Looking for more classic growl in a simple, contemporary overdrive? CopperSound’s Alex Guaraldi explains how to swap the clipping LEDS in an ultra-affordable EarthQuaker Devices Plumes for germanium diodes, in nine easy steps.
Pedals offer a lot of opportunities for DIY projects. One of the coolest and easiest is removing the LED clipping diodes in a modern overdrive pedal and replacing them with old-school-sounding germanium ones. The result will be a more raw, aggressive tone. For this project, I used the popular and affordable EarthQuaker Devices Plumes ($99 street). Whether your version is the original with through-hole-type components or the current model with surface-mount components, you’ll easily be able to perform this mod because both versions contain through-hole-type LEDs.
Tools Required
These tools and supplies are available online. StewMac, for example, sells soldering irons, a desoldering pump, and other tools for instrument work, while nut drivers and germanium diodes can be acquired via a number of sources, including Amazon.
• Soldering iron
• Solder
• Desoldering pump
• No. 2 Phillips-head screwdriver
• Small flathead screwdriver
• 8 mm (5/16") nut driver/wrench
• 10 mm (25/64") nut driver/wrench
• 11 mm (7/16") nut driver/wrench
• 14 mm(9/16") wrench
• Flush cutters
• Small needle-nose pliers
• Germanium diodes
Step 1: Remove back cover.
Using a No. 2 Phillips-head screwdriver, remove the four screws holding the back cover on.
Step 2: Remove external hardware.
The fastest way to swap diodes may be to do it from the component side, without even removing the circuit board from the enclosure. But for easier access and less difficulty, I’m going to remove the entire printed circuit board (PCB) from the enclosure. Since almost everything is mounted directly to the PCB, this should be easy.
Using a small flathead screwdriver, remove the knobs from the potentiometer shafts. Only loosen the knob set screws enough to slide the knobs off. No need to be searching the floor for tiny screws.
Next, using an 8 mm (5/16") nut driver or wrench, remove the nut from the toggle switch. Then, using a 10 mm (25/64”) nut driver or wrench, remove the three nuts and washers from the potentiometers.
Photo 1
For the last piece of external hardware located on the face—the footswitch—we’ll actually want to go inside and disconnect its plug from the board.
On the bottom left side of the PCB, there will be a white rectangular connector. We need to unplug the female end from the male end. This is where small needle-nose pliers can help. A small screwdriver or even fingers may do the trick, too. Finesse is key. We don’t want to break the wires from the female connector.
Photo 2
Once dislocated, we can go back to the face and remove the footswitch using a 14 mm (9/16") wrench.
Step 3: Remove external hardware on the back heel.
The last external hardware to remove is the audio jack bushings.
Photo 3
Removing these will allow the PCB to slide out of the enclosure. Using an 11mm (7/16") nut driver or wrench, remove the bushings and beveled washers from the audio jacks. Now, the circuit board is free to be removed from the enclosure.
Step 4: Remove the PCB from the enclosure.
The four controls and two audio jacks that interface with the enclosure may create some resistance when trying to remove the PCB. Typically, it’s from the collars of the audio jacks. Using a small screwdriver in one of the top corners and gently prying the PCB back usually does the trick.
Photo 4
Step 5: Locating the clipping LEDs.
Now that the PCB is removed from the enclosure, we need to locate the clipping LEDs from the top side. They are the two small red silos at the center of the pedal.
Photo 5
Then, we need to locate the pads (the exposed metal on the PCB) for them on the bottom side, and, once again, they are centrally located.
Photo 6
Step 6: Removing the clipping LEDs.
Now that we’ve located the LEDs, let’s go ahead and remove them. Quick note: The Plumes I worked on was a new unit consisting primarily of surface mount device (SMD) components. The LEDs are located between the pots and switch, so they can be difficult to access from the bottom side. The easiest way to remove the LEDs is to actually snip them from the top side, after noting how they are soldered in place.
Photo 7
We’re not planning on using them, and they’re cheap enough to purchase again, so breaking them is no worry. We just need to be sure not to damage any of the nearby components. The best approach may be to break the shell/bulb of the LEDs. Doing this will expose the two leads.
Photo 8
With these two leads exposed, we can easily remove each lead from the solder pads on the top side. Let’s apply heat to each pad and remove the leads with small needle-nose pliers. Jump to the alternate approach section in step seven if you experience solder removal difficulties. (Quick tips: Existing solder tends to flow better when a bit of fresh solder is applied to it. You’ll also want to heat the lead/pad and then grab the lead with the pliers. Grabbing the lead with the pliers first will take longer because the heat will transfer to the metal of the pliers. Don’t apply heat to a solder pad longer than needed. Doing this can compromise the pad.)
Once the leads are removed, we need to remove the remaining solder from the pads. This is where the desoldering pump (commonly referred to as a “solder sucker”) comes in. Apply a bit of fresh solder to the pads and remove it using the pump. YouTube is your friend here, for some quick desoldering pump lessons.
