MPDI-4 User Manual Version 1
Contents
1. T 4 7 OUTPUT IMPEDANCE 47 FREQUENCY RESPONSE MIC PREAMP eive vs MP Ub PES 10 Hz 80 kHz 0 1 dB Wiese 10 Hz 50 kHz 0 1 dB NOISE FLOOR MIC PREAMP 128 dBu 20 Hz 20 kHz MAX LEVEL BEFORE CLIP MIC PREAMP 2222 PES SOUROO C PEEEE FECI ES PE 27 dBu or better DISTORTION MIC PREAMP 003 at 27 dBu DIMENSIONS FRONT TO BACK 12 25 WITH HEAT SINKS and 14 P PO Cm 17 25 RACKEARS c EE Ure etas ERR 19 WEIGHT ACTUAL 12 165 DIE PING dis rad Uic ee seds 15 8 Ibs 132. MAXIMUM COLORATION or THAT 60 s SOUND We are a huge fans of the sound of recordings made in the 60 s When you listen carefully to these recordings be it British Rock or Motown you will notice A LOT of distortion Back then they were doing every thing possible to minimize noise and distortion but the limitations of the gear unavoidably resulted in signifi cant amounts of it and in most cases it sounded awesome The preset below will allow you to add as much distortion and coloration as you like without risk of clipping your converters Picture 8 OUTPUT 10 As you can see Picture 8 we have highlighted the controls that are important The 10 output pad is engaged the Xfrmr output transformer is engaged and the LOAD is turned on The input transformer should also be engaged but make sure to choose the impedance that best matches the microphone you are using see item 5 on Page 10 The other controls can be set to accommodate your specific recording setup and circumstances PRESET 2 ROCK COLORATION or THAT 70 s SOUND As you get into the 705 you start to see equipment that has more head room like the API QUAD 8 and NEVE circuits There are still lots of transformers in the path as well as a higher overall THD Picture 9 OUTPUT 10 gt gt Picture 9 shows that the Output Pad is now in the OUT position The LOAD switch is on and both the input and output tr
3. resolved install the spare fuse and you are ready to go Picture 1 ximum Power nsumption 25W Voltage select in fuse drawer Picture 1 shows the MPDI 4 set in the 110 V mode This will work for voltages from 110 Picture 2 imum Power nsumption 25W Voltage select in fuse drawer Picture 2 shows the MPDI 4 set in the 240 V mode This will work for voltages from 220 V 240 V Picture 3 110W Picture 4 shows the PCB voltage selector 3 RACK MOUNTING As you have seen repeatedly in this manual the MPDI 4 is a Class A device Class A circuitry unavoidably generates heat How one chooses to rack mount these devices can have a significant affect on the ambient temperature inside the enclosure We have done everything we can short of using a fan to improve the thermal performance and we have put them through worst case rack mounting scenarios to make sure that they will perform reliably under those conditions However we just want to make people aware of how the various rack mounting options will affect the thermal performance THE WORST POSSIBLE WAY TO MOUNT MULTIPLE MPDI 4s IN A RACK IS TO STACK THEM ONE ON TOP OF EACH OTHER When three MPDI 4s are stacked on top of each other in a rack the one in the middle will maintain an average internal ambient temperature of about 120 49 C If you stack 6 of them the middle units can get up to 130 54 8 of them can get over 140 60 C The MPDI 4
4. 4 as a DI When a 1 4 cable is plugged in both the front and rear mic inputs are disabled 2 MIC GAIN This rotary switch allows you to adjust the amount of gain on the mic pre from 10 dB to 60 dB in 5 dB steps 3 PAD This toggle switch engages the passive 20 dB pad before the mic pre There is no padding when the switch is in the up or 0 position 20 dB of padding is added when the switch is in the down or 20 position 4 48V OFF This toggle switch turns on or off the 48 V phantom power Turn this on when using microphones that require phantom power to function Turning the 48 V phantom power on or off can cause a very loud low frequency thump to come out of the mic pre Make sure you turn down your monitors or headphones when changing the 48 V setting NOTE Some ribbon microphones can be damaged by phantom power It is always best to turn off the phantom power before plugging in any type of passive ribbon mic 5 LOW HI NoX This 3 position toggle switch selects the transformer mode for the input of mic preamp LOW In the UP or LOW position the input transformer is configured for a low impedance high gain input This setting works especially well for passive ribbon microphones You will typically get an added 3 or 4 dB of gain with no additional amplifier noise It also has sonic benefits as well We have found the ribbon mics to sound clearer and more balanced in this mode HI This mode is best
