiers of audio electronics forward as they've honed their cutting-edge skills whilst the rest of us in the audio industry remain trapped in our dark ages, going round in circles like the Bismarck chasing inaudible non-issues! And we wonder why young, A1 grade electronic engineers (like my eldest son) don't find the audio industry an attractive career path?!
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

    Comment


    • #62
      Re: Ultimate Integrated Amp For Compact 7ES-3 and SHL-5

      Interesting discussion. Somehow I agree that sonic differences between top grade amplifiers can be small to the point of indistinguishable under controlled listening environments and blind tests as shown in the test results of the report. However, the fact that remains is there are still minor sound differences between these amps. My only grouch is the Pioneer AV amp was said to be strikingly close to the Mark Levinson amp in sound quality. Maybe those batch of listeners have been having a few drinks.....just kidding.

      Anyway I am confident that I would have little difficulty in picking out my Sony AV amps being the inferior ones compared to the current crop of "good" amps that I have now, blindfolded or not.

      Comment


      • #63
        Good AV amps and parts-list generic components .....

        Don't underestimate the design skills that go into those AV amps - the good ones from the big brands are designed by engineers at the very top end of the audio ladder. Those engineers understand amplifiers so well that they can specify the custom made IC's (chips) down to the finest details. The poor relation - the audiophile hi-fi industry - doesn't have the resources, the purchasing power, perhaps even the engineering design expertise to contemplate custom-designed chips for our amps.The best we can do is scour conventional parts catalogues for yesterday's technology and try and find yet more technically interesting ways of combining those boring old off-the-shelf components, and spin up another uninspiring marketing story fixated on some weirdness of the circuit design, the case, the size, shape or colour. It's all so desperately uninspiring.

        If we want to build better amps, we as an industry have to break away from bog-standard parts-list components available to every TV repair man in ones and twos and actually design innovative new components. At fundamental chip level as we did in my previous industry. But that won't happen in 'audiphile' audio for the reasons I've explained.
        Alan A. Shaw
        Designer, owner
        Harbeth Audio UK

        Comment


        • #64
          Re: Amplifiers .... distortion thresholds

          Originally posted by A.S. View Post
          So, back to my question: what did they find was a 'just detectable' distortion contribution superimposed on music or speech? 10% or 0.001% perhaps?
          Well, here is an article by Professor Edward M Cherry quoting that human detectable distortion can be as high as 10% http://news.google.com/newspapers?ni...g=3909,4708574

          Professor Cherry patented the Monash Cherry amplifier in 1983, which was the most accurate amplifier design at that time, and sold the design for some 2 million AUD. I was doing 2nd year Electrical Engineering at Monash University at that time, and was very impressed by his achievements. I would have chosen to do a project under him if I had continued my study in Electrical Engineering. I was meant to be doing a double degree in Computer Science and EE, but I was captivated by Computer Science so I opted not to continue with EE and continued on to do postgraduate study in Computer Science instead.

          I remembered reading an article mentioning that TIM was not measurable by the measuring instrument used, which has a threshold of 0.1%. Anyway TIM brought up an interesting question for me - which is temporal distortion. I remembered seeing a graph posted by Alan that there is a small phase lag on the base region as compared to the treble region. I understand that this is inevitable because of the inertial of the cone material.

          My question is - how much can the human ear tolerate such phase incoherence across the spectrum?

          Cheers,
          Yee
          Last edited by yeecn; 12-08-2009, 02:45 PM. Reason: grammer corrections

          Comment


          • #65
            Re: Ultimate Integrated Amp For Compact 7ES-3 and SHL-5

            Alan,
            Was it 0.1 or 'point one' per cent as proposed by H.J.Leak ?

            Comment


            • #66
              Re: Ultimate Integrated Amp For Compact 7ES-3 and SHL-5

              Good memory! I'll dig out the papers tonight.
              Alan A. Shaw
              Designer, owner
              Harbeth Audio UK

              Comment


              • #67
                Phase audibility

                I take my hat off to you ... it's you that should be sitting here not me! Can I re-phrase your comment "that human detectable distortion can be as high as 10%" in a more dramatic way thus .... Distortion can be as high as 10% and may not be detectable to the human ear.

                Only 10%? I think that it can probably be much higher than that in the bass frequencies and not be detectable, and just as well. Does one seriously think that a 5" or 8", even 12" cone can produce perfectly clean LF at medium/high volumes? And the port?

