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©2020 StewMac   •   All rights reserved   •   i-2352 Updated September 2020 

stewmac.com

BASED ON THE MDX 

TONE CONTROL THAT 

FENDER DEVELOPED 

FOR CLAPTON’S STRAT. 

This Hi-Fi pedal soups up the sound of any guitar and amp 
combination. With just a boost and volume knob, stomping 
the footswitch will boost your mids and push you right out 
to the front of the mix. Take your lead tone to the next level 
with this almost forgotten circuit of guitar history.

POWER 

This pedal requires a standard 9V DC center-negative 
power supply (not included) and consumes only 
25mA. There’s no battery option.

EC EXPANDER

PEDAL KIT 

INSTRUCTION GUIDE

22nJ

.1J63

47nJ

22nJ

3n3K

.1J63

47nJ

IN    GND    SW    OUT

TECHNICAL SUPPORT

If you have any questions at all, our Tech Support Team 
is here to help. Email us at [email protected], and 
we’ll respond quickly!

Summary of Contents for EC EXPANDER PEDAL KIT

Page 1: ... you right out to the front of the mix Take your lead tone to the next level with this almost forgotten circuit of guitar history POWER This pedal requires a standard 9V DC center negative power supply not included and consumes only 25mA There s no battery option EC EXPANDER PEDAL KIT INSTRUCTION GUIDE 22nJ 1J63 47nJ 22nJ 3n3K 1J63 47nJ IN GND SW OUT TECHNICAL SUPPORT If you have any questions at ...

Page 2: ...lder 0505 Wire Cutter 1607 Long nose pliers 1610 Fine gauge Wire Stripper 1606 Guitar Tech Screwdriver and Wrench Set 3693 Not pictured Clear silicone adhesive and spray finish PC Board Holder 0500 Magnifying glass or OptiVISOR 1685 Soldering Aids 0521 Multimeter 3607 3M Gold Fre Cut Sandpaper 220 grit 5097 ...

Page 3: ...pacitor 1 7526 6 8nF capacitor 1 7474 120pF capacitor 1 7472 100 IIC 121 1nF capacitor 1 7302 102J 1N5817 rectifier diode 1 7522 2N5088 transistor 3 7513 2N5 088 2N5087 transistor 1 7512 2N5 087 82nF capacitor 1 7525 823 47Ω resistor 1 7351 Yellow Violet Black Gold Brown Yellow Violet Black Black Brown Brown Gray Black Brown Brown Red Red Black Brown Brown Red Red Black Red Brown Orange Orange Bla...

Page 4: ...1611 A250K audio taper boost pot 1 7531 A50K audio taper volume pot 1 7530 24 of lead wire 1 5960 Adhesive foam tape square 4 7560 5mm LED mounting bezel 1 7432 2 1mm DC power jack 1 7468 PARTS LIST CONT Printed circuit board 1 Breakout board 1 BOOST VOLUME 1 4 mono jack 2 4652 Sticker sheet 1 IN GND SW OUT Control knob 2 7501 Pre drilled enclosure top 1 Pre drilled enclosure bottom not pictured 1...

Page 5: ...5 100 000 5 BLUE 6 6 6 1 000 000 25 VIOLET 7 7 7 10M 1 GRAY 8 8 8 01 SILVER WHITE 9 9 9 1 GOLD 0 SOLDERING MORE HELPFUL SOLDERING TIPS AND TRICKS Keep your soldering tip clean by wiping it often on a damp sponge Also keep it tinned by occasionally melting a little solder onto it Don t blow on the hot solder or touch anything until the joint has cooled completely A good solder joint is shiny a sign...

Page 6: ... printed on the component The key values with caps are their voltage and capacitance The voltage spec for a cap refers to how much DC voltage it can handle at any given time If this rating is exceeded the capacitor will fail Capacitance measured in farads refers to how much electricity a capacitor can hold One farad 1F would be much too large for use in a pedal Caps for pedals are rated between mi...

