Capacitor Location in tone circuit - Does it matter?

[bert123]

I've got multiple diagrams for 2 pickup, 2 volume pots, 2 tone pots, 3 way switch.
On some diagrams the capacitor is between the volume pot and the tone pot(i.e. the schematics on the SD web site).

On others the capacitor is between the 'ground' lug of the tone pot and system ground (instructions are to solder the end of the capacitor to the pot).

Any difference if behavior between the two methods?

 

[That90'sGuy]

Re: Capacitor Location in tone circuit - Does it matter?

I've seen them both ways as well and IIRC, there is no difference.

 

[MikeRocker]

Re: Capacitor Location in tone circuit - Does it matter?

It's funny that you post this, I just called Seymour Duncan tech support yesterday to ask the same thing. The tech said that there are several ways to wire tone circuits which produce the same results. I plan to go with the simplest (least amount of wiring) on my current project!

 

[Kent S.]

Re: Capacitor Location in tone circuit - Does it matter?

I've got multiple diagrams for 2 pickup, 2 volume pots, 2 tone pots, 3 way switch.
On some diagrams the capacitor is between the volume pot and the tone pot(i.e. the schematics on the SD web site).

On others the capacitor is between the 'ground' lug of the tone pot and system ground (instructions are to solder the end of the capacitor to the pot).

Any difference if behavior between the two methods?

What you refer to here, specifically ... NO, no difference. There are other interactions which can occur in more complex tone systems, but not here in this case.

 

[bert123]

Re: Capacitor Location in tone circuit - Does it matter?

Thanks for the info.

If was looking at an explanation of the treble/mid/bass tone stack in Fender/Marshall/Vox amps at ax84.com and they start with an explanation of high pass and low pass filters which only differed in order of the resistor and capacitor. I went back and looked at the filter diagrams an noticed that there the first capacitor(resistor) was in the signal path with its opposite member connected to ground.

 

[Lewguitar]

Re: Capacitor Location in tone circuit - Does it matter?

I've always throught therehad to be a difference in tone but that I couldn't be certain of it.

If you think about it, the cap is a filter that blocks the lows and mids and allows the highs to pass through the tone control to ground and escape the circuit when the tone control is turned down.

So if you have the cap between the volume control and tone control the cap blocks the lows and mids before they enter the tone control, so the tone control is only dealing with treble frequencies.

If you have the tone control connected directly to the volume control, the tone control sees the whole frequency range and when you turn it down, you allow all the frequencies to pass through the tone control and then the cap blocks all but the treble from escaping to ground.

So it seems to me there must be some difference in the way the two wiring methods behave!

But all the experts say that ultimately there is no diff...so maybe they're right.

My brother Bruce says there is no diff...I trust his expertise.

 

[TwilightOdyssey]

Re: Capacitor Location in tone circuit - Does it matter?

Welcome back, Lew! Good information, as always. I'm going to shoot you a PM today about obtaining a couple of pups.

 

[Lewguitar]

Re: Capacitor Location in tone circuit - Does it matter?

Thanks! I think there is a big diff in where the cap or tone control is connected to the volume control:

1. connected to the wiper or middle terminal retains treble better when the volume control is turned down. That's the 50's mod.

2. connected to the top/input (same terminal as the pickups or selector switch is connected to) means that the tone control is seeing the full output of the pickups at all times and the tone is not as bright and clear when the volume is turned down.

Just depends what tone you're comfortable with.

I tend to prefer the first (or 50's mod) method myself...unless I'm dealing with a very bright guitar. Then I'll go with the second method.

Lew

 

[Artie]

Re: Capacitor Location in tone circuit - Does it matter?

If what we're talking about here is simply whether the cap or pot comes first in line, then there is no difference.

Look at it this way. Consider the tone control at any given setting, say, on "5". Lets assume a linear taper, 500k pot to keep the math easy. Since we only use two terminals on a tone pot, we essentially have a 250k resistor, in series with a cap.

Now, remember, we're dealing with AC here, so one half of the waveform see's the cap first, the other half sees the resistor first. Its only because of convention, that we even refer to "ground". Since what happens on one side of the cap is controlled by what happens on the other, the electrical interaction is identical.

Now, what bert is talking about is completely different, becuase there's a connection between the cap and resistor. So, its where you send what to ground that counts. In a guitar tone circuit, there's nothing between the cap and pot. Regardless of which comes first.

Hope this helps.

Artie

 

[Kent S.]

Re: Capacitor Location in tone circuit - Does it matter?

Thanks for the info.

If was looking at an explanation of the treble/mid/bass tone stack in Fender/Marshall/Vox amps at ax84.com and they start with an explanation of high pass and low pass filters which only differed in order of the resistor and capacitor. I went back and looked at the filter diagrams an noticed that there the first capacitor(resistor) was in the signal path with its opposite member connected to ground.

You're trying to mix oil and water here, two different things, *yours* are in series (with no other junctions cooming off of them), yours make up a series shunt to ground, theirs is different ... If you need to learn about high pass and low pass filters you need to start with just those.
You are looking at two different signal paths in that tone stack, you are looking at only one in a standard guitars tone circuit. Plus the signal actually goes thru the tone stack, not so in the common guitar circuit (referring to watch you hear).
Technically the guitar's tone circiut is a low pass filter with variable attenuation (or limited attenutaion as it's also know as).
Also, even in the amp's tone stack and other filter applications the placement of R and C, as two which is first make a difference (I'm not referring to reassigning their roles, just order). But that's, that and not guitar, don't confuse the two. The strat style (R>C>ground), works exactly like the lp style (C>R>ground).