                The phase thing: you've reminded me that once again, this was researched by Harwood and colleagues at the BBC decades ago. Why? Because in broadcasting, there are very long signal lines from studios to transmitters up and down the country via telephone exchanges. Even at the speed of light, there are small but detectable time delays sending signals along those long lines, and that means there are small phase differences.

                The BBC needed to put some numbers to what was acceptable. The reason was that when stereo was in its infancy (long before digital distribution systems) the left channel and right channel were not necessarily sent on adjacent pairs of wires from London north to say, Glasgow in Scotland 400 miles away. Although one stereo channel may pass directly along the shortest direct route, the other channel just might leave London, pass along a Post Office trunk phone wire bundle to, say, Bristol in the east, then across to Belfast in Ireland then back to Manchester and finally arrive in Glasgow. The BBC had no control (and no need to control) how the PO distributed the signal providing that it arrived.

                Imagine then when these two signal are brought together at the Glasgow studio, one with a tremendous delay due to it's extra long routing how that would cause a big phase problem. So the BBC set about quantifying the effect on stereo and concluded that the ear was remarkably tolerant of phase shift and that providing the phase was not too far out of step the ear was not able to detect the slip.

                Sorry to say (or rather, please to report) that it's another non-issue. I'll dig out the papers.
                Alan A. Shaw
                Designer, owner
                Harbeth Audio UK

                Comment


                • #68
                  BBC conclusions about (interchanel) phase shift

                  I've found one of the papers, written by our Dudley Harwood and his then boss, D.E.L. Shorter when they led the BBC Research Department's audio work.

                  They concentrated their efforts on verifying work carried out by the European Broadcasting Union (EBU) at around 1960, and improving the understanding of the subject (with stereo radio planned to start service). Their work was then submitted to the EBU and finally adopted (in the form of Fig 5) as CCIR1963 across Europe.

                  What this shows is that human perception of inter-channel phase is somewhat frequency dependent. The red curve (Fig 4g) dips around 200-400Hz (the midrange) and this means that the ear is a little more sensitive to phase shift (in the midrange) than at other frequencies above and below. But from about 1kHz upwards, typically a whopping 55 degrees of phase shift ( that's about a seventh of a complete cycle at 1kHz) is inaudible to the trained listener and in the low frequencies, an incredible 90 degrees is inaudible* under perfect conditions. So, one again, the facts illustrate the point that the ear is incredibly easily deceived. Unless real care and attention to construct proper, controlled critical listening comparisons (just like these at the BBC) the subjective results are, in engineering terms, meaningless. But when care is applied, it always reveals that the organic, flesh and blood ear, is far less reliable an instrument than many (but not I) wish to believe.

                  I would imagine an audiophile would find it incredible that the ear could be so astonishingly deaf to phase, but these are the facts.

                  * Common sense tells you that the ears must be extremely poor at resolving phase at low frequencies. If they were more sensitive it would be impossible to position two or more loudspeakers for satisfying stereo in the normal, untreated, asymmetrical, reflective listening room. The listener's head would be swimming as the notes seemed to shift from left to right through the musical spectrum: a nauseous experience.

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

                  Comment


                  • #69
                    Re: Phase audibility

                    You are very right Alan, our ears are much more imperfect that we thought!

                    http://www.axiomaudio.com/distortion.html

                    Put another way, our ability to hear the test frequency ?noise? tones at frequencies of 40 Hz and below is extremely crude. Indeed, the results show we are virtually deaf to these distortions at those frequencies. Even in the mid-bass at 280 Hz and lower, the ?noise? can be around -14 dB (20% distortion), about half as loud as the music itself, before we hear it.

                    The amount of hocus pocus in the audiophile industry is truly amazing. I am glad that you created this forum for us mere mortals to have a glimpse of reality.

                    Cheers,
                    Yee

                    Comment


                    • #70
                      Re: Ultimate Integrated Amp For Compact 7ES-3 and SHL-5

                      I have the M30 at home right now but i?m about to change them with the SHL5 as i had them here at home for two weeks, and it was simply breathtaking how they sounded with my set up. The M30 where allready what i called the best sound i had at home until i had the chance to try the SHL5.

