What to look for when upgrading capacitors?

Discussion in 'DIY' started by Ryuji, Oct 17, 2020.

  1. Ryuji

    Ryuji New

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    Yo

    I'd like to upgrade some of the electrolytic caps of my headphone tube amp.

    djPUgjo.jpg

    Do i only have to look for the same microfarad value and maximum rated voltage? Or does the type of capacitor matter aswell?

    Do you typically also upgrade the big red caps (i believe they are Nichicon Chemicon)? I only found "audiiophile" capacitors from Mundorf with those values, but they are electrolytic aswell.


    Except transformers and wires, what would be some other good things to upgrade?

    Please let me know if it's not displaying the image, i may have uploaded it twice and can't delete them by editing the post.

    Cheers
     
    Last edited by a moderator: Oct 17, 2020
  2. lehmanhill

    lehmanhill Almost "Made"

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    Hi Ryuji,

    Just a reminder. If you haven't yet, you should introduce yourself on the new members thread.

    You and I don't get photo posting pictures privileges, yet. The way to do that is to post your photo somewhere else online, for example, Google Photos, then insert a link to the photo in your post.

    Regarding the big red caps that you mentioned, they are likely power supply caps to smooth out the DC in the power supply. In addition to capacitance, voltage, and things like size and lead spacing, something to pay attention to is ESR or equivalent series resistance. If an amp calls for more power, the power supply caps need to be able to provide that that power very quickly or the amp can't correctly provide the amplified signal. If the internal resistance of the cap is high, the cap responds more slowly. The Mundorf caps you mentioned often have a rated low ESR, for example, 7 mOhms for a 10,000 uF cap. And, of course, they are very expensive.

    As for other electrolytic caps in your amp, those in the signal path are likely to have the biggest affect on sound. Ideally, there wouldn't be any electrolytic caps in the signal path, at least in my opinion. But tubes often need them and which caps are an upgrade may be very hard to tell.

    My advice to you is to find sources or forums that have your exact amp and learn what other people have done to improve the sound of their amp. It may be that the caps in your amp are already pretty good and your money could be better spent elsewhere. After all, tubes themselves have a great difference in sound, so a little tube rolling might be a good choice. At the moment, I am breaking in a pair of early 1970's Siemens 6922 tubes in my dac and they are sounding sweet. Of course, they cost twice as much as the tubes I removed.

    Good luck and enjoy.
     
  3. Ryuji

    Ryuji New

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    hI Lehmahnhill

    Thank you for your kind answer and good advice.

    Yes, the Siemens 6922 are indeed very sweet sounding, i have a Siemens cca myself. Although, i currently prefer the Reflketor 1975 SWGP (Holy Grail), then 2 Hungarian Tungsram El84 and a Svetlana 5u4g rectifier. I think that's pretty much endgame as far as tube goes.

    Anyway, this is the interior of the amp.

    https://imgur.com/a/eWSftSj

    To be a bit more specific, the idea was to replace the big 450v 220uf rated ones, (i believe they are from Chemicon) the horizontal black ones are german made F&T (22 uf 500v). No idea about the vertical black ones.

    These are the Mundorfs https://www.hificollective.co.uk/components/mcap_mlytic_hv.html that would replace the big ones.

    I actually don't know which ones are the power supply caps and which ones for the signal.
     
  4. purr1n

    purr1n Desire for betterer is endless.

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    I wouldn't bother replacing those big caps unless those caps are old and bad.

    They look like PS caps. Those big Mundorf 'lytics you linked are extremely expensive. Better off taking that money and saving it up for a better amp or getting better output transformers. The most "boutique" I would ever go on those kinds of caps is audio grade Nichicon or the low ESL Pannys.

    Unless you know exactly what you are doing, it's a crapshoot, a very expensive one if using boutique parts. In fact, because of the evidence of other high-quality parts in strategic locations on this amp, it's likely that the designer intentionally selected each part for a desired voicing. You may very well end up making it sound worse.

    There was a member here who replaced 'lytic caps or paralleled expensive quality boutique film caps with bigger 'lytics in his EC AF, the cathode bypass caps on the output tubes (and many other places). All he ended up doing was making it sound different (actually worse to my ears).

    This isn't Head-Fi where folks replace a random part or two (without knowing WTF they are doing) and then announcing that is suddenly sounds great because it sounds different. IME, without understanding what one is doing, there is no difference 50% of the time, and other 50% when there is a difference, 50% of the time it sounds worse.
     
    Last edited: Oct 17, 2020
  5. fastfwd

    fastfwd Friend

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  6. lehmanhill

    lehmanhill Almost "Made"

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    Now that I can see the picture and you have identified the caps, I agree with Marv that the caps in your amp have likely been picked for voicing and that you could just as easily change the sound for the worse. For example, the F&T axial caps are not your typical Mouser or Farnell source and were very likely selected for their sound.

    If it helps, Nelson Pass used $4 Elna Slimics in the signal path of his $10,000 amps. It doesn't have to be expensive to work. Anyway, have fun whatever you choose.
     

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