Part 1
A lot of the musical sounds that we listen to everyday have certain underlying problems that often lead to deterioration of signal quality. PROVIDENCE has developed a product that focuses on preventing such signal deterioration. Called the "VITALIZER", this product is unlike equalizers or enhancers which utilize specific frequencies, and also differs from buffers in that it does not color the sound. The VITALIZER is essentially a product that represents a breakthrough in effectors so as to eliminate signal deterioration and produce a sound quality that exactly matches the original sound.
But, we could ask, "what actually goes into the make up of the VITALIZER and "what are the effects that it produces?" In this series, running over several parts, Mr. Kawakami, a writer for various music magazines, lays out the characteristics of the VITALIZER for us in a clear and an easy-to-understand manner.
Chapter 1: Sound quality deteriorates merely by connecting a cable!

I have heard complaints that a guitar sound deteriorates when a longer cable is used or when effectors, tuning devices, etc., are connected between the guitar and an amplifier, but, people who are aware enough to recognize such problems are probably the exception. I would like those who can do so, to obtain cables of the same brand and model numbers, but of different lengths, and take the opportunity to compare the differences in sound quality when cables of different lengths are used.
When a 1-meter cable is used, for example, compared with a 10-meter cable, the differences in the sound characteristics will become apparent to virtually everyone. But, for people with a trained ear, the differences in sound characteristics will likely be recognized even when the cables being compared are of a shorter length. Also, in instances when an effector is used, even when the effector is turned off, the sound will often be different from that which is heard when the guitar is connected directly to an amplifier by a single cable.
Before I delve into the effects of the VITALIZER in this multipart series, first let me describe the mechanism by which such sound deterioration occurs.
Signals output from a traditional electric guitar are set at a high-impedance in order to gain the required signal level for amplification by a guitar amplifier and to produce an attractive sound.
When a longer cable is used for transmitting high-impedance signals, the signal level drops and the sound quality also deteriorates in the high ranges. It might be easier to understand signal deterioration simply by putting it isway: the longer the cable is, the more resistance increases.
  
Signal deterioration in the high range is caused by cable capacitance (*1). Capacitance occurs between the plus core, which runs through the center of a cable, and the minus shield wire and causes high range signals to flow to ground, based on the same logic as the tone control circuit for the guitar itself.

To cope with signal deterioration in the high range, cable makers have striven to develop cables to overcome this problem. However, due to structural and functional requirements of a cable itself which need to be met, realistically speaking, it's a problem which cannot be avoided 100%. If a longer cable is used, the sound quality inevitably deteriorates in the high range. One option for improving this problem is to convert signals output from a guitar into low-impedance signals; however, in this case as well, the guitarist with a trained ear will still sense sound deterioration when a longer cable is used.

Let's listen to the sound when we simply plug a 3-meter cable directly into an amplifier.
Distortion Sound (Marshall JCM2000)
※1) Capacitance: The amount of charge accumulated in an insulated conductor such as a capacitor. Also, called “electric capacity” or “capacitance”. This is indicated by the quantifier "C" and by units in "farad" [F].
For example, if a charge of 1 coulomb [Q] is stored after applying an electric voltage of 1V to a certain body, the capacitance of this body will be "1" farad [F]. A capacitance of 1F is extremely large and with the capacitors that are generally used as electronic components, a capacitance in microfarads [μF] which is a fraction of a millionth of 1F (1E-6) and capacitance in picofarad [pF] which is a trillionth part of 1F (1E-12), are frequently used.

Chapter 2: Deterioration of sound quality when an effector is connected

Next, let’s take a look at changes in sound quality when an effector or a tuning device is connected.

Prepare a 5-meter cable and two 2.5-meter cables, for example; to check the differences in sound quality produced when a guitar is directly connected to an amplifier using the 5-meter cable with the sound quality when an effector or tuning device set to the OFF state is connected between the guitar and the amplifier using two 2.5-meter cables. The differences in sound quality can be clearly sensed depending on the type of an effector or a tuning device used. This frequently occurs when a buffer amplifier which is built into the equipment is used.

A buffer amplifier is used for converting high-impedance signals into low-impedance signals without amplifying the signals. Although one might have the idea that sound quality deterioration can be reduced by using equipment with a built-in buffer-amplifier circuit, this is a misconception.

In the case of compact effectors or tuning devices with a built-in buffer circuit that are generally in use today, usually the buffer circuit is incorporated merely for the purpose of ensuring normal operation and to avoid electrical problems when other equipment is connected before or after the pertinent effector or tuning device, and not for the purpose of improving the overall guitar sound.

Also, even when a buffer-amplifier circuit is incorporated, frequently signals with insufficiently low impedance are output and subsequently pass through a long cable, resulting in sound quality deterioration in the high range.

Although it can be said that a buffer circuit does "not amplify signals", the sound color may be changed slightly merely by passing through the circuit. Such sound tends to be altered by the buffer and can be termed a "buffer-colored" or "bufferish" sound. Even in the case of products touted for having a "built-in buffer circuit in consideration of sound quality", sound production techniques need to be incorporated to compensate for sound deterioration in the higher range caused by use of a cable and the sound produced by such products definitely differs from the original sound produced by a guitar that is connected by means of only a single cable.

Let's connect a volume pedal between a guitar and an amplifier to monitor sound quality and see how much the sound deteriorates.
Distortion Sound (Marshall JCM2000)


 
A recent trend in effectors, in order to minimize such sound quality deterioration is to employ a "true bypass switch" which does not allow signals to pass through the buffer circuit while the effector, etc., is in the OFF state. However, a true bypass switch does not solve problems which are related to impedance. If a longer cable is employed after the equipment having a true bypass switch, the sound quality will still deteriorate. Also, in cases where multiple effectors are used simultaneously, if even one of the effectors has a built-in buffer circuit, the true bypass switch becomes irrelevant.
However, on the actual live music scene such as at concerts venues and live houses, we cannot simply connect a guitar to an amplifier using a single short cable. As multiple effectors are used for such performances, naturally longer cables are required to connect them. As a result, a guitar sound that is totally different from the original sound will be produced. Not only that, if the length of cables used at live concerts is changed to meet the requirements of the venue, the guitar sound also changes based on the setup used. It was with the goal of solving such problems that the VITALIZER was developed.
Now, let’s listen to the sound produced when a volume pedal is connected to the "Send/Return" terminals of the VITALIZER and compare the sound produced with the sound which we monitored previously.
Distortion Sound (3m Cable)
Distortion Sound (Vol. Pdl)
Distortion Sound (Vol.Pdl+Vitalizer)

I assume that now you understand how changes in guitar sound can occur at some point along the way due to the use of cables and buffer amplifiers. Not only that, quite a number of guitarists and bassists are troubled by the phenomena of sound quality deterioration in the high range which occurs simultaneously with changing the volume using a volume pedal.

In the next part in this series, we look at the various situations and compelling problems that resulted in the need for use of equipment such as the VITALIZER through examining actual situations occurring in the music scene. We also discuss the background of development of the VITALIZER in an interview with Yukihiro Hayashi, of Free the Tone, the person who developed the VITALIZER.

(By Keishi Kawakami)