The Fender "Magic Six" amp setup

Den folgenden Text hab' ich irgendwann, irgendwo im Internet gefunden. Ist nicht unbedingt etwas für die "Masters of the Bratguitar", aber sicher wichtig für die Fender-Fraktion, ob nun mit Fender-Gitarre oder Fender-Amp aber immer mit Fender-Sound. Der Originalauthor ist im Text angegeben, d.h. dies ist leider nicht auf meinem Mist gewachsen. Die Info's sind sicher auf den einen oder anderen Amp übertragbar, wenn man gerafft hat wo die Reise hingeht!

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I´m sure you all know what we are talking about when you hear the term
"classic Fender sound", right ?!? It´s this vintage tone from the old Fender tube
amps you can hear on countless records - bright, sparkling, percussive,
fenderish. Do you have such an amp and want to get this sound ? Great, here is
what you have to do, it´s from the "Fuzz-Magazine" issue1 (2002) and was first
posted by Bjorn Juhl at http://www.custom-sounds.com

It was some time in 1979 when one of the "big guys" showed me how to dial in
that Fender or Music Man amps that always seemed to be on stage wherever you
play: "Easy" he said. "It's the magic six". Volume to 6, Treble to 6, Middle to 3
and Bass to 2 (6, 6, and 3x2=6). Bright should be on, reverb set for two and
master volume (if one) set so that you can be heard above the drums without
drenching the vocals. "The rest of the knobs you can just ignore" because no one
used tremolo in late 70's and the footswitch was always disappeared…
The effect was almost like having the key to Holy Grail - I have to admit that he
was right and I joined the Magical Six Choir.

It wasn't until years later, when I was absorbing schematics that I understood
why there is magic in the six. In an amplifier with the topology input stage, tone
control, volume control, voltage amplifier (tremolo- and reverb amplifier if
fitted), phase splitter and output stage it is the first four controls that will set
what is going to distort and how much.

The first stage runs essentially clean if nothing else but a guitar is connected.
The voltage amplifier will hit the ceiling as volume is turned pass 4.
The tone controls are placed before the volume control and will control what is
being fed into it.

The purpose of the setting Treble=6, Middle=3 and Bass=2 is to:

1. Cut a bit of bass to get balance between high E-string and low E-string
distortion. The bass-frequencies will have overtones far up in the midrange and
may therefore build into disturbing high overtones that can make certain chords
(D7) sound out of tune on the top three strings. Some amps will even oscillate
when exposed to the combination of high amplification and lots of bass.

2. To control "The Mud Frequency 249,5Hz". Too much of this frequency and the
tone will be muddy and too little and it will sound hollow and thin.

3. Cut some midrange (approx. 340Hz) to gain output power while keeping intermodulation
distortion at a minimum. Amplification factor will also be highest in
the treble (above 2 kHz) and that is compensating the treble-loss of passive
pickups. Open E-strings (high and low) played at the same time should now have
approximately the same volume level with little more distortion on the top-string.
Both strings should be clearly recognizable.

Inter-modulation distortion is a sort of mathematical distortion in that the sum
and difference of two incoming frequencies are obtained as harmonics and will
therefore build up so called "ghost notes" (these are notes that are not played
and that are not in musical relation to the notes played). This can make certain
chords sound dissonant as opposed to what we know as harmonic distortion
where overtones follow the pattern of 2x, 3x, 4x.. in upper frequency, something
that makes the probability of so called ghost notes being produced a lot lower.

The risk of inter-modulation distortion is quite high on Fender amps, mostly
because of the working-points of the different stages.
Ironically enough some of the modifications that were performed at the factory
to reduce the total amount of distortion will, while reducing total distortion, rise
the amount of 7th overtone, which is said to be the least pleasing of all.

4. Obtaining the correct treble response on most amplifiers made for guitar the
treble-control does not work the same way as on your Hi-Fi, regulating the
amount of treble. On guitar-amps the position of Treble-knob will very much
affect to bass and midrange and it works more like a balance between bass and
treble. In fact the tone stack system as used in most amplifiers is derived from a
so called "Baxendall type" Hi-Fi circuit. Treble has been set to full while an
isolation resistor often placed between the treble and bass controls is used to
control treble (or actually tone balance between treble and bass).
Balance is obtained when the treble pot is in it electrical center - that is between
5 and 7 depending on the taper on the pot. Final regulation of treble is best to be
done with the bright-switch.
The bright-switch seems to work best if the volume is set to between 5 and 7.

5. If the volume-control is set to 6, stage #2 will be fed from highest possible
impedance and there will be certain current limitation. Stage #2 will also be fed
with as much as it can take without getting some rather odd distortion as
feedback through B+ tree that is appropriated as the true distortion generator is
the stage #3 (reverb-mix amp).
Where some peculiarities take place such as rectifier action between grid and
cathode and glazing-spikes because of cathode decoupling etc…

6. And so 6, 6, 3, 2 (2x3=6) The Magical number 6.

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Gruß Zoppo

ich habs probiert klingt klasse
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Fender Telecaster,
Fender Rock Pro 700,
Ibanez Overdrive OD 855,
Cry Baby Wahpedal
und viel inspiration

Wow, klingt sehr interessant (der Bericht), werde ich mal probieren, wenn ich Volume mal wieder auf 6 drehen kann