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Cp554 Diode Bridge Compressor Similar To Neve 2254 Fp

Introducing the CP554: A Modern Take on Classic Diode Bridge Compression.

The CP554 is a feature-rich diode bridge compressor that offers a clear tonal response when not operated in vintage mode, providing you with the freedom to maintain sonic clarity when desired.

Incorporating diode bridge circuitry as the gain reduction element adds a touch of harmonic coloration, a characteristic that can enhance your sound and introduce

CP554 employs the specially developed adaptive HRK soft-knee characteristic, created by B. Hrk. This intuitive feature simplifies the use of the compressor, making it accessible to users of all experience levels.

With its user-friendly design, even beginners can produce professional-grade results. The versatile HRK soft-knee curve is impressively musical and adapts seamlessly to a diverse range of music genres and signal types, granting you exceptional flexibility in shaping your sound.

In Vintage Mode, the HRK Custom Analog Circuitry (not a DSP) replicates harmonics closely resembling those generated by the transformers and circuits of classic vintage diode bridge compressors like the Neve 2254, 2264, 33609. This attribute gives you access to analog warmth and character at the flip of a switch.

CP554 is not a clone of any well-known diode bridge compressor. The design of the CP554 is based on engineering principles similar to which were incorporated in the classic or vintage equipment.

The CP554, designed and constructed using traditional methods, offers an authentic analog experience, embodying the golden era of audio processing.

CP554 | Diode Bridge Compressor Introduction and Demo

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CP554 vs. NEVE 2254, 2264, 33609

The CP554 is based on the same principles of operation as the NEVE 2254, 2264 and 33609.

All the above compressors use the Diode Bridge as a circuit which controls the level of the signal.

CP554, however, is based on modern components and produces a lot less self-noise compared to vintage NEVE designs. Which means that CP554 is better suited for stereo-bus applications.

Furthermore, CP554 in a default mode produces a far more neutral tonal response and if the NEVE-like character is required, the Vintage Mode can be engaged to add extra transformer harmonics to the signal, providing more flexibility for various studio applications.

Why Are Diode Bridge Compressors So Expensive?

The market filled with a multitude of studio-grade compressors, with VCA, FET, and opto-compressors being the most prevalent. In contrast, diode bridge compressors are comparatively rare and expensive, with limited options primarily comprised of AMS-Neve units based on Rupert Neve’s original designs, such as the 2254, 2264, and 33609 stereo compressors.

While some manufacturers attempt to create Neve clones using accessible original diagrams, it is crucial to note that even the most precise clone cannot replicate the original Neve, as the sole source of transformers today is Carnhill, which manufactures transformers based on the original Marinair’s specification, providing only substitutes for Marinair transformers used in classic Neve’s units.

Utilizing a diode-bridge element as the gain control block necessitates a particularly designed circuitry, where the ideal signal symmetry is of utmost importance. In the 60s, only transformers could deliver this perfect signal symmetry.

Traditional diode-bridge compressors are also known for their heightened noise floor. An inadequately designed circuitry can drastically amplify the noise, making the compressor unsuitable for studio applications.

Reproducing Neve’s compressors may be feasible, but it does not guarantee high-quality results. A profound understanding of diode-bridge compressor design is the true key to success.

The CP554 stands apart from mere clones. It is meticulously designed to adhere to the principles of diode-bridge circuitry while striving to achieve optimal performance. CP554 delivers an unparalleled sonic experience, bridging the gap between rarity and excellence for discerning audio enthusiasts.

Experience the Classic Sound of Transformers Delivered by Advanced Technology

Discover the tone of vintage transformers merged with contemporary innovation in the CP554 Diode Bridge Compressor. While the classic diode bridge compressors designed by Rupert Neve extensively utilized transformers, their application was largely dictated by the technological constraints of the 60s and 70s.

Transformers were, at the time, the sole devices capable of performing specific functions in professional audio circuitry, such as impedance matching, level reduction or amplification, and signal transformation from balanced to unbalanced, or vice versa.

The CP554, however, is engineered with modern electronic components, transcending these limitations. While it adheres to the traditional diode-bridge compressor design principles, it is neither a copy nor a clone of any vintage unit. The extensive use of transformers in the diode bridge is no longer a necessity.

Transformers can now be substituted with state-of-the-art electronic components, resulting in superior signal-to-noise ratio and enhanced immunity to electromagnetic interferences. These advancements maintain the cherished sound quality of vintage units while capitalizing on contemporary technology.

