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INTRODUCTION - PLEASE READ FIRST TO UNDERSTAND THIS FORUM!

"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, since deviations from a flat frequency response at any point along the signal chain from microphone to ear is likely to create an audible sonic personality in what you hear. That includes the contribution of the listening room itself. To accurately reproduce the recorded sound, as Harbeth speakers are designed to do, you would be advised to select system components (sources, electronics, cables and so on) that do not color the sound before it reaches the speakers.

For example, the design of and interaction between the hifi amplifier and its speaker load can and potentially will alter the sound balance of what you hear. This may or may not be what you wish to achieve, but on the face of it, any deviation from a flat response - and the frequency balance of tube amplifiers are usually influenced by their speaker load - is a step away from a truly neutral system. HUG has extensively discussed amplifiers and the methods for seeking the most objectively neutral amongst a plethora of available product choices.

HUG specialises in making complex technical matters simple to understand, aiding the identification of audio components likely to maintain a faithful relationship between the recorded sound and the sound you hear. With our heritage of natural sound and pragmatism, HUG cannot be expected to be a place to discuss the selection, approval or endorsement of non-Harbeth system elements selected, knowingly or not, to create a significantly personalised 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.

Please consider carefully how much you should rely upon and be influenced by the subjective opinions of strangers. Their hearing acuity and taste will be different to yours, as will be their motives and budget, their listening distance, loudness and room treatment, not necessarily leading to appropriate equipment selection and listening satisfaction for you.

If faithfully reproducing the sound intended by the composer, score, conductor and musicians in your home and over Harbeth speakers is your audio dream, then understanding something of the issues likely to fulfill that intention is what this forum has been helping to do since 2006. Welcome!"


Feb. 2018
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Why audio equipment malfunctions and fails

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  • Why audio equipment malfunctions and fails

    This topic covers the ageing process related to the electronic components used in audio equipment. The physical nature of electronic components as it relates to their life expectancy is well understood by engineers and researchers, and as with all manufactured products, commercial decisions are taken by it's makers as to the trade-off between long term durability, cost, size and selling price.

    Where cost is not a significant constraint, such as in the design of a communications satellite or by NASA in a deep-space probe expected to work for decades, we can be confident that certain components of notoriously short life-expectancy - such as conventional electrolytic capacitors - will be designed out to extend operational life.

    Sadly, consumer electronics are riddled with these electrolytic capacitors which provide the perfect solution to high capacity values in small spaces at low cost. They are also most likely the primary cause of equipment failure and end-of-life. It is said that most PCs fail not because of digital component malfunction, but because of break down (literally) in penny electrolytic capacitors used extensively throughout.
    Alan A. Shaw
    Designer, owner
    Harbeth Audio UK

  • #2
    The retired quad nl service engineer who refurbished my quad 303 and later quad 606-2 and 405-2 had a very simple policy: replace all resistors and capacitors. Component cost is low, testing is meaningless and labour is expensive. Replacing the lot is easiest and guarantees best results.

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    • #3
      In recent years I've had Quad 909 stereo and mono and sold them only because the power button is on the back panel. When I sold them, to buyers in Norway and Germany, I sent them to Quad who did the fixed price (60) capacitor replacement, provided a new box if needed (12) and then sent them to my buyer who then knew they had a unit that was effectively as new and would be good for the next 10 years. Their shipping costs saved my buyer a load of money.

      My 20-year old son has a 1980s Inca Tech Claymore amplifier, a highly regarded integrated unit with a mm/mc phono stage compared favourably to its contemporary, the original Naim Nait. A year or two back we sent it to the unofficial service engineer who replaced all the capacitors, and he then sent it to Colin Wonfor who designed and built it in the first place and he upgraded some FETs and fixed a couple of things. The total cost was 125 (140, $160) including shipping. I have taken to using headphones in my office (MrSpeaker Aeon) with the stunning Mojo DAC, where I have P3ESR. Tonight I made the massive mistake of lending my P3ESR to my son.

      Playing (my) original pressing of Songs of Love and Hate off his basic Pro-ject turntable with an AT m/m cartridge through this 30+ years old serviced 50w amplifier sounded absolutely stunning. The beaming smile on his face was some thing else. He was amazed by the P3ESR, as was I (again). A bit like giving a dog a bone, may be difficult to get them back.

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      • #4
        I just completed a clone of the Audio Note kit 4. (The kit is based on the Sansui HF-V60 / HF-V6K dated 1955 and 1956). Spend about double of what it normally would cost by selecting only the best parts - e.g. medical grade long life capacitors rated for 105C and 100,000 hours. Since the amplifier has an internal temperature of approx 40C the life expectancy is even further extended. Similarly I use a TKD volume control rated for a minimum of 100,000 rotations versus the normal Alps which normally are rated for 15,000 - 25,000 rotations. Transformers are Hashimoto (who originally made the Sansui transformers) having 4,8 and 16 Ohm taps. Using only valves that are currently in production so not relying on some old stock that sooner or later become unavailable. Protective circuits have been build in with extra fusing. I used a PCB with a cover plate so when repair is needed the PCB does not need removing and can be tested while operational. I can replace the 6V6 output valves with the 6L6 and make one change to the cathode resistors and then I will have 3, 6 and 11.5 Ohm output impedances (ideal for the 11 Ohm LS3/5A versions).

        I've mentioned elsewhere why I prefer tube amplifiers, not the least being that if something goes wrong in an amp I do not want the speakers to be damaged in the process. I always look at the longer term picture when purchasing something: the TCO (Total Cost of Ownership), if it is twice as expensive but is designed for a 30 to 50 year life span then it is a lot cheaper than something for half the price that only works for 5 years. There are Sansui amplifiers still running today, they are a bit of a sought after amp in Japan.

        The plan is that in 2018 I'll be buying a set of Harbeths, I am not sure if it will be the P3ESR (had Rogers LS3/5A and also had the LS5/12A) or one of the bigger models.



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