Which caps after regs?

[nad]

Which caps do you use after regs?

I ask as I've read Rubycon ZA/ZL's are ideal after regs but I've also read that low esr caps are not good after regs. ZA's are low esr so which is correct? ZA's = good/bad?

Ta.

[nad]

Ah bugger it, seems ZA's are a bad idea after regs.

[Marlowe]

It depends on what the regulator is, what the loading is, and what your preference is. A universal answer does not exist.

[SoNic_real_one]

Low ESR caps are not good on the power lines, regardless of the location (before or after regs). Inductance of the power strips coupled with capacitance under variable load creates oscillations that need to be damped. Usually, the "normal" ESR values are enough to do that damping, but if you go on the low ESR route, there will be some ringing or worse.

Low ESR caps are to be used only series with the signal or where are employed means to damp the oscillations. Or oscillations don't matter - switched PS.

[nad]

Originally Posted by SoNic_real_one

Low ESR caps are not good on the power lines, regardless of the location (before or after regs). Inductance of the power strips coupled with capacitance under variable load creates oscillations that need to be damped. Usually, the "normal" ESR values are enough to do that damping, but if you go on the low ESR route, there will be some ringing or worse.

Low ESR caps are to be used only series with the signal or where are employed means to damp the oscillations. Or oscillations don't matter - switched PS.

That's what many have told me, I did a little research after posting and it seems the majority of literature also claims/proves the same.

Shame really, I trusted the judgement of a fellow member on this forum who also owns/runs a upgrade website/shop facilty and even states on his site that ZA's are ideal after regs.


Nevermind, you live and learn I suppose.

[Mooly]

With apologies to SoNic_real_one as I know we are at odds over decoupling issues.

Perhaps the answer is to actually fit some of each type and do some real measurements rather than just taking everything on trust.

At least the low e.s.r. types offer the intriguing possibility (based on the above) of the performance improving as the caps age and e.s.r. increases... does this explain the fad of burning in exotic parts... the "newness" soon wears off.

[nad]

Originally Posted by Mooly

Perhaps the answer is to actually fit some of each type and do some real measurements rather than just taking everything on trust.

If you can't trust a so called 'audio engineer', who can you trust? I thought a diy audio forum that consists of thousands of members might be a good place to start, guess not.

[SoNic_real_one]

There are 2 kinds of audio "afficiando".
- The ones that trust the measurements, the electrical and acoustical theories, try to understand them, their limitations and work with them to achieve better designs.
- The ones that don't understand the science behind all this, they prefer to disregard all the measurements and scientific theories and rely on word of the mouth in choosing their equipment/designs. They are actually a special kind of "belivers" in religion-like "audiophile" legends, in a certain "magic" that cannot be quantifyed in formulas.

One just have to choose a side...

[nad]

Originally Posted by SoNic_real_one

There are 2 kinds of audio "afficiando".
- The ones that trust the measurements, the electrical and acoustical theories, try to understand them, their limitations and work with them to achieve better designs.
- The ones that don't understand the science behind all this, they prefer to disregard all the measurements and scientific theories and rely on word of the mouth in choosing their equipment/designs. They are actually a special kind of "belivers" in religion-like "audiophile" legends, in a certain "magic" that cannot be quantifyed in formulas.

One just have to choose a side...

Yes I understand (kind of), after I was told Rubycon ZA's would release detail I thought that was what I was looking for, it turns out that I couldn't be further away if I tried. The ZA's are detailed but theoretically and actually they sound bob (technical term), where's the music gone? all I can hear is detail.

Oh well, folk do push what they sell.

Ne'mind,

[Gordy]

Hi nad, caps don't have a 'sound quality' as such, so ignore those who try to sell you an idea (or actual part) based upon the notion of components having such a quality.

What caps have are electrical characteristics which you have to manipulate to get what you want out of the circuit. I think there are three approaches to this... 1) learn all about impedance, reactance, and power supply decoupling, then buy some test kit and measure things accurately, or 2) read up on the subject from knowledgeable people and then try a few experiments (...low esr cap + 1 Ohm in series, low esr cap + 2 Ohms in series, etc., etc.) or 3) just 'hit and hope'. However number 3 is a receipe for frustration!

It probably comes down to maintaining the output impedance of the regulator over an extended band-width, while ensuring good transient response. There were a couple of good documents on the web about the subject but unfortunately I did not note the references.

Buying a few low ohm resistors to experiment in series with your low esr caps might be an idea. Good luck.