                      I?m running my Harbeth with Lavardin IT, Tom Evans The Groove and a DPS 3 Turntable with Immedia RPM II arm and a Lyra Cartridge, all connected with Stereovox cabling.
                      Sound is amazing to me


                      Yakamozan

                      Comment


                      • #71
                        Re: Amplifiers .... distortion thresholds

                        Originally posted by A.S. View Post
                        I'm sorry but I don't know who "J.F." is. And I certainly don't use "J.F's" amplifiers!
                        John Farlowe of Exposure!

                        Comment


                        • #72
                          Re: Ultimate Integrated Amp For Compact 7ES-3 and SHL-5

                          Originally posted by Yakamozan View Post
                          I have the M30 at home right now but i?m about to change them with the SHL5 as i had them here at home for two weeks, and it was simply breathtaking how they sounded with my set up. The M30 where allready what i called the best sound i had at home until i had the chance to try the SHL5.

                          I?m running my Harbeth with Lavardin IT, Tom Evans The Groove and a DPS 3 Turntable with Immedia RPM II arm and a Lyra Cartridge, all connected with Stereovox cabling.
                          Sound is amazing to me


                          Yakamozan
                          Not much mentioned here but Lavardin is also a very good match with Harbeth IMHO. You have a very good analogue setup there.

                          Comment


                          • #73
                            Re: Eyes open or shut?

                            Agree that price only reflects quality to an extent and the relationship is far from linear. While on this topic im looking for an extremely affordable solid state amplifier (something below USD 900) to run a pair of SHL?5?s to tie me over the summer months. the tube amp I have just runs unacceptably hot and switching on the aircon only adds background noise. ive shortlisted the marantz 6003?s, a creek evolution (on sale here) as well as a rotel ra 04. Any suggestions are most welcome. I know the decision making process gets only harder when there are constraints. Thanks.

                            Comment


                            • #74
                              Re: Eyes open or shut?

                              Originally posted by kittykat View Post
                              Agree that price only reflects quality to an extent and the relationship is far from linear. While on this topic im looking for an extremely affordable solid state amplifier (something below USD 900) to run a pair of SHL?5?s to tie me over the summer months. the tube amp I have just runs unacceptably hot and switching on the aircon only adds background noise. ive shortlisted the marantz 6003?s, a creek evolution (on sale here) as well as a rotel ra 04. Any suggestions are most welcome. I know the decision making process gets only harder when there are constraints. Thanks.
                              Hi,
                              science is a good thing, but don't forget to land on earth, on real world when spending money. McIntosh (that I own) has poor or not at all service & support here in Greece. Numerous other exotic or non-exotic brands, have the same problem. Technicians (after guarantee has expired) are a tricky and doubtful choice to do. One dealer closed and the next one proved of very low credibility in servicing some exotic tube amps from Italy, though the latter is next door.

                              So, I'm not worried about my SHL5s, concerning that Alan is very aware of spare parts, support & service for his customers worldwide for the past 20 and the next 20 years, as we have seen to happen... I'm aware of other brands and merchants that usually disappear in the short future, when needed...

                              The matter is that you'd better choose something that would be credible, well supported, easily repaired or serviced/changed if needed at your area. I've posted a comment about what happened with one of my VU meters, earlier in this discussion. So, don't underestimate my humble advice. Get a Volkswagen and trip around Europe. If you get a Ferrari, you should have waiting a helicopter from Maranello to check what went wrong on that mountain road across the Alps... And pay accordingly...

                              Most things (like new cars, electronics, etc.) are made to last short nowadays. For this, I wouldn't pay a fortune. If you buy some really good stuff, make sure that it has something like an "Alan Shaw" behind it!

                              Cheers from Athens,
                              Thanos

                              Comment


                              • #75
                                Re: Eyes open or shut?

                                Originally posted by kittykat View Post
                                Agree that price only reflects quality to an extent and the relationship is far from linear. While on this topic im looking for an extremely affordable solid state amplifier (something below USD 900) to run a pair of SHL?5?s to tie me over the summer months. the tube amp I have just runs unacceptably hot and switching on the aircon only adds background noise. ive shortlisted the marantz 6003?s, a creek evolution (on sale here) as well as a rotel ra 04. Any suggestions are most welcome. I know the decision making process gets only harder when there are constraints. Thanks.
                                Not wishing to offend but I wouldn't give house room to any of those three. If I really, really had to choose it would be the Creek but only as the best of a bad bunch. Is there any chance of you hearing a Rega Brio or Mira ? Well within your budget and streets ahead in terms of sound. IMO

                                Comment

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