Trace Elliot V4[1]
Contents
1. incorporates a switch which switches into the mid circuit and C5 out This alters the point at which the mid range circuit works upwards to about 2kHz R12 and R13 provide D C paths to ground from the mid shift contacts to reduce switching noisa Deep and bright switches The deep switch SW1 provides a MID and TREBLE cut to accentuate the bass response by shorting out R11 and bringing C7 into the tone network The bright switch SW3 brings C8 into circuit placing it in parallel with the top half of the gain control This creates a high pass filter with a shallow roll off to accentuate the high frequency response This function is disabled when the gain control is at a maximum as the capacitor is then by passed R14 is used to decouple any D C on the switch to ground Third stage The output from the tone network is fed from RV4 to gain control and then directly into the first half of This is a gain stage to bring the signal up to a suitable level to drive a power amplifier l The signal is then fed directly into the second half of V2 which is a cathode follower stage this provides slightly less than unity gain but is designed to give a low impedance output to drive a power amplifier The output signal is passed via C11 to the volume control RV5 and then onto the output jack socket SKBB3 This is only true for the rack mount version n the head and combo the signal from RV5 pin 22. 10K 72 RMIOK 1 R24 RES 1 4W 1 5 72 RMIKS 3 R6 R16 R18 RES 1 4W 27K 72 RM27K 1 R1 RES 1 4W 330K 72 RM330K RES 1 4W 47K 72 RM47K 8 R25 R22 RES 1 4W 560K 72 560 1 R11 RES 1 4W 560R 72 RM560R R33 R34 RES 1 4W 5K6 72 5 6 RES 1 4W 8K2 72 RM8K2 1 R19 CAP POLY BOX 72 C1 250VP 1 C2 CAP ELEC RADIAL 72 C1 63VER C14 C15 4 C5 0 2 10uF ELEC RADIAL 72 C10 35VER 2 MOD ACROSS 28 amp R29 ve legs nearest IC1 CAP 10uF ELEC RADIAL 72 10 63 C16 C17 CAP 1000uF ELEC RAD 72 C1000 63VER C22 CAP 100N POLY BOX 72 C100N 250VP C4 C24 C25 C26 C27 CAP 100P CER DISC 72 C100P 100V CD2 C18 C28 150P DISC 72 C150P 50V CD 1 C8 CAP 200P Polystyrene 72 C200P 630VPA 22uF ELEC AXIAL 72 C22 450VEA 2 C20 C21 CAP 22N POLY BOX 72 C22N 400VP C12 C13 CAP 47uF ELEC RADIAL 72 C47 63VER C9 C10 CAP 470uF ELEC RAD 72 C470 63VER 23 CAP 470N POLY BOX 72 C470N 250VP CAP 47N POLY BOX 72 C47N 100VP 1 CAP 47N POLY BOX 72 C47N 400VP C5 C7 CAP 4N7 POLY BOX 72 CAN7 400 VP CAP 100uF ELEC RAD 72 CAP 100400V TRANSISTOR BC549C 72 TBC549C 1 TRI 8 WAY SOCKET 72 SOCKET 8W FOR IC RC4558P 72 IC RC4558P 1 ICI POT A 250K 73 POT A250K 2 P2 P4 POT A 25K 73 POT A25K POT A25K PULL SWITCH 73 POT A25K PS 1 P3 Ee ___ ____________ MINI TOGGLE SWITCH 73 SWT M TGL PCB SW1 SW3 SW4 SW5 2 WAY HEADER 0 1 72 HEAD 2W 4 _
3. is passed directly to the power amp section and a fixed level signal is taken from RV5 pin 3 to the line out socket This is attenuated by a potential divider network of R38 and R39 to give a line level signal output D I output pre eq 0 1 signal is taken from the junction of R8 and RQ in the anode circuit of the second half of V1 before the signal is passed through the tone network via C13 post eq D I signal is passed via C12 from the output cathode of V2 oW4 selects each of these signals with R21 and R22 providing a D C path to ground The signal is then attenuated by the potential divider of R23 and R24 to provide a suitable level for the 1 The signal enters the inverting input of i C 1 via and R25 The output on pin 1 of this half af the I C is passed via C16 and R33 to provide the negative or anti phase 