Here’s our starting point. Velcro already on the board so I made a few cuts where the mounting screws will go.

We’ll be using a piece of aluminum flat bar as a mounting bracket, so holes on the pedalboard are spaced to fit the flat bar. Here I used four #6 countersunk screws, 3/4″ in length because I had them around but any small screw will work here.

Mounting bracket was purchased from eBay- it’s a 1/2″ thick piece of aluminum flat bar that’s 3″ wide and 6″ long. Aluminum flat bar comes unfinished so plan on time to paint after drilling if you care about that. I needed about 3/8″ of clearance so the power cables will have clearance over the support bars so I went with a 1/2″ to be safe. I’d recommend getting a 0.125″ or .250″ plate and using spacers to get the correct clearance since this bracket is unnecessarily heavy. It’s attached using locking nuts.

Here’s a test fit of the ISO-Brick.

And here is a picture showing the cable clearance when using a 1/2″ thick mounting bracket.

The ISO-Brick has two screws keeping the enclosure together. What’s really nice is these screws go straight through the chassis and if I replace them with longer screws I can use them as a mounting point for the power supply to the bracket. The stock screws are hex (allen) socket M4-0.7 x 40mm. I replaced them with stainless M4-0.7 x 60mm which gives the result above.

View from above of where it’s at so far. Bracket is attached, holes are drilled for the power supply mounting screws, and it’s ready to finish this up.

The power supply fits, there’s enough clearance for the cables, the power supply isn’t so tall that it touches the ground when the pedal is flipped over.

Two M4 nuts to hold the power supply to the bracket.

And a view from the back of the pedalboard showing that there’s enough clearance to allow the power cable to be unplugged if needed.

So this is everything- 6 screws and a lot of measuring to make sure the clearances all would work. The big takeaway would be to get a 0.125″ or 0.250″ at the most for the aluminum plate thickness and use washers or spacers to give the clearance needed to reach about 1/2″. Without that clearance you won’t be able to plug power cables into the power outlets of the ISO-Brick. If using a thinner plate you’ll also want to get shorter M4-0.7 x 60mm screws for the power supply itself, likely 55mm depending on the thickness of your plate.

Most wahs on the market rely on a rack and pinion to turn the potentiometer which creates the wah-wah effect. This system is used by the big players like Dunlop and Vox as well as most of the other clones on the market. It’s a great, reliable setup and I have no complaints with it.

Colorsound decided to go a different route and used a lever that attaches to the pot which allows for a much wider sweep. If you look at the photos above you can see how much wider the Colorsound wah (blue) rocks back compared to a stock Dunlop Crybaby (black). This gives the pedal a bit more sweep and changes the feel of the pedal because of the longer distance traveled.  Although a wider sweep may be better there are still people that prefer the shorter travel yet sturdier casing found in the Dunlop/Vox style wah casing.

Customers often ask why there is a $25 additional fee for the Chinese made Pro Co Rat 2 (technically Rat 3) and how to identify if their model will be subject to this fee. This is an issue that has been come up a few times over the years so I’ll show why the build quality of the new Rat pedals causes us to charge more.

Let’s start with the basics: To remove the knobs on most pedals you simply pull the knobs off. When doing this on the newest Rat pedals the entire shaft rips out and the potentiometer then needs to be replaced. If you look above you can see the knob with the shaft stuck in it on the right. The brass-threaded potentiometer on the left is a high quality replacement that we use if the pots are in fact broken in the process.

While I’m not familiar with Pro Co’s pedal production timeline it appears that the consensus is that the problem pedals are:

• Likely made after 2009
• Made in China
• Have smaller, 16mm potentiometers instead of the traditional 24mm.
• Serial number above 300,000
• Knobs look different than the classic rat knobs with the knurled edges

If you aren’t sure please remove the back of your pedal and take a photo of the circuit board before mailing the pedal in.

First up is the Script Logo Phase 90 which gets its name from the elaborate script font used on the casing. This is the holy grail of Phase 90s and has been in such high demand that MXR reissued the pedal made using the same circuit board as the original one seen below:

The most noticeable difference between this model and the future iterations is this one has six ICs all of which are single op-amps. This likely has little to do with tone and more to do with the availability and cost of ICs at the time. This model was released in 1974 and lasted until 1977.