5. NO audible distortion However while technically impressive low distortion may not always sound the most musical Many popular vintage mic preamps have much higher harmonic distortion signatures as much as 20 30 times the distortion of the MPDI 4 The LOAD switch puts the UTA mic preamp into the same harmonic distortion range as many of the vintage pre amps There are other differences as well It emphasizes the low order part of the THD and has a softer transition into clipping With the LOAD switch off the harmonic distortion has a crunchier quality to it where you mostly hear it clipping on the transients while the level is pushed With the LOAD switch on the harmonic distortion has a thicker smoother softer quality that can add a nice high frequency energy to a sound It is important to know that using the LOAD switch will change how the output of the MPDI 4 interacts with other devices If the LOAD switch is on and the output is plugged directly into a device that also has a 600 O input UA 1176 LA2A Pultec etc you will experience an additional increase in harmonic distortion and a further loss of headroom THE 10 dB OUTPUT PAD We have always used the UTA preamps with a UTA console This allowed us to push the gain of the preamps and pad the signal with a fader or line trim control prior to sending the signal to a DAW or a tape machine We know that many people will plug their mic preamps directly into the input of the
6. cable runs when the pad is engaged You can use the output pad knowing that the sound of the device will not change or be compromised in any way 9 PH 180 This toggle switch allows you to reverse the polarity of the signal coming out of any one of the mic preamps THE PHASE REVERSE ONLY FUNCTIONS WHEN THE OUTPUT TRANSFORMER IS ENGAGED The phase will be the same as the incoming signal when the UP or PH position The phase will be reversed 180 degrees from the incoming signal when in the DOWN or 180 position 10 Xfrmr OUT This toggle switch allows you to have the output transformer either added or re moved from the output signal When the switch is in the Up or Xfrmr position the output trans former will be added to the output signal and add all of the output transformer related functions output pad amp phase reverse When in the DOWN or OUT position the output transformer will be removed from the output signal and neither the output pad or the phase reverse will function 11 LOAD OFF This toggle switch turns on or off the optional 600 O Load on the output In the UP or LOAD position the load is added In the DOWN or OFF position the 600 O Load is removed The 600 O Load adds additional harmonic coloration that can sound very musical in certain situa tions 12 Meter This Rotary switch selects which of the 4 mic preamps are sending signal to the VU meter 9 6 HARMONIC DISTORTION OK SO WE KNOW
7. the power cord INSTRUCTIONS POUR 220 240VAC FONCTIONNEMENT Avant de commencer d branchez le cordon d alimentation de la prise secteur Cet appareil est fourni avec un cordon d alimentation pour l Am rique du Nord 110 120VAC 60 Hz Pour une utilisation dans d autres endroits et ou d autres sources de tension utiliser le bon type de cordon d alimentation de votre r gion et source de tension 3 Cet appareil est fourni avec T 0 4A AC Mains fusibles install s pour une op ration 110 120 V et comprend T 0 2A accessoires fusibles pour un fonctionnement 220 240VAC emball s s par ment Ouvrez le tiroir du fusible sur la prise secteur l arri re de l appareil et remplacer le fusible de 0 4A T avec l accessoire fusible T 0 2A 4 Dans le tiroir de fusible changer les secteur CA passer de la position 110V la position 240V 5 Assurez vous que le tiroir fusibles est fix ferm avant de fixer le cordon d alimentation POWERING UP Before you connect the AC power cable check to make sure the AC operating voltage on the unit is set to properly match the volt age of your AC outlets The options are 110 V appropriate for 110 V 120 V range or 240 V appropriate for 220 V 240 V range The operating voltage of the MPDI 4 can be changed by removing the small tray in the power entry module Simply flip around the small PCB inside the tray so the correct voltage is showing in the window when the tray is re inserted i
8. 0 PH pes Xfrmr fj LOAD 10 PH Xfrmr fj LOAD 4 10 PH Xfrmr fj LOAD MIC d MIC d i p GAIN M Ned 7 M 180 Ned 7 M 180 Ned 7 180 Ned f 5 x 29 5 x SO 45 x SO 45 x n 9 m n m n 9 s S SC 48 LOW gt 4 gi T nf i EO 53 m i EO 53 m OFF 20 BO MIC DI IN x4 These Neutrik combo jacks allow you to plug either male XLR or a 1 4 instrument con nector directly into the front of the unit When a male XLR connector is plugged in the combo jack auto matically switches to only allow signal from the front MIC IN jack to go to the mic preamp When a 1 4 jack is plugged in the combo jack automatically switches the circuitry to function as a Class A DI and also disconnects the rear MIC IN jack 5 FRONT PANEL CONTROLS 8 9 1011 12 Picture 7 OUTPUT 10 Xfrmr LOAD vV 180 OUT Eod 45 40 Uu LOW 20 ied NoX DESCRIPTION OF FRONT PANEL CONTROLS 1 FRONT MIC AND DI INPUT This combo jack input allows you to plug either a microphone cable or 1 4 instrument cable directly into the front of the unit Plugging a mic cable into the front mic input automatically disables the rear mic input Plugging in a 1 4 instrument cable allows you to use the MPDI
