Capacitors

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

  1. spwath

    spwath Collegiate hijinks master

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    yeah, It's literally a peice of foil and an insulater, wrapped up. Can't cost more than a few $ to make..
     
  2. dubiousmike

    dubiousmike Friend

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    Depending on how many amps you are are planning on, it might be interesting to find out what RTI would charge to roll a batch of custom teflons akin to what they produce for ARC and others. Given that several of us were able to score cast-offs for our mainlines from TCtubes at $80/ea, the price per cap must be fairly reasonable, and they are damn nice.
     
  3. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    This ever go anywhere? I know I like the sound of old Russian Paper-in-Oil caps but I've been curious to pop in something a bit more premium in an MHDT.
     
  4. msommers

    msommers High on Epipens

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    I'm likely getting a custom preamp made with Jupiter copper foils after lots of good feedback vs the beeswax and others. I initially wanted Mundorf gold silver but was told they were worse. Then I was told to go the theta/teflon as they're just as good and cheaper as the Jupiter. Still I'd like to go balls to the wall with Duelands but he said it's insane and the 2.2uF I need are basically coke cans!
     
  5. JoeBinx

    JoeBinx Rando

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    ugh, nothing but praise for those Jupiter coppers... they are haunting me, can't really justify spending $60 per cap when I need two and my base unit only cost $180ish. Not now, not as my first soldering/hard-modding attempt

    is there any real difference in the el Cheapo capacitors, are there some better than others in that $2-10 range
     
  6. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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    Don't do that with a cheap piece of electronics, expensive caps are a rip off by and large. Sure they can sound better, but spend proportionately.
     
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  7. msommers

    msommers High on Epipens

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    Have you guys heard of DuRoch caps? I can't find a damn thing about them online other than PrimaLuna uses them in the power and signal path. The Mundorf GoldSilver EVOs in the output are decent but nothing like Jupiters (sadly I don't think replacement 2.2uF will fit).

    [​IMG]
     
    Last edited: Sep 4, 2017
  8. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    I wouldn't recap a cheap unit. It's not like they can make something mediocre great.
     
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  9. Mban

    Mban Almost "Made"

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  10. JoeBinx

    JoeBinx Rando

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    Well how do you define mediocre?

    At those entry level price points what are the compromises, I see there are $2 caps and $70 caps? The idea with recapping a cheap unit is to see how much a difference it makes, if it does make an improvement, I'll replace other parts and see what difference they make, so forth and so on. Since I've never modded anything, I don't intend to buy something expensive and wind up destroying it, Worst comes to worse I destroy it and I'm only out a hundred or so dollars, as opposed to have a much higher loss!!! On a more expensive unit. On the other hand with a cheaper unit I'm curious to see what each component I replace does to the sound. Some people feel that the Caps are where cheaper unit's cost costs. So in apparently in some cases you have a good design held back by a few poor components, I intend to explore that line of thought and see what happens.

    Frankly I'm tired of listening to peoples impressions, I've got the funds and the time to hear for my self what difference can be had so I intended to learn through trial and error. Though @HitmanFluffy I like the idea of spending proportionally. I certainly intend to start there, and depending on what difference is gain'd I may even stop there. Won't know till it's done
     
  11. Mban

    Mban Almost "Made"

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    If you show us an image of the internals of your unit we may be able to advise on which cap positions may make the most difference and to spend a little more on |\/|
     
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  12. willsw

    willsw Friend

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    We recently did some cap rolling on our ZOTL40. The best ears among us correctly identified, without hesitation, which amp with which cap even after we randomized the amps and used different speakers, so I'm pretty convinced, in addition to what I heard. In our amps the Jumpiters (the Hi-tech ones, I think) were beautiful and detailed, but had a bit too much high end, which is a problem with ZOTL stuff. We've been using KT77s and they might be a perfect match for EL34s. Mundorf top of the lines were overall winners, with all good everything (sorry about the shitty descriptions, this was a while ago). V-caps also had great detail and were overall excellent, but the price was always there. The Deulund JAM caps were not very interesting, nor were the Audience Auricap. The Audience teflon cap didn't come in the right value.

    We've also been doing some cap rolling in the MZ2, and the Mundorf electrolytics open things up and are a significant improvement, we just have to figure out how to fit the fucks in there.
     
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  13. sphinxvc

    sphinxvc Gear Master (retired)

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    Aiy guys, I was reading over some tube amp safety tips (I plan to pop the hood of my A318B soon), and I came across this statement about caps:

    "Electrolytic (and other type) filter capacitors can hold lethal charges - be sure to discharge them before working on an amplifier. This can be done by shorting the "+" side to the "-" side, or the "+" side to the chassis (unless the cap is in a negative voltage supply, like the bias supply, where you must short the "-" side to the chassis), using a wire or a screwdriver. This will make a big spark and a loud noise, which is sure to impress any onlookers. If you'd rather do it more discreetly, make a jumper cable consisting of alligator clips on the ends, with a resistor in series in the middle of the jumper. Use a value of somewhere between 10K and 100K, with a power rating of 5W or so (a high power rating is not really necessary for dissipation reasons, but mainly because the higher power resistors are physically more robust and won't tend to break). Be sure to adequately insulate the resistor with heat-shrink tubing so the wires aren't exposed, or you'll get shocked while trying to discharge the capacitors. The larger the value of the resistor, the longer it will take to discharge the caps, and the less of a spark you will see. If you use a large value resistor, be sure to leave it in place long enough for it to drain all the charge out of the capacitor (if in doubt, measure the voltage across the capacitor to make sure it is close to zero). Note that many amplifiers will incorporate "bleeder" resistors, which will drain the capacitor charge automatically in a few minutes after the amp is turned off. Don't depend on this resistor to do it's job!"​

    How many of you actually do this?
     
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  14. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    I'm too lazy to do that, but I leave everything off for at least 24 hours before working on it and I ground myself before touching anything.

    I assume I'm doing it wrong.
     
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  15. Mban

    Mban Almost "Made"

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    I would highly suggest doing both: Leave the piece of gear off and unplugged for some time (e.g. 1-2 hours min), and also use a resistor to bridge the terminals of the caps. If tube gear, make sure that the resistor is rated to handle the voltage held in the caps.
     
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  16. HitmanFluffy

    HitmanFluffy Hoping to see real genitals someday!

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    Hell yeah I discharge my lytic caps. It's fun.
     
  17. Luckbad

    Luckbad Traded in a unicorn for a Corolla

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    I figure a couple of alligator clips, a resistor, heatshrink, and a bit of wiring... Cheap and easy to make. I'll do it next time.
     
  18. Elnrik

    Elnrik Super Friendly

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    I lick the terminals. You should try it. The taste will blow your mind.
     
  19. murray

    murray Friend

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    Using a resistor is vital. Jumpering with a dead short, while creating an impressive spark, can permanently damage or degrade the capacitor due to the massive instantaneous current. I learnt this decades ago when repairing computer power supplies with capacitors the size of baked bean cans.
     
  20. Riotvan

    Riotvan Got lost for three weeks at Delft City Hall

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    I have an old custom headphone tube amp that is at least 15 years old maybe even closer to 20. Do you guys reckon it's time for a recap? As far as i can tell it only uses electrolytic caps from Rubycon and Jamicon and some others.
    What do you guys think?
     
    Last edited: Dec 8, 2017

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