Those 68,000uF capacitors probably need something a bit bigger to bypass them effectively. Something like a 100uF electrolytic designed for switched-mode power supplies, and connected adjacent to the load might be a good idea.
I've never been entirely happy with the sound of SM.
I've never been entirely happy with the sound of SM.
EC8010 said:
SM??? I know the bedroom version....sounds pretty bad😉 but I guess you mean something else?
Any recomendations of decoupling caps for PS?? and why so big, 100uF sounds like a lot in my ears.
Magura🙂
Torture?
SM (Silvered Mica) seems to screech a bit to me. Agreed, 100uF seems large, but it's tiny compared to 68,000uF. Just look for a capacitor with low ESR (Equivalent Series Resistance) that's intended for switchers.
SM (Silvered Mica) seems to screech a bit to me. Agreed, 100uF seems large, but it's tiny compared to 68,000uF. Just look for a capacitor with low ESR (Equivalent Series Resistance) that's intended for switchers.
Hi,
Sean Connery would shay: Thoshe are Shilvered Mica capashitorsh, shon.
Reread the entire sentence,Magura, 100µF close to the load.
You can still get rid of your teflon caps at the same point.😀
BTW, I'd be careful with bypassing.
Increased risk of stray inductance and I often hear these bypassed electrolytics as if they'd be emphasizing the high frequencies somehow.
I find it much less obvious by using big values like 10µF MKPs, ocasionally bypassed with a single 0.100µF MKP of the same brand.
Cheers, 😉
P.S. I did not get your e-mail.
Sean Connery would shay: Thoshe are Shilvered Mica capashitorsh, shon.
Reread the entire sentence,Magura, 100µF close to the load.
You can still get rid of your teflon caps at the same point.😀
BTW, I'd be careful with bypassing.
Increased risk of stray inductance and I often hear these bypassed electrolytics as if they'd be emphasizing the high frequencies somehow.
I find it much less obvious by using big values like 10µF MKPs, ocasionally bypassed with a single 0.100µF MKP of the same brand.
Cheers, 😉
P.S. I did not get your e-mail.
I just mailed you again cause i thought something like that had happened. Obviously your through diyaudio mail dosnt work.
Try if you can mail me.
Magura:
Try if you can mail me.
Magura:
fdegrove said:
Yesh, and so might anyone else if they used polyeshter capashitorsh.
Exaggerated characteristics (just for fun):
Silvered mica: That screeching voice when woken up with a hangover.
PTFE: Big and bouncy.
Polypropylene: A bit like a supermodel; refined, elegant, but perhaps a tad too thin?
Polycarbonate (now unavailable): Rose tinted.
Polyester: Lishps.
Paper: Varies from soggy cardboard to ethereal tissue.
fdegrove said:
So the clever boys would buy a handfull of 10uF MKP's and a couple of 0.1uF.....or leave the 0.1uF out?
MAgura🙂
EC8010 said:
Conclusion...theyre all crap 😉
PP I never liked supermodels, neither in your analogy.
SM is out of the question.
PTFE may be to my liking, but unobtainable in 10uF
PC Unavailable
Polyester...no lishping accepted.
Paper ???????
Magura🙂
Hi,
I must shay it'sh a pretty accurate deshcripshion and that ishn't sho funny.
The MKC are still around, RS still seems to stock them.
This silly boy does it much cheaper with 1 of my favourite 0.100µF polyprops and a cathode resistor per PP half.
Adjust value to whatever's needed...the cap, I mean.
Cheers,😉
I must shay it'sh a pretty accurate deshcripshion and that ishn't sho funny.
The MKC are still around, RS still seems to stock them.
This silly boy does it much cheaper with 1 of my favourite 0.100µF polyprops and a cathode resistor per PP half.
Adjust value to whatever's needed...the cap, I mean.
Cheers,😉
So it would be possible to experiment with PTFE like that??
A resistor in series with the cap thats in paralel??
