Capacitor recomendations for a cross over

[pucho812]

Looking for the following capacitors to recap a pair of crossovers in some old urei's.

8uF
12uF
16uF
20uF
32uF

minimum 50Vdc on all of those. 

What do people like in capacitors these days? Anyone?

 

[JohnRoberts]

Tough question... Film caps for values that large would be huge if they existed.

Electrolytic cap technology has evolved to lower ESR/ESL caps. Hopefully these new improved caps will not have unintended consequences for crossover tuning.

Good luck...

JR

 

[usekgb]

Film caps of this size do exist, but they are large, and can be expensive.

I've actually had pretty good luck with the Dayton brand caps from Parts Express in re-building speaker crossovers.  They are also less expensive than the comparable Solens.

 

[usekgb]

8.2 uF. http://www.parts-express.com/dayton-audio-dmpc-82-82uf-250v-polypropylene-capacitor--027-426

12 uF. http://www.parts-express.com/dayton-audio-dmpc-12-12uf-250v-polypropylene-capacitor--027-430

20uF  http://www.parts-express.com/dayton-audio-dmpc-20-20uf-250v-polypropylene-capacitor--027-436

33uF  http://www.parts-express.com/dayton-audio-dmpc-33-33uf-250v-polypropylene-capacitor--027-441

The other values can be made from various combinations.

 

[Winetree]

I used the Daytons in my NS-10 crossovers. Made a big difference.

 

[pucho812]

I used the Daytons in my NS-10 crossovers. Made a big difference.

bad, good or just different?

 

[pucho812]

8.2 uF. http://www.parts-express.com/dayton-audio-dmpc-82-82uf-250v-polypropylene-capacitor--027-426

12 uF. http://www.parts-express.com/dayton-audio-dmpc-12-12uf-250v-polypropylene-capacitor--027-430

20uF  http://www.parts-express.com/dayton-audio-dmpc-20-20uf-250v-polypropylene-capacitor--027-436

33uF  http://www.parts-express.com/dayton-audio-dmpc-33-33uf-250v-polypropylene-capacitor--027-441

The other values can be made from various combinations.

I saw some of those yesterday. they also have a 16uF and 8.2uF at parts express from another brand.  Since caps that large have tolorances of +/-10% on average can easily work into something that will be fine without being audiophool expensive. I don't need the 100 dollar and up stuff.

 

[Winetree]

Overall Good, Better tonal balance, imaging, stereo field and depth. YMHO

 

[pucho812]

Overall Good, Better tonal balance, imaging, stereo field and depth. YMHO

Interesting.

 

[emrr]

I rebuilt 3 sets of home speakers with the Dayton caps, all sound fine, of course better than the worn out caps previously loaded. 

 

[JohnRoberts]

Passive loudspeaker crossovers are one area where I am not surprised about reports of audible differences between capacitors. These caps can be carrying amps of current so not the typical light lifting inside normal circuitry. 

JR

 

[gridcurrent]

Buy or make bi-polar electrolytics a bit smaller than the values you need.
Bypass the bi-polars with film capacitors to arrive at required values.
The hi-fi nuts think bypassing is smart; we are doing it just to be cheap.

 

[JohnRoberts]

Buy or make bi-polar electrolytics a bit smaller than the values you need.
Bypass the bi-polars with film capacitors to arrive at required values.
The hi-fi nuts think bypassing is smart; we are doing it just to be cheap.

I did some bench testing back in the '70s to see how much film cap in parallel it takes to make the compound cap act like a big film cap. On my bench the film cap needed to be at least 10% of the total C. This was decades ago so maybe modern low Z electrolytic caps are better but at 10% for the values listed we are talking about pretty large film caps. Putting small film caps across large electrolytic may make you feel better but won't affect the circuit much.

JR

 

[gridcurrent]

Buy or make bi-polar electrolytics a bit smaller than the values you need.
Bypass the bi-polars with film capacitors to arrive at required values.
The hi-fi nuts think bypassing is smart; we are doing it just to be cheap.

