EIGENTAKT - Ultra Linear and Robust Class D Amplifier Technology

The EIGENTAKT Class D Amplifier Technology from PURIFI is the result of extensive research and patented IP aimed at addressing persistent challenges in Class D technology. This innovative technology delivers ultra-linear and extraordinarily robust performance that meets the needs of audio developers and end-users alike. It enables system integrators to design and manufacture products that are top-of-the-line in terms of audio performance, industrial-level reliability, and cost-effectiveness.

Unlike traditional Class D technology, EIGENTAKT eliminates common stigmas such as "harsh sound" and "frail reliability". This has been confirmed by objective measurements, subjective listening tests, and harsh robustness testing.

EIGENTAKT is available in multiple forms ranging from a line of drop-in Amplifier Modules to Amplifier Designs for Licensing by OEM's. At PURIFI, we are open to discussing custom or semi-custom EIGENTAKT Designs based on our IP.

Unrivalled Performance

Best-in-class linearity specifications translate into crisp and clear music reproduction across all levels, frequencies and loads.
No inherent "sonic fingerprint" - just complete transparency.
Enables development of top tier end-products with little development effort.

Robust & Reliable

Purposely designed and tested with extreme ruggedness and quality as main objectives.
End result is a negligible low amount of field returns or quality claims.
Saves cost, increases end-product profitability and enhances brand value for OEM's.
Improves user experience.

Integrates Easily

Compact footprint (size) with well-defined interface.
Resilient against power-supply variation/quality.
Optimized for low EMC and adopts at the application level without integration headaches.
Significantly shortens and reduces end-product development time and cost.

EIGENTAKT - Amplifier Modules

Do you want your audio products to have sublime sonic performance? Then, incorporating PURIFI's EIGENTAKT Modules will be a very attractive choice...

EIGENTAKT modules are compact, easy to integrate, super robust, and cost-effective. And yes, of course, with unsurpassed linearity specification resulting in best-in-class audio performance which will set your end-product apart from the competition.

To make evaluation simple, we offer 'EVAL' kits that in addition to the EIGENTAKT module(s) include a neutral, high-performance audio front-end. You can easily connect the EVAL kit to a power supply and conduct your own measurements and listening tests. The EVAL kits are also perfect for DIY enthusiasts who want to create a high-end audio amplifier that outperforms commercially available amplifiers, but at a fraction of the cost.

For a more information, including detailed datasheets and users guides, please visit our webshop.

Product Catalog & Data Sheets

Amplifier Modules & Evaluation Kits

General Products & Evaluation Kits

Mono/Stereo Evaluation kits consist of a front-end board + 1ET400A amplifier module(s).
The front-end board contains a pre-gain stage, low-voltage regulators, balanced analog input (XLR), speaker terminals and connectors for PSU/control. (PSU must be sourced separately)

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OEM Amplifier Products

In addition to our Catalog modules (presently, 1ET400A and 1ET7040SA), PURIFI also develops custom or semi-custom products based on EIGENTAKT IP. Please contact us directly to explorer this option.

OEM EIGENTAKT

What Makes EIGENTAKT So Special?

Firstly, we recommend that you experience EIGENTAKT with your ears by listening to your favorite music. No data sheet can fully convey the clarity, detail and enjoyment that EIGENTAKT offers during a listening session.

However, objective data sets are also essential to explore and compare when auditioning amplifier technologies. Hence, we strive to create detailed, accurate, and reliable data sheets with an abundance of relevant information. Please feel free to contact us directly if you find any missing information.

EIGENTAKT incorporates a comprehensive protection system that makes it tremendously robust and easy to integrate. Please refer to data sheet for details.

Here's some important characteristics worth noticing:

Negligible THD & IMD

The patented EIGENTAKT ErrorCorrection IP ensures ultra-high loop gain (>75dB) in the entire audio band. This figure corresponds to an unprecedented 110MHz Gain-Bandwidth Product and produces consistent ultra-high performance across the audio spectrum unmatched by audio amplifiers of any technology or operating class.

Intermodulation Distortion (IMD) is a very good measure for how well an amplifier handles complex signals. Sonically low IMD means a highly resolved and stable stereo image across the whole spectrum, even during very complex and busy passages.

THD remains extremely low at any frequency and any power level right until clipping. This translates into a total lack of sonic signature, and an ability to reproduce any type of music without preference for genres or production style.

Negligible audible noise. Deep black silences and a generous and detailed sound even at very low playback volumes.

Load-invariant Frequency Response & Negligible Output Impedance

EIGENTAKT handles difficult loudspeakers with ease, including those that challenge most other amplifiers. The Frequency Response (FR) is very flat in the entire audio-band with a sensible 60kHz bandwidth. Variation between high-impedance and low-impedance loads is completely negligible as indicated by perfectly overlapping 2-ohm to "open-load" FR plots.

Minimized sensitivity to out-of-band noise from DACs reduces requirements on the DAC reconstruction filter and enables possibility of a shorter signal path between DAC and loudspeaker (integrated products). The reduced sensitivity also ensures problem-free operation with outboard DACs over which you may have no control.

Output Impedance in the sub milli-ohm range resulting in a five-digit Damping Factor.

Very low Idle Losses & Reduced Electromagnetic Interference (EMI)

EIGENTAKT ErrorCorrection allows relaxed timing of the power MOSFETs without degrading audio performance. This brings additional benefits in terms of very low Idle Losses and low Electromagnetic Interference (EMI).

