The unique feature of Passive Equalizer is the ability to Cut and Boost at the same time.
The EQ550P can create sophisticated EQ curves which cannot be achieved by the active shelf equalizers.
The ability to select three different frequencies independently for Cut and Boost provides countless possibilities in creating custom EQ curves.
The plots below show a few examples of such EQ curves.
Like any other equalizer, the EQ550P can be used to cut or boost the shelf frequencies.
The plots below show the maximum cut and boost for each band and frequency settings.
Bart Hrk developed the propitiatory design of an Active Transformer to solve the problems of the common passive transformers.
Passive transformers are susceptible to electromagnetic interference (50Hz Hum, RF Smog) and the frequency response is dependent on load and source impedance, negatively influencing the overall performance of analogue studio equipment.
The HRK Active Transformer solves the problems of the passive transformer while preserving and even enhancing the positive trades of the transformer output stage, including the harmonics content and the tonal response.
The HRK Active Transformer delivers the sound that we love, including the harmonics content and the tonal response, and removes all the hassles associated with passive transformers.
The Active Transformer produces a subtle “Air” effect and provides extended LF performance.
The Active Transfomer saturation depends on the output level. Higher output signal levels will saturate the Active Transfomer more, like in the classic studio equipment.
The demo video presenting the older version of the EQ550P with a Silver front panels.
The current Black front panel version is delivers the same performance as the units presented in the video.
All videos are server hosted to insure the best quality of sound without the YouTube compression or normalization.
|Input Type / Input Impedance||Balanced Electronic||20k|
|Output Type / Output Impedance||Balanced HRK Active Transformer||Less than 10R|
|Initial Gain||0dB||All controls set to flat response|
|Max Output Level||+25dBu@1%THD||Balanced Signal|
|Power Consumption||180mA max.|
|Format||API 500 Format|
|Phase Reverse||No||0 deg.|
|Static Noise||-89dBu@10Hz-22kHz||All controls set to flat response|
|Thermionic Valve||NOS Dual Triode||High Quality NOS Selected Tube|
All HRK Products are tested with the industry best audio measuring equipment
|Country / Region||Shipping Cost||Customs Fee||VAT|
|All 27 European Union Countries Delivery Time: 2-7 Days||– 14.99USD for orders below 349USD- FREE shipping for orders over 349USD||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 349USD- FREE shipping for orders over 299USD||NO Customs Fees||No VAT charge. HMRC collects the VAT.|
|USA, Canada Delivery Time: 5-10 Days||– 14.99USD for orders below 349USD- FREE shipping for orders over 349USD||NO Customs Fees for orders up to 800USD – charged by the USA Customs Office||No VAT charge.|
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|Russia, Belarus – NOT AVAILABLE||NOT AVAILABLE||NOT AVAILABLE||NOT AVAILABLE|
|Worldwide Destination Delivery Time: 3-14 Days||– 29.99USD||Refer to local regulations.||No VAT charge.|
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Please enter your EU VAT Number at the checkout, and the VAT will be deducted from the Total Payment. The VAT number is automatically checked in the VIES database.
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We ship directly to United Kingdom.
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Switched-mode power supplies (SMPS) are ubiquitous in modern electronics due to their efficiency and compact size. However, they can cause issues with analog audio circuitry. The primary reason is that SMPS operates by rapidly switching on and off, typically at high frequencies. This operation can generate noise and harmonics across a wide frequency spectrum, which can infiltrate sensitive analog audio circuits and degrade audio performance. This issue is often termed as “switching noise.”
The ripple voltage, which is the residual periodic variation of the DC voltage, can also be a source of concern. In an audio system, this ripple voltage can couple into the audio path, leading to audible noise or hum.
The problems caused by SMPSU can be mitigated by implementing an additional active PSU filter. This filter works by suppressing the switching noise and reducing the ripple voltage. It does so by providing a low impedance path at the switching frequency, which effectively ‘shorts out’ the noise, preventing it from entering the audio circuitry.
Moreover, it can improve the Power Supply Rejection Ratio (PSRR), a measure of how well an audio device rejects noise coming from the switched-mode power supply. A higher PSRR means the circuit is less susceptible to power supply noise, thereby improving the overall sound quality of the analog audio system.
Therefore, HRK Active PSU filter is an effective solution to ensure the integrity and quality of audio in analog systems powered by switched-mode power supplies.