Hi Chris
I've seen excellent correlation with caps that specify ESR notably elecros designed for switching PS (SMPS), Self Resonance is a function of case size mostly, for any cap really.
Ceramics have a sharper minima because the Xc is usually higher than electros and SR is higher. They don't bottom out because ESR is really low compared to Xc. Excepting high C stacked MLC ie custom exotics.
Don't discount X7R ceramics used in PS bypassing and active device decoupling. Also useful in RF up to uwaves using NPO and single layer types.
Film caps are best for critical signal applications like timing, pulse shaping, most high impedance high gain circuits like loop filters/active filters , sample and hold is probably the most stringent application for DA.
Film caps used to pass high currents (passive crossovers) need to be specifically designed for that. They typically will specify dV/dt for a given value (pulse cap). They are constructed with attention to foil/metallization to termination lead-out using low resistance methods ie flame spray,
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Hi Eric,
No, I have a 129 GB partition that has 125 GB used space. It's all app notes and and other technical information. I'm in serious need of a larger hard drive and some reorganizing. Looking through there for these reports will be work. I know I have them in there - somewhere!
Haaalp!
Thank you for posting those links, as I said, excellent reading for everyone.
Hi Bill,
I'll have a look at those, thank you.
Hi infinia,
Really good post.
So you can actually see a resonant peak with these? Cool! I just learned something. Earlier caps I looked at had far too much loss to show anything but a very broad curve, low Q due to high losses.
I have been experimenting with caps meant for SMPS on and off for a while. Some look good and others really don't. I should devote more time to this when I can organize an unbroken stretch.
The world of capacitors. "Better" is not a constant and price doesn't guarantee the suitability of a part for your application. The "best part" is the one that addresses your needs for that specific application. This is where all those "part swapper " guys tend to get it wrong.
-Chris
No, I have a 129 GB partition that has 125 GB used space. It's all app notes and and other technical information. I'm in serious need of a larger hard drive and some reorganizing. Looking through there for these reports will be work. I know I have them in there - somewhere!
Haaalp!Thank you for posting those links, as I said, excellent reading for everyone.
Hi Bill,
I'll have a look at those, thank you.
Hi infinia,
Really good post.
So you can actually see a resonant peak with these? Cool! I just learned something. Earlier caps I looked at had far too much loss to show anything but a very broad curve, low Q due to high losses.
I have been experimenting with caps meant for SMPS on and off for a while. Some look good and others really don't. I should devote more time to this when I can organize an unbroken stretch.
Agree
Stuck with this type in surface mount.
Some care is needed to damp the peaks, small electrolytics work for that. (high losses)
Yes, but things are getting hairy up there. Trace dimensions become components and your PCB material may get exotic. "Dead bug" is one way around that, free air point to point.
Depending on the film dielectric, absolutely. I also use Mica and NP0/C0G type Ceramics as well. I love Polystyrene caps, too bad they are going away. Critical junctions need to be flying to avoid PCB leakage currents, contaminants are another issue. Looks messy but this works better. You can also remove the PCB material around connections like these and guard the remaining ends. That should make construction easier and more consistent.
Now this is an area where understanding is poor. A speaker crossover is a good example. High currents require foil, otherwise the film goes away slowly over time. One clue are the "self repairing" feature of film capacitors. Anything that is self repairing will not survive in applications with high pulse currents. This same issue exists with regular electrolytic capacitors (as opposed to the ones for switching power supplies.
Oh yeah! The concentration of current flow needs to be controlled. The foil connections are typically along the ends in order to avoid current flow around the foil, which also gives you a low inductance design. All these things work together to allow higher dV/dT (which tends to constrict current flow). This is why there is a dV/dT rating on these caps. Regular capacitors don't fair so well with this, so they normally don't even give them a rating.
The world of capacitors. "Better" is not a constant and price doesn't guarantee the suitability of a part for your application. The "best part" is the one that addresses your needs for that specific application. This is where all those "part swapper " guys tend to get it wrong.
-Chris
I think some people would be surprised at how well the impedance of electrolytics holds up at high frequencies. It calls into question the sense of the smallish film cap bypasses that some claim make such a huge difference (good or bad depending on the poster). Here are some more analyzer plots.
Hi Bill
Thanks for all the data, Those Panasonic and Elna electros look really nice into the MHz.
I think it would be interesting to see what some old electros look like or even new "off brand" parts for a comparison.
I've just ordered four Sic Safco Felsic 125 68000uF 16V caps for use in a Hiraga Le Monstre amplifier. The max ripple current of these caps is 35A at 85degreesC and 100Hz - this looks substantially better than Rifa PEH200 25V 68000uF which can handle 23.4A at the same temp and frequency. The PEH200 has marginally lower ESR at 8mohm vs. 10mohm for the Felsic.
Anyone tried these caps? they seem to be used in high-end Naim gear.
http://exxelia.com/fichiers/produits/20090409_133028_felsic_125_frs.pdf
Anyone tried these caps? they seem to be used in high-end Naim gear.
http://exxelia.com/fichiers/produits/20090409_133028_felsic_125_frs.pdf
Are there magazines for the industry with quality tests and comparison tests between certainly capacitors of different brands?If somebody needs them, i have both Jung articles about capacitors. They are very interesting esp. regarding to the most common materials.
Your observation about using different brands is a smart one
Hello Bill
I have two questions:
- The capacitors that you test are they new or used?
