I’m on the hunt for an attenuator, so I’ve been prowling music shops and hunting online to find just the right one that will preserve my tone, but reduce it to a volume that will keep the neighbors from calling the cops—or keep a club’s soundman off my back.
“What’s an attenuator?” That’s a question we get a lot at PG, and the answer is: a device that allows you to drive your tube amp hard without the volume that comes with turning up. As we all know, pushing tubes really makes an amp sing, and getting that tone at a reduced volume can be a feel-good experience for everybody.
An attenuator is connected between an amp and a speaker using two regular speaker cables—one from the amp to the attenuator and one from the attenuator to the speaker. Then you dial in your tone and volume, and you’re set.
“Pushing tubes really makes an amp sing, and getting that tone at a reduced volume can be a feel-good experience for everybody.”
There are four types of attenuators: passive, active, resistive, and reactive. Passive attenuators rely on weakening the power of the signal and improving the impedance match between the guitar and the amp. They don’t require any sort of external power supply, and they used to have a reputation for frying tubes and overheating amps, but modern tech has reportedly cured those concerns. Active attenuators do require external power. This is because they are designed not only to attenuate a signal but also to boost it. So, essentially, an active amp attenuator takes a portion of the amp’s signal and reduces it or increases it to give it more drive.
The main difference between resistive and reactive load attenuators is that a reactive attenuator lowers the amp’s output while maintaining its impedance curve. This means that, regardless of the amount of attenuation, your tone will maintain as much transparency as possible. Resistive attenuators don’t maintain that impedance curve, and as attenuation increases, the color of your tone changes, becoming more compressed and darker.
Now, let’s take a look at some of the attenuators I investigated, in different price ranges.
JHS Little Black Amp Box
This is a passive attenuator, meant for use only through an effects loop. It does an effective job of attenuation, but it sounds thin compared to the active (and more costly) attenuators I listened to. It changes the tone more, too, but at a $65 street price it can easily get you in the game.
Two Notes Torpedo Captor X
The Torpedo Captor X from Two Notes is a multi-function tool with lots of bells and whistles. It’s a compact and portable reactive load box, amp attenuator, miked-cab simulator, IR loader, and stereo expander. Although I didn’t get to experiment with all of its capabilities, this is a great sounding attenuator—very effective, and it maintains your tone while lowering the volume. But at $599 street, it’s an investment, as are all top-shelf attenuators.
Radial Headload Prodigy
The Prodigy is an excellent sounding box and does a good job attenuating the signal to your speaker. Like the Two Notes, it has more functions than attenuation, but you can choose 100 percent, 50 percent, or 25 percent attenuation. It includes a DI and nice high and low EQ controls—along with a built-in headphone amp. The Prodigy uses custom ceramic-coated resister coils to convert the excess power from your amp into heat. And like the Torpedo Captor X, it’s priced at $599 street.
Dr. Z Brake-Lite
This attenuator from amp-builder Dr. Z sounds great and does a good job of maintaining sound and tone while lowering the volume of your amp. It’s very simple to use, with a 5-position switch for different amounts of attenuation. This box accepts 4-, 8-, or 16-ohm loads. It has parallel speaker outputs, letting you run multiple cabinets. It’s only compatible with tube amps up to 45 watts, so it won’t work with your Marshall stack. But this device packs a lot of bang for $399 street.
Universal Audio OX Amp Top Box
This is the Cadillac of attenuators—a very high-quality device using premium analog components. In addition to a top-notch attenuation circuit, the OX Box features Universal Audio’s Dynamic Speaker modeling technology, giving you access to dozens of spot-on mic and guitar cabinet emulations. But like a Cadillac, it ain’t cheap, at $1,499 street. PS: If you’re a Buddy Miller fan, the OX is an important component of his tone.
What I discovered in my hunt is that if you’re looking to maintain your tone at lower volumes, you are probably better off spending more on an active attenuator. Passive attenuators tend to change your tone while bringing your volume down. So, if it’s within your budget, it’s worth paying more for the good stuff.
- Ultimate Attenuator Review ›
- Tone Tips: The Lowdown on Load Boxes, Attenuators, and Reamps ›
- Amp Too Damn Loud? Here Are 10 Attenuators That'll Save Your Bacon ›
Maxon OD-9 Overdrive Pedal
The Maxon OD-9 Overdrive Effects Pedal may look like your old favorite but that's where the similarity ends. Improved circuitry with a new chip yields the ultra-smooth dynamic overdrive guitarists crave. Drive and Level controls tweak the intensity and volume while the Hi-Boost/Hi-Cut tone controls adjust brightness. Features true bypass switching, a die-cast zinc case, and 3-year warranty. From subtle cries to shattering screams, the Maxon OD-9 delivers a huge range of tones.
