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Mil Spec Ag-Pd Tantalum Caps anyone?

Discussion in 'd.i.y.' started by Jonathan, Jun 10, 2019.

  1. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    PSRR is pretty good in he Naim circuit and has zilch to do with feedback caps.
     
  2. sq225917

    sq225917 situation engineer

    You must be looking at the magic -90db psrr version that naim never made... ;-)
     
  3. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    It's not that bad and far from the worst of its ill's... and still unrelated to feedback caps
     
  4. Dougunn

    Dougunn pfm Member

    Jonathan

    Without wanting to be too pedantic :), my point is that 'mil-spec' means nothing per-se (and is frequently used to suggest high quality). It is not however an actual specific specification. What we are talking about here is tantalum capacitors; to say they are 'mil-spec' without saying what the specific military specification is tells you nothing. For example a 'tantalum capacitor of 10uF +/-0.1uF at 20 centigrade' would be the begining of a specification.
     
  5. sq225917

    sq225917 situation engineer

    Reread what I said. I didnt say the caps affected the psrr, I said they were particularly audible because of the low part, effect not cause.
     
  6. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I know what you said... doesn't matter..
     
  7. Jonathan

    Jonathan pfm Member

    indeed!

    if the term 'mil spec' upsets you - maybe you would be so kind as to suggest another term i use ... personally i just found it kind of handy ....
     
  8. Dougunn

    Dougunn pfm Member

    Maybe just state the actual spec! Clear, unambiguous and actually useful!
     
  9. 337alant

    337alant Negatively Biased

    The mil specs for wet tantalums M39006/22 & M39006/25 are focused on reliability and failure rate to operate for a time / Temp within a specific value
    The caps are rigerously type tested for compliance with the standard, so you do get a good quality cap that meets the requirements of the spec.

    In the Naim clone amps I do only use a 68 - 100 uf Wet tantalum for the Feedback position as it just sounds right to me and I disagree about colouration comment they are very transparent IMHO. solid tantalums are a different animal (Yuk)
    For the input cap no cap sounds best

    Alan

     
  10. Jonathan

    Jonathan pfm Member


    Glad i used a 68µF wet tantalum in the feedback of my Qudos boards - perhaps it was even on your recommendation (?) - so far i like what i'm hearing for the most part
     
  11. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    Add a DC servo and the cap can be a 0.1uF polyprop;)
     
  12. Dougunn

    Dougunn pfm Member

    YES! An actual spec! Just so happens to be military, but with this it is possible to determine how good/bad they might be in an audio application.

    I'll butt out now! I've hi-jacked this thread with my pedantry enough already :)

    Doug
     
  13. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    No it isn't! If building a missile guidance system it may be of help in knowing the parts can withstand the G force and heat but it has bugger all to do with hi fi applications and potential sound quality.
     
    glenn jarrett likes this.
  14. Dougunn

    Dougunn pfm Member

    But that is my point, now you can look at the spec and see if it addresses the parameters that might affect sound quality.

    It might as easily be a spec for a cheap low-quality component as a super dooper one. Without stating the specific spec how would you know?

    D
     
  15. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    And what would those be? :rolleyes:
     
  16. Dougunn

    Dougunn pfm Member

    I have absolutely no idea! But I'm sure you know what you look for when choosing components
     
  17. Arkless Electronics

    Arkless Electronics Trade: Amp design and repairs.

    I choose what I consider to be decent quality for the price but I don't regard passive component choice as particularly important. It is blown out of all proportion by non technical people who obviously don't understand how amplifiers work and what is actually important but can see a big shiny "boutique" capacitor with red and gold writing and a silly price tag and assume it must sound loads better than an already very good industrial polypropylene cap that's a tenth of the price...
     
    glenn jarrett likes this.
  18. Dougunn

    Dougunn pfm Member

    Yes, and my point is that 'mil-spec' is thrown around (like the red and gold writing and silly price) as indicative of quality/suitability, when it is nothing of the sort. Worse still, without stating the specific spec it actually means nothing anyway.
     
    Arkless Electronics likes this.
  19. 337alant

    337alant Negatively Biased

    As I Said in #29 the mill spec is related to reliability and a set of working parameters for a wet tantalum capacitor, this specification has nothing to do with sound quality, its about producing a Wet Tant that is very reliable for a specific application in military equipment, this also has nothing to do with HIFI equipment.
    There is nothing in this spec that will tell you how good the capacitor will sound just how reliable it will be.
    This is a statement from AVX on the typical use for Wet Tants
    The major benefit of wet tantalum is their high bulk capacitance and extended voltage range, for use in high power designs where solid tantalum capacitors are not always suitable. ... In DC applications they can also be used for a wide range of voltage hold-up and timing applications.
    This is a statement from Vishay
    Tantalum electrolytic capacitors are the preferred choice in applications where volumetric efficiency, stable electrical parameters, high reliability and long service life are the primary considerations. The stability and resistance to elevated temperatures of the tantalum/tantalum oxide system make wet tantalum capacitors an appropriate choice for today's technology.

    It just so happens that these wet tants also sound good in a particular application, however new ones from the likes of AVX cost a fortune

    alan
     
  20. sq225917

    sq225917 situation engineer

    Fortunately I have a bag of 47ufs lying round, let me know if you need a pair
     

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