Active Pedals: True or False statement?

George Kimery · From: Limestone, TN, USA

If you want to hear what your guitar will sound like with an active pedal, just plug your guitar direct into the amp and bypass your current pedal. TRUE OR FALSE?

Since the manufacturer's of the active pedals claim that the pedal is transparent and does not change the tone, then why wouldn't just plugging directly into the amp give you the sound that you would get if you use an active pedal? The claim that an active pedal does not change your sound is debatable. I have talked to some of the most well know players about an active pedal. Some of them will not use them because they feel that contrary to the claims, they suck the tone out of your guitar. After years of playing, maybe their ears are just so set on the sound of a pot pedal that anything else sounds to them like they are losing tone with an active pedal.

Georg Sørtun · From: Mandal, Agder, Norway

George Kimery · From: Limestone, TN, USA

It looks like either a passive pedal or an active pedal, for better or worse, changes the sound of your guitar. The tone of a passive pedal does change as you go from low volume to high volume. The tone on an active pedal does not change, so I guess that is where the claim made by active pedal manufacturer's that their pedal is transparent and does not change the tone.

Georg Sørtun · From: Mandal, Agder, Norway

Well, a passive pedal doesn't change "tone" as such.

The passive volume pedal, being a variable resistor in combination with cable capacitance and amplifier input impedance, changes "load on the PU" along the pedal's travel. The PU, being one part in this passive RCL chain, does change its output and phase along the frequency-range depending on what the load on it happens to be. Voila: the passive pedal causes change in "tone".

An active pedal (or a passive pedal preceded by an active stage), has a buffer-stage at its input that is keeping the load on the PU constant regardless of the pedal's position along its travel. No change in load on the PU = no change in PU's output and phase along the frequency-range = no change in perceived "tone".

George Kimery · From: Limestone, TN, USA

Ok, so a passive pedal does not change the tone, per se. But the tone get's changed by electronic manifestations. If you put lipstick on a pig, at the end of the day, it is still a pig. It is easier for me to understand that the tone get's changed by the pedal and my ears don't know the difference, even though technically speaking, I am wrong.

Thanks, George for taking the time to explain it all to me. Very much appreciated.

Georg Sørtun · From: Mandal, Agder, Norway

You're most welcome.

Knowing how things work makes it so much easier to change them to our satisfaction Very Happy

Donny Hinson · From: Glen Burnie, Md. U.S.A.

For the umpteenth time, there is no good tone or bad tone. Tone is never this piece of gear or that thing you plug into. Tone is merely the sound YOU want. For some players, it's an active pedal, a buffer, or a matcher. For others, it's a pot pedal, a cord, or a control. What sounds better or worse is nothing but somebody's opinion. There is no concensus on what people like, so there can never be a single answer to the "tone problem" so many steelers seem to have.

However, I do find it both interesting and amusing that over 99.99% of all electric guitars have a volume pot in them. Whoa!

"Lucyyyy...splain dis to me..." Laughing

Georg Sørtun · From: Mandal, Agder, Norway

Jim Priebe · From: Queensland, Australia - R.I.P.

I too am a bit puzzled with this post.

Georg Sørtun · From: Mandal, Agder, Norway

Roger Kelly · From: Bristol,Tennessee

Peavey Amplifiers have had a "Pedal Patch" feature since 1980. One might revisit Mike Brown's Article and have a better understanding of what Peavey Amp owners already have without spending a lot of money.

http://peavey.com/media/pdf/steelguitar/pre_eqpatch.pdf

George Kimery · From: Limestone, TN, USA

I was at the Dallas show last month. Dave Beaty was sitting on the floor running the Telonic's pedal through it's paces as a steel player was sitting at the steel. I may have taken what Dave said out of context, but he said the pedal is transparent and does not change the tone of the guitar. As I mentioned above, maybe he was referring to the up and down movement not changing the tone, not the pedal in general. Regardless of what is happening in all the electronic chain, if the sound of the guitar changes when you hook up a volume pedal, to me, the pedal is making it sound different, just in an indirect way.

Georg Sørtun · From: Mandal, Agder, Norway

Jim Priebe · From: Queensland, Australia - R.I.P.

