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Capacitor Upgrades

post #1 of 9
Thread Starter 

I see a lot of people saying that they upgraded the capacitors on their amp and gotten better sound. What does one capacitor do better than another (of the same value) that results in better sound. If you were looking to upgrade a given capacitor how would you know that any given capacitor was going to be better than what you already have?

post #2 of 9

There can be many advantages depending on the ratings of the stock resistor. Based on the mistakes of the circuit designer, one can gain a lot from changing the capacitor. Since you can’t change the value of the capacitor, what one can change is the voltage rating of the capacitor. Higher the voltage rating of the capacitor, the more voltage it can produce at the output efficiently without any issues. The second thing that be improved is the tolerance of the capacitor, you’ll have to buy a bit more expensive capacitor but it’ll give you a better result for sure. 

post #3 of 9

It really depends on what the cap is there for. For power supply filtering, you're looking for low ESR ratings, and generally, the bigger the better (in terms of capacitance - farads), while keeping at least the rated voltage.

 

For signal coupling caps, there is a huge difference between capacitor types (electrolytic vs film is a pretty drastic change), and there are tons of "audiophile" capacitors out there. Signal caps are generally the first to "upgrade".

post #4 of 9
Quote:
Originally Posted by FallenAngel View Post
 

It really depends on what the cap is there for. For power supply filtering, you're looking for low ESR ratings, and generally, the bigger the better (in terms of capacitance - farads), while keeping at least the rated voltage.

 

For signal coupling caps, there is a huge difference between capacitor types (electrolytic vs film is a pretty drastic change), and there are tons of "audiophile" capacitors out there. Signal caps are generally the first to "upgrade".


^ this.

 

Also, you may have read remarks from people restoring vintage equipment.  Unfortunately, electrolytic capacitors have a finite lifetime.  There's a fluid between layers of dielectric rolled up inside the "can."  That fluid evaporates over time and even quicker when in use (we're talking decades, perhaps, though).  So, the first thing you often hear when someone is looking to restore a vintage piece of audiophile gear is "re-capping."

post #5 of 9
Quote:
Originally Posted by HPiper View Post

If you were looking to upgrade a given capacitor how would you know that any given capacitor was going to be better than what you already have?

Good question.

The short answer is that there is no easy way of telling if the change you have made is an improvement, even after you have made it.

There might be a measurable improvement in distortion. Got an accurate distortion meter?

There might be an audible change. Got a second unmodified amp for side-by-side comparison? How you gonna tell if the change is for the better? Got an expert listening panel handy?

There are many different types of capacitors. It takes time to become familiar with their characteristics. There are places in circuits where caps are more or less likely to affect the sound. Know which are which?

Guys like to frig around with things, they like to be thought of as experts. Change a cap or two, probably you didn't break anything, you can claim you've made a big improvement, who can prove any different?

w
post #6 of 9
Quote:
Originally Posted by fakir View Post
 

There can be many advantages depending on the ratings of the stock resistor. Based on the mistakes of the circuit designer, one can gain a lot from changing the capacitor. Since you can’t change the value of the capacitor, what one can change is the voltage rating of the capacitor. Higher the voltage rating of the capacitor, the more voltage it can produce at the output efficiently without any issues. The second thing that be improved is the tolerance of the capacitor, you’ll have to buy a bit more expensive capacitor but it’ll give you a better result for sure. 

This is false in regards to voltage rating. The voltage rating is what the capacitor can handle. Let's assume a transformer secondary = 32VAC We simply multiply this by the square root of 2 (approx. 1.4142) Therefore, Working Voltage WV = 32VAC X 1.4142 = 45.25V. Thus, you want to use the next higher rating, which is 50v rating.

 

Now, when looking for a quality capacitor, you typically want the lowest ESR, along with the highest ripple rating that you can get within your size dimension. Capacitor uf values differ in their applications,  but for a power supply section, the more the better. Cost has really dropped the past decade, so diminishing returns isn't such a big issue anymore.

 

Tolerance is primarily when you're dealing with sensitive applications like precise filters and crossovers. However, film caps are typically much better than electrolytics if you have the physical space and funds for them.

 

Cheers,

Brunk

post #7 of 9
post #8 of 9
Quote:
Originally Posted by tomb View Post
 


^ this.

 

Also, you may have read remarks from people restoring vintage equipment.  Unfortunately, electrolytic capacitors have a finite lifetime.  There's a fluid between layers of dielectric rolled up inside the "can."  That fluid evaporates over time and even quicker when in use (we're talking decades, perhaps, though).  So, the first thing you often hear when someone is looking to restore a vintage piece of audiophile gear is "re-capping."

Indeed, and even the better quality ones dry out.

 

I took apart a Marantz CD60 last year, which had finally reached the end of its economically serviceable life after 23 years and many repairs.

 

The main power supply caps were Elna (one of the better audio quality capacitor brands), and I disassembled one (carefully, the electrolyte may contain toxic components).  The paper separator was fairly dry and covered in patches of brown crystallized electrolyte.

post #9 of 9
Quote:
Originally Posted by brunk View Post
 

Tolerance is primarily when you're dealing with sensitive applications like precise filters and crossovers. However, film caps are typically much better than electrolytics if you have the physical space and funds for them.

 

Cheers,

Brunk

Yup

 

You will rarely find electrolytic capacitors used where tolerance is of importance.  Your typical electrolytic cap has a capacitance tolerance of 20% (even expensive audio-graded ones), some 10%.

 

This has one advantage; if you are replacing electrolytic caps the exact capacitance <probably> doesn't matter too much.  Not all capacitance values in all voltage ratings of the type you are looking for are always available.  Often you can get away with the nearest one (just  make sure you use at least the appropriate minimum voltage rating though).

 

Most manufacturers optimise the components they use not only on value/rating, but also on cost of mechanised placement on the PCB prior to soldering.  Thus if ideally a 33microFarad 25V cap would be called for, but the board is already populated by a load of 47microFarad 25V ones, the manufacturer may simply opt to use another 47microfarad one instead, if that saves having to use any 33microFarad/25V ones at all.  The same applies to a smaller degree to resistors, transistors etc, wherever the exact rating of the component matter less. Cheaper to make that way.

 

This is one reason niche high-end audio equipment ends up being more expensive.  There they usually DO use the optimal value component from an audio engineering perspective, even if that means a marginal increase in production cost.  And if they are entirely hand-built, there is no need to reduce the variety of componens to minimise the cost of the production run.


Edited by 2leftears - 2/25/14 at 6:08am
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