Capacitors - Bypassing vs. Film & Foil in Crossover

[milton10]

Which is better, bypassing polypropolyne caps with high quality film

and foils (with .1uf values), or just using film & foils in a

crossover (cost NOT a consideration)?

I am presently using Northcreek Zen capacitors in my Heresys, and am

either going to bypass them with film & foil bypass caps or get a

whole new set of AudiocapThetas (which are film & foil). Will

there be a noticable difference between either option?

Thanks in advance for your answers!

[Frzninvt]

I would certainly think the real McCoy's (Auricap's) would be much better than tacking bypass capacitors all over the place.

You can always go with the Kimber's if the Auricap's or Hovland's are too pricey. If ordering from Parts Express it is best to get someone to go in with you on the order since the price drops with the more you purchase.

I recently finished up my '88 Khorn's and caps are expensive but the sound improvement was worth it to me. I went with the Kimber's and I am happy I was going to go with the Auricaps but one of the values that I needed was out of stock.

[milton10]

I have thought of Auricaps & Kimbers, but they are polyproplyne,

not film & foil types. When you say that Auricaps are "the

real McCoy's," are you saying that they would be the best crossover

caps, regardless of what type they are?

The reason I am asking is that although my Heresy's sound crisp, they could use some smoothing out in sound.

[Frzninvt]

Why are caught up with the film and foils? All I know is that I am using the Kimbers and Auricaps with excellent results. If you are looking for a capacitor that is not as forward in the high range get some Jensen PIO's. I think what you are trying to say is your Heresy's are a bit bright for you and if that is the case I would use the Jensen's or some of Bob C's GE's.

[consistent]

Milton,
check out this site http://home.zonnet.nl/geenius/Cap.html this guy tested a whole bunch of caps. I started using Hovland and Sonicaps in my pre-amp-what a difference!

cheers

[djk]

"but they are polyproplyne, not film & foil types"

A foil cap has to have a dielectric layer, usually film, usually polypropylene. Most film & foil types are therefore polypropylene.

The difference between a 'regular' polypropylene and a 'film & foil' polypropylene is the metal sheet in the F&F type. A regular cap has a metalized film instead (like those mirrored balloons you see).

The big difference in sound comes from the way the leads are attached to the ends of the caps. With a F&F type they can be soldered, with a regular type cap they are just pressed into the ends with some tin paste. This makes a difference with a lot of current flowing, like in a speaker crossover.

[Deang]

JBL bypasses all of their electrolytics with metallized polypropylene capacitors -- so there is probably something to it. It's primarily used as a cost cutting solution in networks to boost the performance of lesser quality capacitors. With this in mind, I think it's best to just go with the best single cap you can afford. You can also cascade the Northcreek way, but it's very expensive. Considering what you are currently running in your networks, you're not going to gain much if anything by changing things out. If you are attemping to bring the top down into a better relationship with the woofer, you need make some changes to the network.

Auricaps, Sonicaps, and Kimbers are metallized polypropylenes. However, they are rolled with a much thicker polpropylene than used in other brands (Solen, Dayton, Jantzen). The film is also virgin, and not of the recycled variety. Because of the thick film, there is no "self healing" property. These caps sound excellent in the squawker section. I think cost considerations limit the use of film and foil types like the Hovland, AudioCap Theta, and the new Solen (film and foil) to tweeter sections. The garden variety metallized types sound fine to me, but the Auricaps and Kimbers definitely add more body and richness to the midrange. The GE motor runs are NOT paper in oil -- they are metallized polypropylene in oil. I think they sound good at low to moderate listening levels. Beyond that, they are too bright for my taste. Even if they weren't -- since they are designed for 50/60Hz applications, I would eschew their use anyway (sorry Bob:).

http://ldsg.snippets.org/appdx-ec.php3

http://www.geindustrial.com/cwc/products?pnlid=4&famid=7&catid=29&id=motorRun〈=en_US

[BEC]

Dean,

DId you ever check the ratings on the oil filled caps that Klipsch used for 40 years? I think you will find most are rated 100 Volts AC, 60 Hz. A cap is not bright or dull. A good cap is a good cap within easily (with the right equipment) measureable values. And two that measure similiarly, ARE, similar in performance whether you want them to be or perceive them to be or not.

