I am about to build a new pair of speakers that will require a 60-80uF cap in series with a fostex fe207e driver (15" eminence alpha 15 handling bass).
I am keen to try the russian military paper in oil caps readily available on Ebay. I've used smaller values of these to great effect both before tweeters and as coupling caps in amps. Has anyone used anything like this before?
Example of Ebay Russian cap
I obviously won't use an electrolytic, and I'm not keen on the big solen fast caps as I don't like what they do as coupling caps. Are there any other options out there that I've missed?
Have a look at this example of a Russian ebay cap. How do you think these would perform in series with a full range driver (operating from 200-300Hz and up)? Obviously you'd need to find one of a suitable value or double up....
Huge Russian PIO cap...
I am keen to try the russian military paper in oil caps readily available on Ebay. I've used smaller values of these to great effect both before tweeters and as coupling caps in amps. Has anyone used anything like this before?
Example of Ebay Russian cap
I obviously won't use an electrolytic, and I'm not keen on the big solen fast caps as I don't like what they do as coupling caps. Are there any other options out there that I've missed?
Have a look at this example of a Russian ebay cap. How do you think these would perform in series with a full range driver (operating from 200-300Hz and up)? Obviously you'd need to find one of a suitable value or double up....
Huge Russian PIO cap...
Hey guys I need an opinion on what cap I should use to replace the blown ones in my crossovers. I bought the speakers 15 years ago and they where store demos to boot. I opened them up to find the same little cap in each speaker to be blown. All other caps seem to be intact (tops of the other electrolytic caps not bulged etc) which they're all the same voltage rating (just physical sizes are different.)
The blown cap is the little green electrolytic in the center of the picture below. It's specs is 6mfd / 100volt / 10% tolerance.
The replacement caps the closest I could find in electrolytic is 6.8uF (which I assume is the same meaning as mfd) / 250volt / 20% tolerance (the blue ones in the pic.) The larger black caps are Dayton Poly caps which I've read are suppose to be better then electrolytic caps. The specs on those are 6.2uF / 250volt / 1% tolerance which spec-wise matches the stock ones more closely.
But on each of my crossovers I noticed they also used the big yellow mylars (two in each crossover) along with the electrolytic caps (I think three in each crossover) plus there looks to be a resistor and the self reseting tweeter fuse. Now I have to wonder and ask you guys, might there be a specific reason they would use both together other then cost where I should replace the caps with the same style (electrolytic) and not use the poly caps?
I know the crossovers have a self reseting tweeter protection circuit, would a electrolytic cap need to be used in this circuit, or are caps specifically used has frequency filters? I've been running the speakers for years with the caps taken out so anything should hopefully be an improvement.
I'm gonna go ahead and install the electrolytic caps for now and if you guys can confirm I can use the higher quality poly caps in place, I'll just go ahead and swap them out later and maybe replace all the electrolytic caps with polys (but I need to confirm they use electrolytics for no specific reason other then cost.)
Thanks for any help. I'll take photos of the crossovers once I take them out.
The blown cap is the little green electrolytic in the center of the picture below. It's specs is 6mfd / 100volt / 10% tolerance.
The replacement caps the closest I could find in electrolytic is 6.8uF (which I assume is the same meaning as mfd) / 250volt / 20% tolerance (the blue ones in the pic.) The larger black caps are Dayton Poly caps which I've read are suppose to be better then electrolytic caps. The specs on those are 6.2uF / 250volt / 1% tolerance which spec-wise matches the stock ones more closely.
But on each of my crossovers I noticed they also used the big yellow mylars (two in each crossover) along with the electrolytic caps (I think three in each crossover) plus there looks to be a resistor and the self reseting tweeter fuse. Now I have to wonder and ask you guys, might there be a specific reason they would use both together other then cost where I should replace the caps with the same style (electrolytic) and not use the poly caps?
I know the crossovers have a self reseting tweeter protection circuit, would a electrolytic cap need to be used in this circuit, or are caps specifically used has frequency filters? I've been running the speakers for years with the caps taken out so anything should hopefully be an improvement.
I'm gonna go ahead and install the electrolytic caps for now and if you guys can confirm I can use the higher quality poly caps in place, I'll just go ahead and swap them out later and maybe replace all the electrolytic caps with polys (but I need to confirm they use electrolytics for no specific reason other then cost.)
Thanks for any help. I'll take photos of the crossovers once I take them out.
