Question about ESR .

[Sam21]

Lets say you design an amp with a certain type of electrolytic capacitor with a certain amount of ESR, but then in a later modification, you replace the old capacitors with a newer, lower ESR set of capacitors, Will that affect the sound at all ? 
 
 
wouldn't that mess things up since you designed the amp with a different type of capacitor that had more ESR ? or would it be negligible ?

 

[tomb]

  Lets say you design an amp with a certain type of electrolytic capacitor with a certain amount of ESR, but then in a later modification, you replace the old capacitors with a newer, lower ESR set of capacitors, Will that affect the sound at all ? 
 
 
wouldn't that mess things up since you designed the amp with a different type of capacitor that had more ESR ? or would it be negligible ?

 
Generally speaking, you don't design an amplifier circuit with specific ESR capacitors.  You design the best amplifier circuit you can and then spec the best capacitors with low ESR that you can get in the sizes/ratings needed.
 
Same for the power supply.
 
As to whether you can tell the difference in sound quality with lower ESR capacitors, it depends on a lot of things.  The circuit itself will have a certain PSRR - Power Supply Rejection Ratio, although I've never found that to be much more than a theoretical shield against power noise.  If your power supply is noisy, no value of PSRR is going to prevent it from sounding bad.  Anyway, if your circuit has a very high PSRR, then the ESR rating of the caps is probably not going to make a big difference, but as I stated - if you go with something very cheap, it will.
 
In general, if you design/build an amp with low-ESR capacitors everywhere and then compare that to the same circuit with very cheap, high-ESR capacitors, you will be able to tell the difference.  Outside of that, if you're looking at a single capacitor or two to improve the sound, it's not going to be noticeable.  JMHO from building many amps through the years.

 

[Sam21]

I am trying to figure out whether it is worth it to upgrade from G109-S to G109-A. According to the manufacturer the G109-A uses lower ESR nichicon capacitors.
 
G109-A:

G109-S:

 
 
I am not sure what type of capacitors the G109-S uses, maybe you would know, are the caps in G109-S as good as the gold caps in the G109-A ?

 

[tomb]

ESR has nothing to do with it.  Those gold caps are Nichicon Muse Fine Gold.  Those are audio-quality caps, meaning they are made to sound good if they're in the signal path.  Their actual power ratings are usually not very good compared to an excellent quality power cap, such as Nichicon PW, HE, or Panasonic FC and FM.  In fact, I would challenge you to find the specific ESR or ripple current of a Nichicon Muse capacitor.  Nichicon doesn't even publish it, because of the reasons I just stated.  You can try to find ESR or ripple ratings here, in fact (you won't): http://www.mouser.com/pdfdocs/NichiconFGaudiocapsdatasheet.pdf
 
IMHO, the differences in those photos is strictly a marketing tactic. Whatever the black caps are, they'd be better off replacing them with Panasonic FM's rather than Nichicon FG's.  Those are smoothing caps in the power supply and unless the amplifier circuit is not very good, they aren't meant to be heard anyway (not in the signal path).  What's needed are excellent power caps with low ESR and high ripple removal ratings.  Nichicon FG's are a total misapplication in that case ... unless the circuit is such that you hear the power filtering through the signal path, which is not good anyway.  In that very poor case, then yeah - audio-quality caps might make an audible difference for the better.
 
I think they just wanted to show off some pretty gold labels and make it sound like that's a good thing to buy.

 

 

[Sam21]

Thanks for your response, so My understanding so far is that those fine gold/black capacitors are used to filter/smooth the power for amplification and are not in the signals path and therefore they would not alter the sound, and, You are saying that for power filtering/smoothing there are other capacitors which would work better. right ?
 
What are your thoughts on AC power conditioners, would their power filtering help sound quality ? lets say something like this 
 
 
I am also wondering if I should buy a USB power cleaner such as JitterBug . what do you think ?

 

[tomb]

  Thanks for your response, so My understanding so far is that those fine gold/black capacitors are used to filter/smooth the power for amplification and are not in the signals path and therefore they would not alter the sound, and, You are saying that for power filtering/smoothing there are other capacitors which would work better. right ?
 
What are your thoughts on AC power conditioners, would their power filtering help sound quality ? lets say something like this 
 
 
I am also wondering if I should buy a USB power cleaner such as JitterBug . what do you think ?

 
Well, it's difficult to explain everything about power supplies and quality audio in a couple of forum posts.  Your first paragraph is generally correct.  However, you should recognize that I allowed for the possibility that the power supply of the Lake People amps may not be that good (not saying that for sure - I simply don't know).  If that's the case, then you would hear an improvement with the Muse FG's, because the power supply is infecting the amplifier circuit with its noise.  Thus, you would be hearing the power supply through the signal path, including the electrolytic capacitors.  (The reason they make audio-quality electrolytic capacitors like the FG's is that most power-type electrolytic capacitors sound bad if they're directly in the signal path.)  The intent in amplifier design is to make the power supply silent to the audio circuit - either through an amplifier circuit design that has a high Power Supply Rejection Ratio (PSRR) or a power supply that is dead silent.
 
