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FOUR CHANNELS MIC PREAMP MP312-4 

 

                                                                     ©2019                                  WWW.AVDAUDIO.COM 

Install input transformer.  

Be sure!  

The black dot on the transformer coincides the dot on the PCB! It is the first pin of 
transformer! 

 

Flip the board and solder the input transformer as shows below: 

 

 

Summary of Contents for MP312-4

Page 1: ...four independent channels Each channel has input gain and output attenuator phantom power supply bottom 48v 20Db pad input gain bottom phase reverse bottom mute bottom The box is with external power s...

Page 2: ...VALUE These parts can be found in the BOM here download MP312 4 BOM Or follow this link http www avdaudio com files boms BOM3124 pdf What you will need for build soldering station basic understanding...

Page 3: ...are not polarized elements All diodes are directional Make sure you insert them in the correct direction Film capacitors are polarized elements But ceramic capacitors are not polarized Remember please...

Page 4: ...n PCB Solder all resistors and diodes Each channel has one diode 1N4004 and eleven resistors Next nominal of resistors you can use per channel 160R 200R 510R two of 750R 5K1 two of 6K98 10K 20K 150K D...

Page 5: ...UDIO COM Don t forget about one 10K resistor It is on the right side of board for power led diode Find three different ceramic capacitors on the each channel 120pf 220pf and two ps of 1000pf Each capa...

Page 6: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM 220pf capacitors are marked as 1000pf capacitors are marked as...

Page 7: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Placed each capacitor and solder these 1000pf capacitor is two ps...

Page 8: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM 220pf and 120pf capacitors are placed Place 4 pushbuttons per each channel on the board...

Page 9: ...Push button placed directly on the PCB Must not have any distance from PCB Turn up board and solder each push button You can solder at first only one leg of each pushbutton Try to press switch to pin...

Page 10: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Do not recommend cut push button s legs For DOA we use HARWIN sockets...

Page 11: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM You need one completed DOA Insert sockets to DOA as I show below To be sure all sockets are installed fully on DOA Install this to PCB...

Page 12: ...HANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Pull the sockets on 1mm from PCB Solder only one leg first Then solder on the other side Solder the three far legs Then solder the rest Or do as we do...

Page 13: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM...

Page 14: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Check our result from other side Ready to do to next step Find four T Pads and four Gain potentiometers...

Page 15: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Install each T Pad to T Pad s place on the board marked T Pad Place the potentiometer directly on the PCB...

Page 16: ...AVDAUDIO COM Check again the distance from PCB We must have not any distance Go to the down side and solder T Pads Solder first only one leg During soldering push T pad Then you solder other legs We...

Page 17: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Check you are done right And all T Pads are on the board Hope you have done this step good...

Page 18: ...the next step Take four Gain potentiometers This one must to be placed directly on PCB too Look to the next picture and start solder Gain potentiometers Install Gain potentiometer to their place mark...

Page 19: ...PREAMP MP312 4 2019 WWW AVDAUDIO COM Break off the locking pin on all potentiometers and T pads You need 9ps from 14 black screws This screws are in the ordered package Tighten all bolts on back wall...

Page 20: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM How to looks the case with installed bottom cover The bottom cover has 7 standoffs for PCB Near future will install PCB to these places...

Page 21: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Stick rubber feet in each corner on the bottom cover This will protect your cover from scratches...

Page 22: ...PREAMP MP312 4 2019 WWW AVDAUDIO COM But now you need XLR connectors Four are MALE and FEMALE See picture below Install each to their place on PCB Installation sites have a different mount and you wil...

Page 23: ...ANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM In the each input we use FEMALE XLR In output we use MALE XLR Install all directly on PCB all XLR Don t solder on this step We need to fix all before so...

Page 24: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Install the connector with board into the enclosure as shown And lower the board to the bottom cover...

Page 25: ...R CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Make sure the Board is on the bottom cover racks and all XLR connectors are in the holes And all the holes on the Board and the cover rack are the s...

Page 26: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Check each side of PCB...

Page 27: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Find the seven bolts in the order as shown And screw the Board to the bottom cover...

Page 28: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Tighten all bolts In the order there are also 16 screws for XLRs...

Page 29: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Tighten all screws too on the back side Solder one leg to the board on each XLR Solder more than one if you can...

