TL Audio EQ
Contents
1. NOLIT A SERVICE Should the equaliser require service it must be taken or posted to an authorised dealer with a description of the fault Please retain the original packing for possible future use and ensure the unit is suitably protected during transit The manufacturer cannot accept responsibility for damage caused during transportation The equaliser is supported by a limited warranty for a period of one year from the date of purchase During this period any faults due to defective materials or workmanship will be repaired free of charge The warranty excludes damage caused by deliberate or accidental misuse tampering operation on the incorrect mains voltage or without the correct type and value of fuse fitted It is the user s responsibility to ensure fitness for purpose in any particular application The warranty is limited to the original purchase price of the equipment and excludes any consequential damage or loss Please record the following details and retain proof of purchase Serial Date Dealer Tony Larking Professional Sales Limited Letchworth England Tel 01462 490600 International 44 1462 490600 Fax 01462 490700 International 44 1462 4907002. Pin 3 Signal Non Phase or cold Unbalanced inputs Pin 1 Ground screen Pin 2 Signal Phase or hot Pin 3 Signal Ground When using unbalanced signals signal ground may be obtained by linking pins 1 and 3 in the mating XLR connector Good quality screened cable should be used particularly for microphone or low level sources to prevent hum or noise pickup Unbalanced Line Inputs An unbalanced line level input is provided for each channel on a 0 25 mono jack socket The mating plugs should be wired as follows Tip Signal Phase hot Screen Ground Auxiliary Inputs A 2 pin mono jack plug is required which should be wired as follows Tip Signal Phase hot Screen Ground Insertion Points The insertion points are interfaced via a 3 pin 0 25 switched jack socket on the rear of the unit The pin connections are Sleeve Ground Tip Send Ring Return The insertion point is unbalanced and operates at a nominal level of 2dBu If used as an additional send only e g as a send to a tape machine or monitor mixing desk the Tip and Ring should be wired together to preserve the signal path through the insertion point Outputs The outputs are via balanced 3 pin male XLR connectors The mating connectors should be wired as follows Pin 1 Ground screen Pin 2
3. Replace the fuse with the correct type and rating only Warning This equipment must be earthed INSTALLATION AC Mains Supply The equaliser is fitted with an internationally approved 3 pin IEC connector A mating socket with power cord and mains plug is supplied All mains wiring should be performed by a qualified electrician with all power switched off and the earth connection must be used Please note that when using this unit with alternate supply voltages in foreign countries for example the position of the voltage selector switch on the rear of the unit may need adjusting The unit may be set for 115V accepting voltages in the range 110V to 120V 60Hz AC or to 230V for voltages in the range 220V to 240V 50Hz AC The setting may be adjusted by inserting a small flat bladed screwdriver into the slot of the switch and sliding the switch to the left for 115V or to the right for 230V Alternate supply voltages may also require a different power cable or mains plug If in doubt consult local electrical regulations Warning attempted operation on the wrong voltage setting or with an incorrect fuse will invalidate the warranty Audio Inputs Each channel has two female 3 pin XLR connectors for mic and line sources Both are compatible with either balanced or unbalanced signals when the mating connectors are appropriately wired Balanced inputs Pin 1 Ground screen Pin 2 Signal Phase or hot
4. low and high mid frequency and HF high frequency However the frequency variation available on each band allows overlapping of two or more bands into the same frequency range This arrangement affords maximum flexibility allowing for example reduction of a narrow band whilst simultaneously boosting an overlapping broader band of frequencies The LM and HM bands have a peaking response whilst the LF and HF bands are switchable to peaking or shelving response Used individually or in combination the filter bands allow comprehensive equalisation of any audio signal with the unique character of valve circuitry Typical response curves and the effect of control setting variations are shown in the specification section of this manual Note the wide 40KHz bandwidth of the EQ2 Stereo Switch Most two channel equalisers require the time consuming and inaccurate practice of attempting to match settings on two sets of controls The EQ2 provides a simple and quick means of ganging the controls into a full stereo equaliser Operation of the Stereo switch signalled by a yellow LED causes the channel A lower set of equaliser controls to operate on both channels Thus the cut boost setting of each band along with frequency and control settings are immediately common to both signal paths The stereo ganging includes the band on off switch but leaves the overall EQ IN switches separate for maximum flexibility in com
