ZOOM G21U
Owner's Manual

M odelng D escr pt on i ii
MESA/BOOGIE Mark III

�c Ref ence f drve ef ect t er or i f ypes and is orgi m odel t i nal s.
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bC

Fender Tweed Deluxe '53

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Marshall JCM800

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Marshall Guv'nor

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The origin of the MESA/BOOGIE amplifier was the modified Fender Princeton. Randall Smith, an amp tech in San Francisco, souped up those small guitar amps to put out 100w power and sold them. The first model was called �Mark I�. Carlos Santana tried one and said, �Shit man, that little thing really Boogies! � -which gave the amplifier the brand name �BOOGIE.� The second model �Mark II� had lead and rhythm channels and a 4-band equalizer to give wider variety to the guitar tone. The special feature of this model was an accomplished simul- power circuitry (the operation could be switched between class A and class AB). The power amplifier section had six power tubes. When the class A operation is selected, two EL34 power tubes are activated and the amp puts out a really smooth sound. When the class AB operation is selected, these two EL34s and other four 6L6GC power tubes are all activated and the amplifier puts out its full potential power. Until the model Mark II, MESA/BOOGIE amps were quite expensive, hand-made amplifiers, but the next model �Mark III� was more affordable. It has one 10� loudspeaker and 60w output power but retains all of the classic BOOGIE features; simul-power circuitry, the graphic EQ, and three (Rhythm1, Rhythm2 and Lead) separate channels. With this Zoom G series, you can select the modeling of the combo type of this �Mark III.�

The very first Fender amplifier was developed by Leo Fender and his trusty partner, the engineer Doc Kaufman in 1945-46. Actually, the earliest models were not made under the �Fender� brand but the �K&F Manufacturing Corporation� named after the Initials of the two. The first amplifier using the �Fender� brand was the �Model 26� in 1947. In 1949, the entry models called �Champion 400/600� series followed. The so-called �Tweed Amps� covered literally with tweeds all over were developed during the 1950s and the 1960s. In these years, the company put out various tweed models like the �Bassman� or the �Bandmaster�. The program of this G series is modeled after, among others, the most representative �Tweed Deluxe� aka the �Wide Panel� from 1953. This amplifier has a 12AY7 and a 2AX7 pre-tubes, two 6V6GT power-tubes, a 5Y3GT rectifier tube and a 12� Jensen loudspeaker and its output power is 10w. Recently the original amplifier is priced quite highly and is very difficult to find in good condition. This amp has two inputs but one is the input for a microphone. It has just one tone knob for treble control. Therefore, it is advisable to use this program on the G series with a flat tone setting except for the treble parameter so that you can enjoy the characteristic sound in the lower registers and the unique sound in the higher registers of the original Fender amp.
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Marshall has continued to produce great amplifiers for up-to-date musical trends in cooperation with the musicians. This brand started with its �JTM- 45 (stands for Jim&Terry Marshall)� in 1962 and now its products are indispensable items in the modern Rock scene. Marshall seems to have been experimenting with different circuit designs of amplifiers but 1981 was the most prolific year for the brand because it released many new models like the �1959� and �1987� with four inputs, �2203� and �2204� with master volumes. In 1983, Marshall added the �2210� and �2205� with two (Normal and Boost) channels as well as effect send/return connectors to its lineup. These models also carried the collective designation �JCM (stands for Jim&Charles Marshall) 800�. They had three ECC83 pre-tubes and four EL34 power-tubes. The tone control circuit was placed after the pre-amp section and this design seems to have become the standard for the modern Marshall amplifiers. For the modeling on this G series, we selected the �2203� with a master volume and it is quite easy to get the distortion. By today�s standards, the amplifier�s distortion is rather moderate, but the sound is very fat, the low-end is quite tight and, above all, the sound cuts through very well. When higher gain is required, this amplifier is often combined with overdrive or booster pedals. For the modeling, we used the head with a �1960A� cabinet that has four 12� loudspeakers and works very well with the �2203�.

The initial sales talk for this serious distortion pedal �Guv�nor� bearing the Marshall brand was that you could get the distortion sound of the Marshall amps with this small stomp box. Depending on which guitar amps you combine, you can actually get the Marshall amps distortion. There are two different versions of the Guv�nor: the Britain-made ones from 1988 and the Korean-made ones from 1998. The program on this G series is modeled after the original version from 1988. The Guv�nor�s characteristic feature is the frequency point you can tweak using the �TREBLE� control. Even if you lower this parameter value, the sound will get fat instead of getting dullish. As you raise the value, the sound will get sweeter and clearer.

