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Tone cap quality?

 
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markusv



Joined: 24 Sep 2009
Posts: 157
Location: Toronto, Ontario

PostPosted: Tue Jun 23, 2015 3:52 pm    Post subject: Tone cap quality? Reply with quote

Folks

I am sure this has been discussed. Please bear with me.- I would like to hear opinions on the effect of tone cap quality in a guitar with 50s tone wiring.

I just replaced a green generic cap with a sprague orange drop. (same value)

I believe I hear a difference even with tone on full -but I am also pretty impressionable. Smile

Please de- mistify

Markus V
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Mr. Clevername



Joined: 08 Dec 2006
Posts: 2448
Location: San Francisco, CA

PostPosted: Tue Jun 23, 2015 9:36 pm    Post subject: Reply with quote

If there's a something other than the placebo effect, it's usually because of a difference in values, not construction. Then again, thousands of guitar players hear things I don't.

http://www.aqdi.com/tonecap.htm
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ghobii



Joined: 10 Jan 2010
Posts: 1372
Location: Phila., PA.

PostPosted: Wed Jun 24, 2015 6:36 am    Post subject: Reply with quote

Mr. Clevername wrote:
If there's a something other than the placebo effect, it's usually because of a difference in values, not construction. Then again, thousands of guitar players hear things I don't.

http://www.aqdi.com/tonecap.htm


+1
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tangelolemon



Joined: 26 Jan 2009
Posts: 2691
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PostPosted: Wed Jun 24, 2015 7:40 am    Post subject: Reply with quote

I don't think you're fooling yourself. Sometimes these things get oversimplified.

To address two common misunderstandings about tone controls: First of all, the cap doesn't "just bleed treble off to ground," and the control is NOT out-of-circuit or out-of-band when full up.

First we have to understand something about guitar pickups-- without anything else at all, just the naked pickup has at least three measurable electronic properties: resistance (the resistance of the wire... 5k to 15k typical), the inductance (measured in Henries... all coils have inductance), and capacitance (each turn of wire laying next to another turn forms a tiny capacitor).

These three factors (inductance and resistance act like they're in series, capacitance acts like it's in parallel) form a tuned resonant circuit. A hot humbucker will have a lower resonant peak than a 50s Strat pickup, which is why the latter sounds "chimey" and the former can sound "stuffy." Again, this is an actual boost in the frequency response.

In theory, the tone control is a variable 6dB/octave (first-order) low-pass (high cut) filter.

In practice, both the tone control and the cable (which has its own capacitance) add additional capacitance in parallel, even when full up, (tone control also adds a variable resistance in series with its capacitance.

So this can shift the resonant peak of the system, in addition to the low-pass filtering effect. It is very much "in circuit" and "in the audio path." People who say "it just bleeds treble off to ground" seem to fail to realize that one side of the pickup is connected to ground. Ground is part of the circuit!

If you feel different capacitors can have sonic impacts in audio circuits, it only stands to reason that this would also be possible in an electric guitar-- in fact, it seems it would be even more likely to be audible than in something like an amplifier, since the system has no error correction (in the form of negative feedback), and its high-impedance signal is amplified an incredible amount.

Food for thought with capacitors in general, in audio devices--

Here's a capacitor's equivalent circuit:



Any real-world capacitor has some degree of leakage resistance, equivalent series resistance, and series inductance. The most significant for our purposes would probably be the equivalent series resistance-- in modern capacitors, the others are typically quite small, and probably mostly of concern in high-speed switching applications. Not pictured on the schematic-- dielectric absorption, which can be very significant at audio frequencies, phase angle of response, which will NOT show up on a simple frequency response plug but CAN be audible, and finally, the fact that some capacitors (ceramics that are not NP0 or C0G types tend to be VERY bad about this) can actually impart some distortion to the signal.

Cyril Bateman has published some extensive, peer-reviewed work on distortion imparted by capacitors, and if you really want to "go deep" I suggest looking up his work. It was fascinating and groundbreaking, and those who are really trying to push the state of the art toward quality take it seriously.

Final word-- anything can sound good in the right situation, and I'm not suggesting that everyone go out and drive themselves crazy trying to afford $100 caps to make their guitar magically sound better. But if you find the orange drop sounds better to you than the cheap ceramic disc, then it's not ridiculous. There are several documented mechanisms by which a polypropylene film cap can perform with audible, empirically provable superiority to an inexpensive ceramic, and also documented mechanisms by which those differences can be audible.[/i]
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twangster



Joined: 05 Aug 2005
Posts: 9512
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PostPosted: Wed Jun 24, 2015 12:02 pm    Post subject: Reply with quote

THAT is a sticky Smile
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markusv



Joined: 24 Sep 2009
Posts: 157
Location: Toronto, Ontario

PostPosted: Wed Jun 24, 2015 12:10 pm    Post subject: Reply with quote

Tangelolemon

Thanks for such an incredibly comprehensive reply!