Donny Hinson · From: Glen Burnie, Md. U.S.A.

What works best is all just personal opinion. As Georg said, the point of reference is critical. Because a pedal must be followed by an amp, and because any musical instrument amp alters the character of a signal, due to factors such as input impedance, available power, linearity, distributed capacitance, speaker type, and cabinet design (see also Heisenberg's Uncertainty Principle), it can probably be argued that the only really "natural" sound of any guitar is when it's not amplified.

Food for thought, anyway.

Jim Sliff · From: Lawndale California, USA

Earnest Bovine · From: Los Angeles CA USA

Dave Beaty · From: Mesa, Arizona, USA

The changes in tone which are often incorrectly attributed solely to volume pedals (passive or active), are actually due to the electrical characteristics of the cable used between the instrument and the pedal, the particular pickup, the type of cable or wiring in the guitar, the electrical characteristics of the neck switch (if applicable), any tone circuits built into the guitar (if applicable), the cable from the pedal to the amplifier, and the input characteristics of the amplifier.

This topic has been posted many, many, times on the Forum, but there have been a few threads that did an especially good job of explaining many of the contributing factors. One such thread was started by Mike Perlowin who posted a good article under the topic heading:
Interesting article about cables
23 May, 2013 at 8:27 pm (so you can search it out)

It was written by Craig Anderton
and entitled:

The Truth About Guitar Cables By Craig Anderton
......A Cable Is Not Just a Piece of Wire....

It should be included as suggested reading for anyone interested in learning the why's and wherefore's of tonal coloration due to component systems in the signal chain.

I'm not sure of the best way to find Mike's post; I searched by the author of the post (Mike Perlowin) and title (Interesting article about cables) under Electronics using the 3 year option and it came up. The exact URL is: http://bb.steelguitarforum.com/viewtopic.php?t=246670&highlight=interesting+article+cables

(I will try to copy and past Craigâ€™s article in this post, just to avoid having people hunt for it.)

Before proceeding, I would point out that the following brief discussion is appropriate to steel guitar pickups and associated potentiometers (â€œpotsâ€) normally used, and NOT to 6 string guitar pickups and pots which are typically a much lower impedance and resistance respectively.

As for the cables, the most critical cable is the one between the guitar and pedal.
One thing one has to remember is that the components of a cable assembly are tonally inert, BUT once configured into a cable assembly (two plugs and a length of cable), the resultant assembly has unique electrical characteristics which can change the frequency characteristics of an audio signal being conducted by the cable.
And, the manner in which the signal is changed, and the amount of those changes is dependant upon the electrical characteristics of

1. the SOURCE (pickup(s), pickup wire/cable, the wire/cable in the guitar, neck switches (if used), tone components like pots and capacitors (if used) and the output jack), and

2. the TERMINATION where the cable plugs into the pedal (input impedance â€“ which is comprised of both the resistive load presented by the pedal and the capacitance and inductance (if there is any appreciable inductance.)

Given what is presented to the cable at the instrument and at the pedal, the electrical characteristics of the cable now play an important part. The most significant of which is the capacitance of the cable (which is a function of the physical relationships of how it is constructed. The greater the capacitance per foot of the cable, the greater will be the high frequency roll-off experienced. All good cable is rated in a consistent capacitance per foot (among other characteristics). This capacitance is additive, so it follows that the longer the cable, the greater will be the capacitance and the greater will be the high frequency roll-off (loss) heard as a result.

Again, in general, the other significant part of this high frequency loss relates to the impedance at the pedal end of the cable. The lower the impedance at the pedal, the greater will be the high frequency loss. This is the reason one hears greater high frequency loss with a pot pedal as opposed to an active/electronics pedal, as virtually all of them have a much higher input impedance than a pot pedal, causing greater high frequency roll-off.

So in short, even though a playerâ€™s focus may be on one component of his signal chain (cables, pedal, pickup, etc), and even though a particular part of that signal chain may be significant with regard to itâ€™s effect on the tone, one cannot attribute the tone achieved to any one component. It is the â€˜combinationâ€ of components which defines the tone achieved, and changing any one component will directly affect the way another component interacts with the other components. It is therefore impractical to attribute oneâ€™s tone to a particular component of the tonal chain. As they say, and quite correctly in this case, â€œeverything mattersâ€.