MESA/BOOGIE Dual Rectifier

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Fender Twin Reverb '65

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BOSS OD-1

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MATCHLESS HOT BOX

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The �Rectifier� model has the improved simul-power circuitry (see the �Mark III� section) and the increased gain in the preamp section. This amp puts out 100w power and has five 12AX7 tubes for the pre-amp and four 6L6GC tubes for the power-amp. As opposed to the �Mark� series, the Rectifier has its tone control circuit after the volume circuit for better effect on the sound. Since this amp had been introduced, the brand image of MESA/BOOGIE has changed from being the premiere amp manufacturer for fusion music to that for heavy metal music. The most prominent feature of this amp is its rectifier circuitry after which it was named. The �Dual Rectifier� employs, as its name suggests, two different rectifier circuits: one uses silicon diodes and another uses tubes. When the diodes are selected, the amp gives you tight and highly powerful sound. When the tube rectifier circuit is selected, you will get a warmer sound. This program is modeled after the combination of a four-12� BOOGIE cabinet and the Dual Rectifier head using the vintage channel and the silicon-diode rectifier circuit.

In the later half of 1965, a reverb unit was added to the �Twin� amp, which was the birth of the �Twin Reverb� model. In 1965, Fender company was sold to CBS because of Leo Fender�s health problem. The program on this G series is modeled after the pre-CBS �Twin Reverb� from 1965 aka �Black Panel�. This amp has four 7025 (12AX7), a 12AX7 and two 12AT7 pre-tubes, four 6L6GC power-tubes and silicon diodes for the rectifier circuit. The diode rectifier is believed to give a tighter sound to the amplifier than the tube rectifier does, which should be the key to the characteristic glittering sound of this �Twin Reverb�. This guitar amplifier has two 12� loudspeakers by Jensen and pus out 80w power. On the program in this G series, you can have the sound with the �Bright� switch on by tweaking the �Harmonics� parameter in the �EXTRA EQ� section. When you turn the reverb effect on, you will get that �Twin Reverb� sound you have been longing for.

The �OD-1� released by BOSS in 1977 was originally developed for the simulation of the natural overdrive sound of tube amplifiers, but this stomp box turned out to be popular as the booster unit to connect to the input of the real tube amplifier to get tighter and more punchy sound with the increased gain. The �OD-1� employs the asymmetrical �clipper� section in its circuit design that uses three diodes to create the overdrive sound that is mild and rich in nuances. The pedal had been in production from 1977 to 1985, but now it is unexpectedly difficult to even find a used one. And if you could locate one, it would be astonishingly expensive. There have been many stomp boxes known as overdrive units. The most famous one is probably the �Tube Screamer� but we chose this very original overdrive pedal �OD-1�. If you are lucky enough to use the real �OD-1�, we invite you to try blind test to turn off all of the effect module except the �OD-1� on the G series and compare the sound of the modeling and that of the real one. We think that you will not hear any difference.

The �HOT BOX� was released as a pedal preamp bearing the MATCHLESS brand. It uses two 12AX7A tubes for the truthful reproduction of the sound of the �MATCHLESS� guitar amplifiers. It has the compressed sound and the quick response, which are distinctive characteristics of tube amps. Its sound is fat and cuts through very well, too. Even if you crank up the gain to get a distorted sound, you will retain the nuances of the original guitar sound. Although it is categorized as preamp, the ideal way to get the best possible sound is to connect it, like usual stomp boxes, to the input of your guitar amp. Its design is also attractive: the case is polished like a mirror and the �MATCHLESS� logo lights up when you turn it on. This �Hot Box� is literally a magic box: you can get the signature sound of the �MATCHLESS� amps regardless of the guitar amplifier you connect it to.

Roland JAZZ CHORUS

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PEAVEY 5150 STACK

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BOSS MT-2

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ZOOM Extreme Distortion

E F F E C T T Y P E : E X T R E M E D IS T O R T IO N

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Simply put, the Roland �JC-120� is the most familiar guitar amplifier among both professionals and amateurs. Released in 1975 from Roland, this amp became known as �portable�, �loud� and �almost trouble-free� (which are the very characteristics Japanese products are known for!). You are pretty sure to find one in any live houses or studios all over the world. The key to that sound of �JC-120� is its unique chorus effect: the slightly delayed vibrato sound comes from one of two 12� loudspeakers and the dry sound from another and both sounds are combined in the air, which creates that distinctive spacey mood. This effect became very popular which is why Roland decided to release the chorus circuit independently as the �CE-1� pedal. Incidentally, the chorus effect on the G series is modeled after its follower �CE-2�. Another unique feature of JC-120 is its �Bright� switch. This function is not included in this modeling program but you can approximate the effect of this switch by tweaking the �Harmonics� parameter in the �Extra EQ� section.

The �5150� and the �5150 MkII� were very famous guitar amplifiers originally developed as the signature models for Eddie Van Halen. Unfortunately, he doesn�t use it anymore because of the expiration of the endorsement contract. The program on this G series is modeled after the first version of the �5150�. This amplifier has two (Rhythm and Lead) channels and puts out 120w power using five 12AX7 pre-tubes and four 6L6GC powertubes. The rectifier circuit employs silicon diodes. The uniqueness of the sound of this amplifier is characterized by its sharp attack, deep and smooth tone, fine distortion and fat and clinging low registers. The program is modeled after the combination of the Lead channel of the 5150 head and a �5150SL�, a four-12� cabinet. Just crank up the gain and play one of Van Halen�s hit �Top Of The World�!

