Capacitors in parallel

[brada220]

I am in the progress of replacing caps in my speaker crossover and I am figuring out what combination of caps are needed -

Lets say I have a group of caps in parallel totaling 162uf - is it better to combine 1 large cap of 150uf with a 12uf cap or 2 sixties and a 42uf cap

Ex2 - for a 16uf cap - is it better to go 15uf plus 1uf or 2 eights if I can't find a 16uf cap?

Thanks for the anticipated replies

 

[dzkfraser]

If cost is a consideration, the lower if caps a generally less expensive. Read a lot about using a high value e-cap and paralling with a low value poly bypass cap, as the e-caps are less expensive. It's said the this gives you the cost benefits of a lower prices electrolytic with the sonic benefits of a poly, don't know if this is true or not, never tried it, but as far a what values to use, I would try to keep them as close as possible, especially with e-caps as a low value paired with a high value, the low value one won't last as long. I'm sure someone will chime in and say I'm completely wrong, but That's what I've read

 

[StimpyWan]

Some feel it best to divide the needed value as evenly as possible, and use equal valued parallel capacitors, whenever possible. Mainly I've read that this will keep from causing phase issues, which can cause an echo type effect to the speaker's sound. Also, it's better to keep values the same, as each capacitor will have the same discharge rate too.

One other thing, if budget is tight, try and use better capacitors for the series capacitors, which are the high pass capacitors, typically used on the tweeters, and the midrange, if it's a 3-way speaker. These will have the greatest impact on sound. I use poly caps there, when I can. Shunt capacitors, wired in parallel to the woofers, can use NPE capacitors, since they're usually connected to ground, and don't influence the sound as greatly as the series parts.

Finally, I like to use bypass capacitors. I usually wire a small value bypass capacitor across each capacitor bundle. I typically use Dayton Film and Foil bypass capacitors, in a 0.01uF value for the tweeters and mids, and a 0.1uF on the larger shunt capacitors. Bypass capacitors can improve the sound quality of inexpensive NPE capacitors, without hurting the budget. They're said to improve the discharge rate, helping the capacitor to sound 'faster', which can improve transient response.

 

[brada220]

I didn't recon on phase issues - thanks for the heads up

I am curious about the bypass capacitors - do you have a pic or a drawing that shows the configuration you are talking about - I am using NPE caps for the larger value caps needed in the crossover - but for the midrange - I have a bundle that totals 162uf - parallel - what combo of caps would you suggest along with the proposed bypass?

Thanks to all who have responded

 

[StimpyWan]

Bypass capacitors are wired in parallel too. Here's a good web picture (thanks to an unknown AK Member) that shows a wired in bypass cap.



You can find the Parts Express F&F caps here. Parts Connexion also sells some very good Vishay bypass caps too. All cheap. So, it's not expensive to try them.

As to where to use a bypass, I use them on pretty much any capacitor. It doesn't hurt (IMO). You can see some on this pair of Acoustic Research AR90 crossover boards, that I'm recapping. I used them on all capacitors. Some are Dayton's, some Auricaps, and some Mundorf.

 

[brada220]

Great pics - thanks

OK - this should be the last question

In my situation where I have the 162uf for the midrange - I was going to go with 2 80uf NPE caps along with a 2uf poly cap -(I can't think of another array except for the 150uf coupled with a 12 poly cap but I am now concerned with a phase issue) - If I understand what you are saying I now add a 0.1uf bypass cap (film) to this bundle

Do I do the same for those caps in series? On my crossover - I have a 60, a 16 and a 4uf - all in a series configuration - based upon your advice i was going to have these as poly caps - do I then add the film capacitors to them as well - such that for the 4uf poly cap I am putting in parallel an 0.01 film cap?

 

[StimpyWan]

Great pics - thanks

You are welcome. Glad to help and pay it forward.

OK - this should be the last question

Keep 'em coming!

In my situation where I have the 162uf for the midrange - I was going to go with 2 80uf NPE caps along with a 2uf poly cap -(I can't think of another array except for the 150uf coupled with a 12 poly cap but I am now concerned with a phase issue) - If I understand what you are saying I now add a 0.1uf bypass cap (film) to this bundle

80+80+2+0.1 - Exactly correct!

Do I do the same for those caps in series? On my crossover - I have a 60, a 16 and a 4uf - all in a series configuration - based upon your advice i was going to have these as poly caps - do I then add the film capacitors to them as well - such that for the 4uf poly cap I am putting in parallel an 0.01 film cap?