In 1977 the Phase 90 transition into its Block Logo form which more or less was the same exact pedal except for one resistor. This resistor– which later became known as “R28″– gives a bit of a midrange boost and adds more resonance in the circuit. Below is a circuit board from 1979/1980 with an arrow highlighting the added feedback resistor.

A short time later MXR introduced an updated version of the Phase 90. This version has R28 mounted on the circuit board and also switch from six op-amps to three TL062 dual op-amps. Some other changes include minor value changes throughout the circuit, modified bias circuit for easier calibration, and pre-emphasis and de-emphasis capacitors. Below is a circuit board from the early 1980’s.

MXR went bankrupt in 1984 and was later purchased by Jim Dunlop. The Phase 90 reissue (M-101) was a modern adaptation of the late block logo circuit with only minor changes to the circuit including better power filtering and using a single TL064 quad op-amp in place of two TL062 ICs. The reissues also have all board mounted components including the potentiometer, jacks, and switch. This makes for easy assembly by the factory but is more expensive to repair and not very good for reliability.

Currently Dunlop has more variations and signature models of the Phase 90 than I could keep track of but they all stem from these original designs (and can all be modified!).

So with that out of the way… on to the video to hear a difference:

The video was recorded using a Fender ’69 Reissue Thinline Telecaster and a vintage Fender Super Reverb. The first video clip is simply the guitar into an unmodified Electro Harmonix Russian Big Muff then into the amp. The second half of the clip is guitar straight into the amp. If the pedal was modified for true bypass it would sound like the second clip. You can hear a massive increase in volume and see the peak around 2-4kHz when the pedal is removed from the signal chain. Click between 0:25 and 0:58 if you’re impatient. I should note that there was absolutely no post editing to the audio and everything was shot in a single take. The yellow lines show the peaks for each frequency and you’ll notice the overall output is a few dB higher.

For more reading on true bypass with basic diagrams.

For information on having your pedals converted.

This is the final layout although I plan on changing a few things. The plan is:
Modded Vox wah (standard overhaul/ true bypass)
Dual Scalpel & Temporary Mute for TU-12 tuner
    (Artwork borrowed from the incredible Daniel Danger)
FXdoctor Overdrive
Big Muff styled Heart Fuzz
Bass Bit Fuzz (added gain control)
8-Bit Fuzz
DM-2 based analog delay (casing used as a place holder)
DD-5 (with high cut and reverse kill)
Ernie Ball Volume pedal
Boss RC-20XL

I’ll substitute in a Metatron for the Heart Fuzz or RC-20XL depending on what band I’m playing with. I’ll build a mini patchbay and use it as a riser for the TU-12 at some point. All powered using a daisy chain and a Visual Sounds power adapter. I’ve used a Dunlop DC Brick in the past but wasn’t impressed so switched back to a daisy chain.

True bypass switches both the input and output of the effect’s circuitry. The signal should go from the input jack, to the switch, to the output jack without any other components in the signal path. This is the purest form of bypass and is essentially has the same impact on your tone as running a small patch cable. The effect’s circuitry is completely isolated from your signal path when bypassed.

Electronic bypass comes in a few forms but using transistors such as FETs is the most commonly used method. This is popular with Boss, DOD, Ibanez, Danelectro, Digitech, and many other manufacturers. The signal is always flowing through some form of active circuitry (referred to as a buffer) and uses transistors to switch the effect in and out of the signal path. If you remove the battery power the signal will not pass through the pedal.

Check out the True Bypass link on FXdoctor Website if interested in having this work performed on your pedals.

1. Vox wah – vocal mod, midrange, California mod, Fasel inductor, true bypass
2. MXR dyna comp- dying battery mod, hi-fi mod
3. EHX Big Muff based fuzz- Body knob, clarity mod, fat switch
4. Boss RC-20XL looper with 2 button phrase select switch
5. Fender PT-100 pedal tuner with true bypass (I prefer it over the Boss TU-2)
6. Right switch = momentary mute / tap tempo for DD-5;
Left switch = volume cut circuit (The Scalpel)
7. Ibanez Tubescreamer based overdrive
8. 8-bit Fuzz
9. Ibanez AD-9 analog delay
10. Boss DD-5 with high cut and reverse kill mods
11. Channel switcher for reverb / tremolo on my amp