5. Signal Phase or Pin 3 Signal Non Phase or cold If an unbalanced output is required pins 1 and 3 should both be connected to ground Nominal Output Level A switch on the rear panel allows the output to be matched to equipment at a nominal operating level of 4dBu or 10dBu Most professional equipment requires 4dBu approximately 1 2V rms but some small mixing consoles portable tape recorders or domestic audio equipment require 10dBu approximately 225mV rms The switch should be set to the position which results in the best signal to noise ratio whilst preserving sufficient headroom Unbalanced Outputs An unbalanced line output is provided for each channel on a 0 25 mono jack socket Tip Signal Phase or hot Screen Ground Ventilation The unit generates a small amount of heat internally mainly due to the valve heaters This heat should be allowed to dissipate by convection through the grill in the front panel which must not be obstructed Do not locate the EQ unit where it will be subject to external heating for example in the hot air flow from a power amplifier or on a radiator The EQ may be free standing or mounted in a standard 19 rack Rear Panel The rear panel connectors are identified in fig 2 914 15401 03068 21198 130131 81 100 1 033900 8 27 8
6. 18100 041 9 3821 i 010 01 J 130 81 8 300 u 8 8 5210117 30012901 5112170 022 Aidaa 30 INPI 01 10893 510141060 ONY 511 488 1 INIT 033160 401 LS INI 1 HOLINS 1123138 0417 INPUT GAIN CONTROL RUX INPUT SOCKET FILTER FREQUENCY CONTROLS 5 gt 8 LINE 4 480 CUT CUT MIC LINE AND AUX SENSITIVITY SWITCH FILTER SELECT SWITCHES PHANTOM POWER SWITCH F1IG 3A INPUT SECTION FREQUENCY CONTROL CUT BOOST CONTROL Q WIDTH CONTROL BAND SELECT SWITCH 38 TYPICAL EQUALISER BAND CONTROLS MASTER COUTPUT LEYEL CONTROL DRIVE AND PEAK LED INDICATOR MASTER STEREO MODE SWITCH IN suitcH 2 1 MASTER SECTION CONTROLS Front Panel The front panel controls are identified in fig 3 Input Stage Ensure that the correct input connector mic or line is being used and that the front panel switch is set to the appropriate position Note that both mic and line inputs may be connected at the same time but only one is selected 48V phantom power is available at the mic socket selected by a front switch and signalled by a red LED Phantom power should only be used in conjunction with suitable microphones CAUTION Operation o
7. T L Audio User Manual EQ2 VALVE EQUALISER Tony Larking Professional Sales Limited Letchworth England Tel 01462 490600 Fax 01462 490700 8089000 18 014 1 1 1 1 1 wann KIUD 4 08 1 77 3007 7 1 1 1 1 2 NOILHSSNI INTRODUCTION Audio 2 Parametric Valve Equaliser combines classic valve techniques with low noise solid state circuitry to produce a unit offering sweepable high and low pass filters plus four bands of fully variable equalisation on each of its two channels Both channels feature a line level input plus a mic input with switchable 48V phantom powering Further flexibility is provided from a front panel auxiliary input and stereo operation mode Typical applications include direct recording to tape instrument preamplifier use as outboard EQ during mixdown and as a main stereo equaliser for monitoring and PA systems The block diagram of one of the channels is shown in fig 1 A solid state electronically balanced input amplifier is used to achieve state of the art performance with very low noise low distortion and wide bandwidth Two XLR input sockets are provided per channel for mic and line inputs The mic input is suitable for low impedance 150 600 ohm microphones with a gain control range of 16 to 60dB A front panel switch pr
