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HUG - here for all audio enthusiasts

The Harbeth User Group is the primary channel for public communication with Harbeth's HQ. If you have a 'scientific mind' and are curious about how the ear works, how it can lead us to make the right - and wrong - audio equipment decisions, and about the technical ins and outs of audio equipment, how it's designed and what choices the designer makes, then the factual Science of Audio sub-forum area of HUG is your place. The objective methods of comparing audio equipment under controlled conditions has been thoroughly examined here on HUG and elsewhere and should be accessible to non-experts and able to be tried-out at home without deep technical knowledge. From a design perspective, today's award winning Harbeths could not have been designed any other way.

Alternatively, if you just like chatting about audio and subjectivity rules for you, then the Subjective Soundings area is you. If you are quite set in your subjectivity, then HUG is likely to be a bit too fact based for you, as many of the contributors have maximised their pleasure in home music reproduction by allowing their head to rule their heart. 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 only, although HUG is really not the best place to have these sort of purely subjective airings.

The Moderators' decision is final in all matters and Harbeth does not necessarily agree with the contents of any member contributions, especially in the Subjective Soundings area, and has no control over external content.

That's it! Enjoy!

{Updated Oct. 2017}
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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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