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Mixing capacitors in a crossover

bamark

bamark

Active Member
Hello and Happy Holidays!

I'm trying to redo the crossovers in a pair of Pioneer HPM-60s.
They are series 2 (pleated surround on the woofer), and the values are as follows:
1 - 6.0 uf cap
1 - 3.0 uf cap
1 - 0.3 uf cap
1 - 8 ohm 10w resistor.

Two questions.
First, can I use slightly different values for the caps - example - 0.33 uf instead of 0.3 or 6.2 uf instead of 6.0.
Second, is there a problem with mixing different types of capacitors, ie polypropylene film and metallized film for one or two of the caps.

I'm trying to stay as close to the original values as possible while at the same time not going overboard on expensive caps.

Thanks very much for any opinions, as I'm right in the middle of rebuilding these speakers. I've already removed the vinyl wrap from one with the intention of applying a real wood veneer and new grill fabrics. I have to clean up the corners a little, but, if I do this right, they should look really nice.

Mark
 
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The original caps had 10% or 20% precision anyway. The rule of thumb is, if you can get within about 10% on the values, it's close enough.

Also, you can parallel caps to get any value you need. 6+0.2 = 6.2 and so on.

There is really no problem mixing film and foil vs. metallized foil. If the original caps were electrolytics, those can have a different ESR profile than films and some people will say stick to the same general type of cap. My opinion is, for a mid-grade speaker with ancient caps, the upgrade is going to sound so much better than the originals that it probably doesn't matter. I wouldn't be worrying about boutique caps with the HPM's. Which is not a judgment on their quality, mind you. If you want to keep tweaking you can always do that, but get those old tired caps out of there and go from there.
 
toxcrusadr said:
The original caps had 10% or 20% precision anyway. The rule of thumb is, if you can get within about 10% on the values, it's close enough.

Also, you can parallel caps to get any value you need. 6+0.2 = 6.2 and so on.

There is really no problem mixing film and foil vs. metallized foil. If the original caps were electrolytics, those can have a different ESR profile than films and some people will say stick to the same general type of cap. My opinion is, for a mid-grade speaker with ancient caps, the upgrade is going to sound so much better than the originals that it probably doesn't matter. I wouldn't be worrying about boutique caps with the HPM's. Which is not a judgment on their quality, mind you. If you want to keep tweaking you can always do that, but get those old tired caps out of there and go from there.
Click to expand...
Thanks for your help. I saw no reason to put expensive caps in when I could use less expensive and achieve the results I wanted. My main concern was not to change any xover values.
 
Good to go with all your questions. No issues. You can parallel as was mentioned to achieve correct values. Prolly good idea.
 
I agree with the 10% of value statement. If you get .33uf instead of .3uf or 6.2uf instead of 6uf you will never hear the difference.
And it will not affect the xover point any more than your stock 10% caps did.

I personally think 5% Dayton poly caps sound decent and they are inexpensive. They are still better than what were in your speakers from the factory
 
elitopus said:
I agree with the 10% of value statement. If you get .33uf instead of .3uf or 6.2uf instead of 6uf you will never hear the difference.
And it will not affect the xover point any more than your stock 10% caps did.

I personally think 5% Dayton poly caps sound decent and they are inexpensive. They are still better than what were in your speakers from the factory
Click to expand...
Thanks. It would sure be a lot easier, given the board constraint, if I could use radial caps instead of axial.
 
toxcrusadr said:
The original caps had 10% or 20% precision anyway. The rule of thumb is, if you can get within about 10% on the values, it's close enough.
Click to expand...
I was advised to get within 5%. It somewhat depends on where the starting point is: If the original caps are +- 20%, the "adequate" range is greater than if the original caps are 5% or 2% jobs.

toxcrusadr said:
Also, you can parallel caps to get any value you need. 6+0.2 = 6.2 and so on.
Click to expand...
I was warned to split the difference as close to the half-way point as possible. As if 3 + 3.2 = 6.2 would be better than 6 + .2 = 6.2. It was never explained to me WHY it is better to have near-equal values rather than one high and one low, but I took it at face value and have done that ever since.

toxcrusadr said:
for a mid-grade speaker with ancient caps, the upgrade is going to sound so much better than the originals that it probably doesn't matter. I wouldn't be worrying about boutique caps with the HPM's. Which is not a judgment on their quality, mind you. If you want to keep tweaking you can always do that, but get those old tired caps out of there and go from there.
Click to expand...
Any electrolytic caps in an HPM will be far beyond their service life. Even fresh electrolytics will be an improvement; although I prefer inexpensive film caps (Dayton, ERSE) for most of my projects (assuming the capacitor values are not so large as to be impractical in film instead of electrolytics.) If I am trying to hold the line on expense, I'll use film caps in the high-frequency section of the crossover, and electrolytics for the bass.

Low-noise resistors can be a help, too. Mills resistors seem to be a nice compromise between quality and cost, and they're physically smaller than the ceramic wire-wound resistors so they often fit the circuit board better than the ceramics.
 
Digging up an old thread that has some good info, but doesn't answer a question I have.
I'm currently working on a midrange xover idea where the first order high pass is around 160uF. To do this in all film seems a bit much for my application, but what I'm wondering is, if I parallel a 150uF electrolytic and 10uF film, would I get any benefit from doing it that way?
 
I think you could get a benefit in that you could save some dough by getting a less expensive 150uF cap and a boutique 10uF cap and reap some sound benefits of the boutique one.
 
I've mixed electrolytic and film together without issue. I needed a 350uF, and used a 330uF Mundorf E-Cap paralleled with a 20uF Axon poly. It seemed fine to me. I've also used a large value NPE with just a small value bypass capacitor. That worked just as well, and is a bit cheaper too.
 
Some people advise against mixing types but others say it's fine. I'd try it, no harm in it. Especially if the smaller one is more than 10x smaller than the larger one, which it is. JBL stacked up to 3 or 4 caps in some of their speakers - they'd add a 0.1 and a 0.01 to that. :D
 
toxcrusadr said:
Some people advise against mixing types but others say it's fine. I'd try it, no harm in it. Especially if the smaller one is more than 10x smaller than the larger one, which it is. JBL stacked up to 3 or 4 caps in some of their speakers - they'd add a 0.1 and a 0.01 to that. :D
Click to expand...

Yep- and Snell actually deliberately mixed mylar and polypropylene caps,in parallel, in some of their crossovers. I always try to re-create that when I re-cap those. Peter Snell was pretty persnickety about his component values and types... and its better to just go back with what he did....


Regards,
Gordon.
 
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