Capacitors

Discussion in 'DIY' started by purr1n, Mar 14, 2017.

  1. k4rstar

    k4rstar Britney fan club president

    Pyrate BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    6,941
    Trophy Points:
    113
    Location:
    Toronto, Canada
    I have the Miflex KFPM in my 45 amp as coupling caps which use straight polypropylene film instead of polypropylene in oil for dielectric. Very even and lively sound. Too much of it at first but that evened out with break-in.

    I would like to try, either in this amp or a future project, Arizona Capacitors 'cactus' line which are popular among Japanese hobbyists for their tone and organic qualities.
     
    Last edited: Jul 27, 2019
  2. evonimos

    evonimos New

    Joined:
    Jul 8, 2020
    Likes Received:
    13
    Trophy Points:
    3
    Location:
    Athens
    Hi,

    I am waiting for some soviet teflon 0.1uF and 1uF polystyrene to arrive. Heard good things about them. Will try them along my other USSR caps.

    I have installed several of those ex-Soviet PIO and PEPT caps in my projects and like their sound.

    I use them in coupling duty and have them in parallel with film caps and/or other PIOs. Film cap of choice are usually green NOS ERO 1813 of larger values. They are polyester film but i prefer them to several polypropylene ones.
     
  3. skem

    skem Friend

    Pyrate
    Joined:
    Nov 1, 2017
    Likes Received:
    1,911
    Trophy Points:
    93
    Location:
    Charles River
    Sadly Miflex seems to have gone up in price.

    The cheapest acceptable coupling capacitors I have found are 940 series Cornell Dubilier, but still far from being as good as some of the fancy audio-grade caps.

    From my prior testing, I found that one cannot generalize sound to polyester and polypropylene. Sound is much more about construction design than the materials. It's hard to do material-to-material comparisons because they rarely have the same design.
     
  4. k4rstar

    k4rstar Britney fan club president

    Pyrate BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    6,941
    Trophy Points:
    113
    Location:
    Toronto, Canada
    yes this is true about construction but I would still say the dominant sound character of a capacitor is determined by the dielectric material. polypropylene has clarity in the entire frequency range but a roughness of sound compared to oil-soaked paper. oil-soaked paper will not have the same clarity at the frequency extremes but the better examples have a noble sound character and no unnatural treble characteristics. it also matters of course where the capacitor is being used. the Miflex KFPM I noted above were always treble-tipped.

    I am restoring some 1950s tube equipment and becoming anal retentive about the capacitors that need replacing. I do not like the exotic sound of modern boutique audiophile capacitors and they upset the balance of sound when placed in vintage circuits. the best choice seems to be hunting ebay for period correct parts in the values I need but this is slow and cumbersome. the best modern choice for large recapping jobs seem to be Orange Drops which are now manufactured by Cornell Dubilier. I wonder how the 940 series you mention compare to the Illinois Capacitor film line, also owned by CDE. I have seen these used by several techs when restoring old tube electronics.
     
  5. skem

    skem Friend

    Pyrate
    Joined:
    Nov 1, 2017
    Likes Received:
    1,911
    Trophy Points:
    93
    Location:
    Charles River
    I can send you some CDE 935’s and I have some 940’s coming. I only test coupling and generally in the 3.3-10uF range, which makes access to samples expensive.

    For vintage, beware of PCBs.
     
  6. evonimos

    evonimos New

    Joined:
    Jul 8, 2020
    Likes Received:
    13
    Trophy Points:
    3
    Location:
    Athens

    I have a 3.3uF from that series by Cornell and they do sound OK but I still prefer Vishay MKT1813.

    And I agree that dielectric material is not the only defining feature.
    They all sound different even though they appear almost identical in specs/materials etc.
     
  7. batriq

    batriq Probably has made you smarter

    Pyrate
    Joined:
    Oct 31, 2015
    Likes Received:
    1,041
    Trophy Points:
    93
  8. k4rstar

    k4rstar Britney fan club president

    Pyrate BWC
    Joined:
    Jun 11, 2016
    Likes Received:
    6,941
    Trophy Points:
    113
    Location:
    Toronto, Canada
    thanks, my current project is a mono Bell 2122 amplifier, circa 1949, no PCBs here! this was a $100 barn find, although the knobs are not original the inside is and very clean. most of the ones I have seen have been completely re-capped.