0 1 signal on pin 3 of the XLR SK5 The signal from pin 1 also enters the inverting input of the second half of L C 1 which re inverts it to give the inphase positive 2 1 signat pin 2 of SK5 C18 is present for high frequency stability D C biasing for 1 1 comes from the potential dividers of R29 an R27 and R8 with R26 which halve the 33V supply to provide the reference points for the signals SWS isolates the ground connection pin 1 on 5 5 to eliminate earth loops when connected to external equipment V Type Pre amp power supply In the rack mount version all supplies are de
4. the chassis and can be adjusted using a trimmer tool 7 Switch unit to Standby and then 8 When cool enough remove BIAS KING from between valves and re insert them into bases 9 Turn to Standby again warm up and then switch on 10 Connect a signal generator to the INPUT and set up controls to give maximum power output 11 Check that this is an acceptable power for the unit in question and that there is no excessive distortion 12 Gently tap each valve with a screwdriver signal on scope should remain stable
5. HPI HP4 SEE 8 WAY HEADER 0 2 72 HEAD 8W 1 PLI VALVE BASE 9 WAY 73 VAL SOCKET VT2 XLR PLUG NEUTRIK 73 XLR PCB M N XLRI JACK SOCKETS 72 SKT JCKBNBG 2 SK1 SK2 FLYLEAD C00 FLY HEATER 1 ACROSS 1 4 SIGNAL LEAD LOOM 00275 From L 0 F to PC00009 SIGNAL LEAD LOOM 00276 1 From send return to PC00009 1 LEAD FOR LAMP LOOM 00277 1 From PL3 to 6 3V lamp N B 1 The four 2 way headers are fitted with their small face to the left This is with the pots facing you oe faked OUTLETS 6 43 026 3 took SOV R3 04 4 658 1 P e Ser HAS OF Cig av Sov VE TPI Rp TPZ PANS zl Fuse 240 2104 12 07 TEES Q O0 6 54 Lane Live ON FRONT PANEL Pa LT PINS 6 amp 7 o 9 160 Fuse 4X Yra A C Si amp bey 215 y 1 Ve v ad V TC H X 2754 Y too o a 0 0 Ma CHASSIS EM Point O A C FaN TRACE ELLIOT HTL in HEAD In 4407 PARTS LIST FOR VA250 POWER MODULE FOR V TYPE HEADS DODS ___ 12277 72 D IN4007 72 D IN4148 2 11072 TT RESISTOES ___________________ ZEROOHML
6. INK ___ 72RCZERO b 478 72 5 ___ 12W 72 RC2K2 5W 1 RM o 12W T2RCSK3 5W X 2 Ro R83 X TZRCAKT SW 1 72 RWWGK84W 1 M 15 7W 7ZRWWISK7W ___ 1 Ra 14297 7ZRCA7K 5W 2 Re R20 _ 82K 72RCE2K 5SW 1 e o 172 RC100K 5W 4 R5 R15 R23 R37 ATOK 4127 2 5 ___ Re 1 1297 7ZRCIMEG 5W 2 IHERMSTOR Oo O MEE L CAPACITORS ___________ C5 _________________________ SOCKETS VALVE 73 VALSOCKET 2 VBi VB RIK DANIELS February 10 1997 PROCEDURE FOR BIASING V4 V6 ISSUE 1 PS 31 8 99 1 Connect BIAS KING valve plug sockets to rear middle two valve sockets on amplifier chassis 2 Insert matched set of KT88 s into all positions 3 Switch unit to Standby mode and allow valves to warm up for at least 1 minute 4 During this time connect unit to appropriate load and set all controls to minimum 5 Switch unit from Standby to fully On 6 By observing the current read out on the LCD display of the BIAS KING and switching between the two valves adjust the quiescent cathode current to give 30mA 2mA on each valve The trim pots are accessible from the top of