Page 30: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM But one will be enough Solder any convenient leg We soldered each of the central leg...

Page 31: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Find it in the order the following bolts for mounting the front panel Take the front panel...

Page 32: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Tighten all bolts on the front panel and front panel Tighten the nut and washer a few can to all T Pads...

Page 33: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM We use this on three T Pads Now Remove all bolts from the PCB...

Page 34: ...xed the PCB using T pads and XLR connectors We soldered on each XLR one leg as you remember This step help us to fix the board into the case And now we can solder and not think that the board can move...

Page 35: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Find in order next positions in the picture You need for this step two of screws washers spring washers and nuts...

Page 36: ...using cut wires from output transformer I had these before And will not show how I do this If you want see next step about install output transformer And do this step after install output transformer...

Page 37: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM On the back side And on the front side...

Page 38: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM To be sure You use wires on the Power XLR And lengths of these wires be be enough to solder on PCB...

Page 39: ...wires correctly If you have other colors of wires or they are different on XLR power supply and preamp Make sure You solder them correctly to the right place And solder all wires Trim excess and long...

Page 40: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM For this step you need Four output transformers And you will need next 8 bolts 16 washers 8 spring washers and 8 nuts...

Page 41: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM One washer I use on the top side of transformer Same for two holes Same washer I use on the bottom side two ps between transformer and PCB...

Page 42: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM And in the end Use spring washer on the bottom side of PCB And lock them with nuts...

Page 43: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Cut each wires of transformer Be sure Length of each wire enough to solder to PCB Check length of each wire before cutting...

Page 44: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Trim excess and long legs Look how it looks like after soldering...

Page 45: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Be sure Each color has right place BROWN and RED wire are here...

Page 46: ...TR2622 input transformers But if you ordered other transformers Check you have correct schematic or you to change something on the PCB Sometimes it could be different Zobel or sometimes without Zobel...

Page 47: ...MP312 4 2019 WWW AVDAUDIO COM Install input transformer Be sure The black dot on the transformer coincides the dot on the PCB It is the first pin of transformer Flip the board and solder the input tr...

Page 48: ...How to looks our preamp after this step We need to solder some capacitors per channel It is 470uf 330uf and 10uf capacitor In the picture below you can see all these capacitors From left to right sid...

Page 49: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Before soldering Be sure You have right position of each capacitor 470uf is in the picture below 330uf capacitor is bellow...

Page 50: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM And 10uf capacitor Flip the board and solder each legs Trim excess and long legs...

Page 51: ...IO COM After soldering capacitors check you have everything done correct And we need to solder two 100uf power capacitors on the right side of PCB Near to Power XLR If you do it with completed case On...

Page 52: ...2 4 2019 WWW AVDAUDIO COM But second one must cut to install on the PCB Otherwise it will rest against by legs into the case PCB is 1 5mm thickness You must have 2 5mm length legs on capacitor Not les...

Page 53: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Then instal the second And soldering all these...

Page 54: ...312 4 2019 WWW AVDAUDIO COM Solder JUMPER to the jumper place You ordered LED diodes separately Find this in your order I will show you how to install this You need four of RED color 48V and one GREEN...

Page 55: ...s shown below The red arrow indicates longer leg must be on the left side Insert the diode into the hole on the PCB Then insert the diode head into the hole on the front panel The diode should fit ver...

Page 56: ...ANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM See picture below For best result you can press to one leg on the bottom side And solder other one It really can help you to install this diode good See...

Page 57: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Solder all legs Disassemble the right side of the preamp as shown in the figure below...

Page 58: ...CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Take Green Led Diode Bend and install in the same way as the red diode Solder this one from top side of PCB Assemble the right side of the preamp agai...

Page 59: ...boards We recommend that you completely disassemble the case and remove the Board Although it is possible to wash and not remove the PCB If you have such experience Be careful the board contains comp...

Page 60: ...FOUR CHANNELS MIC PREAMP MP312 4 2019 WWW AVDAUDIO COM Install the top cover and tighten all bolts Install the caps on the push buttons...

Page 61: ...After the last step Take the knobs you ordered Set all control knobs to GAIN and OUTPUT The MP312 4 Preamp is now complete Congratulations Wish you the best recordings with our staff For comments or...

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