Apex GX-230 - user manual
Contents
1. ERES Lr aud Figure C Diving 94 peer Er wil Dre 34 t Irrir 1 Unban zad I nbslancad aub E 1 Ground Ht zvixh r m E D lots yn uid Sl pr ES tur uid Figure D The Equaliser Yt es MERLE ARE SAG LL M 52 S Sue aaa ie 152 aa T uos c wa m E k EE NM NH EH EH UM EE HE pa paa AA DE ENS NEE a GEN a mg p po ge i 7 E E CONS i ron A Y 240 O A HHHH a ammi SERVES zio CALMER 4 2 P qu POWER When pressing the power button AC mains is applied to the unit The red led below the power switch illuminates as you switch on the apparatus The fail safe relays will open switching the filters between the input and the output of the unit When switching power off the fail safe relays will link the input of each O LOAD The O LOAD indicator illuminates when the peak signal voltage anywhere in the unit exceeds 18dBm This level is about 2 dB below clipping of the equaliser s internal circuits The overload led is commanded by a peak stretching circuit for better e visualisation of overload conditions and will light for LEVEL dB The LEVEL control adjusts the input level to the equaliser and filler sections of the unit Being preceded by the input stage the level control does not permit to adjust signal le2. The impedance to ground from each output terminal is approximately 10 KZ Output connections are via a standard 3 pin XLR male socket Because the output is made electronically floating you may ground eihter terminal 2 or 3 without fear of short circuiting an op amp output to ground Moreover you loose 6dB of signal Some general rules for output connections Always ground the shield at the equaliser side only by connecting it to terminal 1 SG of the XLR socket e When driving an unbalanced load connect terminal 2 to the signal input and terminal 3 to the circuit ground of the driven equipment See figure B and D p18 e When driving a balanced input connections are straightforward Check carefully for correct phase relative to input connections Grounding Because it is not always possible to determine whether the equipment connected to the equaliser have their circuit ground connected to earth and because the mains earth is not always of good quality it is hardly possible to give general rules for One and only one ground path should exist between each piece of equipment he circuit ground of the equaliser should not be left floating A ground loop generally causes a steady hum If you encounter a ground loop you can often break it using the ground lift switch on the rear panel When using the ground lift switch the circuit ground of the equaliser is disconnected from the chassis ground Chass
3. paths The complete unit can be bypassed by switching it off The failsafe relays will react as if there were a mains failure and will link the input of each channel to its corresponding output The GX230 has electronically balanced inputs and balanced floating output stages Each output circuit actually simulate a transformer with a 10KOhm impedance to ground for each leg Both the input and output circuits are factory adjusted for optimum balance at low and high frequencies This results in increased interference immunity of the unit The overall gain of each channel of the GX230 is variable from Performance Highlights Two independent channels 30 band constant Q precision DLT graphic equalisers owitchable 30Hz highpass filters with 18dB oct slope Graphic equalisers in out switchable Switchable scale 6 12 dB on graphic equalisers 6 dB of gain available Extremely low distortion and noise True differential input circuitry Effective HF interference cancelation on in and outputs through perfectly HF balanced stages XLR in and outputs Accurate peak stretching overload indicators Failsafe bypass Earth lift switch Power transformer with low flux windings and magnetic screening reducing magnetic stray field to other units Wide mains voltage range Professional parts and construction Installation NOTE In addition to these operating instructions and the GX 230 equaliser the packa
4. repair of the unit Unless you are a highly skilled technician do not try to repair this unit Moreover specialised components are used in this apparatus and for several of them it is very doubtful if you could find a correct replacement Therefore contact your dealer in the event of failure He or she has notice of the Apex authorised service centres and can advice you about what to do Copy the service request form on the next page fill it out and ship it with the defective unit It will help the service technician to localise the problem It is often more expedient to call your dealer or our factory 20 SERVICE REQUEST FORM Please copy and complete this form as completely as possible and return it to Apex or an authorised Apex service centre together with the defective unit MNA MIO EN TU t eccl Mei lI ea So quia Model A Purchased Date Describe symptoms of malfunction e Under what conditions does the malfunction occur All the time After a while At high signal levels At high temperatures Other please explain moO WD gt How often did the problem occur What did you do to isolate the problem to
