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ARCHIVED FORUM -- April 2007 to March 2012
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This is the first Archived Forum which was active between 17th April 2007 and 1st March February 2012

 

Latest post 08-06-2007 4:02 PM by Die_Bogener. 38 replies.
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  • 08-02-2007 6:09 AM In reply to

    • yachadm
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    Re: Capacitors

    This is certainly the place for Martin to step in and clarify, but in my experience, I have always used Audio Grade capacitors in the Output Amplifier stages, and Low-ESR, High-Ripple-Stability 105* capacitors in the rest of the circuit.

    Examples of Audio-Grade caps:

    Nichicon Muse, BlackGate, Elna Silmic, Auricaps, Solen & Axon, Dynamicap

    Check out www.percyaudio.com for Audio-Grade capacitors

     

    Examples of High-Quality Low-ESR 105* Electrolytics at reasonable prices:

    Nichicon HE or PW, Panasonic FM or EB

    Check out www.mouser.com or www.digikey.com

     

    It is important to buy from suppliers whose stock turns over rapidly.

    All capacitors should have a date-code on them - buy only those manufactured within the last 2 years. 

    Never, never buy old (NOS) capacitors - at worst, they can damage your system.

     

     

    Learn from the mistakes of others - you'll not live long enough to make them all yourself!

  • 08-02-2007 7:13 AM In reply to

    • Puncher
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    Re: Capacitors

    As in all things HiFi there is a lot a bo**ocks talked about capacitors (similar to cables etc). I agree with yachadm in principal but I would be wary of some of the prices of some of the so called audio-grade caps - many are priced for selling to the cable brigade!

    For a decent, unbiased read on the effects of various types of capacitor see HERE

    Generally speaking, you aren't learning much if your lips are moving.

  • 08-02-2007 7:50 AM In reply to

    Re: Capacitors

    I think, the best capacitor is the one, that is not built in :)

    All capacitors have an effect on sound, some more, some less.

    If you look into the "BM7000 Workshop", more than 60% of all capacitors were eliminated, they were simply not necessary. And the effect on sound was great. Less means sometimes more ;)

    I agree, Low ESR 105 are the best ones for power supplys.

    Plastic types like MKP, MKT or Styrol are very good in amplifiers for the signal. Expensive, but at least neutral to sound.

    The worst is a polarized elko, followed by a bipolar elko. They are the worst thing in an Hifi amplifier.

  • 08-02-2007 8:12 AM In reply to

    • yachadm
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    Re: Capacitors

    Yes, I like Rod Eliott's website - lots of good, intelligent words there.

    And yes, I agree that the best capacitor is the one that isn't there!

    But if there needs to be, the right choice makes a big difference.

    What is the BM7000 workshop?

    Learn from the mistakes of others - you'll not live long enough to make them all yourself!

  • 08-02-2007 9:05 AM In reply to

    Re: Capacitors

    It's an article how to improve the BM6500 BM7000. 

    http://forum.beoworld.org/forums/thread/14361.aspx

  • 08-02-2007 3:04 PM In reply to

    Re: Capacitors

    Puncher:

    As in all things HiFi there is a lot a bo**ocks talked about capacitors (similar to cables etc). I agree with yachadm in principal but I would be wary of some of the prices of some of the so called audio-grade caps - many are priced for selling to the cable brigade!

    For a decent, unbiased read on the effects of various types of capacitor see HERE

     

    Are we discussing two things here?

     

    There are problems caused by capacitors if they deteriorate over time, am I right in thinking that this isn't a controversial area?

     
    and

     

    Whether or not buying high-end caps instead of ordinary ones makes an audible difference which is where I am guessing the controversy is.

     

    Have I read it correctly?

     

    Simon 

  • 08-02-2007 7:32 PM In reply to

    • Puncher
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    Re: Capacitors

    wirralsimon:
    Puncher:

    As in all things HiFi there is a lot a bo**ocks talked about capacitors (similar to cables etc). I agree with yachadm in principal but I would be wary of some of the prices of some of the so called audio-grade caps - many are priced for selling to the cable brigade!

    For a decent, unbiased read on the effects of various types of capacitor see HERE

     

    Are we discussing two things here?

     

    There are problems caused by capacitors if they deteriorate over time, am I right in thinking that this isn't a controversial area?


    and

     

    Whether or not buying high-end caps instead of ordinary ones makes an audible difference which is where I am guessing the controversy is.

     

    Have I read it correctly?

     

    Simon 

    Sorry - yes. there are two different issues. Yes electrolytic caps age and need replacing, but what with?? For crossovers then at least bipolar electrolyitcs, obviously rather than polarised, but most film caps would be better (if you can live with the size incease). The debate starts when replacing with bipolar electrolytics - how much better are the really expensive "Audio" grade caps than run of the mill bipolars?? My answer is that, for the same capacitance,  if the voltage and temp ratings are OK, then negligable! The parasitic effects of electrolytic caps are well understood and if the design was properly dimensioned at the off then paying (vastly) over the odds for "specialist" replacements gets you exactly nothing!

    There are those that will argue strongly but I will in turn ask for objective proof that these parts make better "pass through" elements than "standard " off-the-shelf bipolars from a reputable manufacturer, and when someone comes up with a scientifically sound answer then i will post her to alter my opinion. (I'll sleep soundly tonightWink)

    Generally speaking, you aren't learning much if your lips are moving.

  • 08-03-2007 4:48 AM In reply to

    Re: Capacitors

    Perfect!

