Electrolytic vs poly caps in "econo" builds

[Drjay]

Hi Gents,

I am going to be building several sets small two way speakers using the DA115 woofers and the ND 20 FA tweeters I bought during the PE $10 flash sale. They will be gifts to friends or sold to aquaintances who like them for $75.00 a pair. So, since these are more of a "mid-fi" speaker by the standards of this forum, will there be an audible difference in SQ if I keep the costs down by using electrolytic caps vs. polys? I am also going to build a set of Hitmakers for myself and will be using polys in it since it is a high resolution speaker but I wonder if it would be fine to use electrolytics in any "econo" builds I do.
Also, while I was fortunate to grab 20, 1.0 mH inductors for $1.00 each on a PE factory buyout, they are sold out now and inductors aren't cheap. Does anyone know of a good source for affordable inductors?

Best,

Jay

[dynamo]

[billfitzmaurice]

My personal opinion is though if my tweeter cap will cost $0.75 for the NPE or $2 for the poly, I’m going poly..

+1. Paying $20 for a 'high end' cap is a different story.

[Geoff Millar]

+1. Paying $20 for a 'high end' cap is a different story.

Would you believe there is a brand of capacitor which sells for $A115 each?!

Aside from that, I buy the best caps I can afford and use electrolytics where there are values like 47 and 100 microfarads: and usually these are in Zobels or shunt parts of the crossover anyway. In Australia the difference between electrolytic and poly isn't that much, maybe the price of a coffee.

Geoff

[Pete Schumacher]

Would you believe there is a brand of capacitor which sells for $A115 each?!

Aside from that, I buy the best caps I can afford and use electrolytics where there are values like 47 and 100 microfarads: and usually these are in Zobels or shunt parts of the crossover anyway. In Australia the difference between electrolytic and poly isn't that much, maybe the price of a coffee.

Geoff

I've built a crossover for a 2-way that cost over $1500 for one speaker. Loaded with Duelund Cast Silver. People with money to spend for the "best" don't hesitate.

I use the Audyn caps all the time. Great value.

[billfitzmaurice]

Would you believe there is a brand of capacitor which sells for $A115 each?!

Some go for ten times that. As quoted from a conversation overheard between a couple of Monster Cable executives, "So long as there are people stupid enough to pay our prices we'll keep on selling it".

[DanP]

I've never found a poly cap in any commercial speaker I've dug into except a pair of Thiels and even then, they used an NPE for the "large" value of 24uF. KEF, Polk, Definitive Technology, Design Acoustics, Paradigm and countless others - none of them high-end per se, but decent speakers - all felt that poly caps were not worth the added expense.

Now, these manufacturers have different priorities than you, so that information should be taken with a grain of salt, but if it were a big deal, I don't think you'd see so many NPEs in good speakers.

Dan

[isaeagle4031]

My sentiments mirror the others. Poly on the tweeter, npe on the woofer.

[billfitzmaurice]

Now, these manufacturers have different priorities than you, so that information should be taken with a grain of salt, but if it were a big deal, I don't think you'd see so many NPEs in good speakers.

I use polys or mylars in high pass filters, where their cost isn't excessive and the high ESR of NPEs is undesirable. I use NPEs in low pass filters where there's no reason to spend more than you must and higher ESR isn't a concern. Where commercial speakers are concerned keeping costs down is a priority, especially in the less than $1k price range, and besides, the customer can't see what's being used and probably wouldn't know the difference if they did. There's another thread commenting on using Dayton reference drivers in $30k speakers. That's hardly surprising when the average $300 speaker is loaded with drivers that cost the manufacturer $5. When they do that you can hardly expect them to pay more for caps than they absolutely have to.

[DanP]

Yeah, I use polys for just about everything, but mostly because I want to lower the risk of failure years down the road. When it comes to sound quality though, I haven't heard a difference between NPEs and cheap polys. They're way smaller too, which is nice for mounting purposes. I wouldn't hesitate to use them if cost is a primary concern.

Dan

[kenrhodes]

Inductors...easy wrap your own. I use wood dowels and disc cut with a hole saw. Once you have picked a gage use the same format for all the time. For example 1 inch wide 3inch disc 18 gage. You will quickly learn how to estamate to get the value you need. A DATS will measure inductance. Otherwise a lcr meter is in order.
Online calculators are nice but none of them are 100%.
If you have a local motor rebuilding shop they might be able to sell you their drops. I've gotten lucky and acquired lots of wire this way.

[craigk]

I've built a crossover for a 2-way that cost over $1500 for one speaker. Loaded with Duelund Cast Silver. People with money to spend for the "best" don't hesitate.

I use the Audyn caps all the time. Great value.

So Pete, could you hear a difference in the high end crossover vs. The standard crossover.

[Pete Schumacher]

So Pete, could you hear a difference in the high end crossover vs. The standard crossover.

Well, I only had about 1 hour with them before they were on their way. That crossover was pairing up the RAAL amorphous core with silver/gold windings and the Accuton C173-6-096E. The "standard" crossover with those still uses what anyone would call boutique components. All that said, I couldn't say whether the much more expensive crossover offered any noticeable improvement. What was dead certain was that the new owner could brag to his buddies that he spared no expense on the components that went into his speakers. And even with all that, you'd still need a subwoofer.



Rock ON!

We did another outrageous crossover that used nothing but Jupiter copper foil and wax capacitors. Go look up those prices! The inductors were all 12ga. copper foils. That paired up the T-labs Beryllium with a custom Audio Technology FlexUnit 8" woofer. Those two crossovers were probably the two most over the top use of components I've ever done. You can be certain I would never do anything like that for myself.

[Wolf]

Yeah- the standard Jup' caps are about half a Benjamin for the 1uF 600V HT cased jobbies. The Cu Foil version is north of 4x that price.

For reference, the Duelund Silver Cast 1uF caps approach 5x that of the Jup' Cu boogers....

Yeesh!!

I have a set of the 1uF Jup' HT 600V that were purchased on sale to try in the Tandems project down the road. I also have a set of 1uF V-Cap TFTF caps to compare with, and will be getting a set of MultiCap RTX for a 3-fer. This will be joined by a fourth component, an Audyn True Copper 1uF which I already have (Tent Sale purchase), to make the comparison of: Teflon/Polystyrene/Wax Film-Tin Foil/Polypropylene with Cu-foil. I'm not certain of the foil material on the RTX and TFTF, but I'm betting tin or aluminum. This ought to be an interesting test. The driver is a compression driver, and just this cap and resistor will be in series with the driver.

Later,
Wolf

[Drjay]

This is probably not news to more advanced forum residents, but I was pleased to measure 8 different PE Npe caps ranging from 4 to 15uf and find that the worst was 6% high and the average was 3.8% high with none testing low. For a cap that is rated at 10% I thought that was pretty impressive.

Cheers,
Jay