Jonasa........My experience with that resistor in series with your parallel woofer shunt capacitor is this: In my simulations, I found that experimenting with different resistor values provided me the ability to shape the rolloff of the woofer frequency response curve when designing my crossover......The rolloff becomes more rounded, depending on the resistor value............Another experiment I am now undertaking is this: I am gonna bypass my woofer shunt capacitor with a 1uF film/foil capacitor........It is reported that this technique improves woofer speed and precision.........Respectfully...Omni
Jonasa......So what capacitors have you decided to buy?.....Yeah, it's been a while, but sometimes that's what it takes......I am in the process of tweaking my own crossover, and am experimenting with a variety of capacitors......I will probably end up with a few cascade bypass techniques in all my sections.....In the woofer shunt position, I have a Solen 80uF which will be bypassed with a 1uF Film/Foil...........Midrange series I have Claritycap SA series which currently is bypassed with a Mundorf Supreme.....That may change to being bypassed with a NorthCreek Harmony capacitor, and then a Film/Foil cap......The tweeter section is the most delicate section to work with and I have replaced my current Claritycap SA with a Hovland, which will need more bypassing.......The problem with the Clarity cap SA in the tweeter section was this: The upper end was smooth sounding, however, it did sound a little rolled off, especially in the sounds of the cymbals, particularly the high hats.......It is kinda weird, though, because when I read Tony Gees' capacitor comparison, he made the same remark regarding the rolled off sound of Clarity cap SA in the upper end......So when I installed the Hovland Musicap, the sound certainly brightened, but, too much.....There is an inherent sibilance occuring.......So I am gonna bypass with a Crecendo Film/Foil cap which from my listening tests will indeed smooth this out.....In addition to that, I will be cascade bypassing with another capacitor......This capacitor is gonna be a Teflon V-cap.........Teflon capacitors are highly regarded for their ability to create a very transparent soundstage....So I am playing with this as well.......There is a great article discussing the importance of the capacitors used for the tweeter section by Lynn Olson, The Evolution of The Crossover..........He is sharing his experience with The Ariel......You may find it interesting................Another change I am making is in the series inductor of the midrange, and a few other value changes in my resistors, however that is an entirely different story............Keep us posted................Omni
I must confess that discussions on the audibility of different capacitor types in audio systems do not hold a lot of interest for me because differences of statistical significance have not been shown in properly conducted tests, that I am aware of. It was therefore a bit surprising to see mention in a recent AES Journal (Audio Eng' Soc') of a paper to be presented on the subject of mechanical resonances in capacitors in audio applications. I imagined it was refering to microphony due to external vibration and did not think much more about it.
A few days ago I received the May issue of Electronics World, which, sadly is not what it used to be re articles on audio. But, lo and behold, there is an article on capacitors for audio by Paul Dodds, Senior engineer at Clarity Cap. The central thesis of the article is mechanical resonances; but not due to microphony from external vibration, but, rather, internal mechanical resonances between the layers of film and metal foil.
With an applied voltage, irrespective of polarity, adjacent layers of the metal foil are attracted thus compressing the dialectric. It is this effect that can excite mechanical resonances in the foil/film. The resonance is excited at twice the frequency of an applied AC signal because the positive half cycle causes attraction between layers, as does the negative half cycle. These resonances are said to lie in the range 5 to 25KHz, presumably meaning 5KHz to 25KHz.
Having identified a distortion? mechanism the company engaged the University of Salford to conduct listening tests on supplied samples of capacitors including low resonance types. In the presence of proper blind test protocols the low resonance types generated a 70 percent preference rating. Preferences for "spatial information" and "clarity" also produced winning scores. So what does it all mean? From some rather poorly described plots it seems the resonances are quite high Q, meaning that if you were to play music in certain keys you may never hear them! For applications such as ordinary coupling capacitors the capacitance value is going to be changed at an audio rate at certain discrete frequencies raising the question; are we talking about a linear distortion or a non linear distortion or maybe neither.
A few days ago I received the May issue of Electronics World, which, sadly is not what it used to be re articles on audio. But, lo and behold, there is an article on capacitors for audio by Paul Dodds, Senior engineer at Clarity Cap. The central thesis of the article is mechanical resonances; but not due to microphony from external vibration, but, rather, internal mechanical resonances between the layers of film and metal foil.
With an applied voltage, irrespective of polarity, adjacent layers of the metal foil are attracted thus compressing the dialectric. It is this effect that can excite mechanical resonances in the foil/film. The resonance is excited at twice the frequency of an applied AC signal because the positive half cycle causes attraction between layers, as does the negative half cycle. These resonances are said to lie in the range 5 to 25KHz, presumably meaning 5KHz to 25KHz.
