Mr. Paul O'Neil, please

[tommoore]

Hey, Paul

I was wondering if you have done any side by side comparisons of crossovers made with electrolytics vs. poly? Do you always use bypass caps?

Thanks, Tom

[bobblickle]

Oh boy!
I'm predicting a pile on in the near future. ;)

bb

> Hey, Paul

> I was wondering if you have done any side by
> side comparisons of crossovers made with
> electrolytics vs. poly? Do you always use
> bypass caps?

> Thanks, Tom

[paul_n_oneal]

> Hey, Paul

> I was wondering if you have done any side by
> side comparisons of crossovers made with
> electrolytics vs. poly? Do you always use
> bypass caps?

> Thanks, Tom

Nope no side by side comparison. I've used both and if I have a high quality design then I go with polys if I feel the extra cost incurred might make a difference. So you got me there. What I do in the design and testing phase is use nothing but electrolytics, 10watt wire round resistors, and whatever inductors I have lying around. I use my LCR meter to measure each component to make sure that it is with the tolerance I need. Some portions of the xover can change dramatically when 1 component is not up to tolerance. I'm taling less than 1uF tolerances here. In the current design I'm working on, one of the cap values has a .3uF tolerance. I have no idea whether the by-pass caps work or not but they make them for some reason and they're only .23 cents so I put them on the positive side of electrolytics in hopes that it will clean it up some if there is anything to clean up. Open up a Bose speaker and I bet they have electrolytics :). So, there are those that say there is a difference, but I sure can't tell the difference except in cost :).

Paul

[paul_n_oneal]

[davidld]

Paul, I agree with you on all of this. I use bypass caps on electrolytics too. Generally I only occasionally use poly caps for small values since the cost differential there is not great. The experiments with cheap vs expensive caps at Dayton DIY 2004 found that few people could hear any difference at all, and for those who seemingly could, many favored the sound of the cheap electrolytics over the expensive boutique poly's.

I see the cap thing as largely another version of the cable and speaker wiring thing. 16 gauge zip cord makes pretty good speaker wire for runs of 25 ft or less at least.

I think electrolytic caps in vintage speakers if replaced ought to be replaced with as similar a cap as well.

D

[dancarroll]

> Hey, Paul

> I was wondering if you have done any side by
> side comparisons of crossovers made with
> electrolytics vs. poly? Do you always use
> bypass caps?

> Thanks, Tom

This issue has been debated endlessly here and elsewhere. There likely is no true correct answer, only personal opinion which, in my view, is very frequently backed up with anecdotal data that is important to the given observer and thus honestly and sincerely given. In other words, if someone who posts here says I only use polys no matter what, that person usually has a good reason to say that, but that does not necessarily make it right for all.

With the preamble, I use two tests: (1) Does the cost and quality of the driver justify the expense (and size!) of a poly cap? Like Mr. Debertin, I will at times use polys in smaller sizes anyway, because the cost just isn't that different. (2) Whatever the answer to (1), is this project going to be around long enough that cap durability will matter? If the answer to that is yes, then I will splurge for poly caps even if I don't think the drivers necessarily justify it -- to a point. I won't likely buy a poly cap with lesser drivers over say 20 uF even if durability is an issue, but I might (and have) with better quality drivers.

I can say that my ears can't tell the difference, but there are folks whose ears can.

My 2 cents.

Dan

[paul_n_oneal]

> Paul, I agree with you on all of this. I use
> bypass caps on electrolytics too. Generally
> I only occasionally use poly caps for small
> values since the cost differential there is
> not great. The experiments with cheap vs
> expensive caps at Dayton DIY 2004 found that
> few people could hear any difference at all,
> and for those who seemingly could, many
> favored the sound of the cheap electrolytics
> over the expensive boutique poly's.

> I see the cap thing as largely another
> version of the cable and speaker wiring
> thing. 16 gauge zip cord makes pretty good
> speaker wire for runs of 25 ft or less at
> least.

> I think electrolytic caps in vintage
> speakers if replaced ought to be replaced
> with as similar a cap as well.

> D

Wow, that is interesting. I knew I really couldn't tell but like you if they're small then I go for it. I've known to use zip cord from HD after I ran out of my spool I bought from PE. Forgot what brand it was, but that was some nice cable for a decent price. No greeny stuff on these guys. It had the grey outer jacket with the red and black covered wires inside it with some poly thread or something running down the middle. Now it's probably tripled in price. Dang I knew I should have ordered more back then. Well, since caps came up I guess resistors and inductors will be next :). Have a good one.

Paul

[AJ]

I use poly's more for a reliabilty factor more then anything else. I like to know that the speakers i build will be around longer than me hopefully. And won't be thrown out because i cheaped out and used an electrolytic and it started leaking.

That said, i am cheap. So check out Madisounds sale pages for great prices on mylar and poly caps. I have used the .90$ 10ufd's they have and tested them. Even though they are rated for 10% tolerance out of the 20 that i tested only one was .15ufd off.

Also,i use iron core inductors in low pass sections for values over 1.5mh and 20 or 18ga aircore in highpass. I also use 10w wirewounds only. Why pay 1.25$ (or more) for the same resistor with gold plated leads?

AJ

[paul_n_oneal]

> I use poly's more for a reliabilty factor
> more then anything else. I like to know that
> the speakers i build will be around longer
> than me hopefully. And won't be thrown out
> because i cheaped out and used an
> electrolytic and it started leaking.

> That said, i am cheap. So check out
> Madisounds sale pages for great prices on
> mylar and poly caps. I have used the .90$
> 10ufd's they have and tested them. Even
> though they are rated for 10% tolerance out
> of the 20 that i tested only one was .15ufd
> off.

> Also,i use iron core inductors in low pass
> sections for values over 1.5mh and 20 or
> 18ga aircore in highpass. I also use 10w
> wirewounds only. Why pay 1.25$ (or more) for
> the same resistor with gold plated leads?

> AJ

When I order from Mad, I always check the surplus stock of those GE caps--good deals sometimes :)

Paul