9. UIA MPDI 4 User Manual Version 1 1 2 2 SAFETY POWERING 66 3 3 RACK 6 4 AUDIO 7 5 FRONT PANEL 8 6 HARMONIC 10 7 PRE EXAMPLE SETTINGS rhon 11 8 THE DI DIRECT INPUT 2 uh no e T eroe rere se 13 9 SPECIFICATION ECOSSE 14 1 INTRODUCTION Congratulations You are the proud owner of the UTA MPDI 4 a wonderfully flexible beautiful sounding Class A Mic Preamp DI The MPDI 4 packs a huge amount of Class A audio power into a single rack unit get up and running right away with your 4 skip to Chapters 2 Powering Up 3 Rack Mounting and 5 Front Panel Controls The most vital information about the proper installation of the MPDI 4 in this manual is in Chapter 3 Rack Mounting The rest of the manual contains more detailed information that is not essential for understanding the unit s basic functionality The mic preamp has gone through exhaustive recording listening and analytical tests to end up with the best po
10. WE KNOW There are a lot of switches on this mic preamp What can we say we like gear that gives us a lot of control over the sound We will do our best to give you simple starting point settings that will make it easy to get great results right away First a little more detail about the intention and function of the 4 features that control the Harmonic distortion character of the MPDI 4 These are the Load switch the 10 dB output pad button the LOW HI NoX and the Xfrmr OUT switch THE LOAD SWITCH While using MPEQ 1s over the past couple of years we noticed a difference in the sound when we plugged in a compressor after the MPEQ 1 that had a 600 input impedance UA 1176 LA2A Pultec etc This basically means that 600 load is being applied to the output stage of the 1 The harmonic dis tortion character changed and for certain things it was a very desirable effect We ultimately made some 600 O adapters that we could use when we wanted the load but weren t using a 600 device after the 1 We then realized that it would be easy and very useful to make it a switchable feature on the front panel of the MPDI 4 The UTA mic preamp is capable of astonishingly low harmonic distortion performance With both transform ers bypassed and no load applied the mic preamp will pass 27 dBu with only 00396 THD That is insanely low especially for a Class A preamp For all practical purposes that is essentially
11. ansformers are still engaged This combination will get you similar results to using Vin tage Class A preamp Neve 1073 or 1272 EMI TGI Helios etc It is a hard hitting sound with a bit of smoothing in the high frequencies 11 PRESET 3 MODERN CLASS A This combination of settings gives you transformer coloration combined with maximum headroom and minimum THD in the active circuitry It is great for recording applications that require a higher degree of clarity and detail The transformers will still add a subtle amount of smoothness to the top end Picture 10 OUTPUT 10 As you can see Picture 105 we have highlighted the controls that are important for this setting The out put pad is not engaged the output transformer is engaged and the LOAD is turned off The input transformer should also be engaged but make sure to choose the impedance that best matches the microphone you are using see item 5 on Page 10 The other controls can be set to accommodate your specific recording setup and circumstances PRESET 4 CLASS A TRANSFORMERLESS This combination of settings creates a circuit that as far as we know has never been available before A balanced Class A mic preamp with excellent common mode rejection that is totally transformerless With a THD of 003 at 27dBu no crossover distortion and phase linearity well beyond 50kHz it could possibly be the most accurate preamp ever created It is a stunni
12. if you want to add input transformer coloration while using either dynamic or con denser type microphones NoX This mode removes the input transformer from the input of the mic preamp It will give you the same input impedance and gain as the HI mode This offers a unique opportunity to hear a transfor merless Class A mic preamp It is a stunningly pristine sound and is ideal for any recording that needs the highest degree of clarity and detail NOTE switching to or from the NoX mode will cause a loud low frequency thump similar to turning the 48V on off Be sure you have your speakers or headphones turned down whenever switching to or from the transformer less mode 6 VU METER This is a VU meter that will show the level being sent from any one of the 4 mic pre amps 7 POWER BUTTON This push button turns on or off the power for the MPDI 4 In the IN position the power is turned on In the OUT position the MPDI 4 will be powered off The LED light illumi nating the VU indicates if the MPDI 4 is turned on or off 8 10 BUTTON This push button engages the 10 dB output pad It is actually a tiny bit less than 10 dB about 9 6 dB The button is changing the ratio of the output transformer to cause the drop in level THIS OUTPUT PAD ONLY FUNCTIONS WHEN THE OUTPUT TRANSFORMER IS ENGAGED We chose to do the PAD with the transformer instead of doing it resistively because it makes the out put less susceptible to loading or long