5. this unit Further comments 26 ADEX WARRANTY Summary Items excluded from warranty Our commitment We APEX nv Bosdel 52 3600 GENK Belgium warrant to you the original purchaser and any subsequent owner of this Apex product for a period of one year from the date of purchase by the original purchaser that the product is free of defects in components and factory workmanship under normal use and service The date of purchase is the date appearing on the first end user s bill of sale or other proof of original purchase from an We are not responsible for product failure caused by misuse accident or neglect This warranty shall not be applicable to any product on which the serial number has been defaced altered or removed It does not cover damage to other components connected to the Apex product resulting from Apex product failure This warranty shall be considered void if this product is subjected to repair work or alteration by persons other than authorised by Apex in such a manner as to injure in the sole judgement of Apex the performance stability reliability or safety During the warranty period when failing to perform as specified Apex will undertake to repair or at its option replace this product at no charge to its owner provided the unit is returned shipping pre paid to the factory or authorised service facility You must notify us of your need for warranty service preferably by filling in the service req
6. with dynamically trimmed hybrid circuits This is what DLT stands for Dynamic Laser Trimming At the factory each filter of the graphic equalisers is laser trimmed to match mother nature s prescription for ideal response This results in perfect combining of the individual filter resoonse curves and therefore a perfectly flat amplitude and phase response All the filter components are incorporated on the hybrid circuits As a final production step each bandpass filter is adjusted for the correct 1 3 octave centre frequency and bandwidth using a specially developed trimming algorithm for adjusting the centre frequency and bandwidth simultaneously Incorporating all filter components on the hybrid circuits yet has another important advantage because of the largely reduced number of soldered connections reliability is boosted to an extent only exceeded by integrated circuits some call it fit and forget technology The controls of the graphic equalisers provide up to 12 dB of reciprocal cut and boost at the 30 distinct centre frequencies The filters of the GX230 preserve optimal filter bandwidth whatever the settings of the controls Because of this constant Q circuitry filter response does not broaden at low cut or boost settings fig 1 2 In this way filter interaction is minimised and the graphic qualities of the equaliser preserved The graphic equalisers of the GX230 are switchable IN and OUT of the signal
7. APEX GX Series Graphic Equalisers GX 230 USER MANUAL APEX nv Contents Section 1 Contents Section 2 Introduction 2 1 The GX 230 Section 3 Performance Highlights Section 4 Installation 4 1 Unpakking the unit 4 2 Checking the mains voltage 4 3 Setting the mains voltage 4 4 Replacing the mains fuse 5 5 The rear pannel 5 6 Rack mounting Section 5 Signal connections 5 1 Input 5 2 Output 5 3 Grounding Section 6 The Equaliser Section 7 General operating instructions 7 1 Introduction 7 2 Level control O load and power 7 3 HP filter 7 4 Graphic equaliser Section 8 Specifications Section 9 Maintenance and service information Section 10 Warranty 10 10 10 11 13 15 16 17 21 21 21 22 22 23 25 27 Introduction The GX 230 The APEX GX230 is a dual channel 30 band 1 3 octave graphic equaliser incorporating our newly developed DLT hybrid circuits A high pass filter precedes the equaliser in each channel and is switchable in and out of the signal path The unit is built to the highest professional standards both for electronics and mechanics The heart of each graphic equaliser is a bank of 30 bandpass filters one filter for each 1 3 octave frequency Conventional equaliser designs use discrete components to realise these bandpass filters Although it is possible to build good equalisers with this technology using precision components far better results can be achieved
8. anged when the fail safe relay activates This is a good starting point for the exploration of the equaliser s functions Once all mains and input and output connections are made correctly switch the unit on by pressing the power switch After app 0 2 seconds the fail safe relay will activate and thereby link the unit in the signal path The graphics on the equaliser s front panel illustrate the different functions of the unit and make it ergonomically pleasant to work Level control O load and power The level control is preceding the filter section of the equaliser and levels the input signals of the filter section The input stage of the equaliser is located before the level control The level control has thus no effect on the levels in the input stage In case the overload led illuminates and decreasing the level with this control has no effect it probably means that the input stage is in overload The only solution to this problem is lowering the signal level at the input of the unit by lowering the output of the driving equipment or by adding an external loss pad to the input wiring Of course the power switch is for turning the unit on and off but if the system is set up well LEVEL at OdB it can be used as a bypass for the complete equaliser making use of the fail safe 21 HP filter Graphic equaliser 22 The HP filter has turnover frequency of 30Hz The filter has a roll off slope of 18dB octave and i