Much appreciated and I will study your words carefully

I'm not one for pursuing "audiophool" trends and fads- that's not rock n roll.
But in this case I can swear my bridge humbucker in particular is smoother- especially when I split the coils.

So you gave me great food for thought

Markus
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markusv



Joined: 24 Sep 2009
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Location: Toronto, Ontario

PostPosted: Wed Jun 24, 2015 12:11 pm    Post subject: Reply with quote

twangster wrote:
THAT is a sticky Smile


O hell yeah!!!! +1
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BrightKJ



Joined: 13 Sep 2008
Posts: 342
Location: Midlothian, VA

PostPosted: Thu Jun 25, 2015 7:19 am    Post subject: Reply with quote

ghobii wrote:
Mr. Clevername wrote:
If there's a something other than the placebo effect, it's usually because of a difference in values, not construction. Then again, thousands of guitar players hear things I don't.

http://www.aqdi.com/tonecap.htm


+1

+1 more on this one

I have degrees in both Electrical and Electronic Engineering and I can tell you this article is spot on. The biggest takeaway from it should be that actual component values, even in supposed 1% and 5% spec components can vary widely. Anything I ever insert into a circuit gets checked at least three times before solder ever touches it.

Secondary to that, most people don't realize you can change the value of a component when you solder it into a board due to heat transfer up the leads of the component. I have personally seen both resistors and capacitors change by 20% or more due to this type of heat damage. It isn't necessary to use a 45W soldering iron when a 25W is more than sufficient.
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ghobii



Joined: 10 Jan 2010
Posts: 1372
Location: Phila., PA.

PostPosted: Sun Jun 28, 2015 8:50 am    Post subject: Reply with quote

I don't doubt any of this is true, but at the end of the day, the only way to hear these kind of differences is sitting in a quiet room with a clean amp. In a band setting these kind of nuances just disappear. And in recording, the audio engineer is going to EQ the poop out of your guitar anyway.
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RandyM



Joined: 10 May 2008
Posts: 6716
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PostPosted: Sun Jun 28, 2015 9:15 am    Post subject: Reply with quote

Mr. Clevername wrote:
If there's a something other than the placebo effect, it's usually because of a difference in values, not construction. Then again, thousands of guitar players hear things I don't.

http://www.aqdi.com/tonecap.htm


In the years I spent learning to be a EE, I proved this to myself time and again.
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Kregg



Joined: 22 Apr 2008
Posts: 3333
Location: Atlanta

PostPosted: Sun Jun 28, 2015 10:33 am    Post subject: Reply with quote

Great Posts guys.
My ears are too damaged to become an audiophile judge.
Allergies and the occasional antibiotic have destroyed my ears.
The question comes down to one thing for me, can I hear everything I want to hear when I play?
That said, when I changed a Les Paul to Bumble Bee's they really opened up what I could hear (+/- 5% Wink).
Were I playing out I'd hire someone with a good ear to set the levels and frequencies so I don't clear the room. Laughing
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orangedrop



Joined: 01 Dec 2015
Posts: 3
Location: New York

PostPosted: Thu Dec 31, 2015 10:15 am    Post subject: Reply with quote

tangelolemon wrote:
I don't think you're fooling yourself. Sometimes these things get oversimplified.

To address two common misunderstandings about tone controls: First of all, the cap doesn't "just bleed treble off to ground," and the control is NOT out-of-circuit or out-of-band when full up.

First we have to understand something about guitar pickups-- without anything else at all, just the naked pickup has at least three measurable electronic properties: resistance (the resistance of the wire... 5k to 15k typical), the inductance (measured in Henries... all coils have inductance), and capacitance (each turn of wire laying next to another turn forms a tiny capacitor).

These three factors (inductance and resistance act like they're in series, capacitance acts like it's in parallel) form a tuned resonant circuit. A hot humbucker will have a lower resonant peak than a 50s Strat pickup, which is why the latter sounds "chimey" and the former can sound "stuffy." Again, this is an actual boost in the frequency response.

In theory, the tone control is a variable 6dB/octave (first-order) low-pass (high cut) filter.

In practice, both the tone control and the cable (which has its own capacitance) add additional capacitance in parallel, even when full up, (tone control also adds a variable resistance in series with its capacitance.

So this can shift the resonant peak of the system, in addition to the low-pass filtering effect. It is very much "in circuit" and "in the audio path." People who say "it just bleeds treble off to ground" seem to fail to realize that one side of the pickup is connected to ground. Ground is part of the circuit!

If you feel different capacitors can have sonic impacts in audio circuits, it only stands to reason that this would also be possible in an electric guitar-- in fact, it seems it would be even more likely to be audible than in something like an amplifier, since the system has no error correction (in the form of negative feedback), and its high-impedance signal is amplified an incredible amount.

