Philips KT347 Radial "Mustard" Capacitors... Any good?

Discussion in 'The Workbench' started by 67Mopar, Jun 26, 2019.

  1. 67Mopar

    67Mopar Well-Known Member

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    I'm thinking about replacing the China made caps in my AC15 with these. Does anyone have any experience with these capacitors? Given the size of the stock axial signal caps, there's no way they can be foil/film. I figure these may be a worthy alternative. I considered using NOS axial Mullard mustards, but they're just too darn big.

    [​IMG]
     
  2. ampmadscientist

    ampmadscientist Well-Known Member

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    Polyester Film Aluminum Foil, Crimped Radial Leads, metalized paper and polyester film dielectric, those capacitors have 10000 V/uS pulse rise time, values that are typical for high quality polystyrene and polypropylene capacitors. High values of pulse rise time provide excellent quality audio blah blah blah.

    I found some for $1 each if you want em.
    https://www.partsconnexion.com/mustard-vintage-film-capacitors.html
     
    Last edited: Jun 26, 2019
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  3. 67Mopar

    67Mopar Well-Known Member

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    Thanks! The ones I need are .1uf 400V and .022 400V. I found some .022 250V, but I can't use them in the tone stack. Has to be 400v. I found some Philips MKT .022 400V, but they are orange.
     
  4. 67Mopar

    67Mopar Well-Known Member

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    Ended up going with CDE 150 series polyester axial caps. Same as Mallory 150, I think?
     
  5. ampmadscientist

    ampmadscientist Well-Known Member

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    The orange caps are still pretty good for audio.
     
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  6. ampmadscientist

    ampmadscientist Well-Known Member

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    I think they are basically the same.
     
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  7. ampmadscientist

    ampmadscientist Well-Known Member

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    I think the ones to get are Packtron.

    [​IMG]

    I have no idea why they sound so good, and what the difference is in construction and materials.
     
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  8. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    I have used those Philips mustard radials ( I used 630volt rated) with great results, though like all mustards they are very smooth, but usually exhibit a darker tone.

    I've used the Philips MKT in a .1uF 400V, and they are very transparent. The orange MKT .1uF Phillips had a very low noise floor when checking outside foil ends.
     
    Last edited: Jun 27, 2019
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  9. FourT6and2

    FourT6and2 Well-Known Member

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    My favorite signal caps in amps are the ERO MKT1813
     
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  10. fifteenohms

    fifteenohms Well-Known Member

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    Forget "what do they sound like" - they have no sound at all.

    Capacitors do not "sound like" anything.

    Without an LCR meter its just a wind-piss trying to figure out how to calculate if a component will affect the circuit or not.
     
  11. fifteenohms

    fifteenohms Well-Known Member

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    Why are these your favorite brand, and by how much in your calculations are they superior?

    Quanitify. Its a math-thing, not a feel-thing.
     
  12. 67Mopar

    67Mopar Well-Known Member

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    Sure they do. It is especially noticeable when using a MV circuit (preamp distortion), or pushing the power section into clipping. Per my experience, signal cap changes are mildly noticeable when playing clean. Filtering plays a roll as well. With power filtering, it's a feel thing... Attack, sustain, and release. i.e. Loose - snug - tight. :naughty:
     
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  13. 67Mopar

    67Mopar Well-Known Member

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    I discovered that I can't use radials, as they would sit too close to the preamp tubes. I don't know what VOX used for axial signal caps, but they are small. SOZO caps are too large to fit between the turrets. I don't want the caps suspended off the board, so I had to track-down some caps that don't exceed 20mm in length. The CDE polyesters fit the bill perfectly. I had to up the voltage on the .022 caps to 630V, as Mouser doesn't stock the 16mm .022 400v caps. Should be fine.

    Here's an AC15 Heritage that Psionic modified with SOZO caps... While they do good work, this type of refit just isn't acceptable. Not for me anyway.

    [​IMG]
     
    Last edited: Jun 27, 2019
  14. fifteenohms

    fifteenohms Well-Known Member

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    Discrete components have no inherent tonal qualities,only their values ranging affects the circuit's equation.
     
  15. Guitar-Rocker

    Guitar-Rocker Well-Known Member

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    I've heard that argument before. My ears say that is just wrong. After building hundred of amps and fine tuning them to their best tonal qualities, I know there are distinct differences, within the exact same values. But to each their own belief.
     
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  16. FourT6and2

    FourT6and2 Well-Known Member

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    Been there done that. Built plenty of amps and A/B'd different types of resistors, caps, transformers, etc. in every single position of an amp and swapped out parts in real-time to compare. I know what parts work for me in the amps I build to get the sound I like and I know why they sound different, but I'm not about to write a dissertation about it.
     
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  17. 67Mopar

    67Mopar Well-Known Member

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    Using this logic, I asked my local supplier to price-match his NOS Mullard 12AX7's to the Mullard reissues... He refused! I then asked him to price-match his NOS "mustard" caps to equivalent value SOZO's, but again, he refused. WTF is wrong with this guy? Should I ask about his USA and Japan made J-FETs, or just write him off as an idiot?
     
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  18. ampmadscientist

    ampmadscientist Well-Known Member

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    Discrete capacitors and other components definitely (beyond any doubt) have their own sound.
    Which is probably why "mustard caps" are so sought after.
    And also why I will use Packtron capacitors (it made a huge change in the sound).

    Further, parts on the board radiate into each other depending on layout, which also radically affects the final tone.

    Which is also why I am using F&T filter caps, which noticeably affect the final sound quality, etc....

    Anybody who tells you otherwise - lacks the experience to know better.
     
  19. ampmadscientist

    ampmadscientist Well-Known Member

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    I wouldn't buy "Sozo" capacitors, which have no specifications sheet and no stated ratings.
    I am very suspicious of undocumented parts, which are made by non-identified manufacturers in un-specified countries....
     
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  20. fifteenohms

    fifteenohms Well-Known Member

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    The both of you:

    How do you measure value drift?
     

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