What's Best in Crossover Capacitors

[ack]

As if this form wasn't technical enough, it's about to get worse... So here's the deal; I am going to punt on buying a new pair of Summit X's and explore upgrading the crossovers in my ML Odyssey's. The sound is so beautiful that I can't justify the X purchase... yet.

So I have the schematic from ML, and there are two crossovers really, one for the panel and another for the woofers. First the woofers - simple crossover per woofer: one inductor in series as you'd expect, one capacitor in parallel with the woofer. The capacitors are 100uF (forward firing) and 170uF (backward firing); these will be replaced by Mundorf MKP, with 100pF and 150pF respectively, and it's hard to find better caps with such high values. Question #1: what will the 150uF cap do to the rear firing woofer, as opposed to the original 170uF, and by extension, what will a 220uF cap do?

Then comes the panel - here we have four capacitors: 10uF, 13uF, 51uF (all polypropelene) and one 47uF polyester. The question is then - what are the best capacitors for this type of application? For the three polypropelenes I can only find the very expensive but super-performing Deulund VSF's, for a total of $1500 per speaker! I can't find yet a *worthy* replacement for the 47uF . Next, what happens if you replace a polyester with a polypropelene?

There are some incredible caps out there, from the Mundorf Supremes, to ClarityCaps, VCaps (some, not all), all the way to the Deulunds, and some interesting comparison blogs, like audiocircle, humblehomemadehifi, and laventure.

Whatever I chose must not alter the overall character - for example, I read that the Mundorf Supreme Silver in Oil et al tip up the treble at the expense of the bass, while the Deulunds are allegedly completely neutral.

What do the more knowledgeable have to suggest?

PS: I'll start another thread on coils and resistors later on; for resistors at least, I am going with Mundorf M-Resist...

[MylesBAstor]

As if this form wasn't technical enough, it's about to get worse... So here's the deal; I am going to punt on buying a new pair of Summit X's and explore upgrading the crossovers in my ML Odyssey's. The sound is so beautiful that I can't justify the X purchase... yet.

So I have the schematic from ML, and there are two crossovers really, one for the panel and another for the woofers. First the woofers - simple crossover per woofer: one inductor in series as you'd expect, one capacitor in parallel with the woofer. The capacitors are 100uF (forward firing) and 170uF (backward firing); these will be replaced by Mundorf MKP, with 100pF and 150pF respectively, and it's hard to find better caps with such high values. Question #1: what will the 150uF cap do to the rear firing woofer, as opposed to the original 170uF, and by extension, what will a 220uF cap do?

Can't you parallel and build a bank of caps totalling 170 uF? That's what I did with my old Maggies to get the correct value. Is it a space issue? As I remember reading, it is preferable to use say 10x10 uF to one 100 uF cap.

Then comes the panel - here we have four capacitors: 10uF, 13uF, 51uF (all polypropelene) and one 47uF polyester. The question is then - what are the best capacitors for this type of application? For the three polypropelenes I can only find the very expensive but super-performing Deulund VSF's, for a total of $1500 per speaker! I can't find yet a *worthy* replacement for the 47uF . Next, what happens if you replace a polyester with a polypropelene?

Didn't do this with the ML but with the 12 uF polyester that was used on the Maggie 3A ribbon. And it was not trivial. More spatial information, less blurring of transient attack, not to mention intranote silence as well as greater transparency. On the midrange, that "Maggie" coloration, that carboardy sound, was vastly reduced and the midrange and bass was much tighter and quicker.

There are some incredible caps out there, from the Mundorf Supremes, to ClarityCaps, VCaps (some, not all), all the way to the Deulunds, and some interesting comparison blogs, like audiocircle, humblehomemadehifi, and laventure.

Whatever I chose must not alter the overall character - for example, I read that the Mundorf Supreme Silver in Oil et al tip up the treble at the expense of the bass, while the Deulunds are allegedly completely neutral.

What do the more knowledgeable have to suggest?

PS: I'll start another thread on coils and resistors later on; for resistors at least, I am going with Mundorf M-Resist...

Only used the Mundorf Au/Ag in oil caps in my tape preamp. and have been very happy. Compared to some other caps, they were smoother, less grainy, greater transparency and much better imaging. In addition, not as harsh as some lesser caps. As far as the Duelands go, am getting some in next week to try in my tape preamp. Am going to burn them in on the Cable Cooker for 300 hrs and then install them. Let you know in 6-8 weeks how they sound compared to the Mundorfs.

[ack]

Can't you parallel and build a bank of caps totalling 170 uF? That's what I did with my old Maggies to get the correct value. Is it a space issue? As I remember reading, it is preferable to use say 10x10 uF to one 100 uF cap.

I hope this is NOT the case - by the time one cap charges the other may discharge and a huge mess ensues. I have tried this on a tweeter before with 3 or 4 caps and the sound was just dead.

