SPL Audio Vitalizer Mk3-T

About: SPL Audio Vitalizer Mk3-T

The patented Vitalizer circuit makes the Vitalizer Mk3-T an unsurpassed sound designer. Audio production sounds more lively, has more details, more transparency, a higher perceived loudness and, if necessary, an overwhelming bass foundation.

The Vitalizer Mk3-T not only swaps the classic, golden guise of the previous model for the new, black design of the SPL Studio series - the higher internal audio voltage of +/-18 V brings the third generation of this SPL classic up a notch higher sound level and shines with even better and more detailed sound.

Vitalize - The five controls of the Vitalizer core circuit

• Drive - Drive regulates the control of the filter network. The control range is between -20 dB and +6 dB. In the center position (0 dB) the drive level is identical to the input level.
• OVL - The OVL LED indicates potential overloading of the input stages as well as internal overloading. The OVL LED lights up 3 dB before clipping. This ensures that the Vitalizer always produces the perfect sound.
• Bass sound - The Bass Sound control can be used to control between two bass tones.
  • Soft: If the Bass Sound control is moved from the center position (0) to the left, the bass range becomes soft and warm, referred to as Soft.
  • Tight: If the Bass Sound control is moved from the center position (0) to the right, the bass range becomes dry and percussive, referred to as tight.
    • The scaling points on the right symbolize this contoured, tight bass sound and are therefore shown square.
• Bass Comp
  • The Stereo Vitalizer Mk3-T is equipped with an easy-to-use and effective "one-button" compressor, which is integrated only into the bass processing path and leaves the original bass component untouched. Attack, release and threshold are preset.
  • By increasing the Bass Comp value, the compression ratio is increased and at the same time the threshold is lowered. The compressor works with a soft knee control characteristic in order to sound as inconspicuous as possible.
  • By integrating it into the bass path, the highs always remain lively and airy even at high compression rates!
  • The Gain Reduction LED “GR” shows when the compressor starts working.
• Mid Hi Tune
  • The Mid-Hi Tune control is used to set the cut-off frequency or lower limit frequency, above which frequencies are boosted with the selected process value or below which frequencies are attenuated accordingly. The control range of the Mid-Hi Tune control is between 1.1 kHz at the right end and 22 kHz at the left end.
  • Behind the filter, a Sovtek 12AX7 double triode tube creates a mixing ratio between the original signal and the output of the filter. The output signal is then fed into the process control stage. In this path, the tube adds its typical overtone characteristics and softens the “Mid-Hi Tune” signal.

Process

The Process control adjusts the intensity of the bass and mid-hi tune in relation to the original signal and attenuates dominant mid frequencies.

LC EQ

The LC-EQ is a mid-high frequency processing stage built around a passive coil-capacitor (LC) network. The LC-EQ creates more presence and definition in the midrange, especially for voices. In the high frequency range, the coil impresses with its extremely low noise. The frequency can be adjusted between approx. 2kHz (low) at the left end and approx. 20kHz (high) at the right end. The treble and overtone structure, improved with the LC-EQ, ensures cleaner separation of the instrumentation and ensures silky highs.

Coils are known for their pleasant sound in filter circuits. In the 60s, coil filters were widely used, which were later replaced by RC (resistor-capacitor network) filters due to their high price. Today people again want the sound of the coils specifically for the mid and high frequency range, as saturating the coil produces a harmonic behavior that is pleasant to the hearing sense. This can be compared to the difference between a tube stage and a transistor stage.

Intensity

The Intensity control determines the level of the LC EQ. As the intensity increases, the gain of the set high and overtones increases. At the same time, the time of sensation is shifted so that quiet high-frequency components are not masked by loud ones. This improves speech intelligibility and clarity. The brilliance of any audio signal can be increased without sounding harsh.

Stereo expanders

The Stereo Expander increases the stereo base width.

The subjective impression of space is improved by simulating a decentralized location of the sound source outside the loudspeaker level.

A Sovtek 12AX7 double triode tube is also used in the stereo expander. The right and left channels are mixed together in it. The tube now adds its typical tube harmonic spectrum to the stereo signal, which mainly consists of straight overtones.

In addition to broadening the stereo image, the tube also produces greater depth gradation, a clearer drawing of the reverberation chambers and a softening of the high-frequency range, which has a particularly positive effect when editing digitally recorded material.

The Vitalizer Mk3-T is activated via the on switch. When activated, the switch lights up. If the device is in bypass mode, the switch does not light up.

When this switch flashes, the device is in “warm-up” mode. The tubes are brought to the optimal operating temperature.

The unmasking

A key feature of Vitalizer technology is the unmasking of superimposed sound components. The Vitalizer relates the time at which a frequency is felt to its volume. Through a minimal temporal offset of loud frequencies, quieter, previously superimposed sound components are “unmasked” and therefore audible.

The Vitalizer equalizes the frequency spectrum to curves of equal loudness, which particularly improves the perception of loudness.

The non-linear sensitivity of human hearing has been known since the 1930s through the Fletcher-Munson curves. These “equal loudness curves” (now defined by the ISO 226:2003 standard) illustrate equal loudness perception as a measure of sound pressure level across the frequency spectrum, at which a listener perceives constant loudness when presented with pure, even tones receives.

Entrances and exits

All inputs and outputs of the Vitalizer Mk3-T are equipped with Neutrik XLR sockets with gold-plated contacts and Neutrik TRS sockets. The XLR and jack sockets are connected in parallel. The signal transmission is electronically balanced at a nominal level of +6 dBu.

• Tip: On the output side, two signals are output per output. The processed signal can therefore be sent to two different devices. If the inputs are assigned twice, the two input signals mix.

Looks good, feels good – and lasts forever

The Vitalizer Mk3-T has a 4 mm thick, black anodized aluminum front panel and a solid aluminum button milled from solid. The housing is made of high-quality steel and powder-coated in elegant black.

Sounds good

Right from the start, we develop all SPL devices not only according to plan, but also by ear. Many of the basic components are installed on the boards using through-hole mounting (THT). This way we can ensure that we can install the components that sound best.

Specifications

• Analog inputs & outputs; XLR (balanced)
  • Input impedance - 22 kΩ
  • Output impedance - 75 Ω 
  • Maximum output gain - 22 dBu
  • Common Mode Rejection Ratio (1 kHz, 30 dB Gain) - 86 dB
  • Frequency range (30 dB Gain) - 10 Hz – 100 kHz 
  • THD + N (0 dBu, 10 Hz – 22 kHz) - 0.01 %
  • Noise (A-weighted) - -88,6 dBu 
  • Dynamic range - 110,6 dB
• Internal Linear Power Supply with Toroidal Transformer
  • Operating voltage for analog audio -  +/- 18 V
  • Operating voltage for relays and LEDs -  + 12 V
  • Tubes anode voltage -  +250 V
  • Tubes heating voltage -  +12.6 V  
• ​Mains Power Supply
  • Mains voltage (selectable) - 230 V AC, 50; 115 V AC, 60 Hz
  • Fuse for 230 V - T 315 mA
  • Fuse for 115 V - T 630 mA
  • Power consumption  - max. 20 W 
• Dimensions WxHxD) - 19 x 1.73 x 9.33 inches (482 x 44 x 237 mm)
• Weight - 7.5 lbs (3.4kg)