High Efficiency Speaker Asylum

What Would You Do ?

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ka7niq

A

In Reply to: RE: Cerwin Vega V 36D In The House posted by ka7niq on August 20, 2017 at 07:24:27

Ok, I layed one speaker down, and pulled the crossover. All Caps are Mylar, except one 4 mfd 100 volt Aluminum Electrolytic.
The woofer to midrange horn crossover is at 1000 hz
If this old aluminum electrolytic cap is part of the high pass of the woofer, and it has lost capacitance over the years, wouldn't that make the woofer play higher in frequency ?

Mylar Capacitors are said to outlive you, but that Bob Crites guy says they can get high ESR over the years, and should be replaced. Of course, he sells capacitors.

Any comments or suggestions ?

Follow Ups:

RE: What Would You Do ? - Coner 00:47:04 08/21/17 (5)
4 uf is way to small for the woofer cap., more likely the
tweeter. It's probably still good, but might as well order
a Dayton PP cap while you're at it.
- Ordered This From Madisound - ka7niq 05:47:04 08/21/17 (4)
  It is the ONLY Electrolytic Cap in there, all the rest are Mylar.
  This Cap is about 2.5 inches long. I could not find a physically close in size 4 mfd 100 volt Electrolytic Cap. Today's Non Polar Electrolytic Caps are physically tiny, so I ordered a Bennic Metallized Polyproplyne Cap. The circuit calls for a 10% 4 mfd 100 volt, so I ordered 5% 3.9 mfd 250 volt cap.
  
  I wish I had a crossover schematic, so I can understand WHY all the caps are Mylar, except the one Electrolytic ?
  
  These Cerwin Vega V 36D speakers are from the early 90's I think, so that would make them 27 years old, kind of a long time, for an Aluminum Electrolytic.
  
  I figure the Mylar Caps, are still good.
  
  What about the speaker diaphragms, how long do they usually last, and how do you tell when they are going bad ?
  - RE: Ordered This From Madisound - Coner 12:02:25 08/21/17 (1)
    VERY STRANGE that the cap is that long, being electrolytic.
    Even a 40uf in only 1.25" or so., Maybe a 400 uf?.
    
    That horn won't load the driver well below 500 Hz, so you're
    kind of stuck with the orig. x-over points. Minimum I'd say
    around 800 Hz.
    - No, The Cap said 4.0 uf at 100 volt - ka7niq 06:21:53 08/22/17 (0)
      I tried to take a picture of it, but my family room is pretty dark, and even though the cell phone camera flashed, it didn't come out very good.
      I freaked too, at the size of that cap, but remember, these bastards are 27 years old.
      
      LOL, I am really jury rigged right now, running 25 feet of 24 gage twisted alarm wire to them. Hey, it is copper at least. My 12 gage wire will be here this week.
      
      I am also just powering them with an Onkyo receiver the NR 809, because it has Audyssey and a 1/2 ass equalizer built in.
      
      However, I have a QSC PLS series amp, as well as a 60 lb Apogee Amp, that is a beast.
  - RE: Ordered This From Madisound - Bill Fitzmaurice 08:10:02 08/21/17 (1)
    I would expect the electrolytic to be a shunt to ground on the low pass section of the midrange filter, as the higher ESR wouldn't be a problem there. But it's still odd, since 4uF mylars and polys aren't at all expensive.
    - The Speakers are 27 years old - ka7niq 08:32:13 08/21/17 (0)
      I know, but whatever it is, it is getting replaced.
      I always thought that Mylar Caps can outlive people, but some say they get high ESR, after 20 + years ?

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