13. ir A D con verters This presents a problem it is impossible to push the level of the mic preamps with out digitally clipping the signal The 10 dB output pad addresses this issue You can now drive the mic preamp as hard as you want and the peak level in the DAW will never exceed 2dBFS It is important to know that our DAW system is calibrated to the standard reference level of 0 dbVU 18 dBFS to achieve this result THE LOW HI NoX and Xfrmr OUT SWITCHES Both the input and output transformers are bypassable on the MPDI 4 The transformers have a slight smoothing effect to the high frequency transients that makes things sound a bit less pointy Overall the high end will sound a bit smoother There is also a very subtle compres sion effect that occurs when the core becomes saturated with low frequencies making the overall level of all the frequencies will drop very slightly You will also experience a slight thickening of the sub frequencies when the transformers are engaged As you can see the combination of the LOAD the OUTPUT and the input output Transformers offer a huge variety of tonal options for the mic pre Some are very subtle and some not so subtle Experiment with the options to find a combination that works best for your taste and style of music In the next section we will give you presets that act as a good starting point to get the desired musical results 10 7 EXAMPLE SETTINGS PRESET 1
14. is protected by thermis tors When the units get in the 140 60 C range the thermistors will start to shut down the various DC voltages THIS IS VERY IMPORTANT IF THE LIGHT IN THE VU METER TURNS OFF AND OR THE MPDI 4 STOPS PASSING AUDIO WHILE THE POWER SWITCH IS TURNED ON THAT MEANS THAT A THERMISTOR HAS TRIPPED BECAUSE THE UNIT IS RUNNING TOO HOT Simply turn off the MPDI 4 change the rack mounting situation such that it allows the unit to run cooler and then power it back up Everything should be fine The thermistors will reset themselves after the unit cools down and if the new rack mounting ar rangement keeps things cool enough it will not happen again The temperature at which components inside the unit would start to actually burn up is around 220 F 105 C We are a long ways away from that but there is a catch the closer you get to that temperature the shorter life span the internal components will have WE STRONGLY RECOMMEND LEAVING A GAP BETWEEN EACH MPDI 4 MOUNTED IN A RACK If you mount the MPDI 4 with even just a 1 3 of a rack space between each unit the average internal ambient temperature will be 105 F 115 41 46 C An MPDI 4 sitting by itself in a rack will maintain an aver age internal temperature of about 100 38 C Here is the crazy thing if you mount an MPDI 4 vertically the average internal temperature drops as low as 80 F 27 C It turns out that the standard the world has chosen for orienting rack
15. is the 10 Xfrmra LOAD most transparent This setting bypasses both transform ers has LOAD and no 10 OUTPUT The gain is typically set somewhere around 20 to 30 with no input PAD This setting is great for capturing a DI signal into your DAW for re amping later or it can also work great for feeding the signal to multiple amps The output of the 7 mu mic preamp can easily handle being mult d to 3 or 4 re E R7 ms amps which are then each feeding different guitar amps The re amp boxes can then provide ground isolation ws OUT Eod uU 48V LOW gt DI COLOR OUTPUT In situations where the DI signal is intended to be used 10 Mul Cea the final sound we will typically turn on both trans xd formers From there you can turn on the LOAD and or the 10 OUTPUT PAD to add more coloration This can be great when recording DI bass synths or drum ma chines although see paragraph 3 this page about potential grounding issues with synths and drum machines OUT Mods 0 48V LOW HI 20 ieu AOD 10 8 SPECIFICATIONS INPUT VOLTAGE os put bes Eee viste ae 110 120 220 240 VAC 60 50 Hz MAINS FUSE TE 0 4A 2 MAXIMUM POWER 25 W INPUT IMPEDANCE MIC IN TRANSFORMERLESS e eee eene 2 2 5000
