Peavey Session 500 Operating Manual

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Operating fluiile

GENERAL DESCRIPTION

Three years ago ourdesign group initiated me Sessiono SOOprogram. Hundreds of ideas coming from professional musicians. music
dealers and field technicians as well as our own staff musicians and electronic/mechanical engineering groups were discussed.
evaluated and distilled lntoa concise set of specifications which formed the basis for the new Sessione. As the project progressed, we
were able to draw from our experience gained in allied areas such as sound reinforcement amplification and the design of new
loudspeakers made from the ground up" in our own speaker/transducer laboratories.

The basic amplifier/speaker system was "road tested" for several months as a bare bones" prototype and the input we got was that
even with the increased power and dynamic range available from the amplifier, the amp could still be overloaded, especiallywhen heavy
power chords" and excessive pedal action were used. During this same period of time, another R 8 0 team had been working on the
special problems of compression related to sound reinforcement power amps..." was natural forthe two R a D teams to combine their
efforts and apply our newly developed "Distortion Detection Technique" compression circuitry (patent pending) toeven further improve

ind enhance our musical instmment amplifiers. The resulting power amp used in the Session6 features DDTO compression that virtually
liminates amplifier clipping with the resulting harsh harmonics and speaker problems that are often encountered when the amplifier is
lriven into hard clipping and square waves are delivered to the speaker system.

The new Sessione tone controls retain many of the equalization characteristics of the old Sassiono but now include a unique state
ariable" midrange equalizer that enables both boost and cut. as well as shifting of the center point of the midrange equalizer. This
:apability further enhances the tremendous tonality and dynamic range available from the Session3 500.

To further satisfy the needs of the touring professional, we have designed a variable electronic crossover into the Session'sfi signal
)rocessing circuitry to allow bi-amping the system through auxiliary power amps/speaker systems. By including this "state variable"

filter/crossover. we have enabled the Session0 500to bethe heart" of a bi-amped system capable of performance heretofore unmatched
in musical instrument amplification,

It has been recognized for many years that the traditional steel guitar/volume pedal/amplifier arrangement commonly used is
definitely not the most ideal setup. Analysis showed that certain relatively minor circuit revisions. including some novel gain balancin
circuitry. could actually allow t e volume pedal to be inserted into the amplifier itself, thus tremendously increasing the overa l
performance of the system from the standpoint of d namic range. noise, and freedom from tonal change as the volume pedal is moved
throughout its range. For the first time. the Session 500's innovative circuitry removes the loading effects and resulting tonal changes
caused by the volume oedals interaction with the instrument's pickup.

Musicians onsta e and in the studio are constantly faced with the problem or "micmg" their amplifiers. or using what is popularly
referred to as direct xes." to get the signals from their instruments into a form compatible with studio or sound reinforcement mixing
consoles. In recognition of the fact that the console should be fed a direct signal that corresponds as closely as possible to what's being
heard through the speaker system. Peavey has designed a transformer balanced line amplifier with roll-off characteristics virtually
identical tot ose encountered in hi h powered muswal instrument loudspeakers. This uniquecircuit enablesa balanced tine level signal
output to be obtained from the essionfi that closely matches what is being heard from the speaker to be fed to the mixing
console....without the use of auxiliary devices such as direct boxes, miolng the amp with the additional problems of extraneous noises,
feedback. etc., etc.

Fu rther comments from the field indicated the desire for an advanced phasor system thatwould allow enhanced phasing effects with
sufficient range to create and/or simulate the many flange/phasing effects being used in contemporary music. Our circuitry utilizes the
latest in sem-conductors and computer-aided design techniques and enables a tremendous range of effects from slow. almost
imperceptible effects to deep "swooshing" effects so characteristic of studio phasing/flanging units. The extreme range of the phase
oscillator yields rates from extremely slow to rapid variations characteristic of tremolo or vibrato.

Another feature often desired by professional steel men is a distortion/string effect with bultt-ln expander and noise gate to allow
virtually infinite sustain with a very quiet standby operation. This circuit can create harmonic effects similar to fiddles as well as previously
unavailable string/sustain effects. After considerable investigation into devices currently being used by studio musicians to achieve
similar effects. our Ft 8. D team devised an entirely new type ofcircultthat features electronic "expansion" combined with a noise gatethat
yields full and mellow string type sounds that have almost unbelievable sustain, The Session0 400 featured a unique complementary
reverb drive which has been retained but refined with new circuitry that allowsthe drive coil itselfto be a part of the negative feedback loop
of the drive amplifier, This circuitry allows a tremendous sustain and dynamic range to be obtained from the Accutronics delay line.
Comparison with competing models will illustrate its marked superiority.

Steel payers have repeatedly asked to have the capability to control the effects and reverb functions remotely. Since both hands and
feet are us when playing pedal steel. we devised a "clip on" control box which is desi had to clamp on the leg of the steel. This
convenient and practical arrangement even further enhances the flexibility of the 500s e ects features!

