bypass capacitor..........

Discussion in 'Archived Threads 2001-2004' started by Chris Carswell, Aug 17, 2002.

  1. Chris Carswell

    Chris Carswell Supporting Actor

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    I see this a lot in xovers. They would use an inexpensive (Solen or Axon) cap with an expensive film and foil bypass cap (Audiocap or Hovland). I understand the economics of it being that it saves lots of $ over using just a single large value film & foil cap. But what else? I've got a good idea & understanding but want to be sure.
    I take it that it is not something you can figure out with X*Over 3 pro and a Clio system. It is more of a listening exercise, done with a trained ear. From what I can gather, expensive bypass cap adds a little something to the xover for a better sound or to achieve more of a certain tonal balance and improve the effective high frequency performance (since this is done more on tweeters than with mids or woofers). Basically a standard metallized cap wouldn't sound as good.
    That's what I could figure out but please LMK what else there is to know about them.
     
  2. Ron D Core

    Ron D Core Stunt Coordinator

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    I use bypass caps in all my x-overs. I've done side to side comparisons between bypassed and non bypassed caps. The difference that I noticed was the a large cap will limit some of the tweeters information retrieval. Some of the subtle nuances are lost and the the sound doesn't seem to come through quite as clear. All of these are very very subtle changes as far as my hearing can tell. I just use the cheaper Dayton .1's to bypass, I would bother spending 8 to 12 dollars on one. I hear it depends allot on the tweeter too. I have only tried it with the Vifa XT25's.
     
  3. Chris Carswell

    Chris Carswell Supporting Actor

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    Thanks Ron [​IMG]
     
  4. Chris Carswell

    Chris Carswell Supporting Actor

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    Ok Ron so you can tell a difference? I take it it's worth the extra $.88 I'm using good Axon 250VDC caps now in the tweeter xover. The values are 3.3uF & 4.7uF. You say to use the cheaper Dayton's rather than the more expensive brands. What would be the pro's / con's of going with the .22uF as long as I'm still within the 5% tolerance area?
    Anyone else have ideas or comments?
    THANKS [​IMG]
     
  5. Ron D Core

    Ron D Core Stunt Coordinator

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    Well 3.3 and 4.7uF are pretty small, so If yo don't have the ordered, don't bother. You only really need to do it when you are dealing with larger values. My crossovers used 21 and 51 uF, so it made a slight noticeable difference. I used the Solens. But I only used the Daytons to bypass. I don't see any point in using an 8 dollar .1uF cap over the 88 cent one. I doubt my ears would notice the diff. Some people will claim to, but I have to wonder. Like i said, don't bother, but then again they are only a few bucks per handful. There is no harm in trying and doing it for your peace of mind. I like to know I'm not loosing anything to the x-over.
     
  6. Mark_E_Smith

    Mark_E_Smith Second Unit

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    I have been told that it really depends on the tweeter, if you are using a ribbon like I do it makes a big difference, if you are using something not quite as clear then it will make less of a difference. In my ribbons I only used theta from PE, and it needed 4 uF (ouch) I also used foil inductors for the tweeter, but I used Dayton caps for the woofer.
     
  7. Chris Carswell

    Chris Carswell Supporting Actor

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    Yowzers..... $25 for 1 cap. You got some deep pockets Mark [​IMG]
    -
    I think for $.88 it will be worth playing with just to see.
     
  8. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Deep pockets? No when you spend $250 on drivers for 1 speaker I dont want to quibble about $25 for a cap that could make or break the SQ [​IMG] If I have time since I have the x-over outside the box I might try a Dayton cap and maybe a bypass cap to see if I can here the difference. Definitely before I proceed with the main upgrade/ redesign. I think I have $75 in the x-over now so if I can get that down with out sacrificing SQ that would be a good thing. But I didnt want to fight a crossover problem when I was designing the speaker.
     
  9. Chris Carswell

    Chris Carswell Supporting Actor

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    I hear what your saying [​IMG] Try a Dayton 4uF metallized cap with a .1uF Dayton Film & Foil bypass cap & tell me what you think. For $2.73 you never know [​IMG]
    I might have a spare .1uF laying arround I could send you. LMS
     
  10. Mark_E_Smith

    Mark_E_Smith Second Unit

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    Actually the way the x-over is constructed it has a 3 uF and a 1 uF paralleled so I could just remove the 3 uF ( and save the little piece of gold) and put a 3 uF Dayton in its place.
     
  11. Chris Carswell

    Chris Carswell Supporting Actor

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    That will work. The 1uF is a Theta I take it that will be the bypass?
     
  12. Ron D Core

    Ron D Core Stunt Coordinator

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    So Chris...Did you finish your x-over? How does it sound? Did you end up bypassing the little caps anyway? Did it make a diff?
     
  13. Chris Carswell

    Chris Carswell Supporting Actor

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    Sorry Ron but no, not yet, no, and not sure. I need to place another order with PE. I just got the drivers though. Have not even taken them out yet. I will Sunday after I recover from the UF vs. Miami game. Thought about selling my ticket to finance another project but naaaa. Look for me on game day. I'll be the drunk guy in blue cheering [​IMG] ......
     

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