Step 7: Adding germanium diodes.
Check the polarity of the diode. For this mod, I chose 1n34a diodes, which are very common and available on Amazon. These diodes are polarized and have a positive and negative side. On the 1n34a, the negative lead is designated by the black band that wraps around the body of the diode (this is not the case for all germanium diodes). On PCBs, square pads denote positive. However, for the diode package that we’re adding, the square pad is negative.
Photo 9
Using Photo 10 for reference, gently bend one of the diode legs so that it’s parallel with the body of the diode. Place the bent legs into their correct pads—the negative side of the diode will go into the square pad and the positive into the circlular pad. Solder the pads from the bottom side of the PCB and snip the excess leg length with a pair of flush cutters. The excess leg length can also be removed with needle-nose pliers by bending the legs back and forth several times.
Photo 10
Alternate approach: If you’re experiencing trouble getting the remaining solder out of each pad, there’s a different approach to try. This approach may actually be helpful for this particular mod, because the pad spacing is small. If a pad connects to a ground plane (a layer of copper typically the size of the entire PCB that connects directly to the main ground pin on the DC jack) or several locations (other components in the schematic) it will require more heat because the applied heat wants to travel to all the connected areas. Typically, with clipping diodes, only one pad will experience this and give desoldering difficulties. In such a case, follow these steps:
1. Establish which pad has remaining solder. For this mod, the square pads are the positive pads, because they hosted LEDs. The diodes we’re adding want to have the negative side go into the square pad.
2. Cut the negative side of the germanium diode lead down to about 5 mm length. The negative side on the 1n34a is the lead closest to the black line indicator seen in Photo 9.
3. Heat the pad that has remaining solder in it and drop the short side lead into the solder.
4. Bend the other lead over like a horseshoe and mate it with the desoldered pad. (See Photo 10)
5. Solder the second side.
6. Repeat for the second diode, keeping in mind that the polarity of the diode needs to be opposite of the first diode that we soldered in as seen in Photo 11.
Photo 11
Step 8: Test.
Before putting everything back together, plugging the unit in as-is can be helpful. This way, if it isn’t working, we can go back and look at solder joints and any potential issues.
Photo 12
Step 9: Put everything back together.
Simply reverse the disassembly steps and enjoy!
A final note: If you love DIY projects or are interested in learning pedal design, my company, CopperSound, has a DIY section on its website, which also includes links to other DIY dealers. We offer integrated breadboards, component substitution boxes, adaptors for toggle switches, and even solder dispensers. For more information, please check out coppersoundpedals.com/DIYIt’s Day 26 of Stompboxtober! Today’s pedal from MXR could be yours—enter now and return tomorrow for more!
MXR M309 Joshua Ambient Echo Pedal
The MXR Joshua Ambient Echo is your ticket to iconic sonic sanctuaries, featuring a foundation of carefully concocted tones and textures, highly customizable delay, and other features to help you craft soundscapes worthy of tonal trips out of the ’60s and ’70s and ethereal ambience from the ’80s.
This pedal requires 9 volts (300mA) and can be powered by the Dunlop ECB003 9-volt adapter or the MXR Iso-Brick Pro, Iso-Brick, and Mini Iso-Brick power supplies. This pedal cannot be powered by a battery.
Vintage-style reverb, tremolo, and vibrato sounds abound in a 3-in-1 stomp that might be the only box you need.
The Keeley ZOMA combines two of iconic amp effects—tremolo and reverb—into one pedal.
Key Features of the ZOMA
● Intuitive Control Layout: Three large knobs give you full control over Reverb Level, Tremolo Rate,and Depth
● Easy Access to Alternate Controls: Adjust Reverb Decay, Reverb Tone, and Tremolo Volume withsimple alt-controls.
● Instant Effect Order Switching: Customize your signal path. Position tremolos after reverb for avintage, black-panel tone or place harmonic tremolo before reverb for a dirty, swampy sound.
● True Bypass or Buffered Trails: Choose the setting that best suits your rig.
Three Reverb and Tremolo Modes:
● SS – Spring Reverb & Sine Tremolo: Classic spring reverb paired with a sine wave tremolo for that timelessblack-panel amp tone.
● PH – Plate Reverb & Harmonic Tremolo: Smooth, bright plate reverb combined with swampy harmonictremolo.
● PV – Plate Reverb & Pitch Vibrato: Achieve a vocal-like vibrato with ethereal plate reverb.
Reverb: Sounds & Controls
● Spring Reverb: Authentic tube amp spring reverb that captures every detail of vintage sound.
● Plate Reverb: Bright and smooth, recreating the lush tones of vibrating metal plates.
● Reverb Decay: Adjust the decay time using the REVERB/ALT SWITCH while turning the Level knob.
● Reverb Tone: Modify the tone of your reverb using the REVERB/ALT SWITCH while turning the Rate knob.
