CompIQ STELLA Pro Compressor Pedal for Bass & Guitar

259,00 309,00 

Build to order, 8-10 workdays

SKU: CIQ—5 Categories: ,

You can order this product in the USA from Gear Hero HQ.

The CompIQ Stella Pro MK2 stands out as a remarkably powerful compressor/limiter pedal, offering a wide array of parameters for unprecedented control over playing dynamics. The Stella proves versatile for studio applications like bus compression and tracking and delivers outstanding results in live performances. It can be utilized with any instrument, such as guitar, bass, keyboards, synths, electro-acoustic guitars, etc., and even with vocals, with an additional microphone pre-amp.

The optional DITOS Transformer-Coupled Balanced Output DI is available as an add-on board. Built with Burr-Brown™ technology and highly advanced line drivers, the DITOS provides complementary signal conditioning and a warm musical voicing to any instrument.

Premier GuitarThis incredibly full-featured comp offers all the controls a rackmount unit offers, but in a pedal format.

Bass Magazine JP ReviewEven if you apply a lot of compression, the amount of sound information does not decrease. There is no noise and the build quality is high.

Bass Player Magazine ReviewAn incredible amount of high-quality dynamic control. The answer to the prayers of any bassist wanting a studio-quality control on stage.

Sound On Sound - Review - July 2020 IssueThe Stella is, essentially, a studio VCA compressor in a pedal. It can sound wonderfully transparent, or full of character, and there’s oodles of control at your fingertips.

Compressor Pedal Reviews - CompIQ StellaI’m not aware of any compressor on the market that packs this much punch in terms of functionality. In many ways the Stella has raised the bar for compressor pedals.

Guitar Pedal XCompared to my various previous compressors, I am more immediately aware of the precision and high fidelity of this device.

Gitarre und Bass Magazine - Test Review - June 2020 IssueIt’s amazing how many options Becos FX has put in these boxes. It is hard to find real alternatives with so much flexibility in one device.

Vintage Guitar Magazine USA - VG Approved Gear Review - May 2020 IssueThe CompIQ Stella has a ridiculous amount of power. Better still, it’s a transparent compressor that only colors the tone as much as you allow it.

Guitar Magazine UK - Editor's Choice Review - September 2019 IssueNotes are thickened without thumping, and chords gel together in a way that makes you sound like a better player. This is a proper gem.

 Manual V2.0 | V1.4
 Manual DITOS
 Setting examples and sound demos
 Video Demo
 What people say
 CompIQ 101
 Compare compressors

Bringing Studio Compression Controls to Pedal Format

The CompIQ STELLA Pro MK2 is a feature-complete and powerful all-analog compressor/limiter pedal for use with guitar, bass, or any other instrument or audio source. It is also one of the very few that can be powered by an internal 9V battery or an external supply in the range of 9-18VDC. It is built around the high-performance 4320 THAT Analog Engine® which incorporates a true RMS-level detector that accurately measures the input signal and processes it through an ultra-transparent-sounding Blackmer® VCA. Unlike peak detection, commonly used in other compressors, the RMS (root mean square) sensor calculates an average peak level of the signal, aligning more closely with how human hearing perceives differences in loudness.

The pedal now offers two selectable compression modes. In Feed Forward mode, emphasis is on speed and accuracy, utilizing a pre-VCA copy of the input signal. This mode can provide subtle compression up to brick-wall limiting based on control settings. The “old-school” Feed-Back compression delivers a smooth response suitable to transparently even out playing dynamics. This mode uses a post-VCA copy of the audio signal for its dynamic processing. While Feed-Back mode excels at low-to-medium compression ratios, it may be less suitable for using compression as an effect or hard peak-limiting. Nevertheless, by adjusting the threshold, employing a hard knee, selecting a higher ratio, setting a fast timing, and even boosting the control signal in the side chain filter, the Stella can function as a genuine Feed-Back limiter. In any settings, both modes sound clean and natural, without pumping, breathing, distortion or other artifacts.

Guitar Pedal X

To my mind the Stella is the very best Pro Studio Style Pedal Compressor you can currently get – there really is nothing else at this level / form factor and degree of surgical precision – really nothing out there is more comprehensive and finely controllable than the CompIQ Stella!

The Stella MK2 features upgraded side-chain capabilities, including a variable Lo-cut/boost filter specifically designed for bass instruments (±12dB @ 90Hz, 12dB/octave). When high-amplitude low frequencies trigger the threshold early, the compressor may engage prematurely, potentially over-compressing high-frequency elements, particularly in specific applications. By cutting lows in the side-chain, compression in the lows at the output is reduced, restoring overall signal energy. Conversely, boosting lows in the side-chain increases compressor sensitivity, aiding with very low-level signals. Moreover, a matching variable Hi-cut/boost filter in the side-chain further refines this balance (±7dB @ 3kHz, 12dB/octave). The cutting side of the filter avoids overly compressing highs, preserving a natural brightness in the output. Conversely, boosting highs in the side-chain enhances compressor sensitivity to high frequencies, which helps with very bright sounding instruments. When both filters are set to cutting, the compressor becomes more sensitive to mid-frequencies within 1-2 kHz, resulting in increased compression in this range at the output. These enhancements effectively manage compression across lows, mids, and highs, delivering impactful dynamics without unwanted pumping and maintaining desired balance in the audio spectrum.