In its default mode, the CP554 offers a subtle infusion of harmonics produced by the diode-bridge circuitry. This approach ensures that the device remains neutral and non-destructive to the musical material, providing an unparalleled balance of sonic nostalgia and modern-day innovation.

CP554 | Diode Bridge Compressor Overview

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The CP554 Vintage Mode Experience

Introducing Vintage Mode, a proprietary circuitry designed by Bart Hrk that brings the enchanting harmonics of classic diode bridge compressors to life through analog processing circuitry. This fully analog design (no DSP) is rooted in an in-depth understanding of the performance, response, and operation of traditional analog circuitry.

Vintage Mode is the culmination of extensive knowledge of transformers and vintage circuitry, coupled with vast experience in analog circuitry design. This potent combination allows us to faithfully reproduce the distinctive performance, character, and vibe of vintage analog circuitry and transformers. After all, electronic engineering is science, not magic!

The Vintage Mode circuitry promises a response akin to that of vintage transformers, where more signals yield more harmonics. The resultant sonic experience mirrors that delivered by vintage units, complete with their unique frequency and tonal responses.

By default, the CP554 is a neutral and versatile tool. It does not impose any strong character on the musical material, significantly expanding its applicability in studio and music production settings. However, when required, the activation of Vintage Mode introduces classic harmonics, transforming the CP554 into a Vintage Diode Bridge Compressor.

With CP554, you’re investing in a dual-purpose tool, an epitome of modern versatility and vintage charm combined. This 2-in-1 design ensures you have the right sonic character for any situation, making it an invaluable addition to your audio production arsenal.

Stereo Buss Operation

Cp554 Diode Bridge Compressor Similar To Neve 2254 Dual

*The Stereo Link cable is provided together with a pair of the CP554.

CP554 | Diode Bridge Compressor  vs. DAW Plugins

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HRK Active Transformer

Hrk Active Transformer

Bart Hrk has developed a proprietary design for an Active Transformer, aimed at addressing the limitations of traditional passive transformers.

Traditional passive transformers are known to be vulnerable to electromagnetic interference, such as 50/60Hz hum and HF RF smog. Additionally, their frequency response is contingent upon load and source impedance, which adversely affects the overall performance of analog studio equipment.

The HRK Active Transformer is a game changer that not only resolves the issues associated with passive transformers but also retains and amplifies the desired characteristics of the transformer output stage. This includes the enrichment of harmonic content and the enhancement of tonal response.

What sets the HRK Active Transformer apart is its ability to deliver the rich, beloved sound that audio enthusiasts seek, including the harmonic content and tonal response, while simultaneously eliminating the drawbacks of passive transformers.

Furthermore, the Active Transformer introduces a delicate “Air” effect and boasts an extended low-frequency (LF) performance, adding depth and clarity to the sound.

Another remarkable feature of the Active Transformer is its dynamic saturation, which is dependent on the output level. As the output signal level increases, the Active Transformer exhibits greater saturation, reminiscent of the warm and rich sound produced by classic studio equipment.

In summary, the HRK Active Transformer is an innovative solution that offers superior sound quality, eliminates electromagnetic interference, and enhances harmonic content and tonal response. It is an invaluable asset for professionals and audiophiles seeking to elevate their audio experience.

CP554 | Diode Bridge Compressor vs. Dione VCA Compressor

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CP554 Specification

Input Type / Input Impedance Balanced Electronic 20k
Output Type / Output Impedance Balanced HRK Active Transformer Less than 10R
Max Output Level +25dBu@0.1%THD with 1k Load * Balanced Signal
Recommended Load Balanced 10k Minimum Supported Load 600R
Initial Gain 0dB Gain Make-up set to 0dB
Phase Reverse No CP554 is not introducing phase reverse in any mode of operation.
Frequency Response 5Hz-80kHz@-1dBr Compressor disengaged.
Static Noise Level -95dBu@10Hz-22kHz Compressor disengaged.
Power Consumption Typically 45mA per unit 60mA max. per unit
Format API 500 Format Compatible with most of the 500 Racks
Type of Compressor Engine Diode-Bridge Symmetric Gain Cell
Compression Curve Adaptive Soft-Knee Depends on the Threshold and Ratio knob settings
Threshold Range -25dB / + 20dB Smooth Continues Potentiometer
Ratio Range 1.5:1 - 8:1 Smooth Continues Potentiometer
Attack Time 250uS - 100mS Smooth Continues Potentiometer
Recovery Time 50mS - 2.5S Smooth Continues Potentiometer
Side Chain HPF 150Hz@6dB/oct Use the HPF Switch
Frequency Response 5Hz-30kHz@-1dBr Compressor engaged.
Recommended Use
CP554 is a line-level compressor. CP554 is not equipped with a microphone preamplifier.