The �MT-2� (�METAL ZONE�) has the strongest distortion. Its unique distortion sound has very fat mid to low range and it has a parametric EQ in addition to the Hi and Low EQs, which is the key to the scooped metal sound. This stomp box is reputed for its flexibility in sound because you can not only get that scooped metal sound by cutting the mid range and boosting the high and low range but also the overdrive sound by reducing the gain and boosting the mid range. This is one of the best-selling stomp boxes among many of the popular line-ups of BOSS products. Once connected, the Strat or the Les Paul will have the �MT-2� sound regardless of the types of guitar pickups. It was first introduced in 1991 and is still in the BOSS�s catalog; a truly a long-seller!

This distortion program is developed especially for the G series. We deliberately made use of the characteristics of digital devices and even emphasized the edge of the digital sound to get the distortion to the maximum. The �TM-01� (Tri Metal) was the pedal that had the deepest distortion sound among the stomp boxes from ZOOM but was discontinued. It had as much as three diode-clipping stages and had very high gain. The �Extreme Distortion� is programmed to get the gain even higher. It raises the signal level to the maximum at the input stage and gets the wild distortion sound at the clipping stage. In fact, you won�t change the distortion rate even if you lower the volume on your guitar! Its distortion is that deep. Contrary to the usual distortion effects whose sound gets thinner as you raise the gain, this �Extreme Distortion� won�t lose the fatness and tightness of the sound.

VOX AC30/6TB

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Marshall JCM2000

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Dallas-Arbiter FUZZ FACE

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ZOOM Digital Fuzz

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The long history of the VOX company harks back to the foundation of �Jennings Musical Instruments� (JMI) in 1958. Originally, this company made amplifiers with 10-15w output power but the musical trend required more powerful amplification, which resulted in the birth of the revered �AC30� guitar amp. The very original AC30 had two Celestion 12� loudspeakers using alnico magnets, EF86 pre-tubes, EL84 power-tubes and a GZ34 rectifier tube. The Shadows and the Beatles used this model and their influence helped this amp become popular among many guitarists. Later, as the musical trend required amplifiers with even more gain, the company developed an add-on device called �Top Boost Unit�. The �AC30-6TB�, which this program in our G series is modeled after, is the later version of the AC30 with an integrated �Top Boost Unit�. After the JMI had sold the VOX brand, the sales of the amplifier regrettably began to decline. However, the KORG Inc. acquired the VOX name recently and rejuvenated the brand by starting to manufacture truthful reissue models. In this G series, the program is modeled after the sound using the Hi input of the normal channel that will give you that clean guitar sound of the Beatles and the Shadows, which are the best examples of the distortion-free sound of the class-A operated amplifiers.

�JCM2000� is based on the reputed �Plexi� amp (aka Old Marshall) whose rich overtones and powerful sound were legendary. It has very flexible sound and can produce the traditional Marshall sound, modern heavy metal sound or sounds suitable for any musical genre. It has the modern Marshall�s standard circuit with four ECC83 pre-tubes and four EL34 power-tubes. It is an all-tube amplifier that can produce clean or heavily distorted sound and you can use it in all kinds of music. The sound is rather grainy but the response is fast and the guitar sound cuts through very well. �JCM2000� series has two different models: the TSL and the DSL. The program on the G series is modeled after the simply designed �DSL-100�. As with the modeling of the �JCM800�, we combined the head with a �1960A� cabinet and used the Lead channel that has more distortion.

�FUZZ FACE� was originally released from the Dallas-Arbiter company in 1966 encased in a uniquely designed housing that literally looked like a face. It is also famous as legendary guitarist Jimi Hendrix�s favorite gear. He combined this �FUZZ FACE� with his Marshall amps because it was hard to get distorted sound from them at that time, and created avantgarde tones. The heavy and fat low end and the fuzz sound with long sustain are the characteristics of this effective device. The earliest model used two PNP germanium transistors and was very different in sound from the later models using silicon transistors. The theory of creating distorted sound is simple. Have you tried to connect the guitar to a microphone input on your radio cassette recorder to emulate that sound? You cannot go too wrong if you think that the circuitry of this device is similar to that. The program on this G series is modeled after this earliest version most satisfactorily.

Forty years ago, my fellow guitar player used to crank up his amp trying to distort his guitar sound and make other guys of the band virtually deaf at the end of the rehearsal. When it was difficult to get the distorted sound out of the amplifiers like in those days, some guys made cuts in the cone loudspeakers to make the sound distorted, which was the origin of the sound of fuzz effects. The fuzz pedals were developed to reproduce that distortion-like sound. In other words, the trick of fuzz effect is to simulate the dirty distortion and that �broken� feel. This �Digital Fuzz� has the very effect described above. Its drastic distortion, relentless cut-offs and noises in the decay are the characteristics that one could simply describe as �broken�. Its fat and tight sound can be seriously recommended for the fuzz maniacs to try. This is literally the Digital Dirty Fuzz that is only possible in the digital domain (are you brave enough to make cuts in your loudspeakers?).

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