The Compression Knee feature provides two options, each with its particular sonic signature. Hard Knee compression is quick and snappy, suitable for peak limiting or enhancing the compression feel. Soft Knee compression is gradual and gentle, creating a transparent effect even at high ratios.

The X-EQ tilting equalization circuit, rooted in the Hi-Fi era of the 1970s, offers two pivot frequency options: High (at 1kHz) suitable for guitars, and Low (at 330Hz) which works better for bass. This post-compression gentle correction can compensate for differences between instruments or be employed to enhance the lows or highs of the instrument. Both settings can be used in either application, each bringing a different but useful and likable EQ result.

Guitar Magazine UK - Editor's Choice Review - September 2019 Issue

The Stella – the brand’s flagship compressor for bass and guitar – is the perfect embodiment of the company’s spirit. Apart from your regular controls like ratio, threshold, attack, release and gain make-up, the Stella also has toggle switches for the side-chain filter, Tilt EQ, and knee. While there’s a lot going on with this pedal – it has nine knobs, seven LEDs, and four switches – it’s a lot more intuitive than it seems. WE SAID Small, but packs all the features of a VCA compressor, and the same audio quality too.

Additionally, the STELLA Pro MK2 features two internal DIP switches for voicing selection. These settings introduce nuanced shifts in the internal dynamic frequency processing, bringing subtle coloring to the sound. The Spark setting adds polished brilliance to the highs, Tight dips the low-mids slightly, providing more depth, and Punch brings a tube-like compression feel with velvety lows and warm highs (which complements even more the DITOS transformer voicing). We will leave the Punch setting activated by default so you can have some fun right away. However, if you want to maintain the most transparent sound response at the output, which always preserves the instrument’s natural character, you may turn the voicing off.

The Dynamic Auto Timing circuit offers user-friendly operation with two selectable options: Fast and Slower. These settings adapt to different playing styles. For added versatility, manual control over Attack and Release timings is available, unlocking a range of other compression possibilities. For instance, setting the compressor for slow attack and fast release allows initial transients to pass through at a higher audio level (set by the Make-up Gain), creating a tight and percussive sound suitable for guitar “chicken picking” or bass “slapping.”

Premier Guitar - Becos CompIQ MINI Pro Compressors Quick Hit Review

This incredibly full-featured compressor offers all the controls a rackmount unit offers, but in a pedal format.

The Stella also features a Dry/Wet Mix, which allows for blending a desired amount of clean signal with the processed signal, resulting in a more natural compression effect. Such a mixing technique (a.k.a. New York style) is usually employed when hard compression is set out as an effect or when limiting must be made more subtle.

An 8-LED gain reduction meter allows for accurate monitoring of the compression applied to the input signal. This feature provides useful visual feedback on the degree of sound processing.

DITOS – Optional Transformer-Coupled Balanced Output DI Board for CompIQ Stella Compressor Pedal

DITOS • Transformer-Coupled Balanced/Unbalanced Output Board

The optional DITOS board featuring a transformer-coupled balanced output in 1/4″ TRS format is available for insertion in the space typically used for the 9V battery. This allows for direct recording or sending of the signal to a mixing console. It can also be utilized as an unbalanced floating output to send the signal to another pedal or amplifier, capturing the warmth of the output transformer. The main output is always functional and may be utilized for sending the signal to another processing chain or tuner.

When Stella is in bypass, the DITOS circuit still processes the signal, accounting for active compression bypass. However, the main output is true-bypassed.

Ground-lift jumpers are available internally to address any potential ground-loop noise issues.

The DITOS board is designed for easy interconnection with CompIQ Stella mainboards manufactured after September 2021 and is also compatible with the older board versions.

DITOS sound demos

Sound demos on bass 

Audio examples graciously provided by jazz artist Jean-François Untrau from France, showcasing the alternating effect of the compressor in bypass and active modes. For specific details on the utilized settings, please refer to the Settings Examples tab located above.


Pristine audio processing

The CompIQ series of compressors preserves the unique tonal characteristics of the input signal. They provide pristine audio compression and offer a high dynamic range, which enables clean, natural-sounding tones with minimal noise and no artifacts or distortions in any settings.