    Thanks a lot Big Smile!!!

     

    Now I have a Beocenter 7002 to repair and from this topic I discovered some important details, now is time to start changing capacitors and  try some little modifications using different caps type. I don't want to transform my Beo to a Frank & Stain, this is a fix point!

     

    Regards again

     

    ciao ciao 

    Eugenio Colazzo

  • 08-03-2007 6:28 AM In reply to

    • Dillen
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    Re: Capacitors

    I don't want to comment much in this thread but agree that
    quality of capacitors matters.
    Mainly in preamp, tonecontrol and other line-level (and below)
    circuits where signals (and eventual noise/distortion etc.) are to be amplified.
    Die_Bogener shows it perfectly in the mild rebuild of the
    Beomasters and CD players in the workshop section.
    This is not at all b*****ks, it makes perfect sense.
    I've done a few myself and it does clear up things. Even better
    is the opamp conversions he does but that's a different story.

    The crossover capacitors (ROE type EN) are original and, I believe, bipolar ones.
    I've seen several bipolar caps with polarity markings.
    Also metal propylene caps as low as a few pF's can have
    polarity markings.
    The markings merely show which end is the shielded one (connected to the aluminum can or outer layer of metal foil).
    In our world, dealing with low-impedance signals that needs no
    further amplification, it doesn't make much difference as long
    as the cans are not physically touching when mounted.

    I agree with Puncher in that we have no need for "audio-grade" caps here.
    The main problem is not the caps initial build quality but the degrading over time.
    Any good quality bipolar cap will do fine and fitting components
    of a bit higher voltage rating will ease the stress.
    The readily available kits contain 100V components and it will be fine
    for all standard setups without "overkilling".

    Martin

  • 08-03-2007 7:03 AM In reply to

    • Puncher
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    Re: Capacitors

    I did not mean to give the impression that the type and quality of capacitor did not matter - the b******ks I was referring to was the over-hyped electrolytic parts from certain suppliers with supposedly exotic seperators and electrolytes etc for which hugely dubious claims are made regarding their abilities in an audio circuit.

    As for parts for signal processing and conditioning then yes, it is important that the most approprate device is selected whose specifications best match the desired performance of the circuit - careful consideration of the parts data sheets is required.

    Generally speaking, you aren't learning much if your lips are moving.

  • 08-03-2007 10:15 AM In reply to

    Re: Capacitors

    We all know, that Hifi equipment and magic spells have something in common ;) A lot of dealers earn a lot of money with this equipment, not telling us everything where the parts come from and their production and the technical data..

    I believe that the own ears are the best tool to decide wether the sound improves by a modification or not. I dont know how to measure "Sound". Measuring distortions, clitches or other things can show how good an amplifier can reproduce a CD, but i have the feeling that not always the most expensive thing is the best one... but a lot of dealers live from this idea.

    We also know that even B&O has to earn money. And there are not only enginiers but businessmen ;) So often not the best part is used, but the cheaper one. And that's why we are here :)

  • 08-06-2007 12:15 PM In reply to

    Re: Capacitors

    Never buy NOS Capacitors?

    Some years ago I had a new reisue Fuzz Face (one of the first guitar overdrives) that needed a tuneup as it did not sound as good as my original 70s one.

    There is only small printboard and 2 volume controls basically so I modified it with a Hendrix schematic and B108 capacitors which decide the output. I did mention the B108 capacitors to my repairman and the next time I met him he had a couple. How old I don't know.

    The B108 needed to be mesured for the right value before soldering them on.  

    One of the problems with those FF pedals back in '66-'67 onwards were the capacistors value were night and day. So out of say 50 units 3 might sound good. As for Jimi he got them modified.

    My modified FF sounds like the 70s one but less noise.

     

  • 08-06-2007 12:51 PM In reply to

    • yachadm
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    Re: Capacitors

    I'm not familiar with a B108, but a basic fact of life (electronically speaking), that of all electronic components, Electrolytic Capacitors have the shortest lifespan of all.

    As an Electrolytic capacitor ages, the electrolyte dries out, or alters its consistency.

    Thus, it loses its ability to "capacitate", and becomes a resistor, or in the worst case, becomes a "short".

    The correct measure of a capacitor's health, is not its capacitance, but its ESR (Equivalent Series Resistance).

    Generally, the older a capacitor, the more its ESR increases (while its capacitance may remain within acceptable limits).

    There are only a few (relatively) inexpensive ESR meters made

    http://members.ozemail.com.au/~bobpar/esrmeter.htm

    http://ludens.cl/Electron/esr/esr.html

    http://www.peakelec.co.uk/acatalog/jz_esr60.html

    See any reputable capacitor manufacturer's datasheets regarding capacitor life.

    Which means simply - buy only recent production caps, and never NOS units.

    IMHO, I'm not aware of any exceptions to that rule.

    Learn from the mistakes of others - you'll not live long enough to make them all yourself!

  • 08-06-2007 4:02 PM In reply to

    Re: Capacitors

    Yes, that's right. An electrolytic capacitor has the shortest lifespan of all electronic parts. 90% of all defects in a B&O tv is a defect of one of these capacitors.

    The standard elko with 85 degrees specification survives just around 1000-2000 hours at 85 degrees environment. That's not very much... in a tv this temperatures are very common. Every 10 degrees more or less halfe or double the lifespan. Of course there are certain influences causing some more effects...

    That's one of the reason why i like 105 degree types... they last around 4 times longer.

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