If you're passionate about gear and want to understand what sets our pedals apart, this article reveals the Unit67's unique development, technical details and tone-shaping features.
"The DryBell Unit67 is a powerful all-in-one analog guitar pedal that combines the precision of 1176-style compression, a flexible EQ section with Rangemaster-inspired treble boost, and a clean boost - packed into a compact design. Whether you're looking to fine-tune your tone - clean or overdriven, add sustain and clarity, stand out in the mix, or push your amp into overdrive, the Unit67 excels. Its versatility makes it a go-to tool for any guitarist, no matter the guitar, amp, or playing style."

World-famous guitarists like Michael Landau, John Mayer, Steve Stevens, Jon Carin, Joe Satriani, etc. are using DryBell pedals for a reason. We're thrilled that our designs are resonating with players, and the Unit67 is no exception. With our passion and live experience poured into every pedal, we love creating gear that's easy to use, practical and sounds amazing. From bedroom jams to arena concerts, the Unit67 consistently delivers. None of us can resist the enjoyment experienced whilst playing through the Unit67, and that same joy is echoed by our customers. So, what's inside the Unit67? If you're looking for a pedal that can transform your tone and enhance your playing feel, the Unit67 is worth checking out. Enjoy reading!
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The Unit67 Internal Signal Path Diagram
In this article, we'll discuss the key components of the Unit67's signal path, their functions and how they provide tonal flexibility for the user. Keep in mind that the Unit67 is not just a compressor. The idea behind Unit67 is quite different. We have designed the pedal in a way that satisfies the most demanding of guitar players. It’s a guitar pedal that contains Equalizer (Low and High) including Rangemaster style ‘treble boost’ EQ control (Range), 1176 type of compression (Sustain) and a high voltage (headroom) clean boost (Boost). For easier understanding of the Unit67’s circuit, look at this simplified block diagram of the Unit67’s internal signal path. We’ll explain every stage/feature separately.
Low-Noise OP Amp Design
By removing the back plate of the Unit67, you will reveal the world we lived in during the development period. It's built with over 360 carefully chosen high-quality electronic components. To achieve optimal signal integrity and dynamic performance, we chose an OP amp based design. This provides the nearly limitless design flexibility needed for this type of pedal. Very high quality OP amps we used for specific electronic stages and purposes. The Unit67’s circuits are designed as high current low noise in all its signal paths, ensuring there’s no cutting corners in any part of its’ design or construction. When you see, hear and feel it, you will know why the Unit67 is such a special piece of gear!
The Unit67's High Headroom Buffered Bypass
Though often desired, true bypass isn't always an optimal design choice. In early Unit67 true bypass prototypes, parasitic capacitance between the main circuit’s input and output created oscillation issues with certain pedalboard switchers (like Boss ES-8), particularly when combined with the pedal's high gain setups. This usually forces the input buffer on the switchers to be activated, limiting a player's setup flexibility.
Seeking a reliable and sonically optimal solution, we instead designed an ultra-low noise and high-headroom buffer (14.0Vpp, 16.1dBu or 13.9dBV) and that’s how the tone integrity is preserved. The main input signal is going directly into that ultra linear, high bandwidth buffer which also eliminates amplitude signal loss common in classic transistor buffered pedals. The buffer’s output is passed to the output switch for Unit67’s smooth buffered bypass operation. Also, the pedal has a nice fade-in/fade-out LED operation when switched on/off.
Our redesigned buffer system solved the early issues and proved so superior that we selected it as the Unit67's sole switching method. As a bonus, it makes the Unit67 a fantastic buffer for your entire pedalboard.

The Compressor Feature Makes the Unit67 a Unique Guitar Pedal for Sustain
Despite its complex internal design, the Unit67's FET compressor is remarkably easy to use and delivers stunning results. The "Sustain" knob lets you precisely dial in the amount of parallel compression, blending your compressed and dry signals for the perfect balance. With just one simple knob, you can add the right amount of sustain while retaining pick dynamics.
The second control, the "Input” gain toggle switch - offers two distinct compression characters: "Low" (+4dB) for more subtle compression and "High" (+10dB) for harder compression effects. You can easily switch it in live, on-stage situations when you pick up different guitars (pickups), in-between sessions, songs, etc. Combining “Sustain” knob and “Input” switch gives you a vast range of characters, from gentle sustain enhancement to long compressed notes, and everything sounds great at any of the settings.
In this single knob design, parameters like Attack, Release and Ratio are fixed internally, but are VERY carefully chosen based on many years of our playing experience. That was a huge task because we had to satisfy a wide range of musicians and playing styles; they are carefully tuned to ensure the pedal's dynamic response is excellent, simplifying operation while maximizing versatility. Our customers simply love this feature.

Compression Inspired by the legendary UREI 1176
The Unit67's compressor feature draws inspiration from the legendary UREI 1176, renowned for its rich, colorful sound. There are tons of compressors out there that we've gone through, classics like the Orange Squeezer or Ross/DynaComp etc. They all sounded good, but we were looking for a little different feel and even lower noise, especially because the compressor signal is amplified by the EQ and Boost stages afterwards. While we went through those testing sessions, the turning point was when we entered the world of studio FET compressors.
The famous UREI 1176, which has been used as one of the most powerful studio workhorses over the last 50 years, stood before us and it was ready to be carefully examined and tested. The UREI's dynamic characteristics added something very unique to the sound and naturally, the decision fell to using an 1176-like design. Zvonch crafted an innovative low-noise compressor circuit that captures that same essence. The FET voltage divider (gain reduction network) principle is the same as the original, but with OP amps around it. He spent countless hours perfecting the feedback network, which greatly defines the compressor's character. Also benefitting from the addition of internal temperature compensation. The Unit67’s compressor will not change its sound whether you’re playing a gig at -5°C/23°F or at + 45°C/113°F (lab-tested for even greater range!). So, whether you’re playing at the North Pole or by a Volcano your Unit67 will perform just as well!
The classic 1176LN design colors the tone. All of the Unit67’s limiting amp design is made to be transparent for guitar and the resulting tone, response and feel is simply beautiful. If you listen carefully, you can hear that in the Unit67’s demos. This is all made with fully analog technology.