The input signal should be connected to the rear XLR input.

It is recommended to use -12dBu input signal level initially and increase the level signal if required.
ALL HRK Products Are Brand New - Assembled and Fully Tested

All HRK Products are tested with the industry’s best audio measuring equipment – The Audio Precision

Audio Precision is an industry leader in providing high-quality audio testing equipment. They are renowned for their test systems’ precision, reliability, and versatility.

When testing studio audio devices, Audio Precision’s equipment can assess parameters like frequency response, harmonic distortion, intermodulation distortion, phase response, signal-to-noise ratio, and cross talk. In-depth and accurate testing allows the identification of even the smallest issues in audio quality, enabling corrections and improvements that can significantly elevate the overall product quality.

In conclusion, using Audio Precision test equipment is an excellent way to ensure that all HRK products are performing at their best, meeting the standards required for the Professional Studio Applications.


Stereo Buss Operation

All Items are dispatched from Poland in the European Union within 1-3 working days.

Country / RegionShipping CostCustoms FeeVAT
All 27 European Union Countries – Delivery Time: 2-7 Days

– 14.99USD for orders below 299USD

– FREE shipping for orders over 299USD

NO Customs Fees– Yes, for personal orders- Not charged with the EU VAT number
United Kingdom – Delivery Time: 3-7 Days

– 14.99USD for orders below 299USD

– FREE shipping for orders over 299USD

No VAT ChargeHMRC collects the VAT or additional Fees if applicable.
USA, Canada – Delivery Time: 5-10 Days

– 14.99USD for orders below 299USD

– FREE shipping for orders over 299USD

NO Customs Fees for orders up to 800USD – charged by the USA Customs OfficeNo VAT charge.
Australia, Japan, South Korea –  Delivery Time: 5-14 Days

– 19.99USD for orders below 299USD

– FREE shipping for orders over 299USD

There is no info available – refer to local regulations.No VAT charge.
Switzerland Delivery Time: 3-7 Days

– 14.99USD for orders below 299USD

– FREE shipping for orders over 299USD

There is no info available – refer to local regulations.No VAT charge.
Norway Delivery Time: 3-7 Days

– 14.99USD for orders below 299USD

– FREE shipping for orders over 299USD

There is no info available – refer to local regulations.No VAT charge.
Worldwide Destination Delivery Time: 3-14 Days– 29.99USDRefer to local regulations.No VAT charge.

EU Customers

EU Customers will not pay any extra customs fees.

Business customers with a valid EU VAT number will not have to pay VAT tax.

Please enter your EU VAT Number at checkout and the VAT will be deducted from the Total Payment. The VAT number is automatically checked in the VIES database.

For personal orders from the EU, VAT will be added at checkout.

UK Custmers

We ship directly to United Kingdom.

UK VAT tax is collected by HRMC

Non-EU Customers

Customers from outside the EU purchase items with no VAT.

Please select the destination country and the VAT will be removed automatically.

If the VAT is not removed, please email customer service via the contact form and a custom invoice will be issued.

USA and Canada

Orders from the USA below 800USD are FREE from customs tax.

We ship directly to the USA and Canada

Payment Options:

You can pay for your order with any Credit Card or Apple Pay!

PayPal – We do not use PayPal as a payment method.

7 Days Return Policy

Our return policy is a part of the general Terms & Conditions, which you must acknowledge at the checkout. We stand by fair rules and a win-win approach.
We understand that our customers may wish to return the product and we provide such an option.
However, because we are a small company, we can’t afford to run a grade B outlet shop like big distributors and provide a 30 day return period. We can’t also scrap every returned unit.
We can charge our customers more to offset the cost of the returns, and this is what major distributors do. Or we can keep our prices low and hope that our customers will appreciate our policy.
This is why we provide the 7 days test period after receiving the package with the ordered items. If you wish to return the item, we will accept the return request, provided that the item is not damaged.

If the item is damaged during transport, we will do our best to help you and provide a replacement product.