Hello!
I'm trying to do a Echo Base (delay guitar pedal), but with good quality components.
I have read threads, and wima capacitor seems to be the best value for price.
There is a lot of capacitor type, and i have found theses posts:
And take a look at the bom:
http://s3.noelshack.com/uploads/images/7393840352019__2.png
Wima FKP2 have a range of 100pF to 0.033uF.
WIMA
So i can only use 4 FKP2!
In my shoping card, all other capacitors are MSK2... And it have been said that they are not good for audio!
So what should i buy?
And i have another project with 20x 100nF capacitors...
I have searched, but haven't found which one buy in this case!
Thanks a lot!
Boris.
I'm trying to do a Echo Base (delay guitar pedal), but with good quality components.
I have read threads, and wima capacitor seems to be the best value for price.
There is a lot of capacitor type, and i have found theses posts:
And take a look at the bom:
http://s3.noelshack.com/uploads/images/7393840352019__2.png
Wima FKP2 have a range of 100pF to 0.033uF.
WIMA
So i can only use 4 FKP2!
In my shoping card, all other capacitors are MSK2... And it have been said that they are not good for audio!
So what should i buy?
And i have another project with 20x 100nF capacitors...
I have searched, but haven't found which one buy in this case!
Thanks a lot!
Boris.
One consideration is the corner frequency of the high pass filter that is created when you place a series capacitor in front of the impedance of your input stage.
I don't see a handy link to a schematic for this project, but it sure would take less time than trying to reverse-engineer the schematic from the PCB layout. The schematic would show you the input stage and allow you to calculate the input impedance from the chip specifications and gain resistors. Once you know the input impedance, you should be able to calculate an appropriate capacitance for your WIMA parts based on the frequency response that you desire. e.g., you might want to extend below 20 Hz for subsonic effect, or you might want to high pass above 20 Hz if your guitar does not need those really low frequencies.
I don't see a handy link to a schematic for this project, but it sure would take less time than trying to reverse-engineer the schematic from the PCB layout. The schematic would show you the input stage and allow you to calculate the input impedance from the chip specifications and gain resistors. Once you know the input impedance, you should be able to calculate an appropriate capacitance for your WIMA parts based on the frequency response that you desire. e.g., you might want to extend below 20 Hz for subsonic effect, or you might want to high pass above 20 Hz if your guitar does not need those really low frequencies.
how do i tell bad caps help
do these look real
from viodol
WIMA Polyester Capacitors MKS4 0.022uF 400V 10% - 3PCS | eBay
do these look real
from viodol
WIMA Polyester Capacitors MKS4 0.022uF 400V 10% - 3PCS | eBay
Attachments
i would take vishay box caps over wima anyday, wima has the bonus of being red, which is why i think they are so popular. other nice small value film and foils (not just metalized films) are the amtrans polypropylene, evox/rifa film and foil and relcap. do not buy wima from ebay full stop; that is 100% fake in that pic. even the legit one would be polyester crap. go for polypropylene whenever size and cost allows
yeah i know that, but most are not film and foils, they are generally metalized film and any of their film and foils in any useful value are massive and meant for much higher voltage than what they are generally used for. i just find all this fuss about wima to the point of their being numerous fakes, to be a bit funny, as they are at best equivalent to numerous other similar parts and in some cases inferior. panasonic make excellent pp film caps also.
i like blue better also 
if the op can find them in the right value, you really cant go past the vishay/sprague orange drop
i recomend checking out audiocap.net they have a good range all in one place, as well as some higher end ones (not crazy high) like auricap, which is another favorite of mine. here is the evox/rifa film and foil small box cap, only in small values up to 4.7nf at that place and they are not easy to find elsewhere.
they have legit fkp 2/3 from wima if you vust and at a decent price. personally for filters i would be looking at polystyrene if the placement isnt going to be subjected to high temp. its a great site and they have a massive range of high end power supply electrolytics too, like the evox/rifa phe169, which others as well as myself see as the best power supply cap on the planet
if the op can find them in the right value, you really cant go past the vishay/sprague orange dropi recomend checking out audiocap.net they have a good range all in one place, as well as some higher end ones (not crazy high) like auricap, which is another favorite of mine. here is the evox/rifa film and foil small box cap, only in small values up to 4.7nf at that place and they are not easy to find elsewhere.
they have legit fkp 2/3 from wima if you vust and at a decent price. personally for filters i would be looking at polystyrene if the placement isnt going to be subjected to high temp. its a great site and they have a massive range of high end power supply electrolytics too, like the evox/rifa phe169, which others as well as myself see as the best power supply cap on the planet
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It's a bit hard to tell without a schematic! A capacitor should be chosen based on what it's intended use is. The datasheet should be able to help with this. At the most basic level if it is a coupling cap then look for coupling cap in the applications of the datasheet for instance you might look at two polypropylene caps, one might say it is good for coupling, the other may be an X2 interference suppression cap Which one would you choose?
without really knowing what the application is, I'll throw the good old vishay MKP1837's into the ring, they would cover most of the values you have on that bom, and their tolerances are excellent.
The other thing you should consider is that some of the caps may be supply decoupling caps for the IC's and depending on the particular IC's some NPO ceramics may actually be the best choice for that duty.
For the values available I do like the FKP2's, though if you are thinking of substituting them for ceramics make sure it is actually the right thing to do (ie ceramics were specced for cost rather than because of the specific advantages they have with high frequencies).
Tony.
for instance you might look at two polypropylene caps, one might say it is good for coupling, the other may be an X2 interference suppression cap Which one would you choose? without really knowing what the application is, I'll throw the good old vishay MKP1837's into the ring, they would cover most of the values you have on that bom, and their tolerances are excellent.
The other thing you should consider is that some of the caps may be supply decoupling caps for the IC's and depending on the particular IC's some NPO ceramics may actually be the best choice for that duty.
For the values available I do like the FKP2's, though if you are thinking of substituting them for ceramics make sure it is actually the right thing to do (ie ceramics were specced for cost rather than because of the specific advantages they have with high frequencies).
Tony.
I've had excellent subjective (transparent sounding) experience with Wima film & foil FKP-2 in treble equalizer and DAC analog reconstruction filter applications. Better than via the (still very good sounding) metalized film MKP types I've tried from various vendors. Unfortunately, the FKP-2 are only available in low nF range of values, which typically precludes them from practical use in audio signal coupling application.
Wima also offers the FKP-3 series of film and foil units ranging up to several hundred nF, which makes them more practical for signal coupling than the FKP-2 series. Other than their range of values, I'm uncertain as to any difference between the FKP-2 and FKP-3 series.
For those of us located in the U.S., both the Wima FKP-2 and FKP-3 may be obtained in single unit quantities from distributor; Mouser.com
Wima also offers the FKP-3 series of film and foil units ranging up to several hundred nF, which makes them more practical for signal coupling than the FKP-2 series. Other than their range of values, I'm uncertain as to any difference between the FKP-2 and FKP-3 series.
For those of us located in the U.S., both the Wima FKP-2 and FKP-3 may be obtained in single unit quantities from distributor; Mouser.com
For the small difference in price I would not be buying from ebay but from the likes of Farnell and RS Components who are reputable dealers.
+1
Capacitors are probably the single most faked component (next to semiconductors like transistors and opamps) available. If building anything other than hodgepodge stuff for benign tasks (like LED flashers or something silly) it's not worth the hassle of fooling around with counterfeit parts.
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