Putting small film caps across large electrolytic may make you feel better but won't affect the circuit much.

JR

We are talking about coming up with the required values using less expensive capacitors, not hi-fi weirdness.

 

[pucho812]

10 bucks for a big film cap is reasonable 100 and upward is not.

 

[gridcurrent]

10 bucks for a big film cap is reasonable 100 and upward is not.

Good point.  Appears that the cost ratio of metalised film to non-polar electrolytics is about 10:1.

 

[JohnRoberts]

Buy or make bi-polar electrolytics a bit smaller than the values you need.
Bypass the bi-polars with film capacitors to arrive at required values.
The hi-fi nuts think bypassing is smart; we are doing it just to be cheap.

Putting small film caps across large electrolytic may make you feel better but won't affect the circuit much.

JR

We are talking about coming up with the required values using less expensive capacitors, not hi-fi weirdness.

You edited out the part of my post that said how to do it right (film cap must be 10% or more of the total C). I said what i did because over the decades I've seen too many audio phools put a 0.01 uF film cap across a 10uF electrolytic and proclaim mission accomplished. 

My research was decades ago and there are probably modern electrolytic caps designed to be used in crossovers that don't suck.

JR

 

[ricardo]

This was decades ago so maybe modern low Z electrolytic caps are better

If you are a major Speaker maker, you get into bed with a Capacitor maker and he will make you some really good Bipolar Electrolytics with low ESR & other good stuff.

They don't sound the same as good films but can often be preferred in DBLTs.

Right until the end of the last Millenium, NONE of the Bipolars available to DIY were anyway near these specials.  Dunno about today.

If you can afford the size & cost, use good films.

If the values force you to use Bipolars, buy the physically largest you can find for the same value & voltage.  This isn't a guarantee of good performance but physically smaller Bipolars are guaranteed to have poorer ESR bla bla and sound worse.

It's a looo.oong time since I bodged up Bipolars with 2 Polars but if you do, use MUCH higher voltage rating, good ESR and CHECK THE FINAL VALUE.

I would never bother bypassing Bipolars with films.  I'd just use a better Bipolar.

 

[usekgb]

I can't tell you how many EAW crossovers I've worked on that use N.P. electrolytics, and they sound pretty darn good.  The Dayton's do sound pretty good though.  They're not high end audiophoolery, but they are good.

 

[JohnRoberts]

This was decades ago so maybe modern low Z electrolytic caps are better

If you are a major Speaker maker, you get into bed with a Capacitor maker and he will make you some really good Bipolar Electrolytics with low ESR & other good stuff.

Never met a cap rep i would bed, but at Peavey we were a large capacitor customer.

They don't sound the same as good films but can often be preferred in DBLTs.

The ESR/ESL no doubt factors into passive crossover design and can shift actual crossover frequency.

Right until the end of the last Millenium, NONE of the Bipolars available to DIY were anyway near these specials.  Dunno about today.

Modern electrolytic caps do deliver lower ESR/ESL driven by switching supply use. 

If you can afford the size & cost, use good films.

I've told this story too often, but i once approved an engineering change to use a film cap in a crossover, because the speaker engineer's actual boss refused to sign it. I don't recall the exact cost increase but it was not much. 

If the values force you to use Bipolars, buy the physically largest you can find for the same value & voltage.  This isn't a guarantee of good performance but physically smaller Bipolars are guaranteed to have poorer ESR bla bla and sound worse.

It's a looo.oong time since I bodged up Bipolars with 2 Polars but if you do, use MUCH higher voltage rating, good ESR and CHECK THE FINAL VALUE.

I would never bother bypassing Bipolars with films.  I'd just use a better Bipolar.

This is why I prefer active crossovers and bi/tri-amping. Capacitors are doing pretty heavy lifting in passive crossovers.

JR