Key features

  • Full analog circuit with true by-pass
  • True RMS-level detector for accurate input signal measurement
  • High-performance Blackmer® VCA compression engine
  • Optional DITOS board for transformer-coupled balanced output (10KΩ impedance)
  • Feed Forward/Feed-back compression modes
  • Ratio 1:1 to infinite:1 (limiter)
  • Threshold -45dBu to +10dBu
  • Make-up Gain -6dB to +20dB
  • Soft/Hard compression knee selection
  • Manual timing: attack 0.12-12 ms/dB of gain reduction, release 1.2-120 ms/dB of gain reduction
  • Fast/Slower dynamic auto attack and release timing with hold for peaks over the threshold
  • X-EQ with selectable frequency pivot 330Hz for bass instrument or 1KHz for guitar or other applications
  • Voicing: Flat, Spark, Tight, Punch (internal DIP-switch selectable)
  • Lows/Highs variable side-chain filter with boost & cut around 90Hz and 3kHz
  • Dry/Wet mix
  • 8-LEDs gain reduction meter
  • High-end quality Burr-Brown FET audio ICs, low tolerance metal-film resistors, Panasonic, Kemet, Cornell Dubilier plastic film audio capacitors, Gold-plated multi-layers PCB, Gold-plated micro-switches
  • Genuine Hammond black-powdered aluminum enclosure
  • Runs on standard 9V internal battery or 9-18 V DC external power supply (not included), center negative, 12mm long barrel plug
  • 3-year warranty (direct to manufacturer, international, transferable)
  • Hand-assembled in Vienna, Austria

Note! Optimal configuration of the CompIQ Stella for studio recording or live performances typically necessitates a solid understanding of audio compression.

More info

 Manual V2.0 | V1.4
 Manual DITOS
 Setting examples & sound demos
 Video Demo
 Compare compressors

Box Weight 0,33 kg
Box Dimensions 13 × 8 × 5,5 cm
Technical Specifications

Input impedance: 1.1MΩ
Main unbalanced output impedance: <100Ω
Optional DITOS transformer-coupled balanced output impedance: 10KΩ
Feed Forward/Feed-back compression modes
Ratio: 1:1 to inf:1
Threshold: -40dBu to +10dBu
Make-up gain: -6dB to +20dB
0dB Referrence Input Level: -20dBu (77.5mV)
Total amount of compression: usually 20dB for -20dBu (77.5mV) input level; 36dB for +4dBu (1.23Vrms) input level, all at inf:1 Ratio
Dynamic Auto Attack time: ~7ms in Fast setting; ~15ms in Slower setting
Dynamic Auto Release time: ~70ms in Fast setting; ~220ms in Slower setting
Dynamic Timing: transients are handled faster; steady signals are handled slower
Manual Attack range: 0.12 to 12ms/dB
Manual Release range: 1.2 to 120ms/dB
Side-Chain Filters: Lows (High-Pass, variable, +/- 12dB @ 90Hz, 12dB per octave), Highs (Low-Pass, variable, +/- 7dB @ 3 kHz, 12dB per octave)
X-EQ: Low (pivot at 330 Hz, +/-6dB), High (pivot at 1 kHz, +/-6dB)
Voicing: Flat (DIP-switches OFF), Spark (DIP-1 ON, DIP-2 OFF), Tight (DIP-1 OFF, DIP-2 ON), Punch (DIP-switches ON)
THD VCA: 0.1% 1kHz, 0dBu in/out, FB mode, 4:1 ratio, -20dBu threshold, +12dB gain, 1KΩ load, 24KHz BW, 12VDC power, through 6th harmonic
THD DITOS: 0.18% 1kHz, 0dBu in/out, FB mode, 4:1 ratio, -20dBu threshold, +12dB gain, 1KΩ load, 24KHz BW, 12VDC power, through 6th harmonic
Max Input Level: +10dBu
Max Output Level: +12dBu
Frequency response for VCA and DITOS outputs: -2dB @ 40Hz; 0dB in between 100Hz and 24KHz
8-LEDs Gain Reduction Display: calibrated for -20dBu reference input level
Internal battery operation: 9V (6F22) alkaline battery recommended
Voltage Range: 9-18VDC, center negative [ – ], power supply not included
DC Power Plug Barrel: Ø 5.1/2.1mm, 12mm long
Current consumption without DITOS board: < 35mAh @ 9VDC; < 44mAh @ 12VDC; < 63mAh @ 18VDC
Current consumption with DITOS board: < 43mAh @ 9VDC; < 52mAh @ 12VDC; < 72mAh @ 18VDC
Simulate on pedalboard: Pedaltrain's https://pedalboardplanner.com

