The No.1 Website for Pro Audio
 Search This Thread  Search This Forum  Search Reviews  Search Gear Database  Search Gear for sale  Search Gearslutz Go Advanced
Capacitors and sound Plugin Presets/Expansions
Old 2 weeks ago
  #1
Gear Addict
 

Thread Starter
Capacitors and sound

Hi guys,

Just chiming in to ask people's own experience with caps and sound improvements/not. I'm gettting some EQ's racked up and of course will be changing the old aluminium types.. but there are many old white polyester caps in the EQ/filter circuit... have many found audible improvement to changing these out to polystyrenes/polpropylene types?? I realise the sound is more the entire circuit/system at play but just wondering peoples thoughts.. if theyve noticed differences in 'tone' to there ears (hard/soft/plastic/metallic etc)

Thanks
Old 2 weeks ago
  #2
Lives for gear
 

PH - this topic has been beat nearly to death and we all want it to stay down....once you do a quick search on this forum, you'll have about a week's worth of strongly-held opinions and a few bits of good info to sort thru. Best, JR
Old 2 weeks ago
  #3
Lives for gear
 

Polystyrenes and polpropylenes are the superior dielectric for audio. There is a very good article on this subject called: "Picking Capacitors parts 1 and 2". You should Google that and read it before you recap your EQ's.
Old 2 weeks ago
  #4
Lives for gear
 
Wavebourn's Avatar
 

Quote:
Originally Posted by PartHunter View Post
Hi guys,

Just chiming in to ask people's own experience with caps and sound improvements/not. I'm gettting some EQ's racked up and of course will be changing the old aluminium types.. but there are many old white polyester caps in the EQ/filter circuit... have many found audible improvement to changing these out to polystyrenes/polpropylene types?? I realise the sound is more the entire circuit/system at play but just wondering peoples thoughts.. if theyve noticed differences in 'tone' to there ears (hard/soft/plastic/metallic etc)

Thanks
It is norm, when people move phenomena from context to context.

For example, in power amps output tubes work on peaks close to their maximal power. That means, control grid voltage hits non-linearity of grid current on peaks of a signal, causing shifted bias. Shift of bias changes the sound adding dynamic distortions. Here the sound of caps would be audible, due to non-linearity of grid current, not the cap itself.

Or, heavily loaded filter electrolytic cap in PS of class AB amp itself may cause distortions, since it's a semiconductor (alluminium oxide) reversely biased, the foil has inductance, the electrolyte has resistance, and on some high frequencies this system can resonate, and resonating AC gets distorted.

In active EQs on resonant frequencies impedance can be pretty small, it overloads outputs of opamps causing extra distortions, so ESR of caps matters: the better the cap, the more opamp distorts.

However, there may be other cases, all depends on context. But what really adds the majority of distortions, active components. Passive components just participate in this activity, that's why changing them sometimes changes the sound.

In the majority of other cases it does not matter.
Old 2 weeks ago
  #5
Gear Addict
 

Thread Starter
Quote:
Originally Posted by Wavebourn View Post
It is norm, when people move phenomena from context to context.

For example, in power amps output tubes work on peaks close to their maximal power. That means, control grid voltage hits non-linearity of grid current on peaks of a signal, causing shifted bias. Shift of bias changes the sound adding dynamic distortions. Here the sound of caps would be audible, due to non-linearity of grid current, not the cap itself.

Or, heavily loaded filter electrolytic cap in PS of class AB amp itself may cause distortions, since it's a semiconductor (alluminium oxide) reversely biased, the foil has inductance, the electrolyte has resistance, and on some high frequencies this system can resonate, and resonating AC gets distorted.

In active EQs on resonant frequencies impedance can be pretty small, it overloads outputs of opamps causing extra distortions, so ESR of caps matters: the better the cap, the more opamp distorts.

However, there may be other cases, all depends on context. But what really adds the majority of distortions, active components. Passive components just participate in this activity, that's why changing them sometimes changes the sound.