Overall, the Session0 sootruly represents the "state of the art" in musical instrument amplification. Just as the Session0 AOOhas been
accepted by uitarists other than steel players, we feel that the new Sessions 500 will be even more desirable tojazz and country players
and even me guitarists desiring almost infinite sustain effects with tremendous tonal control. power output capability. and dynamic
range. We invite you to check and compare the Session0 500's features with any amplifier on the market today. regardless of price, and
you will readily see that it is truly without peer.

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FRONT PANEL
INPUTS (1) (2)

The Session8 has two inputs, one featuring high gain and the other having half as much gain. The high gain jack (1) is the input
normally used unless the signal from your instrument is overloading the Input preamp. If your input signal is overloading (distorting) the
high gain jack. then the low gain (-6 dB) jack (2) should be used.

Because of the unique switchin design of the Session'se input circuitry, the gain of both high and low gain jacks balance
automatically when instruments are p ugged Into both jacks.

PEDAL INPUTS (if) (4)

One of the most frequent complaints of steel guitar players is that the tonality of their Instrument changes with different positions of
the pedal volume control. The reason for this Is that a simple pot or control as used in most pedal volume controls causes different
impedance loadings on the instruments output and also on the amp's input. As the pedal control is varied through its range, the various
impedances interact with each other to produce the familiar tonal change.

As part of the Session9 R 5 D effort. we were determined to eliminate this tonal variation by enabling the instrument to be plugged
directly Into the amp, thus matching the pickup with an extremely high input impedance which would not vary as did the pedal volume
control. The output from the input preamp was designed to present much higher signal levels and much lower impedance levels to the
pedal volume control, while leading the pedal output back into an extremely high input impedance. The result of this arrangement was to
not only eliminate tonal change but also to place a substantial portion of the glln before the pedal volume, thus resulting in greatly
reduced noise. By placing the input gain stage before the pedal, the residual preamp noise (hiss) is attenuated at the same time as the
guitart signal. The old system of pedal volume resulted in a constant amount of amp noise since the volume pedal was before all
ampi ication.

This innovative but simple system is extremely easy to use and requires only two extra patch cables.

1. The instrument is patched direct to the SessionsU input.

2. Patch from the normal pedal input to the Session'so pedal to jack.

3. Patch a cable from the normal pedal out to the Session'se pedal from jack.

NOTE
ALL INPUT AND PEDAL PATCHING FUNCTIONS MUST BE PERFORMED USING SHIELDED CABLES.

While it may take some players a little longer to get used to this new system. the tremendous increase in performance will be well
worth the effort.
PFIE GAIN (5)

The input circuitry of the Session9 is designed using variable negative feedback" in order to optimize the inputdynamic ran ge, input
impedance, and low noise operation. This unique input circuitry utilizes specially selected low noise, high slew rate semiconductors that
have been precisely specified for this particularly demanding professional application. The pre gain control is the element that
determines the amount of signal that is fed back" within the input preamp, thereby determining the amount of gain available in the input
sta e. This system is vastly superior to older designs with fixed gain stages which utilize the level control as a passive element by merely
divtding down the output from the preamp circuitry. By regulating the amount of amplification actually taking place, this unique circurt
configuration eliminates unnecessary noise and distortion while maintaining extremely high input impedance to avoid loading effects on
musical instrument pickups. The high degree of stability and relative freedom from intermodulation distortion inherent in this unique
input circuitry provide clean signal voltage to the succeeding stages of the Session0 500.

STRING EFFECT

The Session8 400 was developed as an all-purpose amplifierfeaturing high power and dynamic range adequate to handle almost any
instrument. Steel guitar has always been one of the most difficult instruments to properly amplify, and most steel men felt the Session3
400 was the best amp then available for that demandingxapplication. In working with the Session0 400, various players gave Peavey
en ineers valuable suggestions as to how the 400 could improved both in features and performance. One repeated request was for a
bu lt-in circuit to allow simulation of a "string section" (fiddles) as was being done by several of the session men in Nashville. We
evaluated the various effects units being used for that purpose and obtained much insight into the needed response curves. gain
structures. and waveform requirements. Our string effect" is a unique circuit that features a built-in expansion capability to enable
sustain never before achieved in an instrument ampwith a noise gate that reduces noise to avery low level during standby operation. This
string effect not only simulates violins (fiddles) but is capableof an extremely wide range ofeffects that make the Session an unmatched
performer for regular electric guitar.

The string effect is actually a kind of "distortion" which can simulate the sound of violins, yet has the added capability of generating
the same gain/distortion characteristic of hard rock. This new and versatile feature adds yet another dimension to the performance
capability of the Suession'8 and, when combined with its other features. makes the SessionGthe mosttechnicafly sophisticated and one of
the best performing amps available anywhere.