Features
Improved circuitry with a new chip yields ultra-smooth dynamic overdrive
Drive and Level controls tweak the intensity and volume
Hi Boost/Hi Cut tone controls adjust brightness
True bypass switching
Die-cast zinc case
AC/DC operation (order optional Maxon AC210N adapter)
Product Specs
Input: 1/4" mono jack
Output: 1/4" mono jack
Power: 9V DC, 6 mA, center pin minus (not included)
Dimensions: (WxDxH) 74 mm x 124 mm x 54 mm
Weight: 580g
Fender’s Greasebucket system is part of Cory Wong’s sonic strategy.
Tone pot with Fender Greasebucket tone system:
This 250k tone pot is a standard CTS pot with a 90/10 audio taper found in all U.S.-built Fender guitars. The Cory Wong guitar uses the Fender Greasebucket system, which is added to the pot as a ready-to-solder PCB. The Greasebucket PCB is also available individually from Fender (part #7713546000), though you can use conventional electronic parts for this.
Fender introduced this feature in 2005 on some of the Highway One models and some assorted Custom Shop Strats. The Greasebucket name (which is a registered Fender trademark, by the way) is my favorite of Fender’s marketing names, but don’t let it fool you: Your tone will get cleaner with this modification, not greasy and dirty.
According to Fender, the Greasebucket tone circuit reduces high frequencies without adding bass as the tone knob is turned down. Don’t let that description confuse you. A standard Strat tone control does not add any bass frequencies! As you already know, with a passive system you can’t add anything that isn’t already there. You can reshape the tone by deemphasizing certain frequencies and making others more prominent. Removing highs makes lows more apparent and vice versa. In addition, the use of inductors (which is how a passive pickup behaves in a guitar circuit) and capacitors can create resonant peaks and valleys (band-passes and notches), further coloring the overall tone.
Cory Wong bringing the funk onstage.
This type of band-pass filter only allows certain frequencies to pass through, while others are blocked. The standard tone circuit in a Strat is called a variable low-pass filter (or a treble-cut filter), which only allows the low frequencies to pass through while the high frequencies get sent to ground via the tone cap.
The Greasebucket’s band-pass filter is a combination of a high-pass and a low-pass filter. This is supposed to cut high frequencies without “adding” bass, which has mostly to do with the resistor in series with the pot. That resistor means the control will never get to zero. You can get a similar effect by simply not turning the Strat’s standard tone control all the way down. (The additional cap on the wiper of the Greasebucket circuit complicates things a bit, though; together with the pickups it forms an RLC circuit, but I really don’t want to get into that here.)
The standard Fender Greasebucket tone system is used in the Cory Wong Strat, which includes a 0.1 μF cap and a 0.022 uF cap, along with a 4.7k-ohm resistor in series. These are the values used on the PCB, and without the PCB it looks like the illustration at the top of this column.
Push-push tone pot with preset overwriting function:
The lower tone pot assigned to the bridge pickup is a 250k audio push-push pot with a DPDT switch. The switch is used to engage a preset sound by overwriting the 5-way pickup-selector switch, no matter what switching position it is in. The preset functionality has a very long tradition in the house of Fender, dating back to the early ’50s, when Leo Fender designed a preset bass sound on position 3 (where the typical neck position is on a modern guitar) of the Broadcaster (and later the Telecaster) circuit. Wong loves the middle-and-neck-in-parallel pickup combination, so that’s the preset sound his push-push tone pot is wired for.
The neck pickup has a dedicated tone control while the middle pickup doesn’t, which is also another interesting feature. This means that when you hit the push-push switch, you will engage the neck and middle pickup together in parallel, no matter what you have dialed in on the 5-way switch. Hit the push-push switch again, and the 5-way switch is back to its normal functionality. Instead of a push-push pot, you can naturally use a push-pull pot or a DPDT toggle switch in combination with a normal 250k audio pot.
Here we go for the wiring. For a much clearer visualization, I used the international symbol for ground wherever possible instead of drawing another black wire, because we already have a ton of crossing wires in this drawing. I also simplified the treble-bleed circuit to keep things clearer; you’ll find the architecture of it with the correct values in the previous column.
Cory Wong Strat wiring
Courtesy of singlecoil.com
Wow, this really is a personalized signature guitar down to the bone, and Wong used his opportunity to create a unique instrument. Often, signature instruments deliver custom colors or very small aesthetic or functional details, so the Cory Wong Stratocaster really stands out.
That’s it! In our next column, we will continue our Stratocaster journey in the 70th year of this guitar by having a look at the famous Rory Gallagher Stratocaster, so stay tuned!
Until then ... keep on modding!
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.