In the majority of other cases it does not matter.
Thats awesome mate thanks. Could I ask if you would know this as well... I'm looking to use non polarized electrolytics in the signal path of some channel strips I have, I've found the correct rated radial types but there are also axials in there.. Ive found some axial types by Mundorf.. these are described as AC non polarized electrolytics, would these work for signal path coupling as well?? I think people mostly use these for loudspeaker crossovers...

Mundorf - Inner Excellence

John klett recapped my console with non polars, and the difference is amazing, very transparent
Old 2 weeks ago
  #6
Gear Addict
 
samwinston123's Avatar
 

You can put radial in place of axial, just bend the leads out to span the gap. If there's enough space you can leave them sticking up vertically, otherwise bend one lead all the way over so it's against the side of the cap, leave the other sticking straight down, and voila you have a fake axial. There's a much better selection of radial caps, as you've probably discovered

Quote:
Originally Posted by PartHunter View Post
Thats awesome mate thanks. Could I ask if you would know this as well... I'm looking to use non polarized electrolytics in the signal path of some channel strips I have, I've found the correct rated radial types but there are also axials in there.. Ive found some axial types by Mundorf.. these are described as AC non polarized electrolytics, would these work for signal path coupling as well?? I think people mostly use these for loudspeaker crossovers...

Mundorf - Inner Excellence

John klett recapped my console with non polars, and the difference is amazing, very transparent
Old 2 weeks ago
  #7
Lives for gear
 

Quote:
Originally Posted by PartHunter View Post
Thats awesome mate thanks.
That may be awesome, but it's totally wrong! Cap distortions are caused by the caps themselves and not the surrounding circuitry. Don't take people's word for things just because you may not know anything about a subject. You need to google things. Most people here just speak off the top of their heads without ever having studied anything.
Old 1 week ago
  #8
Lives for gear
 

Quote:
Originally Posted by PartHunter View Post
Hi guys,

Just chiming in to ask people's own experience with caps and sound improvements/not. I'm gettting some EQ's racked up and of course will be changing the old aluminium types.. but there are many old white polyester caps in the EQ/filter circuit... have many found audible improvement to changing these out to polystyrenes/polpropylene types?? I realise the sound is more the entire circuit/system at play but just wondering peoples thoughts.. if theyve noticed differences in 'tone' to there ears (hard/soft/plastic/metallic etc)

Thanks
do not change any film caps unless you want to alter the tone of the device. filter caps do have a huge impact on eqs. so if you like the sound- stick with them. if you want to experiment with the tone, solder in a rotary with some different types - same value. thats what i did before modding my desks eq.

yes, i would change any electrolytics personally. the biggest cost in maintainance is always taking apart the module. so why not change that old cr*p while its open? takes 6 minutes. if we are talking 70s transistor gear its most likely all leaky. thats my experience.... for signal decoupling i personally like elnas. for psu i reach for panasonic fc/fm. i use philips (now vishay) for axials. kemet for tantalums. hope this helps. good luck
Old 1 week ago
  #9
Lives for gear
 

ps: id never change polyester for polyprop... i personally cant stand polyprop in eqs. i like the old mustard, v161 caps - all polyester but axial wound. i also like paper in oil ( i use the k42 russian type - cheap and awesome) and siemens mkl. but i do not enjoy modern, stacked polyprops at all. lots will dissagree....
Old 1 week ago
  #10
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by Vitalis View Post
That may be awesome, but it's totally wrong! Cap distortions are caused by the caps themselves and not the surrounding circuitry. Don't take people's word for things just because you may not know anything about a subject. You need to google things. Most people here just speak off the top of their heads without ever having studied anything.
Capacitor nonlinearity depends very much on the application.

For example one common nonlinearity called voltage coefficient refers to capacitance change wrt terminal voltage. In circuits like an EQ filter, capacitors will see a lot of changing terminal voltage so that term matters. In a DC blocking application there is little or no terminal voltage change so not a factor.

Likewise current matters for other nonlinearities, so a capacitor in a high current loudspeaker crossover will be stressed far more than a low level circuit.

Lots of details available from reading cap spec sheets.

JR

PS Yes the WWW is a firehose of opinion and only a trickle of wisdom... the hard part is telling which is which. Good luck.
Old 1 week ago
  #11
Lives for gear
 

Little known fact. All caps have polarity.

