Peavey XR-400 Operating Manual

OPERATING GUIDE
CAUTION
TO PREVENT ELECTRICAL SHOCK OR FIRE HAZARD, DO NOT EXPOSE
THIS INSTRUMENT TO RAIN OR MOISTURE. BEFORE USING THIS
INSTRUMENT, READ BACK COVER FOR FURTHER WARNINGS.
GENERAL DESCRIPTION
The new XR-400 reoresents our latest effort to combine professional features previously lound only in separaie mixer/equalizer/power amp
components into a single compact and ruggec package. The design of ihe XR-400 utilizes the latest advances in semiconductor technology and
the overall circuitry has Deen designed and opiimized by use of the latest computer-aided design techniques. This unit's improved specifications
have been made possible by a thorough and complete design elfort resulting in all new circuitry from the input jack through to the speaker output.
The XR-400 features four independent input channels and includes a separaie pie" monitor send active shelving type high and low
equalization, and a post'' etfects send
orreach
channel. Master level controls are provided for themain. monitor, and reverb return. A full five bend
graphicequaiizer has deen Dull into the system and utilizes the most conterrpo'ary active fitter circuitry available. Additional flexibility is provided by
Ihe
XR-400*s patch panel, enablng this versatile unit to be used in conjunction with an ©xtromoly wide range of auxiliary equipment
The 100-watt power amplifier ot the XR-400 utilizes four high-voltage, high-speed TO-3 power devices bolted to a massive heatsink. Tho
Internal power supply consists of a very large power (mains) transformer featuring agrain oriented silicon stool com and a high degree of magnetic
shielding to minimize extraneous hum fields. Silicon rectifiers connected in a full wave bridge loed power to largo olectrolylic filter banks and provide
considerably more music power than the 100 watt RMS power rating would indicate.
Overall, the XR-400 brings professional performance together in an extremely versatile and compact package, offering features and
Specifications formerly available only with separate components in a single portable package.
FRONT PANEL
INPUT JACKS (A) and (B)
Each channel of the XR-400 is equipped with two >nput jacks which are connected in a unique circuit that allows a wide range of inputs to be
handled. When only one microphone is used, the "A" input jack is more sensitive than the 'B input jack. This high and low cam feature enables
optimum microphone matching. If a high oufpuf microphone is overloading the sensitive "A" input simply reconnect this mike into the lowgam * B
jack When two inputs are used in each channel, the input circuit automatically balances to equalize ihe gam in both Aand B jacks Thissimp'e. but
effective, switching system gives the user much greater flexibility in choice of input sensitivities and overload protection.
CHANNEL CONTROLS
Each of :h© XR 400's four independent channels contain five controls: Gain. Monitor. Effects and High and Low Equalization.
CHANNEL GAIN CONTROL (C)
The Channel gain control varies the gain of the inpu! preamplifier. This input preamp is designed around a variable negative feedback approach
and provides optimum cynamic range as well as extremely bw noise operation. This control is used to set the level of the respective channels to
achieve the main mix.
CHANNEL MONITOR CONTROL (D)
The channel monitor control is a totally Independent level adjustment used for deriving the proper monitor mix. It is imoortant that the user be
aware mat this channel monitor send is total y independent from all other channel cont-ols and feeds directly into the monitor buss whose output is
determined by the master monitor control (I).
CHANNEL EQUALIZATION CONTROLS
The channel equalization controls are of ihe active ' shelving" type and provide 15 dB of bcost or cut in their respective frequency ranges.
These equalization controls are extremely elfective and will allow the user to achieve almost any blend of high's and low's with proper adjustment.
Since these EQ controls are capable of a 30 CB range, carest-ou^d be taken to properly utilize their capabilities. Excessive boosting of lows can
cause muffled' or boomy" sounds, as well as tending to prematurely overload the power amp because of excessive low frequency power
requirements. Cve'boosting the high's will tenctocauso a "strident" or"screechy" tonality, as well as tending to emphasize residual preamp noise
and susceptibility to acoustic feedback. Care should be observed when ushg excessive cut in either frequency rangesmee excessive cutting may
degrade the dynamic range capabilities of the input preamp and create poor tonality.
These channel equalization controls have been provided to achieve tonal balance.as well as feedback control in the individual channels for the
main mix only. All experimentation should begin with these controls set in the flat "0" (straight up or 12:00) position Use of the individual channel
controls in conjunction with the master graphic equalizer is vital to provide the user with optimum equalization.
CHANNEL LOW EQUALIZATION CONTROL (E)
The low equalization control determines whether the low frequencies will be boosted or cut. Boost occurs in the clcckwise settings, whle cut
occurs in Ihe counterclockwise settings. Flat responso is obtained in the "0" or vertical position
CHANNEL HIGH EQUALIZATION CONTROL (F)
The high equalization control determ nes whether the high frequencies will be boosted or cut Bcost occurs in the clockwise settings, while cut
occurs in the counte'dockwise settings. Flat response is obtained
n
the "0 or vertical position.
CHANNEL EFFECTS CONTROL (G)
The channel effects send control adjusts the signal level applied to the effects mix buss which feeds the internal reverberation system, as well
as the effects output on the patch panel. The overall settings of Ihe channel effects send controls determine tne amoimt of reverb d'ive. as well as
the sigral oulput level available from the effects output jack. It is important to note that :he effects send control is a 'post type adjustment which is
located in the circu t after the channel gain and equalization controls. The user should be aware that use of the internal reverberation system can
only occur when the channel gain, the channel effects send, the master reverb return and the master gam controls are an properly adjusted.
MASTER SECTION
The XR-400 mastoi section contains the overall master level control. Ihe master monitor control and the reverb return (to master) control, as
well as a five-band graphic equalizer and patch panel. As the name implies, the master controls operate as the final control element for their
respective mixing busses and the master graphic EO determines the final overall equalization
MASTER LEVEL CONTROL (H)
The master level control adjusts the gain of the main mixing buss and determines the level at the main line output jack (Q). as well as
determining the signal level applied to tha input of Ihe graphic equalizer/power amplifier It is generally good practice to operate the maste' level
control somewhere in the middle of its operating range to allow maximum flexibility in adjusting overall levels, ie . it rs poor practice to run the
individual channel gains way up and the master control way down
since
this limits the headroom ol the input stages and could cause distortion