9. dard rack units Mounting the unit directly over large heat producing devices may shorten component life and therefore is not recommended Ambient temperature should not exceed 50 degrees Celsius when the equipment is powered Because of the chassis mechanical construction the GX230 has no need for support at the rear when mounted in a rack cabinet This feature facilitates manipulation of the unit while ensuring perfect mechanical stability Make sure there is enough room for air circulation between different pieces of equipment and through the heatsink at the back 13 14 Signal connections Input For maximum performance the use of two conductor shielded cable is recommend Because the shield does not carry signal interference between signal current and shield current is minimised in this way Ordinarily the shield is connected to ground at one end The inputs of the equaliser are electronically balanced The input impedances of the and legs are made equal so that common mode rejection CMR is practically independent from the impedance of the driving source HF and LF trims are provided to optimise the CMR and null out circuit tolerances These electronically balanced inputs are compatible with most professional and semi professional balanced or unbalanced sound equipment A low pass filter precedes the input stages of the equaliser When driving the equaliser from a high impedance source overall frequ
10. ency response can be compromised because of the low pass filter capacitors When the source impedance is higher than 2 2 unbalanced or 4KZ balanced it is advisable to change the cutoff frequency of the input filters In this case contact your dealer to make the modifications Generally the output impedance of modern audio equipment is 15 Output 16 Some general rules for input connections e Although not necessary because of input circuit symmetry it is best to always use the and input terminals when wiring the equaliser In this way hum pick up from the open terminal is avoided When the GX230 is driven from a balanced source ground the shield at the source end only and leave terminal 1 SG on the GX230 disconnected Wiring of the other input terminals is straightforward Check carefully for correct phase relative to output connections See figure A and B p18 When the equaliser is driven from an unbalanced source connect the shield to the circuit ground of the source and to terminal 1 signal ground of the input XLR connector Depending on whether the circuit ground of the driving equipment is connected to earth or not it may be advantageous to lift circuit ground from chassis ground on the equaliser using the ground lift switch You can experiment with this and leave the switch in the position that gives minimum hum or buzz The output electronics of the equaliser simulate true transformer operation
11. ging also contains power cord see note for U K This apparatus must be earthed The wires of the mains lead are coloured in accordance with the following code Green and yellow Earth Blue Neutral Brown Live As the colours of the wires in the mains lead may not correspond with the coloured marking in your plug proceed as follows Unpacking the unit The equaliser comes in a cardboard safety box specially designed for protection of the unit against damage during transport Save all the packing materials for future use if you ever need to ship the unit again Please inspect the unit carefully for any signs of damage occurred during transport Your GX230 has undergone stringent quality control inspection and tests at the factory It left in perfect condition If damage is found notify the transport company immediately Only you the consignee may institute a claim against the carrier for damage during shipment Make sure to retain the damaged Checking Check if the voltage selector on the rear of the equaliser indicates the correct supply voltage before connecting the the mains voltage equaliser to the mains Setting e Remove the plug from the wall socket and check if the mains the mains voltage fuse is of the correct rating Replacing e Withdraw the fuse holder from the equaliser by turning the locking screw half revolution counter clockwise and pull out the mains fuse i j the fuse holder