    I found an ebay seller offering a re-cap kit with the aforementioned Illinois Capacitors https://www.ebay.com/itm/64155405353

    ordered it because I want to get this thing going ASAP.

    [​IMG]
     
  9. evonimos

    evonimos New

    Joined:
    Jul 8, 2020
    Likes Received:
    13
    Trophy Points:
    3
    Location:
    Athens
    Thanks for the suggestion.
    I'd also like to try Cerafine for filtering in power supply.
    I use Silmic II for cathode bypass duties since they can still be found pretty easily.

    Will be trying teflon caps for the first time, when those 0.1uF soviets arrive.
    Most folk seem to like them but the consensus is that they require some extra time to burn-in.
    What's your take on that?
     
  10. skem

    skem Friend

    Pyrate
    Joined:
    Nov 1, 2017
    Likes Received:
    1,911
    Trophy Points:
    93
    Location:
    Charles River
    looking forward to a cap report. I have 4 different new ones coming. All affordable. I’ll write up notes.
     
  11. murray

    murray Friend

    Pyrate
    Joined:
    Sep 29, 2015
    Likes Received:
    478
    Trophy Points:
    63
    Location:
    N.Z.
  12. ergopower

    ergopower Friend

    Pyrate
    Joined:
    Mar 21, 2018
    Likes Received:
    815
    Trophy Points:
    93
    Location:
    South Central PA
  13. murray

    murray Friend

    Pyrate
    Joined:
    Sep 29, 2015
    Likes Received:
    478
    Trophy Points:
    63
    Location:
    N.Z.
    Please refer to @skem ’s post. ... “beware of PCB’s” for old capacitors.

    Beware of ambiguous TLAs ;-)
     
  14. m17xr2b

    m17xr2b Friend

    Pyrate Banned
    Joined:
    Mar 26, 2016
    Likes Received:
    3,988
    Trophy Points:
    93
    Location:
    United kingdomland of fish and chips
    I hate that caps have a sound and have to painstakingly try and choose which is top 5% for any specific application.
    My theory is construction and materials are the best indicators so broadly speaking the hierarchy goes like this:
    - generic electrolitics e.g. nichicon
    - audio electrolitics e.g. jensen, unicon
    - mkp(broad variation from the industrial epcos,wima,kemet to mundorf and other posh brands)
    - mkp oil(even broaded variation with considering the mundorf variants, silver, sgo, evo etc.). The damping properties of oil are what makes it better than the plastic variants(again broadly speaking, ClarityCap MR,CMR,TC are exceptional)
    - aluminium foil PIO
    - copper foil(my preferred for signal)
    - stupid foil(silver, tin and other hyper expensive ones)

    For coupling caps copper foil is the way to go for the midrange purist regardless of brand, tin aka Vcap for the detail freak yet I didn't enjoy the TFTF as much as the miflex KPCU.

    I'm beginning to be an advocate of 90%+10% caps for large values where a single one is prohibitively expensive or not possible due to cost/size.
    Take my recent experience with the mundorf supreme silver gold oil 4.3uF:
    It's an extremely good capacitor but the rest of the system has to be considered otherwise the amp can fall into to over detailed category. Using it in the signal path as a parafeed cap
    Positives:
    - reference class low end, lets the power supply shine
    - reference speed, detail and air. If placed properly it's a remarkable experience in technicalities.
    - compact size for value and high voltage dielectric
    - exceptional depth of instruments
    Negatives:
    - upper treble focused, the HD650 never sounded better but was suspiciously neutral and other headphones were overly bright. Still a fantastic stock HD650 experience.
    - lacks mid range harmonics, cool sounding which IMO is a neutral/negative mark. Stellaris is o so yummy and I suspect the duelund CuAg coupling caps have a large part to play.