Build Option

Without DITOS Trafo Output, With DITOS Trafo Output Installed

Note! The product name, design, circuit, components, description, pictures, technical specifications, functionality, etc. may change anytime and without prior notice (Terms and Conditions). We advise you to check the manual (only available as a downloadable PDF above in this page) for details on the product's current features and functionality. If you spot errors, inconsistencies, or if you need more information or assistance, please contact us.
The CompIQ series of compressors
|<<     <<     SWIPE TABLE     >>     >>|
Circuit Design
Dynamic Processing
Analog Engines®
Control Element
Side-Chain Topology
Side-Chain Detection
Side-Chain Filter
Side-Chain Frequency Compensation
Voicing
Adjustable Input Level
Input Clipping LED
Balanced Output
Crossover
Compression Ratio
Threshold
Dynamic Auto Timing
Attack Time
Release Time
Make-up Gain
Compression Knee
EQ
EQ Bypass
Dry/Wet Mix
Saturation
Saturation Filters
Compression Display
9V Battery Operation
DC Power Range
Current Consumption
More Info
Compressor / Limiter
Dual Band / Stacking
2
Blackmer® VCA
Feed Forward
True RMS-Level Sensor
Normal / Low / Deep
lows only
YES
-
-9dB to +6dB
> +6dBu signal levels
-
Linkwitz–Riley
70Hz to 1KHz
1:1 to inf:1
both bands
-40dBu to +10dBu
both bands
Auto Fast / Slower
both bands
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
both bands
Hard / Soft
both bands
Through Make-up Gains on Wet line (boost/cut)
-
YES
On Dry Line
adjustable
Lo / Hi Cut filters and Level controls
6-LED
both bands
-
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 69mAh @ 9VDC
< 110mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
Feed Forward / Feed-Back
True RMS-Level Sensor
Variable Lows / Highs
YES
Flat, Spark, Tight, Punch
-
-
Transformer Balanced / Unbalanced (Floating)
with optional DITOS DI board
-
1:1 to inf:1
-45dBu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
Manual: 0.12 ms/dB to 12 ms/dB
F / S: 70ms / 100‐220ms
Manual: 1.2 ms/dB to 120 ms/dB
-6dB to +20dB
Hard / Soft
X-EQ +/-6dB with Hi / Lo frequency pivots
-
YES
-
-
8-LED
YES
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 35mAh @ 9VDC
< 63mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
Feed Forward / Feed-Back
True RMS-Level Sensor
Variable Lows
YES
-
-
-
-
-
1:1 to inf:1
-40dbu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
Hard / Soft
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 25mAh @ 9VDC
< 38mAh @ 12VDC
Compressor
Single Channel
1
Blackmer® VCA
Feed Forward
True RMS-Level Sensor
Normal
YES
-
-
-
-
-
1:1 to inf:1
Lo: -40dBu / Hi: -30dBu
Auto Slow
12ms
220ms
-6dB to +20dB
Hard
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 15mAh @ 9VDC
< 23mAh @ 12VDC
MINI Pro vs. other minions

Do you want to know more about mini compressor pedals? We compiled a Technical Shootout for the most performance and popular mini compressor pedals available. Find out how our CompIQ MINIs stand out.

Blackmer® VCA

Originally designed by David Blackmer, the founder of dbx Inc., the dbx 202 “Black Can” Voltage Controlled Amplifiers (VCAs) are still in use in audio consoles today. These pioneering VCAs were the first of their kind suitable for professional audio equipment. They were constructed with a gain cell made up of eight individual transistors. Over time, advancements in integrated circuit technology have surpassed the limitations of earlier designs, leading to significantly improved performance.

For example, the CompIQ series of compressors incorporates THAT Corporation’s Blackmer® VCAs. These VCAs are recognized for their unique exponential control characteristic, where the gain changes directly in decibels. They offer an exceptionally wide dynamic range and maintain low signal distortion. What sets them apart is their neutral tonal character, which means they don’t introduce any significant coloration to audio signals. This makes them an excellent choice for audio professionals seeking high-quality, transparent signal processing.

RMS-Level Sensor

David Blackmer, the founder of dbx Inc., is known for inventing the RMS-level detector. It calculates the Root Mean Square level of input signals in a way that mimics how our ears perceive sound, which is in a logarithmic format.

This detector’s exact envelope is then used to control the Voltage Controlled Amplifier (VCA) based on user-defined settings like Ratio, Knee, SCF, Threshold, Attack, Release, and Gain.

Threshold Range

The CompIQ compressors have a versatile Threshold control that can handle a wide range of input signals, from weak to pro-audio levels, preventing distortion from high-level spikes. The threshold range scale is logarithmic and spans from approximately -40dBu to +10dBu, suitable for various applications. Typically, the optimal threshold for pickup signals falls between -30dBu to -20dBu.

For desired peak compression, set the Threshold knob at around 9 o’clock or slightly higher. Higher compression ratios are unnecessary unless you’re aiming for limiting. If you want more noticeable compression, lower the threshold, but use smaller compression ratios to avoid excessive signal compression, unless you intend to achieve a specific effect, like the “New York compression style,” which blends compressed and unprocessed signals for a balanced dynamic range.

Side Chain Filter

The Side Chain Filter (SCF) is a feature that affects compression based on frequency. It prevents high-amplitude low-frequency content from prematurely triggering compression and dulling the sound. This is achieved by filtering the side-chain downwards from 1kHz, as shown in the graph. By doing this, compression doesn’t affect those specific low frequencies in the VCA that the program sound passes through. As a result, the low frequencies come out louder and less compressed, creating a distinct and fuller, more natural, or punchier sound.

