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Eq522 Germanium 2 Band Equalizer Bart Hrk

Ultrasmooth 2 Band Germanium Equalizer

The EQ552 is a user-friendly, two-band equalizer that uses vintage Germanium transistors for superior sound quality. It offers four frequency settings for each band, giving you plenty of options to fine-tune your music.

What sets the EQ552 apart is its use of separate Discrete Operational Amplifiers, made with high-quality, military-grade Germanium transistors from the 1960s. This ensures a smooth and natural sound, even at high boost levels, unlike some modern equalizers that can make your music sound harsh.

The EQ552 is versatile and works well with any music genre, as it doesn’t impose a specific tone character. It enhances the details in your music while preserving its original sound.

Each band in the EQ552 has its own circuit, preventing any interference between the bands and reducing phase issues. This feature makes the EQ552 perfect for stereo operation, tracking, 2-bus processing, and mastering.

With 41 stepped potentiometer positions, the EQ552 offers precision control, making it a great tool for any music enthusiast or professional.

EQ522 Review Video – HD Audio

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Why Germanium Transistors Sound Good?

Firstly, germanium transistors are known for their warm, smooth, and vintage sound. They have a unique tonal characteristic that is often described as more “musical” compared to other types of transistors. This is due to the way germanium transistors handle signals, which results in a more pleasing harmonic distortion that many audio professionals and musicians find desirable.

Secondly, germanium transistors can operate at higher speeds and slew-rates than early silicon devices. This was an important consideration in the 1960s and is still relevant today in certain applications.

Lastly, the use of germanium transistors in studio equipment can be seen as a nod to the golden age of music production. Many classic sounds are associated with germanium-based products like EMI’s first solid-state TG mixers, Neve’s 1053 and contemporary modules, and some of the vintage Fairchild and Telefunken products.

Germanium Opamp Eq522 Two Band Equaliser

EQ522 Demo and Introduction

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Stereo Buss Operation

Stereo Spk
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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.


  • Balanced Input – Impedance 20kΩ
  • Balanced Active Transformer Output – Impedance less than 50Ω
  • LF Frequency Setting – 160Hz, 90Hz, 60Hz, 45Hz
  • HF Frequency Setting – 16kHz, 10kHz, 8kHz, 6kHz
  • LF and HF boost/cut – +/-12dB
  • Nominal Gain  – Knobs set to 12 o’clock – 0dB
  • Typical THD+N – Less than 0.02%@1k in 10Hz-22kHz
  • Noise Floor EQ Engaged – Less than -90dBu@10Hz-22kHz
  • Bandwith at flat response  – 10Hz – 60kHz@-1dB
  • Maximum Output Level – +24dBu@0.1%THD
  • Power Consuption – Less than 60mA
  • Compatibile with any standard 500 Rack
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.