SPL Channel One Mk3 Premium

High-quality and extensive processing of audio signals

SPL's Channel One Mk3 Premium offers a comprehensive collection of features to ensure the convenient processing of audio signals. The channel strip now includes a higher internal audio voltage (+/- 18V) for optimal and detailed sound as well as a preamp section with transient designer, a tube saturation stage and a mic A/B comparison option for two microphones. In addition to the "normal" version of the Channel One Mk3, the "Premium" version features Lundahl transformers for the microphone input. The transformer significantly enhances the sound and also provides a gain of up to +14dB, which must then be added to the scaling!

Controls

On the front of the Channel One Mk3 Premium there is a switch on the left-hand side for selecting the input source. There you can choose between Mic A, Mic B and Line/Instrument. When connecting a microphone to the Channel One Mk3 Premium, it is possible to activate 48V phantom power, which supplies the microphone with power via the XLR cable. This switch can be activated separately for both microphone inputs. If attenuation of the microphone input signal is required, this can be achieved using the PAD switch. The attenuation has a value of 20dB, which means that the channel strip can also handle very high levels. The Channel One Mk3 Premium also offers the option of phase reversal via the Ø button, which reverses the polarity of the signal and rotates the Phase and 180°, which is useful if the phases are cancelled out due to the same basic sound over a longer period of time. The adjacent high-pass filter is used to reduce subsonic noise below 80Hz and can be used for all inputs of the Channel One Mk3 Premium.

The controls for the discrete preamplifier are located below the buttons described above. A preamplification of up to 68dB can be achieved for microphone signals using the gain control. The tube saturation control next to it is used to adjust the degree of tube saturation of the device. In conjunction with a further effects section, this can be used to create subtle to harmonic distortion of the audio signal. The tube post switch changes the order of the tube saturation in the signal flow, whereby the tube saturation stage is positioned after the EQ stage but before the output stage when the button is pressed. If the button is not pressed, the stage is located directly after the Preamp and before the de-esser.

The Channel One Mk3 Premium also has the option of reducing the intensity of S-sounds by changing the position of the S-Reduction control. As soon as an S-sound is detected, a small yellow LED lights up in the lower middle of the device. The "Low & High" buttons of the S-reduction section can each be used to activate a different mid-frequency for the de-esser. If the "Low" switch is pressed, the low de-essing band is activated with a centre frequency of 6.4 kHz and a bandwidth of 4.4 kHz. If the "High" switch is pressed, the high de-essing band is activated with a centre frequency of 11.2 kHz and a bandwidth of 4.9 kHz. If both switches are pressed, the low and high band de-esser are active.

Another feature of the Channel One Mk3 Premium is the sustain control, which can boost or cut the decay phase of a signal by up to 24 dB. The decay time increases when the sustain control is in the positive range and decreases with a negative value. If you want to change the input phase instead, you can use the Attack control, which can boost or cut the attack phase of a signal by up to 15dB. The "On" switch activates the complete Transient Designer section, consisting of attack and sustain controls.

The compressor section on the right-hand side of the device also consists of two controls and a switch. The Compression control is used to set a threshold value between 0dB and 20dB; the lower the value, the more the compressor works. The Make-Up Gain control, on the other hand, raises the level, which has been reduced by the overall level reduction caused by compression, to the set level. A value of 0dB to 20dB can be set, to which the level is raised again after compression. The entire compressor section must first be switched on using the "On" switch.

The EQ and Air Band section of the Channel One Mk3 consists of a total of 5 controls. Two of these are responsible for the LMF, which produces a semi-parametric bass/midrange filter. The adjustable frequency range of the filter is between 30Hz and 700Hz and the gain/attenuation is determined via the "-/+" control. In addition to the LMF, the device also has a semi-parametric mid/high frequency filter(MHF) with an adjustable frequency range of 680Hz to 15kHz. The gain or attenuation can also be varied using the "-/+" control. The maximum gain and attenuation values for LMF and HMF are +/- 12dB. Finally, this section contains the knob for the air filter. This is used to process the top frequency range and consists of a coil-capacitor filter with a bell characteristic. Its center frequency is 19kHz, with a possible attenuation/boost of -/+10dB. To activate the equalizer section, the "On" switch must be flipped. The Channel One Mk3 offers the option of pressing the "EQ pre TD" button to swap the order of EQ and Transient Designer so that the EQ works before the compressor in the chain. If the button is not pressed, the order remains unchanged.

The output level of the device is controlled using the output control in the bottom right-hand corner. The control can attenuate the signal by up to -20dB or boost it by up to +6dB. This function ensures that subsequent devices are optimally controlled. The set output level is visually displayed on the large VU meter in the middle of the Channel One Mk3 Premium when the VU switch is in the "Out" position. In addition to displaying the output level, the VU meter can also display the input level or the gain reduction level, depending on the setting of the VU switch. For a better and more intuitive visualization of the signal levels, the display range of the VU meter can be adapted to different signal levels. This is done using the left-hand VU switch, which can be engaged at +6dBu, 0dBu and +12dBu. In the 0 switch position, 0 dB on the VU meter corresponds to an output level of +6 dBu. The VU meter does not display an output level if the mute switch is activated, which mutes the output signal completely. If an overload is detected in the device, the red "OVL" LED lights up. The display taps into all relevant points of the signal flow.