The SPL Channel One Mk3 Premium Channel Strip is an extremely powerful, world-class tool for audio recording. Improving on its predecessor's Transistor Tube Preamplifier while integrating a Transient Designer for efficient compression, a magical-sounding Tube Saturation stage, and a highly useful Mic A/B comparison option as well as much more, the Channel One Mk3 can make any mic, line, or instrument signal sound like a professionally recorded track.
 
Like the older Channel One, the Mk3 still sports the essential channel strip features needed by any serious engineer or artists. You still get a dynamic and versatile dual-band de-esser, a simple yet powerful compressor with up to -20 dB of gain reduction, and a 3-band semi-parametric EQ with a wide range of 30 Hz to 19 kHz. Separate mic and line XLR inputs are provided as well as a 1/4" instrument input, and you get multiple line outputs with a special direct Preamp output for parallel tracking on your DAW. And with an enhanced ±18V internal operating voltage, the Mk3 delivers a more detailed sound.
 
The Three Input Pre-Amp Stag​​​​​e
- The microphone input features 48V phantom power, phase reverse function and a subsonic filter
- The low-impedance Line input has a balancing stage for connecting studio equipment
- The low-noise, high-impedance instrument input is accessible on the front panel
 
That Tube Sound
With this control, the amount of tube saturation can be determined, and the output level is accommodated automatically; in extreme settings, the level increases by only 6 dB. Therefore modest to expressive harmonic distortions can be easily dialed in by turning just one knob.
 
Saturation effects are generated through the tube being pushed to and beyond its normal operating limits. In contrast to semiconductors, a tube thus pushed to such levels does not clip from a certain level, approaching more gradually its level limits and thereby producing its typical tonal result, which in audio signal processing can have such often profitable aural effects—on one hand (and depending on the amount applied), from subtle to extensive harmonic distortion and on the other hand, a compaction of the sonic event, that is, a limiting effect that exhibits a pleasant, rounded, or soft sound.
 
De-Esser
Subtly removes offending sibilants by eliminating only the "S" sounding frequencies with phase-cancelling processing technology. The unit's auto-threshold assists in constant processing, even with varying microphone distances.
- S-Reduction control adjusts the intensity of the S-sound reduction
- The Low switch activates the low de-esser band with a center frequency of 6.4 kHz and a bandwidth of 4.4 kHz
- The High switch activates the high de-esser band with a center frequency of 11.2 kHz and a bandwidth of 5.5 kHz
- Both switches can be used together for full bandwidth de-essing
 
SPL Transient Designer
With the Transient Designer, it is possible to manipulate the envelopes of audio signals level independently (no threshold). Accelerate or slow down transients, lengthen or shorten sustain times—with just two controls: attack and sustain. All time constants are automated in a musical way and optimize themselves adaptively, according to the characteristics of the input signal.
 
Insert (Send / Return)
Allows for insertion of external processors or can be used to record the pure preamplifier signal.
 
Compressor / Limiter
Use SPL's Double-VCA-Drive circuitry for improved noise and distortion characteristics with control via a single knob and signal-dependent automation and musical results in just about any situation.
 
Three Band EQ
Provides an EQ design optimized to process vocals, acoustic, and electronic instruments.
- LMF controls low and mid frequencies from 30 to 700 Hz, covering a range of about 4.5 octaves
- MHF governs the mid and high frequencies from 680 Hz to 15 kHz, also covering a 4.5 octave range
- Both filters allow for a boost or cut of up to 12 dB
- Air is a high-frequency, coil-capacitor filter with bell characteristics and a center frequency of 19 kHz
- Air filter provides maximum attenuation and accentuation of 10 dB
 
VU Meter
The illuminated VU meter displays the input level, output level, and gain reduction. With the VU switch on the right, below the VU meter, it's possible to select which level is displayed.
 
Headphone Monitor Stage
Provides an individual mix for the singer or speaker without the latency problems often associated with digital systems.
 
A/B Comparisons
Channel One Mk3 offers two microphone inputs on the rear panel—Mic A and Mic B. Two microphones can be connected. This enormously simplifies the workflow. Thus, when comparing or changing microphones, it is no longer necessary to unplug them.
 
Connections
The inputs and outputs of the Channel One Mk3 are equipped with Neutrik XLR sockets and plugs with gold-plated contacts. The signal transmission is electronically balanced, at a nominal level of +6 dBu.
- Separate Mic In A and B for A/B mic comparisons during recording sessions
- Dedicated line-level XLR input
- Direct mic Preamp Out connection for backup DAW track recordings or processing-free takes
- Two separate XLR line outputs
- Front-panel high-impedance instrument input with 1/4" jack
- A switch can select between Mic A, Mic B, and Line/Instrument inputs
 
Output Balancing
The Channel One Mk3 comes in two different output balancing flavors: electronically balanced (Channel One Mk3 standard) or transformer balanced using Lundahl transformers (Channel One Mk3 Premium). Transformers are used as an alternative to electronic balancing stages in the inputs and outputs.
 
Transformers can be found in many classics of audio engineering. They make the bass and fundamental tines rounder and give it a little more punch. The high and overtone range sounds a bit silkier and more present, making them ideal for vocals and voices. For highest precision and speed in signal transmission (transient processing), however, electronic stages are better suited.
 
Die Hard
Channel One Mk3 has a 4mm thick, black anodized aluminum front panel and knobs milled from solid aluminum. The housing is made of high-quality steel and is powder coated in elegant black.
 
Premium Electronics
As with all SPL devices, the Channel One Mk3 was developed not only according to plan, but also by ear. Many important components are installed on the circuit boards using Through-hole technology.
 
This way SPL can ensure that only the best sounding components are used. Also like all SPL products, this device was manufactured in SPL's own production facility in the Lower Rhine, Germany.