Yes, correct again. And I would. I just recapped a pair of AR1MS mini-monitors using Dayton 5% polys. But, for whatever reason, the speakers sounded sibilant and 'spitty' after the recap. So, I went back in and added 0.01uF F&F Dayton bypass caps on the tweeter and woofers caps, and that eliminated the sibilance. They sound wonderful now, with a smooth detailed sound, with very good soundstage depth. Fun little speakers.

 

[brada220]

Thanks for all of the advice

I am a beginner at this as I am sure you can tell

By the way - I have a NAD 7150 with a pair of A400 Boston Acoustics - can't wait until I am finished with this project

Thanks again.

 

[StimpyWan]

That's a very nice system. My first real amp was a NAD 3140. I used it with Boston Acoustics A40's and a M&K V3B 12" sub. Sweet. And a local store carried the full Boston line, and I remember the A400's as very impressive speakers, with great bass. They'll respond well to a recap.

Welcome to AK, and keep us updated on your progress!

 

[markn2wae]

What is the tolerance of the total capacitor?, the .1 may not be needed.

Mark T.

 

[elnaldo]

I agree. 0.1uF in 160 (less than 1/1000), I don't think it will provide any extra benefit. Not even the 2uF to have "162", I think 160 is close enough. But that 2uF film cap will be the "bypass" capacitor. It's a bit more than 1/100 of the electrolytic value.

 

[StimpyWan]

What is the tolerance of the total capacitor?, the .1 may not be needed.

Mark T.

The bypass is not used to add to the total value of the paralleled capacitors. It's felt that cascading a bypass capacitor combines the sound quality of the 2 types of parts. It's there to enhance the sound, as a Film and Foil capacitor is a higher quality capacitor than a NPE, or a standard poly. For whatever reason, it works in my experience, and with others whose ears I trust.

 

[markn2wae]

It would seem that the added .1 capacitor is not for the total capacitance (that may have a tolerance)
but for sonic reasons (the above sibilance mentioned above).

Mark T.

 

[Oilmaster]

For some inspiration : http://www.humblehomemadehifi.com/Cap.html

Although I keep an objective distance from subjective reviews, I tried a couple of his proposed capacitor mixes (to make up a given value), as well as the 10nF bypass caps (Vishay MKP1837 / 0,01uF MKP 100VDC), and I can say that the latter small bypass does add some transparency and wider staging. Such small bypass caps are (of course) no use for the woofer circuits;

I can't measure it with all my gear, accept for listening
And trying and trying and trying.... (and spending and spending and spending)

 

[MCM_Fan]

Some feel it best to divide the needed value as evenly as possible, and use equal valued parallel capacitors, whenever possible. Mainly I've read that this will keep from causing phase issues, which can cause an echo type effect to the speaker's sound. Also, it's better to keep values the same, as each capacitor will have the same discharge rate too.

One other thing, if budget is tight, try and use better capacitors for the series capacitors, which are the high pass capacitors, typically used on the tweeters, and the midrange, if it's a 3-way speaker. These will have the greatest impact on sound. I use poly caps there, when I can. Shunt capacitors, wired in parallel to the woofers, can use NPE capacitors, since they're usually connected to ground, and don't influence the sound as greatly as the series parts.

Finally, I like to use bypass capacitors. I usually wire a small value bypass capacitor across each capacitor bundle. I typically use Dayton Film and Foil bypass capacitors, in a 0.01uF value for the tweeters and mids, and a 0.1uF on the larger shunt capacitors. Bypass capacitors can improve the sound quality of inexpensive NPE capacitors, without hurting the budget. They're said to improve the discharge rate, helping the capacitor to sound 'faster', which can improve transient response.

Excellent reply. I agree with everything you wrote. It comes down to personal preference and budget, but I like to use Sonicap Gen1 and ClarityCap PX as series tweeter and midrange caps, bypassed with 0.01uF Vishay-Roderstein MKP1837. I use Mundorf E-Cap NPE in woofer shunt circuits.

I've been lucky so far in that I haven't had to use parallel caps in any of my tweeter or midrange circuits. For the woofer shunt caps, I've been trying to run two of equal value in parallel.

Here's a simple two-way crossover for a JBL 4301B Control Monitor I just finished rebuilding yesterday:

That's a 7.0uF Sonicap Gen1 bypassed with a 0.01uF Vishay-Roderstein MKP1837 in the tweeter circuit and a pair of 8.2uF Mundorf E-Cap NPEs bypassed by a 0.1uF Vishay-Roderstein MKP1837 in the woofer shunt circuit.