16. mount equipment horizontally SUCKS for thermal dissipation If you have the option of mounting the MPDI 4 vertically it is unquestionably the best way to do it this is also true for most all rack mounted gear At the end of the day keeping the internal temperature of the MPDI 4 lower will most likely give it a longer life span How much longer Well we are not really sure We expect the MPDI 4 to function without any need for service for about 15 years Will stacking these on top of each other in a rack shave off 1 2 or 3 years from that expectation We just won t know for sure for about 10 15 years from now We recommend mounting the units in a way that will keep them as cool as possible whenever possible 4 AUDIO CONNECTIONS REAR AUDIO INPUTS OUTPUTS Picture 5 MicOut 1 Mic In MicOut 4 Mic In MicOut 3 MicIn MicOut 2 Mic In 4 J 7 n 4 thes Designed and built in California by Undertone Audio Inc MIC IN REAR x4 These are one of 2 input connectors available for getting signal into the mic preamps The rear mic inputs are convenient to use if the MPDI 4 is rack mounted and wired to a patch bay The rear mic input connectors will automatically be disconnected as soon as an XLR or 1 4 cable is plugged into its corresponding front Mic DI input jack MIC OUT x4 These male XLR connectors give you access to the output signal of the mic preamp FRONT AUDIO INPUTS Picture 6 OUTPUT OUTPUT OUTPUT OUTPUT Ee 1
17. n the power entry module When changing the MPDI 4 to a different operating voltage you must also change to the appropriate fuse value to be sure it is either properly protected or won t immediately blow the fuse see Picture 1 or 2for appropriate fuse values PLUGGING THE MPDI 4 INTO A 220 V 240 V OUTLET WHEN SET FOR 110 V OPERATION WILL LIKELY RESULT IN DAMAGE TO THE POWER SUPPLY OF THE UNIT AND REQUIRE SENDING IT BACK TO UTA FOR REPAIR Once you have confirmed that the operating voltage is set cor rectly make sure the power switch is in the OFF or OUT position Plug the supplied IEC AC power cable into the AC power recep tacle on the back of the unit Plug the other end into an appropri ate grounded AC outlet You are now ready to power up the unit Simply push the power switch on the front panel to the ON or IN position When the MPDI 4 is powered you will see the VU meter jump around for a couple of seconds This is normal The illumina tion of the VU backlight LED is the indication that the MPDI 4 is powered up and ready for use The MPDI 4 is protected by a slow blow or time delay fuse The fuse can be found mounted in the removable tray see Picture 3 There is also a small compartment that holds a spare fuse The spare fuse is a 4 fuse for 110 V operation If the MPDI 4 blows a fuse it is best to first try to determine what caused the fuse to fail before installing the spare Once the cause for failure has been
18. ngly pristine sound This setting is ideal for situations where the highest degree of detail and clarity are essential Picture 1 1 OUTPUT 10 Picture 11 shows that the Output Pad is in the OUT position The LOAD switch is OFF and both the input and output transformers are BYPASSED 12 8 THE DI DIRECT INPUT The DI was optimized for use with passive guitars and basses We were looking to make a DI that would sound as trans parent as possible for the purpose of re amping This DI achieves this better than any others we have used It sounds as close to plugging directly into your amp as you can possibly get The function of a DI is pretty straight forward itis an impedance matching stage The output impedance of a passive gui tar or bass is typically quite high usually in the 1 MO range The input impedance of mic preamps is typically much lower usually in the 1 kO range Why is that a problem Well if you plugged a guitar or bass directly into a mic preamp without any impedance matching stage the interaction of those impedances capacitances and inductance of the pick ups would make the instrument sound like it was coming over a telephone Impedance matching is EXTREMELY IMPORTANT There are two main ways to create this impedance matching stage One can do it passively with a transformer or actively Each approach has their advantages and disadvantages We chose to go the active route beca
19. safe operation of the device follow these guidelines 1 10 11 Read the instruction manual in its entirety before operating the equipment Retain the manual for future reference Observe all safety precautions warnings and instructions noted in this manual Always unplug this device from the wall socket before cleaning Use only dry cloth Do not use aerosols or solvents Keep this device away from sources of water such as pools bathtubs and sinks and do not expose it to rain or splashes of water Do not place objects filled with fluid on the device Vents are provided for heat dissipation on the sides and the rear of the device Maintain at least 2 bcm space around these vents to provide sufficient ventilation Keep the device away from sources of heat and open flame such as heaters radiators stoves lit candles etc Make sure the power cord is intact before plugging it into the device Do not use cords with visible damage to the insulation or connectors This device is equipped with a safety feature that requires the use of a three pin grounding power plug Do not defeat the safety purpose of the grounding plug If the provided plug does not fit your outlet consult an electrician to replace your obsolete power outlet Use only accessories listed in this manual or otherwise specified by the manufacturer Do not install this product on carts or other moving objects When the device is in use route the power cord in such a