Side Chain HPF Options in CompIQ PRO Stella Compressor (-12dB at 90Hz & -12dB at 200Hz)

Using the SCF helps reduce unwanted pumping artifacts often seen in “high ratio / low threshold” compression techniques. The compression achieved with the SCF is unique compared to other methods of avoiding pumping, like adjusting the threshold, ratio, using soft-knee compression, or mixing dry and wet signals. Combining the SCF with other controls provides more flexibility for applying compression to different audio content.

The SCF circuitry was improved post-2022 for some of our compressors. The MK2 Mini and Stella’s SCF now include a boost function integrated into the same variable control for low-frequencies. Rotating the control CCW boosts the frequency in the side chain, CW cuts it, and center position keeps SC frequencies unchanged. This continuous adjustment adds versatility. Boosting the preset frequency makes the compressor more responsive to those frequencies, useful for weak signals or pickups lacking low-frequency content.

Moreover, Stella MK2 now includes a Highs Side Chain Filter for frequencies above 3K. This refinement helps manage overly bright signals by adjusting compressor sensitivity to target these frequencies selectively.

Side Chain Frequency Compensation

Frequency compensation involves adjusting the audio spectrum for the Side Chain Detector. In music, dominant frequencies and harmonics are present in each note. When notes have lower dominant frequencies, like in low guitar strings, they can trigger compression too soon, over-compressing harmonics and higher notes. To tackle this, we use gradual filtering starting at 20KHz and moving downwards with additional high-pass filters at 1KHz. This progressive approach prevents “pumping” and results in a more natural, dynamic processing, especially noticeable in percussive or bass-rich instruments.

Our compressors use a standard side-chain roll-off curve that aligns with human hearing, reducing -12dB at 2KHz compared to 20KHz.Side Chain HPF Options in CompIQ PRO Stella Compressor (-12dB at 90Hz & -12dB at 200Hz)

For the CompIQ Stella and CompIQ Twain compressors, we offer three Side Chain Filter options: Normal (based on human perception), Low (-12dB per octave at 90Hz), and Deep (-12dB per octave at 200Hz).

The new variable SCF option on the CompIQ Mini can be adjusted by turning the knob clockwise to free up -12dB per octave at 90Hz, suitable for guitar and bass instruments. At noon, the SCF provides Normal processing, and turning the knob counterclockwise boosts low frequencies below 90Hz with up to +12dB per octave, making it more sensitive to signals from instruments like single coil guitars.

Side Chain Feed (Forward/Backward)

The CompIQ Mini, Stella, and Twain models produced after 2022, 2024, and ongoing, offer selectable side chain processing. In Feed-Forward mode, the control signal is pre-VCA, resulting in an fast “in your face” compression feel. The new Feed-Back mode, however, uses the control signal post-VCA for a softer processing feel due to inherently longer attack and release times and the particularity of this way of controlling the side chain. In Feed-Back mode, an adjustable gain control within the VCA reduces overall noise from Make-Up Gain. This way of processing is different from the classical feed-back circuits which usually employ a fixed high gain placed after the gain reduction element.

Though Feed-Back mode limits compression ratio due to finite gain control, our compressors can combine Hard Knee with Fast Auto or Manual Timing (in Stella) for enhanced compression speed and amount. With a higher variable Threshold targeting high-amplitude frequencies, our compressors can effectively function as soft limiters, leaving the core sound intact. Notably, the RMS level sensor also adds to the natural feel of dynamic processing of our compressors.

Crossover

The CompIQ Twain features a variable-range Linkwitz-Riley crossover (70Hz to 1KHz), which splits the input signal into two separate frequency bands processed by dual compression engines. The crossover output also feeds the Dry Line, allowing seamless blending of Dry and Wet signals without phase cancellations, no matter where the crossover is set.

To illustrate, a chart shows matched levels of internal and external circuits with the crossover at 1KHz, output set to buffer level, and Mix at 100% Wet. The chart demonstrates nearly perfect alignment of phase across the audio spectrum.

Twain Crossover Phase Shift Plot

The input signal’s phase remains a straight line, but the output signal’s phase gradually shifts from 0° at the lows to 400° at the highs. This is a normal result of the signal separation and recombination by the crossover’s band filters and compression engines. When switching from Bypass to Effect, there might be a perceived frequency delay, although no audible frequency loss occurs across the audio spectrum.

The following drawing illustrates the Crossover Knob Frequency Scale and the most suitable setting for utilizing the Saturation feature.