7. TRACE ELLIOT SERVICE MANUAL NO SM00019 Date Product Code Model No Technical File No ISSUE 1 October 28 1996 T0105 V Type V4 Head 00019 Issued by Trace Elliot Limited Blackwater Trading Estate The Causeway Maldon Essex CM4 460 33 HEAD AND COMBO ONLY ON BACK PCB PCaodeg Vi V2 12AX7 0 N ISOLATE ej 0 1 EARTH LET DECOUPLING TO CHASSIS ROSE MON TED UNIT PARALLEL MRED FAR AEV 3 MANI SPST LIVE EARTH LIFT EARTH CIRCUIT DESIGN BY A EWEN RAGE V Type V TYPE PREAMPLIFIER V Type preamplifier is used in the following units V type head 220 watt all valve amp head V type combo 250 watt hybrid 15 combo V type rack mount 1u ail valve preamplifier TECHNICAL SPECIFICATIONS Inputs Passive bass impedance 1M OHM Input range 25mV to 1 5V peak peak Active bass Impedance 100K OHMS Effects return Outputs Effects send Line output Head and comba Line output Rack mount DI output Frequency response Sensitivity Passive input Active input Input range 25mV to 6 0V Impedance greater than 1M Nominal input level OdBu 0 775 VRMS Impedance less than 1K OHM Nominal level OdBu Impedance 8K OHMS Nominal level OdBu 0 775 VRMS Maximum level 4dBu 3V RMS impedance 25K OHMS Nominal level OdBu 0 775 RMS Maximu
8. m levei 20dBu 1 AVRMS G00ohms balanced Nominal level pins 2 and 3 AdB at 22Hz and 25kHz 13mV 56mV V Type V TYPE CIRCUIT DESCRIPTION Input SK 1 SK2 SK1 and SK2 are the instrument inputs to the V type pre amplifier A signal entering SK1 is passed to the first stage via H1 with R2 in parallel Resistor R3 is to decouple any D C appearing on the input to ground A signal entering SK2 is passed to the first stage via R2 again with R3 as a D C path to ground This time however R1 has one end connected to ground via the switched contract on SK1 This provides a high degree of attenuation to input 2 for use with active or high output basses with the combination of R2 and R1 acting as a potential divider across the input First stage effects loop The first stage consists of one half of V1 which is a cathode follower stage to provide a low impedance output to feed the effects loop R7 is there to decouple any D C to ground SKBBI and SKBB2 form a seriai effects loop with the switching contacts on SKBB2 effects return providing the break into the circuit Therefore SKBB2 can also be used as a line in The signal from the effects return is passed via C27 D C blocking to the second half of V1 Second stage Tone network The tone circuit forms the anode load for the second half of V1 C3 and RV4 form the treble circuit C4 and RV2 form the bass circuit and C5 and RV3 form the mid range circuit RV3
9. rived fram a single torroidal transformer This provides 250V A C for the HT lines bridge rectified and smoothed by C19 C20 and C21 R36 is present to stop any signal from HT2 getting onto HT1 which could cause feedback problems t also provides 6 3V AC for the valve heaters and 40V A C rectified and smoothed by C22 for the supply This is regulated by a 549 transistor a 33v zener diode and 5K6 resistor with C23 for smoothing purposes The same transformer is used in the combo version in conjunction with a larger torroidal to supply power to the output stage In the Head version the large mains transformer used for the phase splitter and output valves is also used for all the pre amp supplies Mains on indication For the head and combo versions a 6 5V A C lamp is used for mains on indication Power for this is derived directly fram the 6 3V heater supply For the rack mount version the 6 3V heater supply is rectified by 09 and 010 to supply D C voltage to the LED built into the mains on switch R40 is used as the current limiting resistor 12 1 V TYPE COMBO HEAD PREAMP MAIN BOARD ISSUE 1 INSERTION LIST ANDY EWEN 11 8 98 DESCRIPTION PART CODE WHERE USED PCB PC00008 ISSUE 2 73 00008 DIODE 72 D IN4007 10 DI DIO RES 2W 100K 72 RC100K 2W 4 R8 R10 R17 R20 72 RCIOK 5W RES 1 4W 100K 72 RM100K 2 R2 R5 RESIAWIO0RR 7 0 1 RES 1 4W
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