Ever try two pieces of the same gear and swear one sounds really good compared to the other? Chances are one had more signal caps installed with the proper polarity then others.

The differences are very small of course and they are collective. One cap reversed may be Unperceivable to the ears and even a scope, but several in series can begin to add up.

Companies who mass produce gear really don't care which way they go in. They have low skilled workers who wouldn't know the difference.

Some caps still include identifiers. One has a thicker leg then the other. One has a longer leg, sometimes its an ink dot, sometimes it just the side its labeled.
Budget caps may have no way to tell you so its simply a 50/50 chance of it being installed right.

I should note its not going to cause any failures, I'm strictly talking about maximizing tone in audio gear.

I wish I could find an article written by an engineer who worked in the cap industry. He also mods amps and goes through them correcting all the signal caps put in backwards. The differences in sound quality and lower noise levels are supposed to be very good. You see in a rolled cap you'd want the Hot signal on the inside and the ground on the outside film to help minimize hum. It can make a big difference when you have a couple of dozen caps in there all wired in backwards.

Found this Video which explains all this nicely. He misses the fact many caps have two leads of different sizes of lengths, but at least he knows enough to test them which is good enough.
YouTube

Allot of hum from a guitar? Could be the caps in backwards. Every little bit counts in audio circuits. This one many simply don't know enough about electronics to recognize the importance.
Old 1 week ago
  #12
Lives for gear
 

Using lab test equipment would it be possible to sort parts (i.e. mark one electrode as reference) or can't the difference be measured?

I don't know in depth the details you mention, I only remember that for DC use, once having been in service some non-polarized capacitors should not be polarized the other way later as it leads to degraded performance (especially applies to some supercapacitors used for energy storage).
Old 6 days ago
  #13
Lives for gear
 

Quote:
Originally Posted by PartHunter View Post
there are many old white polyester caps in the EQ/filter circuit... have many found audible improvement to changing these out to polystyrenes/polpropylene types??
Leave them alone. They are old mylars and should sound fine for the period they were made in. I'd keep it original. Upgrading to polystyrenes or polyprops will give a slightly different sound, sometimes better, sometimes not, when you change out all mylars on the board. Changing out a single cap may not make much difference.

Polystyrenes have a very polite sound and may not be what you are looking for. I occasionally use Relcap RTX polystyrenes and they are a mixed bag. They give a lot of detail but also can sound a bit sterile. Expensive caps do not always work as planned, and at other times they do wonders when the original caps are dung.
Old 6 days ago
  #14
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by wrgkmc View Post
Little known fact. All caps have polarity.

Ever try two pieces of the same gear and swear one sounds really good compared to the other? Chances are one had more signal caps installed with the proper polarity then others.

The differences are very small of course and they are collective. One cap reversed may be Unperceivable to the ears and even a scope, but several in series can begin to add up.

Companies who mass produce gear really don't care which way they go in. They have low skilled workers who wouldn't know the difference.

Some caps still include identifiers. One has a thicker leg then the other. One has a longer leg, sometimes its an ink dot, sometimes it just the side its labeled.
Budget caps may have no way to tell you so its simply a 50/50 chance of it being installed right.

I should note its not going to cause any failures, I'm strictly talking about maximizing tone in audio gear.

I wish I could find an article written by an engineer who worked in the cap industry. He also mods amps and goes through them correcting all the signal caps put in backwards. The differences in sound quality and lower noise levels are supposed to be very good. You see in a rolled cap you'd want the Hot signal on the inside and the ground on the outside film to help minimize hum. It can make a big difference when you have a couple of dozen caps in there all wired in backwards.

Found this Video which explains all this nicely. He misses the fact many caps have two leads of different sizes of lengths, but at least he knows enough to test them which is good enough.
YouTube

Allot of hum from a guitar? Could be the caps in backwards. Every little bit counts in audio circuits. This one many simply don't know enough about electronics to recognize the importance.
I am not enthusiastic about claiming that non-polar capacitors have polarity.

