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U SERS M ANUAL

1. Filter Balanced Output Buffer Power Amp Driver Power Amp Power Requirements max Mains Protection Fuse Dimensions WxHxD Weight Specifications are subject to change without notice 1 Mohms passive 100 kohms active 20dBv passive 8dBv active Shelving 12 dB 80 Hz Shelving 12 dB 8 kHz 0 12 dB 5 kHz Pwr amp feedback 10 dBv 1 GND 2 Hot 3 Cold GND Lift 90 W RMS 4 or 8 ohms 1x 7025 low noise 2x 12AU7 1x 12AT7 2x 6550 200 W T1 5A 230 240V T3 15A 100 120V 537 x 267 x 243 mm 21 1 x 10 5 x 9 57 17 1 kg 38 Ibs BLOCK DIAGRAM A0NaSidHd SUIUO p O J 2 i AJ SUIUO g O INdLno OAONWV Ivo SININION Yslsal ld WV SLAdLNO HAMOd dAAVddsS annoy BAISSEd SLNdNI OM C Tl Tl m Pr o gt m zZ D C har d i gt 0 G A1ddadl NOILOJS Hdil1ld INPUTS Connect your instrument to one of these inputs active or passive Use the active input for instruments with high out put and the passive one for instruments with low output If both inputs are connected only the passive input will work VOLUME This knob controls the volume of unit for the exception of the balanced output XLR which is not effected by the this setting BASS and TREBLE These two controls the tone stack of the ClassicT90 The design is purely passive yet it is designed as a boost cut filter for best performance No feedback
2. is present here and this filter is driven by a class A driving stage See next page for filter characteristics graph PRESENCE Controls the high frequency response over the poweramp feedback cir cuitry Very useful for defining the edge or attack of a sound Note that this control does not effect the balanced output STANDBY This switch mutes the amp by disconnecting the high voltage from the tubes The associated lamp indicated when the amp is operable When powering up allow the to amp warm up for a period of 5 minutes prior of activating with standby POWER Powers the amp on or off FRONT AND REAR PANEL BALANCED OUTPUT Is a high qual ity balanced output that functions as a line box for connecting to PA mixing consoles or to studio or broadcast recording units Lifting ground is a great aid in many occasions When required set the GND switch to OFF position to disconnect the ground from the output This balanced output is a direct driven tube output for best possible performance AC INLET Connects the amp to the mains This inlet also houses the mains fuse SPEAKER OUTPUTS The two Speakon connectors allow you to connect the amp to your favorite cabinets IMPORTANT Use only ONE speaker output and the one that is TOTAL D EBS will not take responsibility for eventual hearing damages caused by the powerful ClassicT90 matching the speaker impedance FILTERS Typical filter
3. 5 minutes for the head to warm up The tubes should now glow 5 Connect your instrument to one of the inputs If your bass is active or has high output it is recommended to use the active input otherwise use the passive one 6 Toggle the standby switch so that the associated lamp light up 7 Move over to the VOLUME knob and adjust for the desired output volume BUILDING THE SOUND Your EBS ClassicT90 features a tone shaping circuit that will enable you to create a variety of vintage bass sounds 10 This The bass and treble filters are basically of the boost cut design This means that the controls practically boost or cut the selected frequency band Gradually increase or decrease the level and tone controls Notice how the sound is affected Proceed to the prescence knob This control adjusts the high frequency response of the power amp and lets you define the crunch when distorting the amp was a brief tutorial of EBS ClassicT90 As you go on further in this manual you will learn how to use and utilize all of the useful features that the EBS ClassicT90 offers you GOOD LUCK INPUT TONE CONTROLS PRESCENCE BALANCED OUTPUT POWER AMP TUBE SELECTION AUXILIARY INFO TECHNICAL SPECIFICATIONS Input Impedance Nominal Input Level Bass Filter Type Treble Filter Type Output Level nominal XLR Connections Options Continuous Output Power Load Impedance Input
4. USERS MANUAL Di el tide e Zf AMfwr LA em a ay Ais N AE r men SEW sic 9 E AY Ta GREE Hea typ s E Aip DEVELO SFE EY ipg an TEEN ACh AR FEE Cag yc WART E ZS E PEORES rea HARE Hean a Emp N pe H We ra em BEG EE SHS Wan A Se Rp ge m CONTENTS PAGE INTRODUCTION 2 FRONT AND REAR PANEL 3 FILTERS 4 MAINTENANCE 5 BLOCK DIAGRAM 6 TECHNICAL SPECIFICATIONS 7 Professional Bass Equipment DESIGNED AND DEVELOPED BY EBS SWEDEN AB gt lt GRINDSTUVAGEN 44 46 SE 167 33 BROMMA SWEDEN SC 46 8 735 00 10 FAX 46 8 735 00 05 E MAIL ebs info bass se WEB www ebssweden com June 2009 INTRODUCTION e GETTING STARTED The EBS ClassicT90 is an all tube amplifier head extremely easy to dial in It is designed to match the EBS ClassicLine cabinets in all styles and situations The sound of the ClassicT90amp is pure vintage yet with a recognizable transparent EBS sound that let your playing style and the character of your instrument speak Versatility is provided by a carefully designed EQ section These brief tutorials will help you to become acquainted with some of the features of the EBS ClassicT 90 GETTING STARTED 1 Carefully unpack the bass head 2 Connect a speaker to the head Make sure that the impedance of the cabinet match exactly with the output of the T90 3 Turn down the Volume and set all other controls to mid position 4 Power up the head and wait five
5. characteristics for Bass and Treble filters 20dB 10dB 12 o clock Bass Treble 10dB 20dB 10Hz Max Bass Treble 100Hz Min Bass Treble 1KHZz 10kHz CHANGING THE TUBES Although it may not be necessary due to tube malfunction changing the tubes once in a while will regain the tone and bring back high performance There are however some points that are important 1 When changing the power amp tubes both tubes must be changed and the tubes need to be a matched pair Recalibration of the bias is always necessary after installing new power tubes 2 The power tube driver 12AT7 should be changed every second time the power tubes are changed 3 The input tube 7025 must be selected for low microphony low noise and high gain Alternately you may use an 12AX7 or ECC83 here 4 The buffer and balanced out tube must be same type as original 12AU7 TUBES PLACEMENT MAINTENANCE SETTING THE BIAS Whenever the power tubes have been changed it is necessary to set the correct bias to ensure long life operation This is the procedure 1 Power the amp at let it warm up for 5 minutes 2 Connect a voltmeter to the bias measurement point VA at the rear panel 3 Switch on the amp by toggling the standby switch 4 Adjust with the associated bias trimmer so that the readout on the meter is 35mV 2mV 5 Repeat for other tube using point VB 6 After first calibration repeat once
6. for verification of bias setting IMPORTANT Incorrectly set bias may cause permanent damage to the amplifier If you are not 100 sure on how to do this please get in touch with a service center Input Buffer Bal output Pwr amp Filter Inverter driver driver QIIE Front panel

U SERS M ANUAL

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