CompIQ Twain Crossover Frequencies & Best Saturation Range

CompIQ Twain Crossover Frequencies & Best Saturation Range

Tape Saturation Lo & Hi-Cut filters

Both the CompIQ Stella and CompIQ Twain MK1 compressors offer an analog Tape Saturation circuit that exclusively affects the Dry signal. This lets you add optional saturation to your signal, which can then be blended with the compressed Wet signal to introduce harmonic distortion and warm up the audio while preserving the compressed signal’s dynamics. Note that you might need to dial in some saturation before it becomes audible due to the high headroom of the saturation circuit.

For the CompIQ Stella, you can activate the LPF and HPF by removing the internal jumpers. The CompIQ Twain has variable filters accessible through small trim knobs. The HPF is for the Lows band, and the LPF is for the High band. In both compressors, the HPF is placed before the Saturation engine, while the LPF is positioned after it.

These filters are recommended for use in conjunction with the Tape Saturation feature, as they may affect the clean, dry signal otherwise. The filters were introduced to provide flexibility when processing different audio sources while maintaining musicality and avoiding undesirable artifacts like muddiness in the low end (especially with bass) or harshness with bright guitar pickups.

X-EQ

The X-EQ section comes after the compressor and before the Mix control, affecting only the wet signal. When mixing dry and processed signals, the X-EQ effect gradually diminishes.

In the Stella, the X-EQ has two frequency pivot points for bass (at 330Hz) or guitar (at 1KHz). At extreme knob settings (fully clockwise or counterclockwise), there’s a total 12dB difference between low and high frequencies. When the X-EQ knob is in the central position, no frequency alterations occur. You can bypass the X-EQ section by adjusting a jumper within the pedal (only available for Stella up to V1.3; for V1.4 the jumper is not physically installed but it can be installed by the user if desired, and starting with V2.0 the jumper is no longer available).

Line-level signals

The CompIQ compressor series can handle input signals ranging from +5dBu to +10dBu without distortion, depending on the model and power voltage. They offer a wide 50dB threshold range from -40dBu to +10dBu, making them suitable for magnetic pickups, line-level signals, line-level FX Loops, and high impedance or line-level inputs on recording interfaces. These compressors provide precise compression thanks to the RMS-level detector, and their LED indication is accurate when the input signal is around the calibrated reference level. The CompIQ series internally sets a “0dB reference input level” at -20dBu (77.5mVrms). The amount of compression (inf:1 Ratio) depends on the input signal level and is typically 20dB for input signals around -20dBu (77.5mVrms) and 36dB for +4dBu (1.23Vrms) input signal levels.

Compressor noise

Compressors can introduce noise due to the amplification of make-up gain. As compression increases, more make-up gain is needed, adding noise to the signal. This noise can be further amplified by subsequent pedals or amplifiers in the signal chain. Additionally, any device before the compressor may introduce noise, which gets amplified by the make-up gain circuit.

It’s important to understand that if a compression setting requires a significant amount of make-up gain, noise will become more noticeable during silent parts. The signal-to-noise ratio drops during pauses, where noise may surpass the signal, leading to a negative SNR. Expecting complete silence when applying a +20dB gain is unrealistic. However, compressing at -20dB and then restoring with +20dB results in minimal but still noticeable amplification noise, especially during pauses. If maximum make-up gain is needed, it’s best to use the compressor for peak limiting rather than compressing the entire signal.

To accurately compare compressors for noise, they should be set with the same threshold, ratio, and make-up gain, fed the same reference signal. Some compressors have lower ratio limits, like 3:1 or 7:1, which makes them “quieter” because they require less re-amplification. Note that the term “quiet” is subjective and can be misleading.

In the case of the CompIQ Twain, the Stacked Mode can produce extra noise if not configured properly. The Twain Settings Examples provide guidance on minimizing amplification noise, primarily by adjusting compression and make-up gain in the second (highs) engine more than in the first (lows) engine. You can also manage the frequencies to compress in the second engine by raising the lows threshold, using the Low or Deep side-chain filter, and employing a soft knee to reduce noise or compression feel. Combining these controls in both engines helps find the optimal setting for your specific needs.

Dual-band processing is more complex and requires specialized compression. What works for full-band compression doesn’t directly apply to dual-band compression. The dual-band compressor’s always-on crossover has passive components that inherently generate thermal noise, which is also amplified by make-up gain.

A practical approach is to understand how compression controls (threshold, ratio, knee, timing, blend, side-chain filter, and gain) affect compression and your desired outcome. Adjust these parameters to minimize the need for high make-up gain.

Noise generated by make-up gain is typically lower with higher input signal levels because the signal is larger. When using a limiting setup with a higher threshold, hard knee, and inf:1 ratio that affects only the signal peaks, any noise is usually inaudible.

For weak magnetic pickup signals, using a 4:1 ratio and a low threshold on the CompIQ can provide compression with noise levels similar to studio-grade equipment. You can further reduce noise by blending in dry signal with the MIX control and using a soft knee to minimize the need for make-up gain.

