A passive tube equaliser operating in Class A.

The MCAudioLab EQ1 is designed to deliver the smooth and musical sound of passive vintage tube EQs. MCAudioLab pays homage to classic EQ topologies with a pleasing sound, but at the same time disrespects the inherent noise and limited headroom of collectors' units: The EQ1 meets the high performance standards required by modern, professional studios. It has a great vintage sound and is as quiet as possible.

The EQ1 is great for vocals, bass, drums, guitars and practically anything you put through it. You can use it to shape a pleasant and musical sound, or just run tracks through the EQ without any EQ to add some vintage-style tube warmth. It also works great on the sum: more than one realist has come back for a second piece of this EQ to use a pair of these EQs on the mixer bus.

On top of this, the reasonable price makes the EQ1 an excellent choice for smaller project studios ready to use instant analogue magic, and for experienced professionals looking for a classic passive EQ with high performance.

Front panel design

The EQ1's low-frequency (LF) shelving filter section features classic boost/undercut ergonomics. Use the stepped frequency knob to move the low-frequency shelving filter between 20, 30, 60, 90 and 150 Hz. While the boost (Boost) shelving starts at the selected frequency, the Cut knob operates at ten times (10x) that frequency to gently attenuate a portion of the low and midrange, which is great for rounding out the sound while removing some boxiness or muddiness from it.

The HMF Boost section operates from 600 Hz -16 kHz and is parametric, giving us additional control over the bandwidth. This is particularly useful for adjusting the interaction with the high-frequency (HF) shelving filter, which gives a pleasant and natural yet effective treble attenuation in the 4 kHz - 20 kHz range.

The EQ1 has additional tube gain to compensate for level changes caused by EQ. Use the Output control to set the final level while visually checking the LED meter. Finally, the Bypass switch allows the EQ circuitry to be completely disconnected from the signal path.

Classic sound without the frills

When realists try the EQ1, their feedback usually reads: "it sounds fabulous even with crazy settings and is incredibly quiet!". MCAudioLab repeats it like a mantra: "we put a huge amount of effort into getting great sound, while keeping our equipment up to the performance standards of modern recording studios". From a design point of view, this means class-A operation, hand-selected tubes, a Lundahl transformer at the output, and an audio signal path as short and clean as possible. And for design purists: yes, you get a Sowter inductor.

If the EQ1 is your first contact with a passive EQ, here's our advice: follow your hearing and don't believe what you see on the panel. This is because it is more of a tone shaping tool than a surgical EQ. You can set ridiculous levels of boost and cut - and in frequency ranges that you would normally be very careful with.

Try boosting 20 Hz and see for yourself: the sound becomes more rounded, smoother and richer, without muddiness or loss of definition. You can make equally strong equalization in the high and mid frequencies without the effect of piercing sharpness. You'll never feel that you've gone too far, and even at extreme filter settings you won't hear frequency drift or the usual weird EQ artefacts.

The most beautiful thing about passive EQs is the extremely musical interaction between frequency bands: use overlapping filter settings to create resonant shelves. Once you've finished adjusting the HF, start adjusting the upper mids and basses to see how this affects the overall tone shaping of the source signal. And when you don't need EQ, you can still pass tracks through EQ1 set flat to take advantage of the subtle, pleasing warmth provided by the tube output stage and Lundahl transformer.

Features

• Single-channel, 3-band passive tube EQ operating in Class A
• LF: shelving EQ, typical Boost/Cut controls, stepped frequency selection knob (Boost 1x, Cut 10x)
• HMF Boost: parametric equalizer, stepped frequency selection knob, Q adjustment.
• HF Cut: shelving correction, stepped frequency selection knob
• Very low distortion and noise, large dynamic range
• Tubed gain stage with Lundahl transformer at output
• 3-diode output level meter
• True-bypass switch