Tremolo: Sounds & Controls
● Sine Wave/Volume Tremolo: Adjusts the volume of the signal up and down with smooth sine wavemodulation.
● Harmonic Tremolo: Replicates classic tube-amp harmonic tremolo, creating a phaser-like effect withphase-split filtering.
● Pitch Vibrato: Delivers pitch bending effects that let you control how far and how fast notes shift.
● Alt-Control Tremolo Boost Volume: Adjust the boost volume by holding the REVERB/ALT footswitch whileturning the Depth knob.
The ZOMA is built with artfully designed circuitry and housed in a proprietary angled aluminum enclosure, ensuring both simplicity and durability. Like all Keeley pedals, it’s proudly designed and manufactured in the USA.
ZOMA Stereo Reverb and Tremolo
The first sound effects built into amplifiers were tremolo and reverb. Keeley’s legendary reverbs are paired with their sultry, vocal-like tremolos to give you an unreal sonic experience.
By now, we’re all familiar with the many options out there for amp modeling. Mic modelers are another reliable asset to digital recording tech, and can rapidly grow your inventory with just a few clicks.
As guitarists, we’re very aware of amp-modeling and profiling technologies, such as the Line 6 Helix, Fractal Axe-Fx, Neural DSP Quad Cortex, and Kemper Profiler. While our bases are covered for these (with modelers available for every “holy grail” amp under the sun), we are still missing another vital area of the recording process—microphones—for the acoustic instruments and vocals we might want to capture.
What if we could record them using holy-grail-modeled microphones? This month, let’s evaluate microphone modeling to help you make better-sounding recordings. Tighten up, the Dojo is now open.
The Sincerest Form of Flattery
Microphone modeling is an intriguing advancement in recording technology, offering great flexibility and possibilities for musicians, producers, and engineers. Makers like Slate Digital, Antelope, and Antares make many offerings, from hardware to software.
Universal Audio’s Sphere DLX ($1299 Street), LX ($799), and their six new Standard Mic series have impeccably modeled classic mics, and when coupled with their classic mic pre and compressor plugins, you can enjoy the same highly coveted mic chains appreciated the world over.
How It Works
The technology behind microphone-modeling systems relies heavily on convolution and impulse response techniques. These techniques involve capturing the unique sonic fingerprint of a microphone by recording its response to a wide range of frequencies and sound pressure levels. The immediate benefit is that this means you can grow your mic locker exponentially and gain access to a wide range of legendary microphone tones and textures all from a single mic! Most modeling microphones are usually either small- or large-diaphragm, multi-pattern, condenser microphones that are capable of capturing a wide frequency range and dynamic response. By adding other modeling mics, you can record in stereo or surround, and/or record multiple instruments at a fraction of the cost of owning multiples of the modeled mics themselves.
A Wealth of Options
One significant advantage of mic-modeling systems is their ability to offer a vast array of microphone options within a single session instead of having the time-consuming duty of swapping them out to achieve different sounds. With a modeling system, you can switch between different mic models instantly and audition various mics to find the perfect tone for the recording.
“The same vintage microphone can sound different on different days depending on temperature, humidity, and the voltage from the wall.”
Another lovely bonus is that microphone-modeling systems also offer the ability to swap microphone characteristics after the recording has been made! Want to swap your AKG C12 for a Neumann U 47 long after the recording session is over? No problem! This is especially useful when the initial microphone choice may not have been ideal or when the production requires a different tonal character than originally intended.
Weighing the Pros and Cons
Some audio purists argue digital emulation can’t truly replicate the sound of a physical microphone, especially when it comes to vintage models that have unique characteristics developed over decades of use. The subtleties of these microphones and their aging components shape the way they interact with different preamps and compressors.
After making over a hundred records at Blackbird over the last eight years, I’ve grown quite familiar with a good portion of our 1,800-plus vintage mics, like Telefunken 251s, AKG C12s, Neumann U 47s and KM 84s, Shure SM7s and SM57s, RCA 44s and 77s, and Royer R-121s. These are the very same mic models that most modeling mics are trying to capture. But experience has taught me that not all microphones sound identical even if they are the same make and model (and year). Also, the same vintage microphone can sound different on different days depending on temperature, humidity, and the voltage from the wall (that’s why Blackbird has its own regulated power and all the studios strive for consistent temperature and humidity year-round).
For home studios and smaller production environments, microphone-modeling systems can be a game changer. You’ll get a wide range of high-end microphone sounds without the need for a large microphone collection, and the ability to change microphone models after the fact gives budding producers and engineers greater confidence and flexibility in their work.
In reality, most users find that the convenience, cost savings, and versatility offered by modeling systems far outweigh any potential shortcomings. Finally, keep in mind that even though the mic “profile” you choose (U 47, U 67, SM7, etc.) will be consistent day in and day out, the modeling mic itself is also still a mic and will require you to be mindful of these same issues I mentioned above in order for your mic “profile” to be as accurate as possible.
Until next time, namaste.