8. er Level Control 15 dB range Outputs Balanced XLRs plus unbalanced jack sockets rear panel switchable to 4dBu or 10dBu nominal level Maximum level 26dBu balanced Valves Six ECC83 12AX7 twin triodes arranged as one valve stage per EQ filter plus a two stage output driver per channel Frequency response 10Hz to 40KHz 0 2dB EQ in and flat filters out Noise 80dBr ref 4dBu nominal level 22Hz 22KHz in and controls centered Dynamic range greater than 100dB Dimensions 3U rack mounted 250mm 10 deep Power requirements 115V or 230V 4 35 The above specifications are subject to change without notice as wy ail 11 0 i 493 Level dEn 4 120 21 TICAL 7 i 602 2 00 Frequenzy mip amo 100 12002 uzi ts 011473115 11 yaar AVS Tet pent 12 27 TYPICAL RESPONSE FEAR 120 40 40 120 2 709 tuwon 200001 Frequeny TYPICAL EF SHELVING eel 1 f a N BFAD 7 25 PN pn 4 Level dba 7
9. f the phantom power switch or plugging a microphone in with phantom power applied may cause a click or thump in your loudspeakers To prevent this happening ensure that the system gain is set to minimum e g on your mixing console fader or power amplifier before operating the switch or plugging in a microphone If the gain required is not known set the control to minimum with the EQ by passed and gradually increase the gain until the required output level is achieved Unity gain OdB is obtained from the line input at the centre detent of the gain control Auxiliary Input The front panel auxiliary input socket accepts signals from guitar keyboard and high impedance pickups or microphones Plugging a jack plug into the auxiliary socket automatically disconnects the channel mic or line inputs and replaces them with the aux input The sensitivity of the Aux input is controlled by the mic line switch In the line position low gain is selected suitable for most keyboards or active guitars whilst in the mic position the gain is increased to match passive guitars and hi z microphones or pickups The input gain control also remains operative when using the Aux input HF and LF Cut Filters Both channels are equipped with high pass also known as LF cut and low pass or HF cut filters with a slope of 12dB per octave Each filter has a continuously variable frequency control and on off switch with yellow LED The filters have c
10. ovides 48V phantom power to both channels The line input has an effective overall gain range of 10 to 35dB allowing the valve stages to be fully driven from line level signals in the range 20 to 20dBu A front panel mounted auxiliary jack socket allows direct access to the channel inputs The input is suitable for a variety of sources including guitar acoustic pickup and keyboard The input section also provides continuously variable individually switchable high and low pass filters to tailor the frequency response to eliminate unwanted LF or HF noise from the input source An insertion point is provided immediately after the input stage to allow a compressor or other processor to be used as required The insertion point is unbalanced at a nominal operating level of 2dBu Both channels feature a four band parametric equaliser Each band is individually switched in or out of circuit and an overall EQ in switch is provided All of the EQ bands comprise centre detented cut or boost control swept frequency and continuously variable Q controls A total of six twin triode valves are employed in the 2 one valve stage EQ band plus a two stage post EQ driver circuit Master level controls are provided post EQ These controls are also centre detented for ease of line up but may be varied in conjunction with the input gain controls to alter the operating level through the valve circuitry to introduce as much or as little of
11. paring the effect of the equalisation being applied The input and output gains and filter controls also remain separate Drive and Peak LEDs The LEDs indicate the signal level at the output of the EQ section immediately after the post EQ valve drive stage At this point the amber drive LED gives a good indication of the extent of the warming or even harmonic content being generated by the valves increasing in intensity over the range 4 to 16dBu as the valves are driven harder The red peak LED illuminates when there is approximatley 2dB of headroom remaining The distortion characteristics of the EQ2 are consistently low up to an operating level through the equaliser stages of about OdBu Although virtually constant over the audio bandwidth a 10dB increase in operating level results in a 10dB approximately 3 times increase in distortion Of course this is predominantly even harmonic distortion which is characteristic of valve equipment and not harsh clipping related distortion Master Output Level The output master level or output gain control is located after the valve circuitry Thus the desired effect may be obtained by adjusting the input gain control to drive the equalisation stages at a low level for a clean sound through gentle valve character to an overdriven effect at high signal level whilst controlling the output level to match the following equipment EQ2 Parametric Equaliser Technical Specification Input