20. ssible combination of components and features The goal was to have something that could give the vintage musicality one would be accustomed to with a Neve or EMI pre but still retain the option of running the mic pre cleaner when needed We came up with a design wherein the user has extraordinary control over the sonic character of the mic preamp by making it possible to bypass either or both of the transformers change the overall headroom of the output stage and alter the THD total harmonic distortion signature of the circuit This flexibility now makes the UTA pre the first pick for almost every recording situa tion There is also a user switchable low impedance mode that changes the strapping of the input transformer This mode performs extraordinarily well with passive ribbon mics We now use the UTA mic pre exclusively with all of our ribbon mics The DI input was optimized for passive guitars and basses Its exceptionally high input im pedance and Class A circuitry make it the perfect choice when capturing passive instruments either for the purpose of re amping or if you want to use the DI signal itself in the mix 2 SAFETY POWERING UP SAFETY INSTRUCTIONS WARNING To reduce the risk of fire or electric shock do not expose this product to rain or moisture CAUTION RISK OF ELECTRIC SHOCK DO NOT OPEN There are no user serviceable parts inside the product Refer servicing to qualified service personnel In order to ensure
21. use it offers the most sonic flexibility It can be extraordinarily transparent or more colored depending on the various settings of the mic preamp The trade off is that we give up the option of being able to lift the ground of the signal plugged into the DI This can become an issue when using the DI for synths and drum machines It is possible to experience a ground loop that causes hum under these circumstances The best solution is to lift the ground XLR Pin 1 on any all outputs of the MPDI 4 being used This can easily be done with XLR ground lift adapters ex Hosa GLT 255 When you plug into the 1 4 jack of the front panel combo input an active Class A JFET stage is automatically added before the mic preamp This stage creates the exceptionally high input impedance of 4 7 MO for the 1 4 input and sub sequently a lower output impedance that is fed directly to the input of the mic preamp stage The high input impedance reduces any interactions with the passive circuitry of your guitar or bass that can cause undesirable tonal changes The Class A circuitry maintains sonic transparency Tonal coloration can then be added in the mic preamp stage if desired EXAMPLE SETTINGS There are two basic ways we like to use the DI One capturing the DI signal for the purpose of re amping a guitar or bass The other is when the DI signal is intended to be used as the final sound RE AMPING 7 OUTPUT When re amping it is best to use the setting that
22. way that will prevent it from being stepped on tripped on pinched or damaged 12 Do not use this device with wall or ceiling mounts not specified by the manufacturer 13 To completely disconnect the device from the AC Mains disconnect the power cord from the AC receptacle For additional protection unplug the device during electrical storms or when not used for long periods of time 14 No user serviceable parts inside Refer servicing to qualified personnel If the unit was exposed to liquid excessive heat or fire or sustained mechanical damage of any kind do not attempt to operate it Disconnect the unit from the wall outlet and consult qualified service personnel INSTRUCTIONS FOR 220 240VAC OPERATION Before proceeding disconnect the power cord from the AC inlet This device is provided with a power cord for North American 110 120VAC operation For operation in other locations and or from other voltage sources use the correct type of power cord for your area and voltage source 3 This device is provided with T 0 4A AC Mains fuses installed for 110 120VAC operation and includes T 0 2A accessory fuses for 220 240VAC operation packed separately Open the fuse drawer on the AC receptacle on the rear of the device and replace the T 0 4 fuse with the T 0 2A accessory fuse 4 In the fuse drawer change the AC Mains switch from the 110V position to the 240V position 5 Assure that the fuse drawer is secured closed before attaching
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