Didn't do this with the ML but with the 12 uF polyester that was used on the Maggie 3A ribbon. And it was not trivial. More spatial information, less blurring of transient attack, not to mention intranote silence as well as greater transparency. On the midrange, that "Maggie" coloration, that carboardy sound, was vastly reduced and the midrange and bass was much tighter and quicker.

So polypropelenes are better than polyester? Good.

As far as the Duelands go, am getting some in next week to try in my tape preamp. Am going to burn them in on the Cable Cooker for 300 hrs and then install them. Let you know in 6-8 weeks how they sound compared to the Mundorfs.

I'd hate if I had to spend $3000 on six capacitors, and still be two short... Cable Cooker huh? I think I may need one too.

Thanks for the fast response.

[MylesBAstor]

I hope this is NOT the case - by the time one cap charges the other may discharge and a huge mess ensues. I have tried this on a tweeter before with 3 or 4 caps and the sound was just dead.

Hmmm....don't quite understand that? Sound more like in series than paralleled. Never heard that in my system. When I did it, I used Rel PPs.

On another note, could also experiment with bypassing some of the polypropes with small value, say teflon (since don't think could find any polystryrenes) caps.

[fas42]

Playing with capacitors like this is far from trivial, if you use the wrong combination of values paralleled you will end up with a mini disaster, as far as sound quality is concerned. Ben Duncan did an excellent series of articles on this over 25 years ago, unfortunately not on the net as far as I know.

A rule of thumb if trying film caps, those with names starting with "poly" is that either you combine values that are very close together or very far apart, use a 50 times or more ratio with the latter. Doing other will allow a resonance, an impedance peak will occur, and you don't want this!!

Paralleling lots of caps of same value is generally good, depending on what you're after ...

Frank

[MylesBAstor]

Playing with capacitors like this is far from trivial, if you use the wrong combination of values paralleled you will end up with a mini disaster, as far as sound quality is concerned. Ben Duncan did an excellent series of articles on this over 25 years ago, unfortunately not on the net as far as I know.

A rule of thumb if trying film caps, those with names starting with "poly" is that either you either combine values that are very close together or very far apart, use a 50 times or more ratio with the latter. Doing other will allow a resonance, an impedance peak will occur, and you don't want this!!

Paralleling lots of caps of same value is generally good, depending on what you're after ...

Frank

I'm not sure they still do it but the old MIT Multi-caps were essentially multiple paralleled caps all rolled up into one.

[ack]

So the results after the first change - the cap to the rear woofer - are very encouraging... I can't believe people still use electrolytics in the crossover. Testing with warble tones after finishing just one speaker, the difference is subtle but audible if you put your ear next to the woofer - the modified is clearly clearer, the other muddier.

Next up, the front woofer electrolytic caps and the Solen panel caps (Class B apparently, popular in power supplies because of the high values and high voltage ratings, but not so good in crossovers).

[MylesBAstor]

So the results after the first change - the cap to the rear woofer - are very encouraging... I can't believe people still use electrolytics in the crossover. Testing with warble tones after finishing just one speaker, the difference is subtle but audible if you put your ear next to the woofer - the modified is clearly clearer, the other muddier.

Next up, the front woofer electrolytic caps and the Solen panel caps (Class B apparently, popular in power supplies because of the high values and high voltage ratings, but not so good in crossovers).

Sounds like you're making the right decision!

It'll take a few hours for the caps to sound good--not to mention, once you shut down the estats, they take 24 hrs to recharge. Hard to judge sound til then

[ack]

Playing with capacitors like this is far from trivial, if you use the wrong combination of values paralleled you will end up with a mini disaster, as far as sound quality is concerned. Ben Duncan did an excellent series of articles on this over 25 years ago, unfortunately not on the net as far as I know.

A rule of thumb if trying film caps, those with names starting with "poly" is that either you combine values that are very close together or very far apart, use a 50 times or more ratio with the latter. Doing other will allow a resonance, an impedance peak will occur, and you don't want this!!

Paralleling lots of caps of same value is generally good, depending on what you're after ...

Frank

Frank, sage advice, thanks! So I am having trouble breaking down a 47uF and a 51uF capacitor - how would you do it? There are extremely expensive 50uF Duelund, or 17uF (3x) ClarityCaps etc., but I don't want to spend thousands of dollars for these two values. I can do two 22uF Mundorfs in place of the 47 (because the value is within the tolerance range), and something similar for the 51 - would that be acceptable?

[Speedskater]

We have a nasty typo here:

The capacitors are 100uF (forward firing) and 170uF (backward firing); these will be replaced by Mundorf MKP, with 100pF and 150pF respectively, and it's hard to find better caps with such high values.

Somehow the uF became pF and that just won't work well.