12. is ground is always connected to earth for safety reasons Signal ground remains connected to terminal 1 of the XLR sockets The input output supply board of the equaliser is provided with place for adding a resistor and a capacitor R107 C107 for those who do not wish to completely disconnect the chassis and circuit grounds Providing a small ceramic capacitor between the two grounds can be helpful for solving HF buzz problems often encountered when using mains ground The figures below shows some grounding schemes for the equaliser If you follow these figures while setting up your system and hum or noise appears don t be afraid to experiment Just keep safety earth connected to the chassis of the equaliser A ground loop consists of two connections to ground so there is always another solution than to disconnect the chassis of the 17 18 Diving 34 peer ER wil Dre paast Irrur Balanced l azrcad on Es Jl i li Ho k i Gand Hit zvixh r Ne E D peer yn uid ERE Figure A Diving 34 peer ER wil Dre Ja raura Irrur I I Unbalanced j ono l I F I 1 Ground zvixh r III l T ebm uud Tle Lr aud Figure B Drsing 34 peer ER wil Dre I U nbslancad zur ced sub I FDE IG Lit zvixh r ML A E
13. of the socket e Remove the old fuse and replace with fuse of the correct rating e 1630 mA slow blow fuse Littlefuse 213 630 for 100 120 V e 315 mA slow blow fuse Littlefuse 213 315 for 220 240 V NOTE Delivery position is 220 V T315mA Wickemann 19195 in all cases The rear panel 7 m SUC Bi l r r hu a E Ln nr EL 4 Tiu EX nr me a t Ika A am i un udi ma Pes T E CNET o FPE Br IT P ir FC Tree ree FRLER EI mm bb D rt N 2 gc 2 Mt LINJI i FEO Tura gu i Turn TE rr rer TE E T n i1 M mal ll i Er len T rr SENET js x io ER en Si ni nr ro 1 DRE SX A un N 1 as Mag un de m VINE E 1 MAINS FUSE Holds the mains fuse 2 MAINS SOCKET e Insert the plug of the mains lead into the mains socket mains connector is a standard 3 pin IEC connector The centre terminal of the connector is directly connected to the chassis of the equaliser Connect the other end to your mains supply via a wall socket that has a connection to earth Mains frequency is 50 60Hz For units set at 100 V 120 V use a UL listed cord set consist ing of a minimum 18 AWG type SVT or SJT three conductor cord a maximum of 15 feet in length and a parallel blade grounding type attachment plug rated 15 A 125 V For units set at 230 V domestic USA
14. onically balanced Absolute overload point 22dBu Impedance 10 KZ each leg equal impedance for and legs CMRR better than 65dB 20Hz 20KHz XLR 3 type connector connections 1 signal ground 2 hot 3 cold OUTPUT Electronically balanced and floating simulating transformer output with app 10 KZ to ground impedance for each leg Max level gt 21dBm into 600 Z Impedance 51 Z each leg Output symmetry balance better than 65dB 20Hz 20KHz IEC XLR 3 type connector connections 1 signal ground 2 hot 3 cold PERFORMANCE Frequency response 0 0 5dB 20Hz 20KHz graphic eq IN THD lt 01 20Hz 20KHz Noise lt 92dBm typ 94dBm graphic and parametric equalisers in circuit OdB settings measurements 22Hz 22KHz RMS unweighted Level control to 6dB Level control OdB cal accuracy 0 2dB overall gain input to output Overload indicator lights for approximately 200ms if the instaneous peak voltage at 23 24 any point in the equaliser comes within 2dB of clipping FILTERS e 30150 centre frequencies 25 2 20 2 1 3 octave Centre frequency tolerance 1 typically better than 0 5 e Qtolerance 1 e Max boost cut 6 or 12dB 0 5dB reciprocal Switchable POWER REQUIREMENTS e Voltage 110 120 220 240V 50 60Hz Consumption 40VA equaliser e ECtype connector SIZE e 482mm 19 inch wide x 133mm 5 2 inch high x 255mm 10 inch deep eq
15. s of the Butterworth type for maximally flat response It is particularly useful in situations where potentially harmful subsonic signals are likely to cause speaker or amplifier overload Phono cartridges and wind in microphones are examples of sources that can produce excessive subsonic outputs It will not have a dramatic effect on sound while providing serious protection against overload The centre frequencies of the graphic equaliser are chosen for perfect filter interpolation For some frequencies this means a slight deviation from the ISO proposed centre frequencies The maximum deviation is about 2 so there should be no problem when using the equaliser in combination with commercial real time analysers that generally use the ISO centre frequencies The 30 controls of the graphic section provide you with a lot of possibilities for shaping sound In doing so it is best to regard following principles It is generally better to attenuate peaks rather than to boost the surrounding frequencies to the same level Noise will be lower and the sound will be more natural in this Way Do not attempt to correct narrow peaks or dips with the graphic section Use the parametric filters for this purpose These aredesigned for narrowband operation and are much more versatile Do not use the graphic equaliser as a gain fix up device It is far better to use the 6dB of available gain from the LEVEL control opecifications INPUT Electr