Having identified a distortion? mechanism the company engaged the University of Salford to conduct listening tests on supplied samples of capacitors including low resonance types. In the presence of proper blind test protocols the low resonance types generated a 70 percent preference rating. Preferences for "spatial information" and "clarity" also produced winning scores. So what does it all mean? From some rather poorly described plots it seems the resonances are quite high Q, meaning that if you were to play music in certain keys you may never hear them! For applications such as ordinary coupling capacitors the capacitance value is going to be changed at an audio rate at certain discrete frequencies raising the question; are we talking about a linear distortion or a non linear distortion or maybe neither.
Re: Crossover capacitor choise
the best capacitors in the world for crossovers is russian - paper in oil in metal container - belive me, i build speakers over 20 years!
for resistor - put 6.8 ohm if your woofer is 8 ohm!
Jonasa said:I want to upgrade the capacitors in my crossover network.
After searching over the net I found that Auricaps are one of the better capacitors for crossover networks.
For the tweeter part in my crossover are two capacitors in the signal path. So it will make sense to choose expensive Auricap capasitors.
But in the woofer part of the crossover is a 12 micro farad capacitor in parallel over the woofer (with a 1 ohm serial resistor, I don't know what the function of this resistor is). This means that the capacitor in not in the signal path.
Does make it sense to choose also an expensive capasitor for the woofer part in de crossover?
the best capacitors in the world for crossovers is russian - paper in oil in metal container - belive me, i build speakers over 20 years!for resistor - put 6.8 ohm if your woofer is 8 ohm!
Member
Joined 2004
Keith Taylor said:
This may be off interest. Paul Dodds explains the research in this short movie:
Dodds on resonances
I am waiting on more info about this research, the paper is under AES copyright now. I expect more info soon.
Regards
Roland
We've been fiddling around with various caps (all 0.22uF/500-630V) in a cheap Chinese headphone amplifier (the 708B). Surprisingly (to me - ever the doubter) there was quite a difference between a number of caps in a couple of the sections.
The cheaper (red writing on a white plastic) Mundorfs were the best that we found, along with some interesting Russian PIO caps. Beating out Rubicons, Hovlands, Vishay (can't remember the type), 'no name yellow', Wimas - amongst others.
Probably not much use for you in you quest - but my advice is: listen. The caps you're looking for might not be the most expensive. This friend of mine, who's helping me with the amp, is running a crossover from his F3 amp, and has found that most of the expensive caps were just too bright - he has these enormous yellow items that cost about $10 each and they do the trick.
The cheaper (red writing on a white plastic) Mundorfs were the best that we found, along with some interesting Russian PIO caps. Beating out Rubicons, Hovlands, Vishay (can't remember the type), 'no name yellow', Wimas - amongst others.
Probably not much use for you in you quest - but my advice is: listen. The caps you're looking for might not be the most expensive. This friend of mine, who's helping me with the amp, is running a crossover from his F3 amp, and has found that most of the expensive caps were just too bright - he has these enormous yellow items that cost about $10 each and they do the trick.
Member
Joined 2004
Hi Rinx,
Cloth ears is as far as i can tell, trying to point out there are no best capacitors. It all depends on the application.
I agree wholeheartly on this! It's a combination. The too bright caps he is talking about may work wonder with a cheap softdome tweeter and could be a disaster with a metal dome.
Just try and listen.
Cloth ears is as far as i can tell, trying to point out there are no best capacitors. It all depends on the application.
I agree wholeheartly on this! It's a combination. The too bright caps he is talking about may work wonder with a cheap softdome tweeter and could be a disaster with a metal dome.
Just try and listen.
roland bios said:
Thanks Roland - exactly!
Rinx, the Vishay (and they are such a large company nowadays) were axial, about 40mm long/10mm diameter, with a blue plastic film over the metal casing. They are at my friends' place, so I cannot be exact - but they were reasonably priced, so would not be the 'good' ones.
I think there's one really good product from Vishay, which are a very good resistor, but they now produce so much (?half the worlds' resistors and capacitors?).
Thank you.
Well, so far I have get very good response using Vishay caps. Some guy in this forum said, they are the very best (of course for his application), even better than Mundorfs and so on + they are not excpencive, about 2-3 bucks for piece.
I ll found post here http://www.diyaudio.com/forums/showthread.php?s=&threadid=105996&highlight=
Mines are blue and grey, block shape. Havent tryed not yet...
Well, so far I have get very good response using Vishay caps. Some guy in this forum said, they are the very best (of course for his application), even better than Mundorfs and so on + they are not excpencive, about 2-3 bucks for piece.
I ll found post here http://www.diyaudio.com/forums/showthread.php?s=&threadid=105996&highlight=
Mines are blue and grey, block shape. Havent tryed not yet...
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