So George, the short answer to your question might best be stated that:
â€œUsing an electronic pedal which provides a flat response across the entire audio frequency range (tonally inert), will normally result in far less high frequency loss than a pot pedal due to the higher input impedance they exhibitâ€. (Of course some pedals and amplifiers offer an adjustable input impedance control to compensate accordingly.)

BUT if you are talking about tonal CHANGE, the fact that you will likely hear more highs with an electronic pedal is, a â€œchangeâ€. Some people will prefer that change, others will not, but it depends on the pickup used and the electrical characteristics of the other system components in your audio chain.

To be meaningful, you just canâ€™t talk about pedals, cables or pickups, etc., alone. All the components interact, and the results will vary from system to system dependant upon the components chosen.

This situation is apparently not well understood, to wit, this discussion. When something is not understood, it sometimes takes on the form of â€œblack magicâ€. But these days, we have, for the most part, stopped burning witches at the stake â€“ and fortunately, for a given set of components, their performance can be accurately modeled, measured and predicted.

(We â€œcouldâ€ eliminate all of this with state-of-the-art electrical and mechanical designs, but there is a great deal of traditionalism in the steel guitar field and most people we have spoken with simply donâ€™t want to make the giant-step changes in system design which are now possible.
Ergo, we â€œpatchâ€ the systems in socially acceptable ways. Matter of fact, I kinda like it this way myselfâ€¦..)

The Truth About Guitar Cables By Craig Anderton

A Cable Is Not Just a Piece of Wire . . .

If a guitar player hears something that an engineer says is impossible, lay your bets on the guitarist. For example, some guitarists can hear differences between different cords. Although some would ridicule that ideaï¿½wire is wire, right?ï¿½different cords can affect your sound, and in some cases, the difference can be drastic. What's more, there's a solid, repeatable, technically valid reason why this is so.

However, cords that sound very different with one amp may sound identical with a different amp, or when using different pickups. No wonder guitarists verge on the superstitious about using a particular pickup, cord, and amp. But you needn't be subjected to this kind of uncertainty if you learn why these differences occur, and how to compensate for them.

THE CORDAL TRINITY

Even before your axe hits its first effect or amp input, much of its sound is already locked in due to three factors:

ï¿½ Pickup output impedance (we assume you're using standard pickups, not active types)

ï¿½ Cable capacitance

ï¿½ Amplifier input impedance

We'll start with cable capacitance, as that's a fairly easy concept to understand. In fact, cable capacitance is really nothing more than a second tone control applied across your pickup.

A standard tone control places a capacitor from your "hot" signal line to ground. A capacitor is a frequency-sensitive component that passes high frequencies more readily than low frequencies. Placing the capacitor across the signal line shunts high frequencies to ground, which reduces the treble.

However the capacitor blocks lower frequencies , so they are not shunted to ground and instead shuffle along to the output. (For the technically-minded, a capacitor consists of two conductors separated by an insulatorï¿½a definition which just happens to describe shielded cable as well.)

Any cable exhibits some capacitanceï¿½not nearly as much as a tone control, but enough to be significant in some situations. However, whether this has a major effect or not depends on the two other factors (guitar output impedance and amp input impedance) mentioned earlier.

AMP INPUT IMPEDANCE

When sending a signal to an amplifier, some of the signal gets lost along the wayï¿½sort of like having a leak in a pipe that's transferring water from one place to another. Whether this leak is a pinhole or gaping chasm depends on the amp's input impedance. With stock guitar pickups, lower input impedances load down the guitar and produce a "duller" sound (interestingly, tubes have an inherently high input impedance, which might account for one aspect of the tube's enduring popularity with guitarists).

Impedance affects not only level, but the tone control action as well. The capacitor itself is only one piece of the tone control puzzle, because it's influenced by the amp's input impedance. The higher the impedance, the greater the effect of the tone control. This is why a tone control can seem very effective with some amps and not with others.

Although a high amp input impedance keeps the level up and provides smooth tone control action (the downside is that high impedances are more susceptible to picking up noise, RF, and other types of interference), it also accentuates the effects of cable capacitance. A cable that robs highs when used with a high input impedance amp can have no audible effect with a low input impedance amp.