Page 7: ...f the LED will be shorter and the cathode side of the LED housing will be flat LEDs are mounted inside of a bezel which protects the LED and insulates the leads from shorting against the enclosure or any internal components UNDERSTANDING ELECTRONIC COMPONENTS PAINTING YOUR PEDAL ENCLOSURE 1 1 To minimize redoing steps make sure you have a solid idea of the look and feel you re going for 2 Lightly ...

Page 8: ...t board that has white values and outlines of the components is the correct side In some cases components must be inserted into the printed circuit board in a specific direction due to their polarity so follow the graphics carefully Note the stripe around one end of the diode This marks the negative lead On the printed circuit board the printed outline of the diode also shows this stripe Install t...

Page 9: ...ange Black Red Brown 100K resistor 1 7365 Brown Black Black Orange Brown 232K resistor 1 7417 Red Orange Red Orange Brown 133K resistor 1 7414 Brown Orange Orange Orange Brown 215K resistor 1 7416 Red Brown Green Orange Brown 1 5M resistor 1 7425 Brown Green Black Yellow Brown INSTALL 3 CAPACITORS 4 10µF capacitor 2 7338 100µF capacitor 1 7339 10 uF 10 0 uF Resistors have a low profile sitting clo...

Page 10: ... 1J63 1J63 1J63 1J63 2n2J630 1J63 1J63 22nJ 22nJ 22nJ 22nJ 1 1 10 1 1 1 1 22nJ 1J63 47nJ 330pJ 10pF capacitor 1 7526 120pF capacitor 1 7472 IIC 121 82nF capacitor 1 7525 100 823 47nF capacitor 1 7307 22nF capacitor 1 7317 1J63 22nJ MMK BH8 50 100nF capacitor 1 7304 47nJ MMK BHN 50 6 8nF capacitor 1 7474 1nF capacitor 1 7302 102J 330pJ 330pF capacitor 1 7473 22nJ 1J63 47nJ 22nJ 330pJ 1J63 47nJ The ...

Page 11: ...e lugs of the footswitch until the breakout board slides over the lugs Solder each lug to the corresponding breakout board eyelet IN GND SW OUT IN G ND SW OUT You can use the pedal enclosure as a mount for the footswitch while you solder the breakout board to it Just lay the enclosure face up and drop the switch in its hole No need to fasten it with a nut from the back if you don t want to Solder ...

Page 12: ...omponents to go onto the printed circuit board are the volume and boost pots They install on the back of the board Each pot has three connecting lugs Note the orientation of each pot INSTALL 2 POTS AND ATTACH FOAM TAPE Use a piece of the adhesive foam tape to insulate the back of the pots from the soldered leads of the other parts on the printed circuit board Once you ve removed any index pins and...

Page 13: ...e The printed circuit board is held in place by the control pots but the LED leads need to pass through their eyelets in the printed circuit board before the pots will pass through the enclosure Pass the longer positive lead of the LED through the eyelet marked A and the shorter negative lead through the eyelet marked K Next secure the pots by installing their shafts through the enclosure and slid...

Page 14: ...the washer and thread the nut onto the shaft enough so that the pot can rotate freely You may need to rotate the jack to provide easier access to setting the solder joints Solder the left most wire at the top of the printed circuit board to the input jack lug that corresponds with the sleeve connection The sleeve lug should be the one closer to the DC jack Solder the 4 wire on the left side of the...

Page 15: ...You may need to rotate the jack to provide easier access to setting the solder joints Solder the right most wire at the top of the printed circuit board to the output jack lug that corresponds with the sleeve connection The sleeve lug should be the one closer to the DC jack Solder the 4 wire on the right side of the breakout board to the lug of the output jack that corresponds with the tip connect...

Page 16: ...e isolated outputs Pedals will make extra noise if there is ripple or unclean power Switching type power supplies daisy chains and non pedal specific power supplies do not filter dirty power as well and let through unwanted noise Do not run at higher voltages Current draw is 25mA VOLUME Controls the overall output volume of the effect BOOST Controls the amount of midrange boost added to the signal...

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