Food for thought with capacitors in general, in audio devices--

Here's a capacitor's equivalent circuit:



Any real-world capacitor has some degree of leakage resistance, equivalent series resistance, and series inductance. The most significant for our purposes would probably be the equivalent series resistance-- in modern capacitors, the others are typically quite small, and probably mostly of concern in high-speed switching applications. Not pictured on the schematic-- dielectric absorption, which can be very significant at audio frequencies, phase angle of response, which will NOT show up on a simple frequency response plug but CAN be audible, and finally, the fact that some capacitors (ceramics that are not NP0 or C0G types tend to be VERY bad about this) can actually impart some distortion to the signal.

Cyril Bateman has published some extensive, peer-reviewed work on distortion imparted by capacitors, and if you really want to "go deep" I suggest looking up his work. It was fascinating and groundbreaking, and those who are really trying to push the state of the art toward quality take it seriously.

Final word-- anything can sound good in the right situation, and I'm not suggesting that everyone go out and drive themselves crazy trying to afford $100 caps to make their guitar magically sound better. But if you find the orange drop sounds better to you than the cheap ceramic disc, then it's not ridiculous. There are several documented mechanisms by which a polypropylene film cap can perform with audible, empirically provable superiority to an inexpensive ceramic, and also documented mechanisms by which those differences can be audible.[/i]

This is true…
I got so tired of all the bashing that I have gone to agreeing with folks and saying "It's mostly errors in value that some one is hearing, but just because you might not hear it does not mean the difference in tone is not there. People have differences in listening acuity, skills and range."

This is usually enough to satisfy both camps and keep arguments from coming to blows or threads being locked down Laughing

Thank you for the reference, I have added it to my links folder.

John
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orangedrop



Joined: 01 Dec 2015
Posts: 3
Location: New York

PostPosted: Thu Dec 31, 2015 10:33 am    Post subject: Reply with quote

tangelolemon wrote:
I don't think you're fooling yourself. Sometimes these things get oversimplified.

To address two common misunderstandings about tone controls: First of all, the cap doesn't "just bleed treble off to ground," and the control is NOT out-of-circuit or out-of-band when full up.

First we have to understand something about guitar pickups-- without anything else at all, just the naked pickup has at least three measurable electronic properties: resistance (the resistance of the wire... 5k to 15k typical), the inductance (measured in Henries... all coils have inductance), and capacitance (each turn of wire laying next to another turn forms a tiny capacitor).

These three factors (inductance and resistance act like they're in series, capacitance acts like it's in parallel) form a tuned resonant circuit. A hot humbucker will have a lower resonant peak than a 50s Strat pickup, which is why the latter sounds "chimey" and the former can sound "stuffy." Again, this is an actual boost in the frequency response.

In theory, the tone control is a variable 6dB/octave (first-order) low-pass (high cut) filter.

In practice, both the tone control and the cable (which has its own capacitance) add additional capacitance in parallel, even when full up, (tone control also adds a variable resistance in series with its capacitance.

So this can shift the resonant peak of the system, in addition to the low-pass filtering effect. It is very much "in circuit" and "in the audio path." People who say "it just bleeds treble off to ground" seem to fail to realize that one side of the pickup is connected to ground. Ground is part of the circuit!

If you feel different capacitors can have sonic impacts in audio circuits, it only stands to reason that this would also be possible in an electric guitar-- in fact, it seems it would be even more likely to be audible than in something like an amplifier, since the system has no error correction (in the form of negative feedback), and its high-impedance signal is amplified an incredible amount.

Food for thought with capacitors in general, in audio devices--

Here's a capacitor's equivalent circuit:



Any real-world capacitor has some degree of leakage resistance, equivalent series resistance, and series inductance. The most significant for our purposes would probably be the equivalent series resistance-- in modern capacitors, the others are typically quite small, and probably mostly of concern in high-speed switching applications. Not pictured on the schematic-- dielectric absorption, which can be very significant at audio frequencies, phase angle of response, which will NOT show up on a simple frequency response plug but CAN be audible, and finally, the fact that some capacitors (ceramics that are not NP0 or C0G types tend to be VERY bad about this) can actually impart some distortion to the signal.

Cyril Bateman has published some extensive, peer-reviewed work on distortion imparted by capacitors, and if you really want to "go deep" I suggest looking up his work. It was fascinating and groundbreaking, and those who are really trying to push the state of the art toward quality take it seriously.

Final word-- anything can sound good in the right situation, and I'm not suggesting that everyone go out and drive themselves crazy trying to afford $100 caps to make their guitar magically sound better. But if you find the orange drop sounds better to you than the cheap ceramic disc, then it's not ridiculous. There are several documented mechanisms by which a polypropylene film cap can perform with audible, empirically provable superiority to an inexpensive ceramic, and also documented mechanisms by which those differences can be audible.[/i]

This is true…
I got so tired of all the bashing that I have gone to agreeing with folks and saying "It's mostly errors in value that some one is hearing, but just because you might not hear it does not mean the difference in tone is not there. People have differences in listening acuity, skills and range."

This is usually enough to satisfy both camps and keep arguments from coming to blows or threads being locked down Laughing

Thank you for the reference Mark, I have added it to my links folder.

John
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