Bob

[Hardhead]

Are you saying that if two capacitors--even made from different materials and/or by different construction methods--measure the same, they'll perform the same?

Do you mean by "perform the same" that they'll sound the same?

[BEC]

Yes, I contend that any two capacitors with the same measured capacitance and ESR will perform the same in a crossover circuit and that the sound will be the same and that in a true blind test, the listener will not be able to tell them apart.

Bob

[djk]

"Yes, I contend that any two capacitors with the same measured capacitance and ESR will perform the same in a crossover circuit and that the sound will be the same and that in a true blind test, the listener will not be able to tell them apart. "

Only if you're as deaf as a post.

The DA of the cap affects the sound, as does the lead material. A mylar cap with a copperweld lead may measure the same for capacitance and ESR as a polypropylene cap with a pure copper lead, but they sound completely different.

[BEC]

"Only if you're as deaf as a post."

That is what they always say. They never perform a real test or give an answer based in science. I have not seen a mylar cap measure good on ESR yet, but if you can find one that does, I contend it will sound the same. Since I could not find mylars that tested good, they were excluded. A measure of ESR and capacitance takes into account everything that a cap can do to the sound in a crossover. The results are consistent, reliable and better than my ears, your ears or the ears of anyone else.

You may assert that I am deaf and I may assert you are deluded. Nothing helpful there. Bring on the proof. Send me two caps that measure the same and sound different to you. I will devise the blind test and inform you of the results. There are even more ears around here in case I am deaf.

Bob Crites

[Hardhead]

That's an interesting idea, and it isn't quite as much like saying "All speakers that measure 8 ohms sound the same'' as it first appears to be.

Although I'm not an expert on electronics, I know little enough about politics (or maybe Heisenberg's Uncertainty Principle, which may be the same thing) to see that with a sufficient number of test frequencies on a test instrument of sufficient sensitivity no two capacitors will ever measure the same--also, that after a little current has been run through it, or perhaps on a day with different humidity, or even after squeezing it a little, the measurement of any capacitor will be different from its previous measurements.

The more accurately we can measure capacitors the more differences we can identify between different capacitors and even between the same capacitor measured at different times. Therefore, any two capacitors must necessarily measure differently, and differences in sound could be explained away as differences in measurements.

[BEC]

You right that instruments are sensitive enough to find some difference between any two caps. In fact much more sensitive in measuring these differences than the ear. I should have modified (and did in my mind) the terms on the caps to allow 2 percent difference in capacitance and 0.1 ohms in ESR.

Bob

[Deang]

Did you ever check the ratings on the oil filled caps that Klipsch used for 40 years? I think you will find most are rated 100 Volts AC, 60 Hz.

Is this the thing that we talked about on the phone once -- that the rating is too low for motors? I did follow up on that, and found that the voltage rating for those old motor runs correlate to what is commonly used in attic and ceiling fans.

I also did some light reading on the harmonics issue and it's a problem related their use in power systems. It's interesting stuff, but sure doesn't look like it has much to do with our application (but makes me wonder when I see a 20 year old Areovox leaking all over a board). As far as 40 years of use goes, I guess all I can say is that they haven't used them for 20!

See note 1 at the bottom of page 2: http://www.epcos.com/inf/20/25/ds/b32324.pdf

http://www.ecmweb.com/mag/electric_effects_harmonics_power_2/

http://www.ce-mag.com/99ARG/Martin103.html

A cap is not bright or dull.

Poorly worded I suppose, let me try again. A network loaded with near loss-less capacitors will make a speaker sound "brighter" and/or more forward in its signature than one that isn't. The various loss factors of the capacitors and inductors play a role in the voicing. I thought we agreed on this?

A good cap is a good cap within easily (with the right equipment) measureable values. And two that measure similiarly, ARE, similar in performance whether you want them to be or perceive them to be or not.