THE FINAL PIECE OF THE PUZZLE

Our final interactive component of this whole mess is the guitar's output impedance. This impedance is equivalent to sticking a resistor in series with the guitar that lowers volume somewhat. Almost all stock pickups have a relatively high output impedance, while active pickups have a low output impedance. As with amp input impedance, this interacts with your cable to alter the sound. Any cable capacitance will be accented if the guitar has a high output impedance, and have less effect if the output impedance is low.

There's one other consideration: the guitar output impedance and amp input impedance interact. Generally, you want a very high amplifier input impedance if you're using stock pickups, as this minimizes loss (in particular, high frequency loss). However, active pickups with low output impedances are relatively immune to an amp's input impedance.

THE BOTTOM LINE

So what does all this mean? Here are a few guidelines.

ï¿½ Low guitar output impedance + low amp input impedance. Cable capacitance won't make much difference, and the capacitor used with a standard tone control may not appear to have much of an effect. Increasing the tone control's capacitor value will give a more pronounced high frequency cut. (Note: if you replace stock pickups with active pickups, keep this in mind if the tone control doesn't seem as effective as it had been.) Bottom line: you can use just about any cord, and it won't make much difference.

ï¿½ Low guitar output impedance + high amp input impedance. With the guitar's volume control up full, the guitar output connects directly to the amp input, so the same basic comments as above (low guitar output Z with low amp input Z) applies. However, turning down the volume control isolates the guitar output from the amp input. At this point, cable capacitance has more of an effect, especially of the control is a high-resistance type (greater than 250k).

ï¿½ High guitar output impedance + low amp input impedance. Just say no. This maims your guitar's level and high frequency response, and is not recommended.

ï¿½ High guitar output impedance + high amp input impedance. This is the common, 50s/60s setup scenario with a passive guitar and tube amp. In this case, cable capacitance can have a major effect. In particular, coil cords have a lot more capacitance than standard cords, and can make a huge sonic difference. However, the amp provides minimum loading on the guitar, which with a quality cord, helps to preserve high end "sheen" and overall level.

Taking all the above into account, if you want a more consistent guitar setup that sounds pretty much the same regardless of what cable you use (and is also relatively immune to amplifier loading), consider replacing your stock pickups with active types.

Alternately, you can add an impedance converter ("buffer board") right after the guitar output (or for that matter, any effect such as a compressor, distortion box, etc. that has a high input impedance and low output impedance). This will isolate your guitar from any negative effects of high-capacitance cables or low impedance amp inputs.

If you're committed to using a stock guitar and high impedance amp, there are still a few things you can do to preserve your sound:

ï¿½ Keep the guitar cord as short as possible. The longer the cable, the greater the accumulated cable capacitance.

ï¿½ Cable specs will include a figure for capacitance (usually specified in "picofarads per foot"). If you make your own cables, choose cable with the lowest pF per foot, consistent with cable strength. (Paradoxically, strong, macho cables often have more capacitance, whereas light weight cables have less.)

ï¿½ Avoid coil cords, and keep your volume control as high up as possible.

ï¿½ Don't believe the hype about "audiophile cords." They may make a difference; they may not. If you don't hear any difference with your setup, then save your money and go with something less expensive.
Before closing, I should mention that this article does simplify matters somewhat because there's also the issue of reactance, and that too interacts with the guitar cable capacitance. However, I feel that the issues covered here are primarily what influence the sound, so let's leave how reactance factors into this for a later day.

Remember, if you axe doesn't sound quite right, don't immediately reach for the amp: There's a lot going on even before your signal hits the amp's input jack. And if a guitarist swears that one cord sounds different from another, that could very well be the caseï¿½however, now you know why that is, and what to do about it.

Craig Anderton is Executive Editor of Electronic Musician magazine. He has played on, mixed, or produced over 20 major label releases (as well as mastered over a hundred tracks for various musicians), and written over a thousand articles for magazines like Guitar Player, Keyboard, Sound on Sound (UK), and Sound + Recording (Germany). He has also lectured on technology and the arts in 38 states, 10 countries, and three languages.

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