16. ualiser WEIGHT 7Kg SPECIFICATIONS SUBJECT TO CHANGE WITHOUT NOTICE Maintenance and service information Preventive maintenance Corrective maintenance Preventive maintenance consists of cleaning and visual inspecting the unit When accomplished regularly preventive maintenance may prevent malfunction and lengthen the apparatus life The severity of the environment in which the equaliser is used determines the required frequency of preventive maintenance Regular cleaning prevents accumulated dust from penetrating potentiometers The front panel can be cleaned with a soft cloth or a small soft bristle brush The brush is particularly useful for dislodging dirt on and around the controls and inside the slider slots Dirt that remains can be removed with a soft cloth dampened in a mild detergent and water solution Do not use strong solvents as they may damage the paint the screened lettering or the plastic control knobs Be careful not to let detergent leak into the potentiometer slots as it may damage the carbon resistance tracks The rear panel can be cleaned in the same way as the front panel The top cover minimizes accumulation of dust inside the unit and should normally be in place when using the equaliser Dirt on components acts as an insulating blanket preventing efficient heat dissipation It also provides an electrical conduction path that Corrective maintenance consists of component replacement and
17. uest form and returning it to us We will give you notice of the authorised service centres to whom you may deliver the product or we will give you an authorization to return it to the factory All components must be shipped in a factory pack shipping prepaid If needed replacement packing can be obtained 27 from us Corrective action will be taken within a reasonable time of the date of receipt of the defective product by us or the service centre If the repairs made by Apex or the authorised service centre are not satisfactory notify Apex or the service centre immediately Repairs Product changes 28 We reserve the right to change the design on any product without prior notice and with no obligation to make corresponding changes in products previously manufactured
18. use a UL listed cord set consisting of a minimum 18 AWG type SVT or SJT three conductor cord a maximum of 15 feet in length and a tandem blade grounding type attachment plug rated 15 A 250 V For units set at 220V 230 V 240 V Europe except U K use a cord set consisting of a minimum 18 AWG cord and ground ing type attachment plug rated 15 A 250 V The cord set should have the appropriate safety approvals for the country in which the equipment will be installed and marked HAR 3 MAINS VOLTAGE SELECTOR The equaliser is designed to be operated with nominal mains voltages of 115V and 230V The circuits can tolerate a deviation of 15 on the mains covering the range 98V to132V and 195V to 264V 11 12 4 SERIAL NUMBER This number is the fingerprint of the unit and should be quoted in any correspondence concerning the unit 5 SIGNAL GROUND LIFT This switch disconnects the signal ground from the mains and chassis earth The switch should be used if hum due to ground loops is experienced and will generally solve the problem 6 8 Balanced IN A B Connects the equaliser to balanced outputs The connector is a female Neutric XLR NC3FD For wiring details see section Signal connections 7 9 Balanced OUT A B Connects the equaliser to balanced inputs The connector is a male Hack mounting The GX 230 is designed for standard 19 rack mounting as well as free standing outside a rack cabinet The unit requires three stan
19. vel in this part of the circuit The equaliser has 6dB of available gain and can be used as a low noise and distortion gain make up amplifier Er The level control lets you adjust gain between to 6dB in a 20 HP IN OUT o SLIDERS NOTE The HP filter has a cutoff frequency of 30Hz The filter has a roll off slope of 18dB octave and is of the Butterworth type for maximally flat response It is particularly useful in situations where potentially harmful subsonic signals are likely to cause The SCALE switch switches the range of the corresponding graphic equaliser section to 6dB or 12dB full scale The IN OUT switch activate or deactivate the corresponding graphic equaliser section The sliders of the graphic equaliser allow centre gain adjustment for each of the indicated centre frequencies Note The rotary controls of the GX 230 are high quality conductive plastic potentiometers However calibration accuracy of these controls is only modest Indications on the front panel therefore are principally intended General operating instructions Introduction If you are not familiar with equalisers the best thing to do before first turn on is to put all controls in their central position When the unit is not powered or the power supply fails the fail safe relay of the equaliser links input and output By putting the controls in their central position you make sure that the overall gain of your system is not ch
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