MAgura🙂
A resistor in series with the cap thats in paralel??
MAgura🙂
Hi,
Sure is.
If you have a PP output stage you bypass the cathode resistor with just that cap.
Works on frequency dependent NFB principles, measuring gear is highly recommended unless you want to change the frequency response of your entire system according to your personal taste.
Cheers,😉
Sure is.
If you have a PP output stage you bypass the cathode resistor with just that cap.
Works on frequency dependent NFB principles, measuring gear is highly recommended unless you want to change the frequency response of your entire system according to your personal taste.
Cheers,😉
The idea of using decoupling caps in the power supply or any place in an amp or DAC is to remove the high frequency noise. The facts are the large electrolytic be come inductors at less than 500 kHz and will pass HF so you have to bypassing them with a smaller cap to filter these higher frequencies.
There are many options and ways to filter this unwanted garbage out that are effective. A 100uf SMPS capacitor will get ride of some of the noise at frequencies up to one to 2 MHz range. However, if you have high frequency over several MHz on the power supply rails you will need to change to a film, a ceramic cap, or even a PI filter.
Most of the caps manufactures have ESR rating, which tell you how well they work at a certain frequency. Most analog amplifiers do not need these caps unless their diode bridge is causing noise or an external source of EMI is getting in to the amp. Therefore, you should be able to see this on a scope, or a spectrum analyzer.
Of course, poor grounding in the unit and your systems will make this problem worse.
🙂
Cheap is always the best but not always possible.
There are many options and ways to filter this unwanted garbage out that are effective. A 100uf SMPS capacitor will get ride of some of the noise at frequencies up to one to 2 MHz range. However, if you have high frequency over several MHz on the power supply rails you will need to change to a film, a ceramic cap, or even a PI filter.
Most of the caps manufactures have ESR rating, which tell you how well they work at a certain frequency. Most analog amplifiers do not need these caps unless their diode bridge is causing noise or an external source of EMI is getting in to the amp. Therefore, you should be able to see this on a scope, or a spectrum analyzer.
Of course, poor grounding in the unit and your systems will make this problem worse.
🙂
Cheap is always the best but not always possible.
Magura: They're not all perfect. Think of it as being like adding herbs/spices during cooking - too much of one kind can be a problem. But we avoid polyeshter if we can, and we're careful in our use of SM.
jewilson: I agree with everything you say. It's just that not everybody has access to a decent spectrum analyser. By the way, I expect you have noticed that electrolytic ESR varies with frequency.
jewilson: I agree with everything you say. It's just that not everybody has access to a decent spectrum analyser. By the way, I expect you have noticed that electrolytic ESR varies with frequency.
EC8010,
Right, ESR will changes with frequency. As frequency goes up their a point N where the resistance increases and the capacitance start to decrease.
Right, ESR will changes with frequency. As frequency goes up their a point N where the resistance increases and the capacitance start to decrease.
Wouldnt a couple of 50uF pp motor run capacitors do the trick for PS decoupling as well??
Magura🙂
Magura🙂
How's this?
Silver Micas - they're better than ceramics.
The description of their sound that others have posted corresponds pretty well to my limited experience with them - I pulled them out of the circuit too fast to really nail their sound down🙂
Silver Micas - they're better than ceramics.
The description of their sound that others have posted corresponds pretty well to my limited experience with them - I pulled them out of the circuit too fast to really nail their sound down🙂
Hi,
To me each belongs to an extreme of the audio scale, one being fine, the other downright a sonic disaster....
Cheers,😉
To me each belongs to an extreme of the audio scale, one being fine, the other downright a sonic disaster....
Cheers,😉
The point of decoupling an amplifier or digital logic circuit from the supply is all about noise filtering. It has very little to do with the sonic capabilites of a capacitor, unless the noise is still there. Also, we would never use a ceramic cap in the signal path it would suck. Just as you would never want to put a eletrolytic cap in the signal path unless it was a Black Gate.
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