It is arguable that some non-polar film caps have a preferred orientation based on which lead attaches to the inner and outer end of a long wrapped electrode. The inner wrap will be somewhat self shielded by the outer wrap. Connecting the outer wrap to low impedance circuit nodes can reduce noise pickup in higher impedance networks.

IIRC the old polystyrene caps I used would have a black line indicating which lead was connected to the outer wrap.

This is clearly not "polarity" and the sonic effect if any will depend on the circuit sensitivity to noise pickup.

JR
Old 6 days ago
  #15
Lives for gear
 

Quote:
Originally Posted by JohnRoberts View Post
Capacitor nonlinearity depends very much on the application.

For example one common nonlinearity called voltage coefficient refers to capacitance change wrt terminal voltage. In circuits like an EQ filter, capacitors will see a lot of changing terminal voltage so that term matters. In a DC blocking application there is little or no terminal voltage change so not a factor.

Likewise current matters for other nonlinearities, so a capacitor in a high current loudspeaker crossover will be stressed far more than a low level circuit.
To tell you the truth John, I couldn't care less about a capacitor, so if you want to run behind everything I post and try to shoot it down, then you are free to do that. The reality is that I'm well aware that no component is perfect, and the wrong cap in any circuit is going to show some form of disadvantage. So who cares? Maybe a NASA engineer would care, but not me. I try to choose the best cap for the job and just move on. There could be a thousand things going wrong inside that cap or evan the circuit, but who cares? Put the best cap you can in the circuit and sit back and enjoy the music.
Old 6 days ago
  #16
Quote:
Originally Posted by PartHunter View Post
John klett recapped my console with non polars, and the difference is amazing, very transparent
Bipolar el caps are two polarized el caps series connected internally. You end up going through double the number of caps. If it's a situation with a varying DC polarity then they are a good choice. They are also used in speaker crossovers to save costs over film caps.

Most don't realize that they own audio gear using polarized el signal coupling caps installed randomly without concern for the DC offset polarity. Rather than replace it with a non-polar cap in it's better to measure the polarity of the DC offset and insert the cap in the correct way. In the case of zero offset one can usually remove the cap and replace it with a wire.

The best sounding cap I ever heard was a short piece of pure silver wire.
Old 6 days ago
  #17
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by Vitalis View Post
To tell you the truth John, I couldn't care less about a capacitor, so if you want to run behind everything I post and try to shoot it down, then you are free to do that. The reality is that I'm well aware that no component is perfect, and the wrong cap in any circuit is going to show some form of disadvantage. So who cares? Maybe a NASA engineer would care, but not me. I try to choose the best cap for the job and just move on. There could be a thousand things going wrong inside that cap or evan the circuit, but who cares? Put the best cap you can in the circuit and sit back and enjoy the music.
I wouldn't follow you around if you were dropping money.

If I quote you, it was because of something you said that I can't agree with.

JR
Old 6 days ago
  #18
Lives for gear
 

Part Hunter waited patiently for a week before I gave him the polite advice he deserved in #2 , which seemed only to act as a catalyst for everyone to immediately come over and track a bunch of mud on the carpet. I've had it up to HERE with you kids and your capacitors! If you can't enjoy a couple of capacitors responsibly, then maybe you just shouldn't have any. Sit back and enjoy THAT music!
Old 6 days ago
  #19
Lives for gear
 

Oh, and happy Valentine's Day / Ash Wednesday to you all...now get out.
Old 6 days ago
  #20
Lives for gear
 

Quote:
Originally Posted by ripple_fx1 View Post
Oh, and happy Valentine's Day
Happy Valentines Day to you too.