When we're talking power supplies in conjunction with amplifiers, we're talking about the power supply of the amplifier circuit design itself.  Remember that the idea is to get clean DC - without any AC artifacts.  However, all of the line voltage we use in the world is AC.  Not only that, but its frequency is directly in the audio band - 60Hz or 50Hz.  If that AC is not completely removed, then the 50/60 Hz gets added to the audio signal of the amp.  Further, no amplifier has zero distortion.  So, you're going to get both odd and even harmonics (distortion) of that 60Hz - if it is audible through the power supply - at 120Hz, 180Hz, 240Hz, and so on.  If the power supply has removed almost all of the AC, then the 60Hz distortion components and its harmonics fade into the overall background noise of the amplifier.
 
All of this occurs within the amplifier itself.  The idea being, as said above - to convert to DC and remove all artifacts of AC voltage/current.  The best audio power supplies will remove the AC down to double digits or single digits of microvolts.  This is an extremely low value and actually requires a special instrument to measure it.  Tangent makes one known as the LNMP - the Low Noise Measurement Preamplifier.  I would note that noise as low as 1-2 mV of AC is audible through many amplifier circuits, especially when headphones are involved.  IOW, microvolts of AC is not an unrealistic target.  So as far as the AC power conditioner you referenced in your link above, I would pose this question for you - what good does it do to clean the AC into "cleaner" AC?  The amplifier still needs to convert that AC into DC and attempt to remove every bit of that "clean" AC to the lowest extent possible.

 

[tomb]

About the Jitterbug - it probably has a marginal improvement with the Dragonfly, but it's not an ultimate solution.  The best DACs have their own power supplies (just like amplifier circuits) that convert line voltage AC into DC.  The same comments about power supplies discussed above apply with high-quality DACs.
 
Many inexpensive DACs are powered through the USB circuitry.  The problem with this is that the USB 5VDC comes from the PC's or laptop's power supply.  Dell, Apple, HP, etc. don't make PC's or laptops with power supplies that are focused on high-quality audio.  So, the 5VDC can be very dirty.  Those same inexpensive DACs (I sell a few, for instance), use a range of regulators throughout the DAC circuit to mitigate the noisy USB from a PC.  Rectification is what converts AC to DC.  However, the act of regulation is what ultimately removes the AC noise from a DC power supply.  Even then - a USB-powered DAC circuit has made some assumptions about how much DC voltage is available.  The actual USB voltage spec can range from 4.75 to 5.25 VDC.  If the USB voltage is down below 5VDC, chances are that the regulators in a DAC circuit are not going to regulate (regulators need to "burn" some DC voltage in order to regulate), because there is not enough voltage available.  This can be unpredictable, but fairly common.
 
What does all that mean?  IMHO, any power-filtering, quieting device for USB needs to have its own power source.  If the device doesn't plug into the wall in some manner (or have a bank of batteries), its quieting effects may be limited.

 

[Sam21]

Hi again, I have purchased the Pioneer XPA700 + USB REGEN as my DAC to pair with my Lake People G109S headphone amplifier.
 
The digital/analog interconnects + the power cord for my HP amplifier are all high quality AudioQuest cables.
 
I also purchased this Double-Conversion UPS from Liebert. I plug the HP amplifier and USB REGEN into this UPS.
 
 
What do you think of my setup ? is the UPS adequate for purifying the AC power or should I spend more on a better UPS ?

 

[tomb]

  Hi again, I have purchased the Pioneer XPA700 + USB REGEN as my DAC to pair with my Lake People G109S headphone amplifier.
 
The digital/analog interconnects + the power cord for my HP amplifier are all high quality AudioQuest cables.
 
I also purchased this Double-Conversion UPS from Liebert. I plug the HP amplifier and USB REGEN into this UPS.
 
 
What do you think of my setup ? is the UPS adequate for purifying the AC power or should I spend more on a better UPS ?

A UPS is not going to "purify" the AC signal.  Maybe you didn't read this in one of my posts above:
"So as far as the AC power conditioner you referenced in your link above, I would pose this question for you - what good does it do to clean the AC into "cleaner" AC?  The amplifier still needs to convert that AC into DC and attempt to remove every bit of that "clean" AC to the lowest extent possible."
 
Uptime is the major concern with a UPS, not noise-filtering.  Liebert, especially, is in that business big-time.  You're talking about a "ride-through" capability from sags and spikes in the AC voltage that may result in dropouts of computer systems, requiring expensive, time-consuming re-boots.  Generally speaking, those are not going to translate into degrading an audio system.  You will probably hear sags and spikes quite clearly, not as noise.  All that said, it's not going to hurt anything, but your money could probably be spent better elsewhere.