I also replaced the 39-year old cement 5 ohm 10W resistor with a 5 ohm 12 W Mills non-inductive resistor.

 

[Oilmaster]

Excellent reply. I agree with everything you wrote. It comes down to personal preference and budget, but I like to use Sonicap Gen1 and ClarityCap PX as series tweeter and midrange caps, bypassed with 0.01uF Vishay-Roderstein MKP1837. I use Mundorf E-Cap NPE in woofer shunt circuits.

I've been lucky so far in that I haven't had to use parallel caps in any of my tweeter or midrange circuits. For the woofer shunt caps, I've been trying to run two of equal value in parallel.

Here's a simple two-way crossover for a JBL 4301B Control Monitor I just finished rebuilding yesterday:

That's a 7.0uF Sonicap Gen1 bypassed with a 0.01uF Vishay-Roderstein MKP1837 in the tweeter circuit and a pair of 8.2uF Mundorf E-Cap NPEs bypassed by a 0.1uF Vishay-Roderstein MKP1837 in the woofer shunt circuit.

I also replaced the 39-year old cement 5 ohm 10W resistor with a 5 ohm 12 W Mills non-inductive resistor.

Nice to see some organized hook-up work !
I'll try to post some photos tonight.

Regarding individual phase shift for paralleled caps: indeed a possible topic of concern.
I measured many phase shift curves for many capacitor brands/models, and each value of each type has it's own phase shift curve.
Hence, when making up a certain value with multiple capacitors, my recommendation would be:
1) try to use one capacitor in the first place
2) use same value caps (or as near as possible values) from the same brand & model, don't break it down in one very large and one very small value
3) only mix different values and/or different brands if you are able to make the phase shift curves

 

[brada220]

I have a question for Elnaldo - The current cross over for the mid-range driver is 162uf combined broken down by 2 60uf NPEs paired with a 42uf - In the posts related to My Boston A400 rebuild - the mid-range driver capacitance is only 160uf - broken down to a 100uf and a 60uf

I thought one needed to replicate the total capacitance to deliver the same quality sound - that's the reason for my having added the 2uf poly cap to the 2 80uf's

What is the viewpoint of the others - do I replicate the total capacitance quantity from the original or do I simply leave it to the round number - 160uf?

 

[brada220]

To Mark T's inquiry - the 2 80mf NPEs have a tolerance of 10% - I was pairing it with a 2.0mf that had a 1% tolerance

 

[StimpyWan]

I'm weird. And anal. I try to replicate the original capacitance as closely as possible, with as tight of tolerance parts as I'm able to find. I have to assume that the stock capacitors were designed for a specific value, for proper performance, for a reason, and why should I second guess that? While I know these older parts can have a 10 or even 20% tolerance, there's no reason to not try and improve upon that. Or use that as an excuse to say a non-stock value should be close enough. I never understood that reasoning?

With the AR90 recap, that I mentioned earlier, all of the series capacitors had a 3% or tighter tolerance. I also paid extra for pair matching too, just to make sure both speakers were L/R matched. I ordered new Mills resistors too, that were matched. Will it help, who knows? Will it hurt? No. So why not?

 

[StimpyWan]

Excellent reply. I agree with everything you wrote. It comes down to personal preference and budget, but I like to use Sonicap Gen1 and ClarityCap PX as series tweeter and midrange caps, bypassed with 0.01uF Vishay-Roderstein MKP1837. I use Mundorf E-Cap NPE in woofer shunt circuits.

I've been lucky so far in that I haven't had to use parallel caps in any of my tweeter or midrange circuits. For the woofer shunt caps, I've been trying to run two of equal value in parallel.

Here's a simple two-way crossover for a JBL 4301B Control Monitor I just finished rebuilding yesterday:

That's a 7.0uF Sonicap Gen1 bypassed with a 0.01uF Vishay-Roderstein MKP1837 in the tweeter circuit and a pair of 8.2uF Mundorf E-Cap NPEs bypassed by a 0.1uF Vishay-Roderstein MKP1837 in the woofer shunt circuit.

I also replaced the 39-year old cement 5 ohm 10W resistor with a 5 ohm 12 W Mills non-inductive resistor.

Thank you for the support and affirmation. It's very appreciated. Plus, I really like your choice of capacitors. I definitely considered SoniCaps and Clarity Caps, for my 90s. But, Jeff at Sonic Craft thought the Mundorf EVO Oils and Supreme caps would work well for me, so that's what I went with.