Even when they don't measure similiarly they are close enough that it shouldn't make a difference - yet it does. Why do I need science to back this up, what's the matter Bob, don't you trust me?[]

[BEC]

"guess all I can say is that they haven't used them for 20!"

Right and that would also be about the same time we saw the cheaper drivers, cheaper cabinets and cheaper crossover components show up.

"Poorly worded I suppose, let me try again. A network loaded with near loss-less capacitors will make a speaker sound "brighter" and/or more forward in its signature than one that isn't. The various loss factors of the capacitors and inductors play a role in the voicing. I thought we agreed on this?"

Near loss-less describes all the polypropylene caps though as far as I can tell. I expect it would also describes the original oil filled cans Klipsch used when they were new. Some higher ESR in the Mylars and PIOs, but the polys are all quite alike.

More about your ears later.

Bob

[Deang]

Right and that would also be about the same time we saw the cheaper drivers, cheaper cabinets and cheaper crossover components show up.

For the most part, what you're saying here doesn't apply to Heritage. In my opinion, the K-55-M and K-77-M are very good drivers, and any inclusion of MDF is an improvement. It adds mass/density which reduces cabinet resonances, and if you don't like lossy capacitors, you shouldn't like lossy cabinets either! As far a crossover parts go -- at the time Klipsch started using them, Mylar film capacitors pretty much represented the best that was available -- and they weren't as inexpensive as they are now. I'm sure the lack of availability of the PIO cans was a contributing factor as well. The continued use of Mylars in the Heritage series is probably a combination of cost and the fact that they like the results they get with them. Incidently, the Reference Series speakers all use polypropylene capacitors.

Near loss-less describes all the polypropylene caps though as far as I can tell. I expect it would also describes the original oil filled cans Klipsch used when they were new. Some higher ESR in the Mylars and PIOs, but the polys are all quite alike.

Why would you think the Klipsch PIO cans were probably near loss-less when new, when you know the best PIO ever made isn't? I suspect they had ESR's similiar to Jensens.

More about your ears later.

You're not allowed to talk about my ears -- they're sensitive scientific instruments.

[BEC]

"Why would you think the Klipsch PIO cans were probably near loss-less when new, when you know the best PIO ever made isn't? I suspect they had ESR's similiar to Jensens."

Actually a good half the old original Klipsch cans test better on ESR now than the new Jensen PIOs. That is why I don't think Klipsh used PIO. Pretty sure that the cans from the 70s are plastic of some sort especially since a lot of the cans are made by "Plastic Capacitor Corp".

"For the most part, what you're saying here doesn't apply to Heritage. In my opinion, the K-55-M and K-77-M are very good drivers, and any inclusion of MDF is an improvement."

Mostly talking about Heresy II and Cornwall II and it was not a comment as to value, but to cost. Having built a ceramic version of the K-77 myself, and an alnico version, I know that I abandoned the alnico because of cost. Just as I think the K-55M would cost less than half as much as the K-55V to make. And I will have to see some 40 year old MDF before I am convinced it is better than plywood. Again, I have had Cornscalas built of MDF and of Plywood. The MDF is much cheaper. Perhaps MDF is better in every way. I would like to think that. I always liked cheaper AND better.

Bob

[Deang]

You mean all those old metal cans are really plastic!!

Well now, isn't this interesting. They must be Mylar/polyester, because I'm pretty sure polypropylene hadn't found it's way into general use for audio yet. Do you think someone at Klipsch might know for sure, or do you think the data is with their Cornwall notes?

[Malcolm]

There are other measurable differences between capacitors than those

mentioned. For one thing, some types have a more nearly linear

capacitive reactance curve than others. Don't know whether the

differences between the types commonly used in crossovers are enough to

hear, though.

Also, the tin paste claim about metallized polypropylene caps doesn't

seem to apply to all of them. The ends of Solen Fast Caps (which

I have in my crossovers) are thermal arc metal sprayed with zinc, and

then the leads are welded to them.