I live in the northern US where we have lots of snow. Every year on Valentines Day I observe a strange phenomenon that almost always replicates itself like clockwork. Many years ago I noticed that exactly on Valentines Day or within two days afterwards, I always see the first Cardinal back from its long winter migration. This observance is so consistent that you could bet on it and make money. So when I woke up this morning and left the house I wondered if I'd again see my first Cardinal for the spring. Ten seconds later there he was singing prolifically in a tree about thirty feet above me. I smiled because it tells me that nature knows that after a long snowy winter, spring is just around the corner.
Old 5 days ago
  #21
Lives for gear
 

Quote:
Originally Posted by JohnRoberts View Post
I wouldn't follow you around if you were dropping money.
So now the insults start coming? That's fine with me.
Old 5 days ago
  #22
Lives for gear
 

Thank you, Frank...smack-dab in the middle of Indiana, we're going to enjoy a few 60-degree days. Maybe a sign of spring, maybe fake news.
If I were the type, my posts #18 & 19 would have whatever emoji is used to denote "somewhat tongue-in-cheek". I will admit this cap thread has been much more informative than the majority of the cap threads I've waded through. With luck, Part Hunter is enjoying dinner and a show, and you'll discover a way to fund your retirement account speculating on cardinals.
Old 5 days ago
  #23
Lives for gear
 

Quote:
Originally Posted by Schoeller View Post
Using lab test equipment would it be possible to sort parts (i.e. mark one electrode as reference) or can't the difference be measured?

I don't know in depth the details you mention, I only remember that for DC use, once having been in service some non-polarized capacitors should not be polarized the other way later as it leads to degraded performance (especially applies to some supercapacitors used for energy storage).
As far as cap values go most millimeters have a built in cap tester which is usually good enough for government work. You can also check for continuity to make sure they aren't shorted.

If you watched the video you would see where having the ground applied to the outer wrap of the foil reduces EMF interference and reduces the noise floor in audio gear. You can measure it with a scope, or can simply use your ears to detect which side produces more hum when connected to the input of an amp.

As far as polarized, non polarized/bipolar and reversing non polarized caps,

Polarized = higher Distortion - smaller in size - cheaper - Can not be used in AC without DC polarizing bias - Value are relatively high

Non Polarized - lower in Distortion - huge in size - More expensive hard to manufacture at a small size - have less leakage - AC and DC - All values

The only caps that shouldn't be reversed are electrolytic's (or similar chemically based caps that have a none reversible dielectric.

You can use a bipolar/non polar electrolytic which is essentially two electrolytic's in series with the polarities reverse from each other. The problem with these is you need to use diodes to prevent reverse voltage from blowing one of the other up when the polarity changes. maybe they could be used in low voltage applications but the losses are quite high if there are no diodes to bridge the reversed cap.
Old 5 days ago
  #24
Lives for gear
 

About the measurements I was referring to the ability to objectively measure differences in capacitor characteristics, for example using a programmable waveform generator and trying to find out if some differences can be assigned to the way an audio signal is influenced.

Common multimeter capacimeters are not very precise and for very low capacitance values many factors influence negatively the measurement.

To be honest, I've read a lot about various types of capacitors used in audio but I just ended sort of confused.

My comment about not inverting the polarity of unpolarized capacitors was referring to DC uses, for example there are supercaps which are not polarized but one you've operated them under DC, you should not use them in circuits where the polarity would be inverted (especially large supercapacitors about the size of a 12 V 190 Ah truck battery) as their performance could be reduced (IIRC the loss is irreversible but manufacturer specs should be checked).
Old 4 days ago
  #25
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by Schoeller View Post
About the measurements I was referring to the ability to objectively measure differences in capacitor characteristics, for example using a programmable waveform generator and trying to find out if some differences can be assigned to the way an audio signal is influenced.
you can objectively measure the wrap orientation sensitivity by placing the capacitor to be tested in the + input of a high impedance gain stage, with the other end of the cap grounded. In the optimal orientation the noise pick up will be reduced compared connecting the outer wrap to the high impedance input. On the bench you can sometimes use a soldering iron as hum noise source.

JR
Quote:
Common multimeter capacimeters are not very precise and for very low capacitance values many factors influence negatively the measurement.

To be honest, I've read a lot about various types of capacitors used in audio but I just ended sort of confused.

My comment about not inverting the polarity of unpolarized capacitors was referring to DC uses, for example there are supercaps which are not polarized but one you've operated them under DC, you should not use them in circuits where the polarity would be inverted (especially large supercapacitors about the size of a 12 V 190 Ah truck battery) as their performance could be reduced (IIRC the loss is irreversible but manufacturer specs should be checked).
Old 3 days ago
  #26
Gear Addict
 

Thread Starter
Thanks for all the info guys, and entertainment!

