DOD FX55b modification
The DODFX55b is like the Boss DS1. Almost everyone has bought one when starting up guitar, and almost everyone despises its tone shortly after for pretty good reasons.
Not all DOD FX series pedals are bad but they all suffer from a pretty poor switching design. On top of this, the FX55b packs as much punch as a wet blanket, has a useless tone control and has less tone than a Dyson hoover. Piece of crap? Yes.
The one I was given was in a pretty poor state and wasn't worse reselling, so I modified it into a usable overdrive. It surely doesn't beat my standard tubescreamers but it comes a lot closer to their tone than it did in its original form.
The aim of the mod is simple: by changing the voicing of the first driving stage, the tone control is now more effective and we get a bit more output level.
The tone is now beefier with more lows and mids, and less piercing highs. It is now possible to go from a mild TS-style overdrive, up to a heavy saturation.
The only remaining problem is that the more you increase the gain, the more the bass end is attenuated. I personally prefer the opposite. To counteract this, you can remove the 3.9M resistor, replace the gain pot with a 1M potentiometer, and reconnect it just like on an Ibanez Tube Screamer. The PCB allows this simple modification. Also, by playing with the values of C11 and C12, it is possible to change the range of the tone control. Have fun!
Boss OD1 modification
The Boss OD1 is the firts compact overdrive produced by Roland. It comes with only two controls: Over Drive and Level. The circuit is quite simply that of an Ibanez Tube Screamer with a removed tone control. This is a good starting point and it even features the fabled JRC4558. The sound goes further into the distortion realms than the TS, and the circuit also offers assymetrical clipping. The only downfalls of this pedal are that the output is below unity gain at low Over Drive settings, and the overall sound is quite trebly in general, rendering it unusable on a clean amp despite a good dynamic range and a natural saturation. Improved top end and increased output
The following mod is extremely simple and has the advantage of curing both problems with only one component.
All there is to do is find the R8 resistor (1), unsolder it gently to avoid damage to the board (use unsoldering braid or a cheap solder pump), and replace it with a 22kOhm resistor (red-red-orange). That's it!
The sound is now a lot thicker with more low mids and bass (but not too much). The output of the pedal is also a lot greater: even with Over Drive on 0, the volume gain is above unity. The pedal is now ideal for slamming the input of a crunching amplifier, or for adding just a bit of dirt to clean parts. It is possible to get more bass out of the OD1 by upping the value of that resistor. However, too much bass is couterproductive for an overdrive pedal as the tone can quickly become mushy: therefore, try staying below 33kOhm (orange-orange-orange).
Change the saturation tone
The JRC4558 is now world-reknown for good and bad reasons. In this circuit, it does sound good but other models sound just as fine. Try replacing it: mark its orientation (the little dent) and unsolder it gently (2). My preferred replacement is the TL072 JFet op-amp with its smooth, very tube-like overdrive. Ask Tech21 what they think about it! You can also play with the following models: LF353, TL062, NE5532, TL082, etc...
For a grittier overdrive, try replacing the D5 and D6 diodes (3) with red LEDs. You'll also get more output that way. Again, respect the diodes polarity when swapping them.
Boss TR2 modification
The Boss TR2 was fast becoming a well-respected standard before the boutique pedal makers flooded the market. It is still present on many pros pedlaboards.
It's most famous problem is the slight volume drop when engaging the effect. It isn't so much a problem if you are playing with a clean amp that compresses a lot, but in most application it is an annoyance. There are many mods on the web to remedy this, but I fell my mod is not only simple, but very effective, while totally preserving the modulation wave shape.
By changing the R12 resistor from 22kOhm (rouge-rouge-orange) to 33kOhm (orange-orange-orange), the level of the tremolo is upped, thereby avoiding the guitar to be lost in the mix when switching the effect on. You can even give it a slight boost by using larger values for R12, but it will be at the expense of the background noise levels and headroom.
Boss DF2 modification
The Boss "Super Distortion & Feedbacker" or"Super Feedbacker & Distortion " (it has been called both) is one of the strangest Boss pedals. The manufacturer generally puts out conservative designs but it has gone wild with this one. When you keep the pedal depress, a mono synth creates a note corresponding to the one your playing, wih a bit of vibrato, thereby creating a fake feedback which in certain occasions can fool the listeners.
The pedal creates some run-of-the-mill distortion sounds that are just usable. That part of the circuit is actually very similar to the ubiquitus DS1. furthermore, even with minimum gain, the drive level is quite high, and it is difficult to use the fake feedback while preserving the tone of the amp.
A more tube-like tone
To make the pedal give a cleanish tone, and a more natural overdrive, we will first replace D3 with a red LED: careful with the polarity! We will then unsolder one end of D2 and connect a germanium diode (a 1N34 fro exemple) to it. Follow the illustration below. Again respect the polarity or it won't work properly. Solder the remaining free end of the germanium diode on the board, where D2 was unsoldered from.
The tone is now more natural, less compressed and with more clarity when playing complex chords. It is now also possible to get cleaner sounds. As a result, the pedal can be used in front of a distorted amp to get a great sounding "feedback" note at any time.
Tonality circuit mods
Just like the DS1, the tone of the DF2 has a dip in the mids: great for bedroom use but not ideal in a hard rocking band context.To avoid being lost in the mix when engaging the pedal, we can sub C12 (100nF, circled in red) with a 47nF capacitor. This has two effects. Firstly, the low mids are now more present, giving a fuller, warmer tone. Secondly, the dip in the mids is lessened allowing the guitar to be more present in a band context, without the need to turn up. At low volume, the tone stays very good, so bedroom players don't sweat!To completely remove the notch in the mids C13 (22nF circled in red) can be replaced by a 47nF cap. All the mids are restored and the tone control is still perfectly usable. All these mods can of course be performed on the Boss DS1.
New possibilities for the DF2
By putting the gain control on zero, it is possible thanks to these mods to obtain quite a transparent sound form the pedal. The drive tones from you amp(s) can be used instead of the pedals more synthetic tones and the fake feedback effect will also blend better into your sound.For more unconventional sounds, unsolder D2 and D3: you can get feedback on a clean tone!