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Capacitors for LaScala AA Networks


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Search for capacitor ESR. It changes with frequency and temperature. It's sometimes found in the spec sheet, but never on the part itself. As capacitors age, the dielectric begins to break down, the ESR climbs - and the cap starts to go resistive. So, an old capacitor is like having a good sized resistor in series with the driver - choking off the signal. 

 

New polyester/Mylar and paper in oil (PIO) capacitors have slightly higher ESR numbers than polypropylene or polystyrene. It does effect the sound. Construction quality will be the determining factor as to how long the capacitor remains stable before trouble sets in. 

 

Some believe Dielectric Absorption has an affect on the sound. I suppose I'm one of those.

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I agree that DA could have an affect on the sound, but feel that it would unlikely be encountered here.  It's my understanding that it largely sets in because of constant DC loading (like power supply filters).  Whatever it is that causes DA (again, in my understanding - and I'm not claiming great depth in this matter) doesn't work so one-sidedly when the cap is exposed only to AC signals.  If anyone knows anything about it, by all means chime in.

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4 hours ago, Deang said:

Search for capacitor ESR. It changes with frequency and temperature. It's sometimes found in the spec sheet, but never on the part itself. As capacitors age, the dielectric begins to break down, the ESR climbs - and the cap starts to go resistive. So, an old capacitor is like having a good sized resistor in series with the driver - choking off the signal. 

 

New polyester/Mylar and paper in oil (PIO) capacitors have slightly higher ESR numbers than polypropylene or polystyrene. It does effect the sound. Construction quality will be the determining factor as to how long the capacitor remains stable before trouble sets in. 

 

Some believe Dielectric Absorption has an affect on the sound. I suppose I'm one of those.

So what should the ESR measure?

 

Or is your point that.... really old caps are almost always junk. Don't over think it...... Replace them! (kinda the vide I'm getting, and it does makes sense).

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8 minutes ago, Heritage_Head said:

2 x 2uf and one 13uf. Brand seems to be the big question (and type). 

A great bang for your buck cap is the Audyn Plus cap from Parts Express.  I've built a few with them and really like them.  Should be a huge difference from what you have now.

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5 hours ago, Heritage_Head said:

For the record doing Bobs xo on my 81 corns was a huge noticeable change (for the better). Im already sold on it. I just want to learn why (even the boring parts).

 

A while back I decided to buy ALK's Universal kit.  It was my first soldering experience,  and even though it looked awful, it worked.  Like you, though, I had trouble understanding how it all worked. 

 

Forward many years, and I think I finally understand most of it, although I still have a lot to learn.  @Deang bumped a thread on inductors.  I think that's great, and I think many would like to understand how a passive device that opposes changing current would also act as a low pass AC filter.

 

Likewise, perhaps a thread on capacitors would be helpful.  It wasn't until recently that I understood how a capacitor works.  Again, I think many would like to understand how a passive device that opposes changing voltage would act as a high pass AC filter.

 

 I found the fact that a capacitor blocks DC and allows AC to pass confusing, to the point that I thought they were invented for both purposes.  Once I realized that this is not the case (the capacitor was invented long before AC was "invented"),  my understanding of crossovers became much clearer.

 

It seems that capacitors are only discussed in crossover upgrades, and then it seems to turn into a discussion on which brand of capacitor is best. 

I'm sure many don't care about the how's and why's of a capacitor,  but perhaps there are many others who do.  It might be interesting to discuss plates and dielectrics instead of brand A vs brand B.  Then again, maybe not.

 

Apologies to the OP.  This was not meant to hijack your thread.

 

Mike

 

 

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14 minutes ago, mboxler said:

 

A while back I decided to buy ALK's Universal kit.  It was my first soldering experience,  and even though it looked awful, it worked.  Like you, though, I had trouble understanding how it all worked. 

 

Forward many years, and I think I finally understand most of it, although I still have a lot to learn.  @Deang bumped a thread on inductors.  I think that's great, and I think many would like to understand how a passive device that opposes changing current would also act as a low pass AC filter.

 

Likewise, perhaps a thread on capacitors would be helpful.  It wasn't until recently that I understood how a capacitor works.  Again, I think many would like to understand how a passive device that opposes changing voltage would act as a high pass AC filter.

 

 I found the fact that a capacitor blocks DC and allows AC to pass confusing, to the point that I thought they were invented for both purposes.  Once I realized that this is not the case (the capacitor was invented long before AC was "invented"),  my understanding of crossovers became much clearer.

 

It seems that capacitors are only discussed in crossover upgrades, and then it seems to turn into a discussion on which brand of capacitor is best. 

I'm sure many don't care about the how's and why's of a capacitor,  but perhaps there are many others who do.  It might be interesting to discuss plates and dielectrics instead of brand A vs brand B.  Then again, maybe not.

 

Apologies to the OP.  This was not meant to hijack your thread.

 

Mike

 

 

Im not the op but....no hijack imo. Thanks 

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