The minimized Idle Losses combined with high Power Efficiency allows the EIGENTAKT technology to run cool even within constraint enclosure sizes and minimal heat sinking. EIGENTAKT is specified for continuous output power with a realistically implemented thermal system.

Low Electromagnetic Interference (EMI) makes it convenient and easy to integrate EIGENTAKT modules at the system level. Typically, regulatory tests are passed with little to no effort needed.

EIGENTAKT - Design Licensing

Design Licensing may be an attractive approach for OEM's wanting to combine in-house circuit design, e.g., differentiated audio front-end features, with the ultimate high-performance power stage - and prefer to manage all aspects of application design, component sourcing and product manufacturing independently.

The process for licensing a power stage design from PURIFI follows a straightforward path covering both technical- and business-level aspects. Read more below - and reach out to us directly for a more in-depth introduction if this piqued your interest.

Design Licensing - Technical

For OEMs seeking a fast, efficient, and proven approach, licensing PURIFI's amplifier designs (e.g., 1ET400A, ET7040SA, etc.) is a great option. PURIFI will provide a comprehensive documentation package, including schematic, bill of materials, gerber (PCB layout), and test procedure for the chosen EIGENTAKT design.

To achieve excellent results, the system integrator needs to precisely replicate the licensed design onto their application PCB. PURIFI's engineers will be available for consultation throughout the application design phase and will conduct a thorough test and characterization of the final product to ensure it meets PURIFI's high standards for performance and robustness. Upon approval, the OEM can begin manufacturing and selling of EIGENTAKT-based products.

Design Licensing is convenient, straightforward, and suitable even for projects with tight timelines and limited development budgets.

Design Licensing - Business

The business aspect of Design Licensing begins with the signing of a non-disclosure agreement (NDA) between both parties. This allows for open discussions on project requirements, timelines, and expectations. Once an agreement is reached, a License and Royalty Agreement is signed, specifying all project deliverables, terms, and financial aspects.

Financial compensation consists of a combination of non-recurring expense (NRE) and volume-based Royalty payments. The NRE covers PURIFI's engineering effort for the project and the volume-based Royalties are paid for each unit manufactured. The NRE is paid upfront, while Royalties are reported and paid at regular intervals.

EIGENTAKT - IP & Design Best Practices

Are you interested in learning about the technology behind EIGENTAKT, the amplifier that delivers unparalleled performance and rugged reliability? Read on to discover how PURIFI's extensive research and patented IP have solved the most pressing problems facing Class D amplification.

EIGENTAKT is built upon a combination of proprietary mathematical models, numerical optimization algorithms, and patented circuit topologies. This approach has enabled us to identify and solve some of the biggest challenges facing Class D amplification, including harsh sound caused by nonlinearities such as magnetic hysteresis in the output filter.

In addition to these patented circuit topologies and optimization techniques, EIGENTAKT also employs a robust design- and test methodology to ensure that each unit meets the highest standards for both audio performance and reliability.

Whether you're an OEM seeking to integrate EIGENTAKT into your products or an end-user looking to experience the benefits of this innovative technology, you can trust that EIGENTAKT has been designed and tested with your needs in mind.

Problem: Magnetic Hysteresis Distortion (MHD)

Magnetic hysteresis in the output filter of Class D amplifiers can lead to a harsh sound quality. This manifests as popping or crackling noises that are difficult to eliminate and detract from the listening experience. You can’t rely on masking to render it inaudible.

Any inductor with a core material that has a higher permeability than air will exhibit hysteresis. However, we aim to eliminate distortion while keeping the magnetic core intact since they offer practical benefits like containing stray fields and reducing power losses while also minimizing the size. Simply switching to different ferrite grades won't be very effective since even the highest quality ferrites are only about twice as effective as standard types. (Read more here)

Solution: EIGENTAKT ErrorCorrection (EEC)

EEC is a "full output feedback" architecture, meaning a correction circuit that encloses the entire power stage including the demodulation filter, inside the loop. So when the inductor gives off one of its hysteretic pops the EEC suppresses it with more that 75dB of compensation. That’s it. Any audible remainder is eliminated.

The result is clear and detailed music on a deep black background, with no hint of smearing or coloration.

Problem: Intermodulation Distortion (IMD)

Some may argue that chasing low Harmonic Distortion (HD) is overrated. Some even go as far as to say that it's a beneficial artifact. Well, we politely disagree on that claim, but it's not a fight worth picking. However, we will go to combat for avoiding its evil twin Intermodulation Distorting (IMD), which unfortunately is an unavoidable companion of Harmonic Distortion. In other words, HD and IMD aren’t two different types of distortion per se, but different ways in which the same distortion mechanism can manifest itself more or less saliently.

Solution: EIGENTAKT ErrorCorrection (EEC)

The numerically optimized EIGENTAKT ErrorCorrection system, which at present stage provide more the 75dB error attenuation across the entire audible range, effectively eliminates harmonic-, intermodulation- and magnetic hysteresis related problems in one blow.

EEC is a "full output feedback" architecture, meaning a correction circuit that encloses the entire power stage including the demodulation filter, inside the loop. The result is clear and detailed music on a deep black background, with no hint of smearing or coloration. Truly an ear-opening experience.