Some people in this forum says that a new capacitors (<600 hours) don't reach its optimum characteristics.
- How long the capacitor will keep its characteristics?
Manufacturers give 10 000 hours with working at max current, voltage and temperature. Fortunately we don't put the device under this extreme environment.
What about the impedance after three years for 24H/24H (>26 000 Hours)?
Does anyone have experience in this domain?
Thanks for theses interesting diagrams, 10µF or 22µF seems to be a good choice.
I have two questions:
- The capacitors that you test are they new or used?
Some people in this forum says that a new capacitors (<600 hours) don't reach its optimum characteristics.
- How long the capacitor will keep its characteristics?
Manufacturers give 10 000 hours with working at max current, voltage and temperature. Fortunately we don't put the device under this extreme environment.
What about the impedance after three years for 24H/24H (>26 000 Hours)?
Does anyone have experience in this domain?
Hi Eric,
From what I see in the field, capacitors will last a long, long time (over 20 years) as long as they are not run hot. If you do run them hot, they can be toast in a couple years flat.
I don't recommend running anything electronic all the time, with the exception of frequency standards and voltage standards. In these items, the power supply is both over designed and redundant with a spare standing by for a hot switchover. Obviously, home systems like furnace or air conditioning control PCBs are designed to run all the time, but our audio gear is not.
New capacitors will often finish forming their plates in the first couple hundred hours or less. No, they will not sound any different to your ears. You could probably measure some very low frequency effects, and you can measure changes in the actual part. I imagine it also depends on how long they have been sitting on a shelf somewhere too.
-Chris
From what I see in the field, capacitors will last a long, long time (over 20 years) as long as they are not run hot. If you do run them hot, they can be toast in a couple years flat.
I don't recommend running anything electronic all the time, with the exception of frequency standards and voltage standards. In these items, the power supply is both over designed and redundant with a spare standing by for a hot switchover. Obviously, home systems like furnace or air conditioning control PCBs are designed to run all the time, but our audio gear is not.
New capacitors will often finish forming their plates in the first couple hundred hours or less. No, they will not sound any different to your ears. You could probably measure some very low frequency effects, and you can measure changes in the actual part. I imagine it also depends on how long they have been sitting on a shelf somewhere too.
-Chris
I suppose its dependent on where you use them.
I've used them as cathode bias cap and they were terrible. Very thin and unmusical.
I've also used them as dac chip bypass and they truncated the highs severely and I was told by a well know digital manufacturer that they will not produce highs in that application. He recommended BGs. I really don't like BG's specifically because of their properties of needing to be on all the time and ridiculously long break in times.
I've used them as cathode bias cap and they were terrible. Very thin and unmusical.
I've also used them as dac chip bypass and they truncated the highs severely and I was told by a well know digital manufacturer that they will not produce highs in that application. He recommended BGs. I really don't like BG's specifically because of their properties of needing to be on all the time and ridiculously long break in times.
FMs 40-70% lower impedance than FCs & 50% higher ripple current than FCs.
I tried Panasonic FC caps in power supply for audio part in cd players and in Sansui AU919 and this is the worst sound that i heard. FM series is more listenable but not crisp like Fc. FC capacitors i use for the first cap after graetz. After stabilizator i use Nichicon Muse Kz. For digital the best cap what i tried is Nipon Chemicon PSE but needs many hours for correct sound. Characteristics of manufacturers is not only condition for the choice of capacitor.
Sound is a product of modifications on the basis it needs to make decisions.
I dont like silmic Ii (RFS) to many unreall bass but lovely high tones. To much bass in sound corrupt the midrange area.
Bypass caps sometimes spoil the sound and must be carefull in the choice. Best cap in signal line is no cap. Whenever i can i eject cap from circuit.
Looking at the relatinship quality-price i think the best buy is Panasonic FM
Sound is a product of modifications on the basis it needs to make decisions.
I dont like silmic Ii (RFS) to many unreall bass but lovely high tones. To much bass in sound corrupt the midrange area.
Bypass caps sometimes spoil the sound and must be carefull in the choice. Best cap in signal line is no cap. Whenever i can i eject cap from circuit.
Looking at the relatinship quality-price i think the best buy is Panasonic FM
The Nichicon KZ are rather affordable in european parts sellers (like RS), I consider them also a best buy.
Yes it is, but for triple price of FM. I use KZ in OP power supply. Many hobby diy-ers not buy KZ because is too expensive. You must spend lot of money if you want use capacitors like KZ in all part of device. 100uF/25V FM is 0,16 euro, 100uF/25V Muse KZ is 0,47 euro
Hi impuls,
The sound of a 100µF 35V is not the sound of a 100µF 50V. Increasing DF (dissipation factor) greatly improve sound rendering.
Does Silmic add coloratura or simply reveal coloratura masked by other capacitors? Sometime, changing few things reveals masked problem. In this case don't mask problem again, prefer solving it. By definition, a good stage has.... no particular sound.
What kind of capacitors did you try?
The sound of a 100µF 35V is not the sound of a 100µF 50V. Increasing DF (dissipation factor) greatly improve sound rendering.
Well, well, what is unrealistic, the sound of Elna Silmic II, or the sound of the stage?
Does Silmic add coloratura or simply reveal coloratura masked by other capacitors? Sometime, changing few things reveals masked problem. In this case don't mask problem again, prefer solving it. By definition, a good stage has.... no particular sound.