Power sources can introduce noise to electronics. Switching power supplies, in particular, are known for introducing hissing sounds. To minimize this, use well-filtered and regulated power sources. Most pedals aren’t designed for extensive power conditioning and filtering, so it’s essential to use quality power sources separately.

Switching noise
It is possible for pops or static noise to manifest when adjusting certain settings while the pedal is engaged. These settings include the knee, timing, side chain filter, EQ pivot, dual-band/stacked mode, and power on/off.

Gain Reduction Meter

The CompIQ line of compressors features a gain reduction meter to show the amount of compression applied to the input signal in dB. However, the number of LEDs in the meter varies between products and may lead to “invisible” compression between LEDs. To achieve optimal metering, a minimum of 20 LEDs is recommended.

Each product’s metering is designed and calibrated with reference to comparators at 9-12VDC, ensuring an accurate indication of gain reduction. However, the CompIQ Twain can also operate at 18VDC. At 18VDC, some calibrated thresholds for metering may shift, resulting in a metering indication of approximately -3dB less. While running an electronic circuit within a fixed voltage range (plus or minus some tolerance) is proper, operating at 80-100% voltage upshifts may alter certain calibrations within the circuit blocks. While this might have audible advantages, it impacts metering precision and introduces variation.

In rare cases, such as when powering the pedal at a higher voltage and switching the knee, the meter LEDs may appear “locked” and remain lit. This happens due to an electric spike caused by knee switching, briefly activating the LEDs even without an input signal. To prevent this, it’s advisable to switch the knee when no input signal is present but with the input and output plugs inserted into the pedal.

To turn off the remaining lit LEDs, the pedal must be powered off and then on again, or you can play a signal louder than the remaining lit LEDs, resetting the comparators. Alternatively, you can power the pedal with 9-12VDC instead of 18VDC.

Powering voltage range for the CompIQ line of compressors

The CompIQ pedal line can function within a power range of 9-18VDC. However, for optimal performance and circuit protection, certain components like the gain reduction meter are designed and calibrated conservatively to operate within the 9-12VDC range. It’s crucial to use high-quality, regulated power sources because exceeding the 18VDC maximum can potentially damage active components.

To prevent voltage spikes during pedal connection, it’s advisable to connect the pedals before powering on the power supply. Additionally, it’s a good practice to power your entire pedalboard simultaneously by switching on the AC switch on the power supply or plugging it into the AC wall wart. This helps control current draw and maintain stable voltages at each power output.

While our pedals incorporate reverse polarity protection, there are limits to what these safeguards can handle. Thus, using power supplies within the recommended voltage range is vital to ensure optimal performance and protect the circuits’ long-term durability.

Demos, reviews & comments

Blog post: The 101 of the CompIQ line of compressors

CompIQ Stella Settings Examples

Before you start

The CompIQ Stella is a full-featured compressor in pedal format which allows complex processing while preserving the dynamics of your playing. A good understanding of compression is normally required to optimally set it up for live performance or studio recording.

We advise testing the CompIQ Stella with an instrument amplifier instead of using headphones. Start by playing with it alone then integrate your settings along with your other pedals.

Here is the Stella Manual for your reference. For more in-depth technical info on our VCA line of compressors please take a look at the CompIQ 101 section. If you have particular questions regarding how Stella works, or you would like to share your feedback please contact us.

Stella sound demos on bass

Each demo has an associated image with pedal’s knobs & switches position used when recorded. A higher resolution image is displayed when loading the track on Soundcloud — along with details regarding the instrument, strings used for that phrase, and playing technique. Start by playing any track in the playlist below and click View Track to load it on Soundcloud for details.

The audio phrase is played twice in each track. First, the dry sound with the pedal in bypass, followed by a take with pedal engaged.

Many thanks to jazz artist Jean-François Untrau (France) who recorded these demonstrations.

Stella + DITOS sound demos on guitar

Back to Product Page

Blog post: CompIQ Stella Settings Examples

IN THE PRESS

For more articles, reviews, and mentions, please check our Blog.

Becos CompIQ Stella + Ditos Reviewed by Bass Magazine Japan - May 2022Usually, when I use a compression pedal, it’s more like an effect because it sounds cooler playing slap, rather than the use it to even out peaks. But the Stella can be set radically: you can hit only the high peaks with some nuances, or you can make it sound tight.

Becos CompIQ Stella + Ditos Reviewed by Bass Player Magazine - June 2022All in, the Stella manages to cram a dizzying number of top-quality features into a standard pedal. At all times, the tone was clear, clean and detailed in the way that I've come to expect from high-end studio plugins. Bravo!

Sound On Sound Magazine UK - Review - July 2020 IssueIn short, it’s what I’ve always wanted of a compressor pedal. The Stella can sound wonderfully transparent, or full of character, and there’s oodles of control at your fingertips. Bass players should absolutely love this thing (though I suspect they may be even more enamored with the company’s new split-band compressor).