I have a question regarding the bipolar coupling caps, thanks there Jim.. I don't have any means of measuring DC etc I'm just a noob replacing caps.. but I have a simple question.. In terms of coupling caps, is it always OK to replace polars with non polars?? In terms of safety and operation? Or could they blow up..
Old 3 days ago
  #27
Lives for gear
 

@ JohnRoberts:
Thanks for your reply. I've never tested it yet.

I'm wondering if capacitor manufacturing quality assurance issues have not become more common than a couple of years ago, while testing and processes have possibly improved, the high pressure on pricing often has a negative effect.
Old 3 days ago
  #28
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by Schoeller View Post
@ JohnRoberts:
Thanks for your reply. I've never tested it yet.

I'm wondering if capacitor manufacturing quality assurance issues have not become more common than a couple of years ago, while testing and processes have possibly improved, the high pressure on pricing often has a negative effect.
At my last day job (last century) I used truckloads of capacitors and quality if anything was constantly improving. That said when you buy components by the truckload stuff happens. I had one capacitor distributor offer to hire me after I told him what was wrong with his capacitors, then took a couple apart to show him.

Another time a highly rated manufacturer had a production problem. A swaging tool that attaches the foil inside an electrolytic cap to the electrode broke and was making a weak mechanical contact. Most of the caps measured good initially but were unlikely to remain reliable. I was lucky because a incoming QA inspector performing tests on a random sample found one that was effectively open (1000uF indicating nF). While statistical sampling would be inclined to ignore just one bad part as an outlier (actually trigger a second test of more parts then ignore the bad one).

I took it apart and discovered the bad swage. This was a common part used inside many products and thousands had already been used in products. I even ended up recalling a container on its way overseas, to rework the faulty capacitors before they got out. The vendor bent over backwards to identify the faulty production lot and get us good parts. We were lucky to nip this one in the bud.

JR

PS: I have more cap stories but that's enough for now. We even had an xray machine so we could look inside the metal cans, but the only way to really inspect a cap is to take it apart and unwind the foil... Of course after this you can't put humpty back together again.
Old 3 days ago
  #29
Lives for gear
 

I wish I had your experience.

Are there serious books or papers about capacitors in audio (I mean really serious stuff, not based on some idiotic audiophoolism)?
Old 3 days ago
  #30
Lives for gear
 
JohnRoberts's Avatar
 

Quote:
Originally Posted by Schoeller View Post
I wish I had your experience.

Are there serious books or papers about capacitors in audio (I mean really serious stuff, not based on some idiotic audiophoolism)?
There have been a few decent capacitor articles (like Cyril Bateman's series in Electronics world). Sam Groner did some interesting research into subtle distortion mechanisms in electrolytic caps but these are typically below path distortion for many applications.

Too many discussions are thinly veiled audiophoolery. Often holding up a real capacitor characteristic but blaming it for some unrelated phenomena (like dielectric absorption... a real problem for sample and hold circuits).

Capacitors are mature technology, and like I said getting better and better... modern NPO/COG caps are very cheap, close to ideal, and should be transparent when used properly.

Any designer worth his salt, should have already used the correct cap dielectric for the sundry different circuit applications so wouldn't leave much room for easy improvement from just throwing more money at it.

Of course opinions vary, and I try not to argue with people about what they say they hear on the WWW.

JR
Topic:
Post Reply

Welcome to the Gearslutz Pro Audio Community!

Registration benefits include:
  • The ability to reply to and create new discussions
  • Access to members-only giveaways & competitions
  • Interact with VIP industry experts in our guest Q&As
  • Access to members-only sub forum discussions
  • Access to members-only Chat Room
  • Get INSTANT ACCESS to the world's best private pro audio Classifieds for only USD $20/year
  • Promote your eBay auctions and Reverb.com listings for free
  • Remove this message!
You need an account to post a reply. Create a username and password below and an account will be created and your post entered.


 
 
Slide to join now Processing…
Thread Tools
Search this Thread
Search this Thread:

Advanced Search
Forum Jump
Forum Jump