MIAD Audio LCPQ4040 Front panel

LCPQ 4040 - Discrete 4 Band Inductor EQ


The LCPQ 4040 is a 4-Band inductor equalizer that combines the characteristics of a high-performance discrete (transistor) circuitry with the musicality that passive RLC filters are known for. Each unit is hand-built and all the components are chosen and tested thoroughly for best performance, musicality and long-term reliability.

Whether it is used on a single channel or on a stereo bus, the LCPQ 4040 is a very musical and precise EQ. Its sound has been described as 'punchy with weight' to the low end, with 'beautiful presence' in the mids and 'fabulously airy highs that can add gloss and sheen without any hint of harshness or grit'.

MIAD Audio LCPQ4040 open case


Each band has a variable +/-6dB or +/-12dB level control. The four bands of equalization offer a total of thirty-four selectable frequency points with additional control over the shape of the curves.

Each band can be independently bypassed. When an EQ band is not engaged, the audio signal still travels through the transformers and the discrete circuit but not through the RLC circuit and thus the unit can be used as a high quality unity gain line amplifier.

In addition to the individual bypass, the unit employs a true bypass relay system (using gold plated contacts) where the input signal is connected directly to the output.

When the unit is not powered (or in situations where the power accidentally goes down), the bypass relay system is automatically activated and therefore the signal will not disappear.

Frequency Points

BAND 1 (Shelv./Bell): 45Hz, 65Hz, 100Hz, 180Hz, 330Hz, 470Hz

BAND 2 (Hi-Q/ LowQ): 180Hz, 220Hz, 270Hz, 330Hz, 390Hz, 470Hz, 560Hz, 680Hz, 820Hz, 1kHz, 1.3kHz

BAND 3 (Hi-Q/ LowQ): 1.2kHz, 1.5kHz, 1.8kHz, 2.2kHz, 2.7kHz, 3.3kHz, 3.9kHz, 4.7kHz, 5.6kHz, 6.8kHz, 8.2kHz

BAND 4 (Shelv./Bell): 3.3kHz, 4.7kHz, 6.8kHz, 10kHz, 15kHz, 23kHz

MIAD Audio LCPQ4040 PCB Grayhill Carnhill Wima


The LCPQ 4040 features Carnhill high-level audio signal input and output transformers and a combination of four Carnhill and custom-wound tapped inductors that were chosen after extended listening tests and measurements.

The unit consists of Grayhill rotary stepped switches for frequency selection, conductive plastic potentiometers (hand-matched) for boosting/cutting, Wima polypropylene (low tolerance) film capacitors in the RLC path, Panasonic audio grade electrolytic capacitors in the active circuit and Neutrik connectors for the audio and power connections.

The unit is housed in a 1U rack-mount aluminium case made from extrusion and therefore excellent EMC performance and rigidity is ensured.

The LCPQ 4040 requires the PS 230 external power supply. A 2-meter power cable with 6-pin Neutrik connectors is supplied with every EQ. 

MIAD Audio LCPQ4040 Inside view


• Fully discrete (transistor) circuit

• Transformer (Carnhill) balanced input and output

• Carnhill and custom made tapped inductors

• Thirty four selectable frequencies

• 12dB (or 6dB) of Gain/ Attenuation per band

• Selectable Shelving/ Bell on Band1 and Band4

• Selectable HiQ/ LowQ on Band2 and Band3

• Individual bypass on each band

• True bypass relay system

• Low components tolerance for stereo configuration

• Hand-built and hand-wired

• 3-year labour and parts warranty


• Frequency Response: 20Hz - 20kHz, +0/ -0.3dB

• THD+N: Less than 0.005%, +4dbu, 20Hz - 22kHz, unity gain, 22kHz BW

• Signal-to-Noise Ratio: <90dB (unweighted) re +4dbu, 22kHz BW, unity gain

• Maximum Output Level: +23dbu, 20Hz - 22kHz into 600 Ohms

• Dynamic Range: 113dB re +21dBu, 22kHz BW

• Input: Transformer Balanced XLR (1.Chassis, 2.Signal +, 3. Signal -)

• Output: Transformer Balanced XLR (1.Chassis, 2.Signal +, 3. Signal -)

Other Information

Price: €1,450 (ex. VAT where applicable)

Operator's Manual (Download)

Recall Sheet (Download)