DIY Replacing Components in Crossovers

I have a couple pair of old speakers that I'm thinking about tinkering around with by replacing existing capacitors and/or resistors with different brands just to get a taste of how different higher quality parts affect the speaker's sound. I don't have any interest in redesigning the crossover networks, only to replace existing parts with better quality parts with the same values to see what kind of results I get. Soldering and the mechanics of replacing the parts isn't an issue for me but I just don't have much experience with the sonics of individual parts. Have any of you done this before? What has worked for you? All things being equal, do you hear much difference replacing crossover parts with better quality components? Any stories to tell? Thanks for looking.



Hey, I have a good suggestion.  Find the caps in series with the tweeter and replace them with something else.  A good brand to start with is Mundorf MKP.  Very affordable and they break in funny. :)  Do the same for the mids. 


Do not replace caps in parallel with drivers.


Thanks Erik. Does Mundorf have a particular sound to them? Curious about "not to replace caps in parallel with the drivers." Is that less bang for the buck doing that?

Some say they don’t matter or matter as much. I find they really do and are in fact in the signal path. If one doubts that, then remove the parallel cap and listen 🤓. Yes, you can save money here and not get the very best. If it’s an electrolytic, then replace as it may have dried out over time.


Don’t forget resistors.  Some nice $5-$7 Mills MRAs will be a very nice sonic improvement for relatively little money.  

Thanks Erik. Does Mundorf have a particular sound to them?


In the affordable kind, I like them a lot more than Solens, very warm, maybe too warm, and like I said, they break in funny so you'll get to hear the sound of caps breaking in.


The issue with parallel caps is that you need to measure the ESR and compensate.  For that you need something like a Parts Express / Dayton DATS which is worth having around. :)

Technically you still need it in series, but it's a little less critical.

This project you have in mind is one of the most cost-effective and rewarding of all the mods or upgrades you could do. The way you are talking is exactly the way to do it. Don't try and reinvent the wheel. Designing a crossover is very technical and very difficult, especially trying to improve on an already professional design.

Most all of the problems people have are due to changing values. The value of caps and inductors affects crossover points, changes the frequency each driver gets, and messes with the sound. Resistors are like volume controls used to turn the volume down on drivers that would other wise be too loud. Almost all the mistakes you hear about are people messing with these values. So measure and be very careful not to change any values.

Audiophiles love to talk about caps. In reality resistors and inductors are equally important. The better ones don't "change" the sound so much as reveal more of what already is there. As you go better and better (read, more expensive) they remove or distort less and less and so you get more and more of what was already there. This is for caps, resistors, and inductors. 

Here is a good source for many different caps -


Here's one for resistors -

 This isn't really comparative but gives some good info on inductors. Coils make a huge difference!


Also if you look at my system page towards the end there are pictures of the crossover upgrade done on my Moab speakers. Several of us on the FB Owner's Group have done projects like this, to varying degrees. Everyone so far extremely happy. You will learn a lot. Good luck!


Great advice guys. Very much appreciated!

MC thanks for the links. I'll give that a study this evening. I wouldn't mind playing around with the inductors as well but I didn't see any values for those on the existing parts. I was simply going to do a one for one replacement for the parts that have their values identified and stick with it for the new part. Yeah, modifying the design of a crossover is way way out of my league. BTW your Melody integrated looks an awful lot like my old Mystery IA21 integrated amplifier I used to have. Wish I never got rid of it. 

Erik, based on your comments it sounds like even replacing parts one for one may be an issue for caps in parallel with the drivers. Your description of verifying the values with a computer program makes my palms sweat a little.

Thanks again guys.


I rebuilt my crossovers with path audio resistors, mundorf silver gold oil caps, jupiter copper foil caps, with duelund silver foil bypass caps on all capacitor !!. the difference was night and day, but it also was a lot of money for the parts. look up humble homemade hifi, you can read all about the difference in capacitors and how they sound. path audio resistors are the best to use sound and size wise.I moved my crossovers to the outside on the back of the speaker in an oak box I built with a plexi glass door, so I can make changes anytime I want without going inside the speaker.

The smart way to go about it, get some high end Deulund bypass caps. Not cheap, but at .01uf you can simply add one to any existing cap and hear improvement without having to buy a cap in some value you might never be able to use anywhere else. Filter caps at .01uf can be used lots of places. The value is too low to affect the circuit, but just enough to smooth and provide rich natural detail.

Next would be resistors. Almost all are the cheap white sand power resistors. Almost anything will be better. Power makes resistors hot, heat increases resistance, resistance lowers voltage. This all happens very fast. Fast enough to affect dynamics. So use quality resistors and don’t hot glue them like everyone does but instead mount them with air flow all around.

