Thoughts on bypass capacitor upgrades for crossovers-more expensive caps

I am considering upgrading my older speakers which have electrolytic caps on a 40 year old crossover. I have used Solen caps on other speakers in the past for other speakers, but I am considering Mundorf Supreme capacitors to upgrade all my capacitors.
Does anyone have any experience on whether the added expense of “higher end” capacitors makes a difference in speaker crossovers? Also, what are your thoughts on bypassing each capacitor with 0.1 uF high end caps?
Asking for your thoughts based on your AUDIBLE results if you have gone in this direction previously? Thanks

1 Like

i have a pair of 1970 richard allen pavanes. i have replaced the crossovers and been through several iterations.
clarity cap on the treble was better, but the midrange series capacitor (it’s a simple xover relying on driver interaction in a big way) sounded best with a cheap alcap non polar electroytic, the “posh” capacitors just didn’t sound right.
this suggests to me that a bypass cap on the treble might be good, but again i doubt it would on the mid range.


What speakers are they, if you don’t mind my asking? Any pictures of the networks?

In general, yes, I would replace all of the electrolytic with film caps, if the values aren’t crazy. Bypassing doesn’t work particularly well in speakers, as compared to certain applications in electronics (like bypassing power supply capacitors).

There are certainly some differences between brands of caps but there is also a certain amount of “cork sniffing” with them too in the community, not that there is anything wrong with that. I just wouldn’t look for absolutes when it comes to these subjective assessments. Within a given construction type, there are certainly differences but not always a better/worse. The mundorf stuff is great, generally, as you mention, but is moderately spendy and your 40 year old speakers might not be worth the dough versus something with newer/better drivers/cabinets etc.

If you feel like the speaker is worth upgrading, it might be also worth look at replacing the resistors (especially in the tweeter network) with something like a mills WW or caddock thick film.


Never mind. I see Chris already responded

1 Like

Bypass caps can make difference and in my experience can take a great speaker to another level of performance. My speakers use Sonicap I in all but the largest values. I use Erse for the big values. I like the Sonicaps because they’re pretty neutral, detailed and not fatiguing. I recently bypassed my tweeter caps with 0.1uF Miflex KFPM copper caps and it was like turning a focus knob. Definitely recommend. You can get both from

1 Like

I’ve had the same experience with adding Miflex bypass caps. It’s as though the circuit takes on the flavor of the Miflex (for the better) over the Sonicap. It’s easy to do and reverse if not what one likes.

I also agree with the suggestion of Mills resistors, particularly to replace sand cast. These parts aren’t all that expensive either.

But yeah, it’s definitely a try and listen and tweak situation. There is no way anyone can tell you what it will do to the sound unless they have precisely the same speakers, gear and room.

The speakers are ESS AMT 1A’s with Heil Air motion tweeter/mid unit. There is one 12" woofer which also handles part of the mids…The low pass is a 75 uF for the woofer, the Heil Transformer has 26uF and 45uF caps… My choices are Mundorf Oil, Mundorf Supreme and Janztzen Superior Z caps. If you have a suggestion for the big 75uF cap that is less expensive but is very good, please suggest an alternative…
So, your suggestion is not to go with 0.1uF bypasses on the caps? Your preference in caps overall is appreciated. ( I had to look up the definition of cork sniffer to understand what you meant… I get it now)
Thank you Chris

It’s my understanding that bypass caps mess with phase and/or transients due to the fact that they have faster charge and discharge times compared to the cap they’re bypassing. @Chris_Brunhaver is this correct? TIA

A 0.1uF cap won’t cause any problems. Also, with high value caps you can parallel smaller caps but they need to be the same value. So if you have a 45uF cap a couple of 22uF caps along with the 0.1uF bypass will do the same job without messing up the sound. Focus on the tweeter caps. Caps that are parallel with the speaker are not in the direct signal path and therefore will not need an expensive cap but it should still be a film cap.

1 Like

This guy has done extensive testing on different caps for crossovers.

I’m currently using Sonicaps bypassed with Miflex KPCU copper caps with very good results. I’m currently working on building a new set of speakers with crossovers that used the Miflex caps as the main caps with Dueland JDM tinned copper foil bypass caps, but the largest caps needed in this crossover are 20uF. Still, this requires two parallel larger-thsn-beer-can sized 10uF caps.

You might also want to take a look at the inductors. If they use iron core inductors, you will definitely benefit by switching to air core, or better yet, copper foil inductors.

1 Like

Thanks , will check out the Humble Cap site for comparisons. I wonder if Chris Brunhaver would share what brands/models of caps he uses in his own home crossovers. I have to assume he would use caps which provide the best sound based on his hearing. Just asking ???

1 Like