Guitar Pedal XEverything here exudes quality and fidelity. 'Pristine' is typically mostly used to describe particularly high quality Reverb algorithms, but it also very much applies here. And you can deploy this pedal very simply if you wish to - and mostly just using the 3 core Ratio, Threshold and Gain controls. You can leave pretty much everything else in the centre, set Fast or Slow Auto Timing, Hard/Soft Knee, and F or B Side Chain Feed - the pedal takes next to no time to set up in the most basic of fashions.

Vintage Guitar Magazine USA - VG Approved Gear Review - May 2020 IssueThe CompIQ Stella has a ridiculous amount of power for a small stompbox. Better still, it's a transparent compression that only colors the tone as much as you allow it, unlike many lower-end boxes that simply squash tone and volume. That's the sign of a good unit - delivering compression power, clarity, and flexibility to control exactly what you want to hear from a guitar.

Guitar.com - Becos Effects’ CompIQ Pro Stella Compressor features rack-style controls on a stomperThis pedal is designed to provide an array of features – with rack unit-levels of tweakability – in a pedalboard-friendly format. A highlight of the CompIQ Pro Stella Compressor is its analog tape saturation circuit.

Music Radar - Guitar and bass stompbox delivers dizzying array of featuresCompIQ PRO Stella for guitar and bass delivers dizzying array of features. There are a staggering number of parameters onboard, which promise the versatility of a rack unit in a compact stompbox.

Extensive review of CompIQ PRO Stella Compressor on TalkBass.com ForumThis is a highly versatile and pedal board friendly compressor. I'm not aware of anything on the market that packs this much punch in terms of functionality. In many ways, it has raised the bar for compressor pedals. The words "Pro Compressor" on the face of the compressor is appropriate. There is a whole lot of versatility in an amazingly small package.

Guitar World - Knob-heavy pedal offers compression, limiting, tape saturation and more.Knob-heavy pedal offers compression, limiting, tape saturation and more.



COMPARE COMPRESSORS

The comparison table is best viewed on large screens, in landscape mode, preferably on desktop.

Circuit Design
Dynamic Processing
Analog Engines®
Control Element
Side-Chain Topology
Side-Chain Detection
Side-Chain Filter
Side-Chain Frequency Compensation
Voicing
Adjustable Input Level
Input Clipping LED
Balanced Output
Crossover
Compression Ratio
Threshold
Dynamic Auto Timing
Attack Time
Release Time
Make-up Gain
Compression Knee
EQ
EQ Bypass
Dry/Wet Mix
Saturation
Saturation Filters
Compression Display
9V Battery Operation
DC Power Range
Current Consumption
More Info
Compressor / Limiter
Dual Band / Stacking
2
Blackmer® VCA
Feed Forward
True RMS-Level Sensor
Normal / Low / Deep
lows only
YES
-
-9dB to +6dB
> +6dBu signal levels
-
Linkwitz–Riley
70Hz to 1KHz
1:1 to inf:1
both bands
-40dBu to +10dBu
both bands
Auto Fast / Slower
both bands
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
both bands
Hard / Soft
both bands
Through Make-up Gains on Wet line (boost/cut)
-
YES
On Dry Line
adjustable
Lo / Hi Cut filters and Level controls
6-LED
both bands
-
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 69mAh @ 9VDC
< 110mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
Feed Forward / Feed-Back
True RMS-Level Sensor
Variable Lows / Highs
YES
Flat, Spark, Tight, Punch
-
-
Transformer Balanced / Unbalanced (Floating)
with optional DITOS DI board
-
1:1 to inf:1
-45dBu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
Manual: 0.12 ms/dB to 12 ms/dB
F / S: 70ms / 100‐220ms
Manual: 1.2 ms/dB to 120 ms/dB
-6dB to +20dB
Hard / Soft
X-EQ +/-6dB with Hi / Lo frequency pivots
-
YES
-
-
8-LED
YES
9-18VDC center negative
Ø 5.1/2.1mm, 12mm long
< 35mAh @ 9VDC
< 63mAh @ 18VDC
Compressor / Limiter
Single Channel
1
Blackmer® VCA
Feed Forward / Feed-Back
True RMS-Level Sensor
Variable Lows
YES
-
-
-
-
-
1:1 to inf:1
-40dbu to +10dBu
Auto Fast / Slower
F / S: 5‐7ms / 10-15ms
F / S: 70ms / 100‐220ms
-6dB to +20dB
Hard / Soft
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 25mAh @ 9VDC
< 38mAh @ 12VDC
Compressor
Single Channel
1
Blackmer® VCA
Feed Forward
True RMS-Level Sensor
Normal
YES
-
-
-
-
-
1:1 to inf:1
Lo: -40dBu / Hi: -30dBu
Auto Slow
12ms
220ms
-6dB to +20dB
Hard
-
-
YES
-
-
5-LED
-
9-12VDC center negative
Ø 5.1/2.1mm, 12mm long
< 15mAh @ 9VDC
< 23mAh @ 12VDC

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