Sculpt Your Sound with a Versatile EQ Set
The EQ section is essential to the Unit67, and perfecting this was a challenge that we relished. The signal from the compressor stage is sent to the EQ section which contains 3 tone controls: Range, Low and High. These controls provide precise control over your clean or overdriven tone, allowing you to sculpt it to perfection. You can turn the entire EQ section on/off with the EQ hard bypass toggle switch for instant tone comparisons or noise reduction. Or, use the compressor on its own by keeping the EQ switched off.
Visit our product page to watch 20+ demo videos and hear the Unit67 on various amps.
Low and High EQ controls
The first two controls in the EQ section are Low (bass) and High (treble), which are quite strightforward, used to precisely sculpt the guitar's tone for any amp or playing style. They don't have simple symmetrical characteristics, and we've carefully tweaked them to be compatible with a wide range of amps. Technical Info: Low -15.8 dB to +9.3 dB, High -13.2 dB to +7.2 dB. Both controls reach unity gain somewhere between 12 and 1 o'clock. They are designed to be useful in many different situations and to be spectrally compatible with the next most important EQ control - The Range.

The Range: Add Sparkle & Shine to Your Tone
One of the key ideas behind the Unit67 is the possibility that the pedal can emphasize specific frequencies for lead guitar. We gave ourselves an additional, clear, but challenging goal: to achieve this with a single knob - not a graphic or parametric EQ with too many options. Simplicity for the user. And we did it!
The knob called “Range” controls a very specific mid-range frequency spectrum, very similar to that of the old classic "Rangemaster" treble booster, tuned to just the right center frequency and a carefully shaped bandwidth. Kruno, with his keen ear and years of playing experience, worked closely with Zvonch to perfect the Range feature. Using complex EQ circuits on the prototype board, they defined its ideal character. This was then distilled into the single "Range" knob.
We’ve balanced the pot’s operation with many different amps to make sure that your tone won't become muffled or too harsh when you play around with the Range knob. While developing this stuff, we always kept simplicity for stage situations in mind. During development, we tested and played the Unit67 through well renowned classic amps like Marshall Plexi, Hiwatt DR504, Fender Deluxe & Band Master, Vox AC30 and many others. No matter what setup is used, the tone and playing feel benefit from the magical touch of the Unit67. For darker-toned amps or guitar pickups, "The Range" will always add a harmonically rich sparkle to your tone.
A great example of the Unit67's versatility is the Range feature combined with a touch of sustain and boost just enough to give you THAT tone. It will give some serious bite to the final sound which is another way to push you through the mix while playing lead. The Unit67’s features work together, rewarding you with lots of impressive tones.
The Range circuit, like all signal path stages in the Unit67 design, also uses a high-current and low-noise design. You can boost/cut the Range spectrum up to +/- 13.1 dB. Unity gain is at exactly 12 o'clock. Trust us, you'll be using this knob a lot!
Unit67's High Output Boost Stage
The signal from the EQ section hits the output amp next. This stage was a tough design challenge, but the result is a beast. Thanks to the high internal power supply voltage (23V), the Unit67 has a huge 20.0Vpp (19.2dBu or 17dBV) output headroom. This lets you drive your amp (or drive pedal) into rich, natural overdrive – further than most boost pedals can manage. These high internal voltages are realized with voltage doublers and triplers. We also carefully tuned the Boost stage to be “semi-clean”, with gentle filtering of bass and treble at higher gain settings (more than 1 o’clock). This prevents the harsh or muddy sound that can happen when boosting amps with full-freq range signals.
Though expensive, the vintage Davies Molding Daka-ware knob was our choice from the start! It's stylish, yes, but also lets you easily control the Unit67's output level with your foot. The Boost stage’s gain is -7dB on minimum (attenuation) or 22.4dB at the knob’s maximum position. Unity gain is at the 10 o'clock mark (the lightning symbol!), but may vary slightly if you're using the compressor feature. The best way to find exact unity gain is by listening to the pedal.

Final Thoughts on the Unit67
As we said before, from the very beginning of Project Unit67, we developed and tested it with a ton of different amps, pedals and guitars. No matter the setup, the Unit67 consistently gives you the tone tools to quickly improve and refine your sound and playing feel. It doesn't matter if you play with a clean or overdriven tone.
Simplicity for the end user was a big focus throughout the pedal’s development. Within seconds of playing, you'll feel right at home with the Unit67 and quickly find the tone you crave.
It's clear that it's not just another effects pedal - its unique combination of features, and precise design, make it a simple tool for achieving the sonic textures you've always dreamed of. We also took inspiration from 60's space consoles for Unit67's visual design, and love the result. It fits in well on any pedalboard.
We're confident that once you try the Unit67, you'll experience its quality, versatility, and ability to elevate your tone. Our carefully crafted design, rigorous testing, and years of continuous production process improvement guarantee exceptional performance and reliability. It's a top-notch musical tool you can rely on.
Ready to experience the Unit67's magic for yourself?
Thanks for reading,
DryBell Team