12. s Line level balanced 4dBu nominal via XLR sockets plus unbalanced on jack sockets Maximum input 24dBu input impedance greater than 5Kohm Instrument input on front panel jack switchable to high low gain for guitar or keyboard Maximum input level 22dBu Input impedance 220Kohm Mic input balanced on XLR with switchable phantom power EIN 127dBu 150 ohms 22Hz 22KHz Input gain range 16dB to 60dB Mic 22dB to 22dB Line Filters Continuously variable individually switched high and low pass filters 12dB per octave LF cut frequency range 30Hz to 2 HF cut frequency range 1KHz to 25KHz Equalisation Four bands per channel individually switched plus overall EQ ON switch Each channel fully parametric with continuously variable cut boost frequency and Q LM and HM bands peaking LF and HF bands switchable to shelving or peaking response Cut and boost 15dB Frequency range LF and LM 30Hz to 3KHz Frequency range HM and HF 1KHz to 20KHz Q range 0 5 to 5 Stereo Operation Full stereo ganging of all EQ controls i e cut boost frequency Q controls and in out buttons Overall EQ IN buttons filters input gain and output gain remain seperate Drive and Peak LEDs Variable intensity drive LEDs start to glow at threshold of valve compression Peak LEDs indicate approximately 2dB of headroom remaining Monitor point is the EQ output prior to master level control Mast
13. the characteristic valve sound as required Variable intensity peak LEDs glow to indicate the degree of valve drive attained The Stereo mode switch is a powerful facility enabling precise tracking of equalisation between channels with quick adjustment and no need to match settings on two sets of controls All of the EQ controls are ganged 1 e Cut Boost Frequency Q and band in out switching The input and output gain controls high and low pass filters and overall EQ in out switches retain individual channel operation for maximum flexibility A solid state electronically balanced output stage with outputs switchable for 4dBu or 10dBu nominal output level completes the channel The balanced signals are terminated on metal XLR sockets with unbalanced line level inputs and outputs provided on 0 25 jack sockets Please read this manual fully before installing or operating the Equaliser PRECAUTIONS The T L Audio EQ2 Parametric Valve Equaliser requires very little installation but like all electrical equipment care must be taken to ensure reliable safe operation The following points should always be observed All mains wiring should be installed and checked by a qualified electrician Ensure the correct operating voltage is selected on the rear panel before connecting to the mains supply Never operate the unit with any cover removed Do not expose to rain or moisture as this may present an electric shock hazard
14. ut only response to tailor the roll off of the frequency response for example to remove unwanted low frequency rumble or hum or excessive high frequency noise or hiss which may be present on the input signal Typical response curves are shown in the specification section of this manual Equalisation Before switching the EQ into circuit it is advisable to set the cut boost controls to their centre or flat position The EQ is brought into circuit with the overall EQ IN push switch signalled by a green LED Each band also has an individual select switch and associated LED Both channels feature four bands of equalisation all with fully variable cut and boost controls offering 15dB of range swept frequency and variable Q The Q of the filter is a measure of the shape of the frequency response curve and is closely related to the bandwidth or range of frequencies controlled by the filter High Q settings about 5 at the maximum setting on the EQ2 result in sharp narrow bandwidths generally used for audio correction or effects Intermediate settings say 1 to 3 are generally used to enhance or reduce a broader range of frequencies typically to make an instrument or vocal stand out or recede into the mix Finally low Q values down to about 0 5 on the EQ2 provide more gentle contouring or sweetening of the response The four bands of EQ per channel are nominally designated as LF low frequency LM and HM
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