Boss TR-2 Tremolo Pedal Mod from Monte Allums

| November 23, 2010 | 0 Comments

The musical instrument term “tremolo” means to rapidly vary the volume of the instrument up and down. On a guitar amplifier you can get this effect simply by rapidly turning the volume control up and down. Tremolo is sometimes confused with the term “vibrato” which means to rapidly vary the frequency up and down. For guitar players this confusion is sometimes enhanced by the common usage of referring to the vibrato-bar or “whammy-bar” on an electric guitar as the tremolo or tremolo-arm. By bending the strings the whammy bar changes the pitch of a note, producing vibrato, not tremolo.

Tremolo was invented in the 16th century, but in contemporary music became a popular effect of early rock bands. Here’s one example from Tommy James & The Shondells, “Crimson & Clover,” where tremolo can be heard throughout, including on vocals at the end of the track.


The BOSS TR-2 Tremolo pedal is designed to provide guitarists with classic tremolo effects in an easy-to-use compact pedal. It reproduces the classic tremolo effects of vintage ’60s amps using a low frequency oscillator (LFO) with variable waveforms from triangle to square for producing a variety of classic tones. Dedicated controls for wave-type, rate and depth provide a wide range of tremolo effect possibilities, from the vintage tremolo of classic rock-surf, to a rotary speaker sound, or a stuttered, staccato tremolo sound.

  • “Rate” control allows for speed adjustment
  • “Wave” control alters LFO waveform from triangle to square
  • “Depth” control determines the strength of the effect

Give a listen to this pedal by clicking on the Boss TR-2 Stock Pedal Demo and by checking out this demo video from Boss.


While the TR-2 is a very popular pedal there have been a number of persistent complaints about its performance. The first is a slight but audible volume drop when the pedal is engaged. Since there is no volume control to compensate this means either leaving it on or off for the full duration of a song.

The second complaint from many guitarists is that it is noisy. This has generally been attributed to the quality of the operational amplifier (op-amp) chips used.


Enter Monte Allums (, a maker of modification kits for pedals and guitars. The Monte Allums TR-2 Modification Kit (parts shown at right) accomplishes the following:

  • Incorporates a potentiometer that not only solves the volume loss issue but also now allows the pedal to be used as a clean boost with the depth knob all the way down.
  • Replaces the stock LED indicator lamp with a super bright white LED.
  • Replaces two stock op-amp chips with higher-quality op-amps. For example the Burr Brown OPA2134 replacement chip is an ultra-low distortion, low-noise operational amplifier designed with a field effect transistor (FET) input stage and increased headroom for high-quality audio applications.

Replacing the op-amps is a modification in itself since the stock chips use a single inline pins (SIP) type of chip, shown at right. The higher quality chips are not available in this format,
so the TR2 modification includes an Op-Amp Adapter Modification kit that replaces the SIP chip with a socket extender, and a small circuit board with two dual-inline pins (DIP) sockets that can hold the higher quality chips. You’ll use the socket extender to raise the adapter and chip so the legs of the adapter may be bent over (see illustration at left). This allows the adapter legs to be bent to fit in pedals that have limited room.

To order this modification you’ll need to know whether your TR2 uses the older or newer printed circuit board, both shown here. You’ll specify which one is needed at time of order.

OK so how does the mod sound? Well first we have a clip from Sean Borton playing a Gretsch Tennessean through a Vox AC30 set to a clean setting. The clip is from Sean’s latest album “What a Party” and the track is titled “This Little Thing They Call Love”. Click to Listen.

Next here’s a video of a kit builder demonstrating the kit.

By the way, here’s the circuit for the stock TR-2 pedal.

We think this kit sounds great. What do you think? Let us know by commenting.

You can order this kit for $28.99 at time of writing.

Category: Pedal & Effects

Leave a Reply

1 + = five