Building the MXR Phase 45 Clone Kit

We added the MXR Phase 45 clone kit today, but before we did, I built one to test it.  I was concerned with making sure the phase shifts as it is designed to do and we didn’t want to start selling them until we were sure it worked.  What I discovered was one of my favorite kits so far.  This kit sounds AMAZING!  I went ahead and tested all of the 2N5952 pairs for the kits to make sure the phasing works correctly with them and they all passed.


I highly recommend getting the Female Header Pin Strip with this kit.  Socketing the JFETs is needed because of how rare the 2N5952 JFETs are and because we don’t stock any extras due to the expense of purchasing them.  It will also allow you to try other JFETs if you want to experiment with it.  Other JFETs will yield a different tone and one of the main reasons for building your own IS because you can tinker with it and make it a unique pedal just to your liking.  You might also consider the Trimpot Adjustment Tool for the 250K Bias Trimmer.

First, there’s a few things you’ll need and a few optional parts I chose to use.

Getting Started

First, cut your board to size.  Double/Triple check your count before cutting because if you cut it too small, there’s no undoing it.  Use a Sharpie/permanent marker to mark where you’re going to cut it.   There’s a number of ways to cut your veroboard, here’s a few:

  • Miter/Chop Saw (My favorite)
  • Bandsaw
  • Dremel with Cutoff Wheel

Next, map out where to make your strip cuts.  Be sure to mark them on the back side of the board and not on the copper/strip side since this will give you a backwards layout.  Once again, use a permanent marker to mark them and double-check them.  For cutting the tracks, I prefer to use the tip of my Unibit and drill just enough to cut the strip, but not any further.  I used a toothpick or a piece of small wire to poke through the holes so I could easily identify which one to drill on the strip side since the board was marked on the top side.  Here’s what that looks like, although this is NOT the actual board for this kit:


drilling the veroboard tracks

NOT MXR Phaser 45 board, shown for reference only.

Next, solder your jumper wires onto the board.  I like using CAT5 Ethernet Cable for jumper wires since it’s inexpensive, it has thin insulation that cuts down on bulkiness, and it goes a long ways.  Some people use 0 ohm wire, either will do.  I followed this step with soldering the resistors and diode onto the board.

Your board should look something like this at this point.

MXR Phase 45 clone kit build

Next I continue by adding the polybox capacitors, ceramic disc and the polyester film capacitors.

WIMA 10nF Polybox 2.5mm and 5mm Capacitors

This kit includes two different size 10nF and it’s important to place them in the correct place.  The 2.5mm capacitor is skinny and there’s only one in the kit.  If you look at the photo below, you will see where it goes.  The 10uF simply go in the remaining locations for the 10nF capacitors.

I then added the sockets and saved the electrolytic capacitors for last.  The order is more of a matter of preference, I usually do it based on clearance space to add the components and the rigidness of the parts.

Sockets For Your IC and Transistors

As I mentioned earlier, these are optional, but highly recommended.  Not only do they prevent accidental overheating of your parts, but they make changing out these parts very simple.  But why would you change them out?  Well, if they ever are faulty or if you decide to experiment with other parts, you’ll appreciate this.  But it also makes tinkering easier if you might want to change out components to tweak the tone of the kit.

MXR Phase 45 kit buildMXR Phase 45 kit build

Finishing Up The Board

The last steps I take are to solder the wires for the off-board wiring and then install the IC chips and JFETs.  This one is a simple kit for this step since it has only 1 potentiometer.

Tuning the bias trimmer

It is highly unlikely the phaser will be tuned correctly to start phasing out of the box.  You’ll need to connect it to your amp and guitar and make sure you’re getting tone through the pedal.  Then, using a Trimpot Adjustment Tool, slowly turn the trimpot while strumming and listening for the phasing.  If everything was built correctly, you will hear it start shifting.  If not, try adjusting the speed potentiometer (5ooK) all the way in one direction and adjust/test it, then in the other direction and adjust/test again.  You’ll definitely notice the rapid phasing when you get it right.  There’s a slight adjustment range for the phasing.  I recommend carefully adjusting it and checking it to find the best sound setting for it.

MXR Phase 45 kit build

2 thoughts on “Building the MXR Phase 45 Clone Kit

  • August 30, 2014 at 12:44 AM

    Got my kit today!! David always surprises me with little extras! I cant wait to use the MKLEC vero – While my supply of veros is still rather large, I really disliked the fact that there is wasted real estate with the boards I have. Plus I am looking forward to using the transistor sockets! This kit will be built this weekend!

  • March 16, 2015 at 8:12 AM

    I just finished building one of this. It is a sweet kit. Thanks for putting great kits together.


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