    Earlier today I switched the parafeed cap to a clarity cap MR 2.7uF 630V.
    Positives
    - better tonal balance without the upper treble enhancement and more enjoyable tone wise
    - at less that 1/4 price it's 89% as good but in a different way, no slouch
    - airy, great separation but not reference
    - almost reference low end as it still let the power supply shine
    Negatives
    - less detail than the mundorf, not by much but the wanting feeling crept in
    - borderline grainy background by comparisons, mundorf was inky black
    - lack of ultimate highly defined separation

    To conclude I bypassed the px4 50uF Jensen oil 250V MKP cathode bypass caps with the mundorf supreme sgo. I believe the bypass cap is in the signal path and crucial to the overall sound. Weirdly the same characteristics apply just 80% as much(or it's 80% due to the larger cap mix).
    Anyway I got the best of both worlds, the insane airy, separation and detail of the sio with the neutral tone of the MR without the upper spike. I can safely say I've found my cathode caps if they need to be used.

    For any cap review consider where it's placed and where you want to use it.
     
    • Like Like x 3
    • Epic Epic x 1
    • List
  15. evonimos

    evonimos New

    Joined:
    Jul 8, 2020
    Likes Received:
    13
    Trophy Points:
    3
    Location:
    Athens
    You did well.
    I also think the bypass caps are part of the signal in broader terms.

    In any case It definitely affects the sound. How much I can't quantify exactly, but it does.
    I've also bypassed the some ELNA SIlmic II electrolytic bypass caps with a plain film cap (MKT1813) and It sounds nicer but the possible combinations are obviously endless..

    Another capacitor I forgot to mention that has performed surprisingly well on a tube RIAA in output coupling duties is the metallised paper series by RIFA. It is an older design that comes in an encapsulated rectangular case with some king of resin. It did improve the mid range and was pretty smooth and dynamic compared to either the MKT1813 and the polypropylene yellow axials by KEMET.

    All the above are pretty reasonably priced and can be found rather easily so it makes for an easy experiment.
    However, I would love to try a Jensen PIO or a Mundorf oil variation when budget allows.
     
  16. m17xr2b

    m17xr2b Friend

    Pyrate Banned
    Joined:
    Mar 26, 2016
    Likes Received:
    3,988
    Trophy Points:
    93
    Location:
    United kingdomland of fish and chips
    I want to try and remove the bypass cap, well see how well that goes. A full array of silicon carbide cree diode bias to provide anywhere from -30 to -40 adjustable fixed bias. I know putting so many diodes in series will hurt the sound quality, more so than using a cap? I'll have to see. Using a small resistor 100-200ohm wouldn't hurt and provide extra stability.
    Here's the bias boards, two will need to be used with adjustable jumpers.
    [​IMG]
     
    Last edited: Jul 15, 2020
  17. evonimos

    evonimos New

    Joined:
    Jul 8, 2020
    Likes Received:
    13
    Trophy Points:
    3
    Location:
    Athens
    I think it will affect gain of that stage (will lower it) and affect the output impedance (increase it).
    In qualitative terms i'm not sure how it'll affect sound though.
     
  18. m17xr2b

    m17xr2b Friend

    Pyrate Banned
    Joined:
    Mar 26, 2016
    Likes Received:
    3,988
    Trophy Points:
    93
    Location:
    United kingdomland of fish and chips
    ^ gain is only affected if just the resistor is present so no low impedance AC path to ground and the cathode resistance is added to the tube plate one and messes up the operating point.

    This is enough of a sample size to get an idea of how coupling caps affect the sound. Miflex is easily top bang for buck.
    [​IMG]

    Parafeed caps, now matching with the coupling one, tinned copper foil oil impregnated.
    [​IMG]
     
    Last edited: Jul 17, 2020
  19. skem

    skem Friend

    Pyrate
    Joined:
    Nov 1, 2017
    Likes Received:
    1,911
    Trophy Points:
    93
    Location:
    Charles River
    I just tried the Vishay MKT1813 and I have to agree. These are excellent. Better than my Audyn Plus and better than the Cornell Dubilier (CDE) 9xx series. The older green body ones (including the pre-Vishay ones made by ERO Roederstein) sound better; the newer yellow body ones seem to have excessive sharpness to them. Also better than the new CDE UNL series, which I also tried. The UNL are very high performance caps and measure well but sound almost indistinguishable from the CDE 9xx series.

    Thanks @evonimos!
     
    Last edited: Jul 25, 2020

Share This Page