Inductors usually have to be measured. This calls for an LCR meter. But you don’t have to measure or even replace inductors to improve them. An inductor is a coil of wire. Coils of wire produce magnetic fields. Magnetic fields interact with wires. To minimize this we place inductors at right angles to each other. At least that is what we’re supposed to do. If your speaker has more than one inductor and they are hot glued flat to the board then you can improve the sound simply by moving one to be at right angles to the other.

Also inductors work slightly better with the signal going from the inside to the outside. Not a huge difference but it is there. If it is easy to reverse the leads then go for it. Don’t cost nothin’.

In case you are keeping score that is 3 crossover upgrades I have given you that cost nothing. And we haven’t even gotten to the rubber bands.

Grannyring, bought a number of Duelund CAST PIO caps as part of a crossover upgrade. These caps are out of stock most places.

So for the midrange section, where I need 13.0uF, I bought 8.2 + 4.7 + 0.1 for one speaker and 8.2 + 3.3 + 1.5 for the other speaker.

The Duelund CAST PIO 100 Vdc caps are disk shaped, with greater uF values (like 8.2 in my case) having modestly greater height or thickness than lesser values like 4.7uF, but the roughly 7” diameter is the same for the two values just mentioned and I think for the 3.3 as well.

It seems to me that the only real option is to put the caps on top on each other, like layers in a layer cake. The leads come out of the top of the caps, close to the outside of the disk-shaped caps. So I would need some sort of spacers so that the top caps aren’t resting on the leads of the cap underneath.

I will also need a way to secure the caps to the board. I don’t like the idea of plastic ties per se, and might be more interested in a bolt screwed through the board with the thread end toward the ceiling, and some sort of clip. Several bolts / clips per cap. I may end up having to settle for plastic ties, though.

I won’t have this problem for the woofer section, where I will be using Auricap XO+ (a brand new ‘uptier’ from the XO which HHHiFi rated 11 vs 15 for the Duelunds that I selected for the other sections), or one of the tweeter caps. The other tweeter cap is 5.6 + 0.22 + 0.22 to get to close to 6.0, so I think only the 13.0 need in the midrange section needs a solution.

Any thoughts on how to best put 8.2 + 4.7 + 0.1 on the one board and 8.2 + 3.3 + 1.5 on the other, and whether stacking the discs on top of one another might cause performance issues due to the magnetic fields of each etc?


you can use hot glue they make it in all strengths. if you want to remove a cap you would use alcohol and a q tip and that will soften the glue. a better way is epoxy but not removable. I stack caps when there is no room. .

If you can get past his self promoting BS this is a good site to get some info too.

how you physically arrange the network plays a significant role, there is a lot happening 

here is a video that he shows the effect of different component layouts.

What kind of speakers do you have? What kind of drivers? How much money do you plan to invest?

I just rebuilt my Altec 604E crossover using original crossover schematics. I just use original inductors. Capacitors in most vintage speakers are of very bad quality, especially electrolytic. Potentiometers also are very bad for sound.

Vintage Altec drivers are very well built with huge alnico magnets and good quality diaphragms. So they are really worth the investment. I can say, these speakers with original and rebuilt crossovers are completely different speakers.

I used Duelund resistors. Mills are transparent but don't hold complex music as good as Duelund.

For the 14uF capacitor I used a mix of: Duelund RS, Jupiter VT, Auricap XO, Dueuland Silver bypass.

For 3uF I used Jensen Aluminum foil PIO and Duelund bypass Cu-Sn.

But I reused most of the capacitors from previous projects.

For good value for money I can recommend Auricap XO or MIFLEX KPCU-01/03 if you want really high quality copper foil capacitors.


Hi @arch2 ,

I also recommend to bypass each capacitor in crossover by Russian polystyrene k71-7 capacitors. It makes sound more smooth and transparent. Even if the big capacitor is already bypassed by Duelund Bypass adding K71-7 helps!




Thanks for the responses guys. I’m going to do baby steps and start with replacing capacitors and resistors just to get a feel for the sound changes with each upgraded part. I’m not going to go crazy with parts expense but decent enough to get a feel for sound vs price. I’ll probably make that my project after Xmas. 

Thanks Erik. Does Mundorf have a particular sound to them? Curious about "not to replace caps in parallel with the drivers." Is that less bang for the buck doing that ~~~~~~~~~~~~~~~~~ type in mundorf caps, you will see all my comments on mundorf caps in xovers. better get a pair of high end full range, dump the vintage.