SPL Neos - 120V Rail 24-Ch. Summing and Monitoring Console

SPL Neos - 120V Rail 24-Ch. Summing and Monitoring Console

Neos The Neos is the first summing and monitoring console based on our proprietary 120V Rail technology. The basic concept behind it was to combine...

Vendor :SPL

Type :analog summing

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The Neos is the first summing and monitoring console based on our proprietary 120V Rail technology. The basic concept behind it was to combine essential summing capabilities, including faders and panorama controls, with a complete and practical monitoring section — all in a compact design. Accordingly, it fulfills the highest expectations regarding sound quality in mixing and monitoring situations.

Thus, the Neos was conceived with sound engineers that set great importance on artistic and musical production in mind and whose workflow does not rely primarily on undo and preset options. Nevertheless, the compact Neos can integrate seamlessly in computer-based environments providing the characteristic high-quality sound and handling of analog devices.


  • Ultimate mix and monitoring quality in 120V Rail technology
  • 24 channel summing console with faders and panorama controls
  • Compact design: 19"/7U
  • Cascadable
  • Ideal for DAW-based studios with emphasis on audio quality
  • Input path with 100-mm ALPS faders, Pan controls, Mono, Cut, Solo, and “To Monitor Only” push buttons, signal LEDs
  • Master path with 100-mm ALPS faders, Inserts, Bend function (Limiting)
  • Comprehensive monitoring section with Volume control, Tape Mix (DAW return), as well as Mute, Dim and Mono push buttons
  • Input: three eight-channel DB25 connectors (balanced, TASCAM standard); balanced XLR connectors: Slave, Insert Return, Tape Return
  • Output connectors (balanced XLR): Recording Out, Monitor A and Monitor B,
  • Output connectors (unbalanced XLR): Alternative Out, Insert Send, Metering
  • Unique 120-volt operating voltage. In comparison with common production mixers, the Neos mixing and monitoring console uses four times as much operating voltage. A higher voltage results in better performance: over 30 dB of headroom at the input, more than 122 dB of dynamic range, 92 dB signal-to-noise ratio over all channels.
  • All selected components for each unit are matched at the pre-production stage
  • Important switching functions are performed via sealed relays
  • Oversized signal traces, generous PCB layout for greater trace separation, star ground scheme, linear power supply
  • Made in Germany

Fundamental research

Shortly after the turn of the millennium, SPL laid down new foundations for the improvement of analog audio signal processing. Thanks to new components, circuitries and manufacturing methods, we were able to increase the operating voltage enormously.

Up to then, average operating voltage ranged form 30 to 36 volts (+/- 15 or 18 volts, considering that voltage supply is symmetrical). Maximum operating voltages reached 60 volts  (+/- 30 volts). At the core of our new technology are the handmade OP-amps that operate at 120 volts (+/- 60 volts), which means that we have in fact doubled the highest levels ever reached until then.

Next-Generation Analog

The first products to integrate the 120-volt technology were exclusive, handmade custom solutions for major mastering studios. At the time, music production had already been uprooted by digital technology and the changes it brought with itself in terms of outfitting and workflow in music studios. Coincidentally, a new „mastering“ sector had already been established — both in terms of the actual process and the gear in studios. If traditional recording and mixing studios were on their way to digitalization, the most sophisticated mastering studios were and have always been keen on analog technology, including high-quality signal processors that can still make a difference compared to the widely available software solutions. But also technically demanding requirements such as superior sounding and designed switching and monitoring consoles were among the products we were able to offer. While analog technology was being heralded as dead, SPL was decisively going in the opposite direction: we were able to deliver analog products of the highest quality whose performance surpassed all previous specifications — regardless of whether it was in the analog or digital realm.

Why is a high operating voltage so important?

If we consider that the basis of every circuit is directly related to a voltage/performance ratio, the operating voltage is crucial for the performance of any circuit. Given that audio technology is conceived to translate sound into voltage, doubling the formerly highest operating voltage available results in a great improvement, specially with regard to signal dynamics and the way they are processed. Technically speaking, a wider dynamic range also means that the gap between the actual signal and other undesired signals, such as noise and distortion, is larger — in the case of the Neos console, for example, this results in not hearing any noises at all, regardless of the situation.

Highest performance for ultimate sound quality

Our measurements reveal the improvements the 120-volt technology offers in comparison to standard solutions. All these advantages are due to the oversized signal traces, the rigorous selection of every single element and, of course, the handmade components that contain no unnecessary audio processing parts (which are very common in mass-produced operation amplifiers). But the technical specifications and design say very little about the actual sound of an audio equipment. At the end of the day, an audio device has to prove itself in use in the hands of sound engineers and musicians. We can state with great satisfaction that our solution not only prevailed — ever since their introduction, our 120-volt products have passed all tests and proven worthy of the best. Now the Neos console represents a solution that transfers unsurpassed performance into ultimate sound quality.

Integration and wiring examples

With a 24-channel interface and DB 25 connectors in TASCAM standard, wiring is almost too easy: connection is given and channel assignment follows the DAW setup.
The following examples cover a bit more complex scenarios that may yield some inspiration for individual solutions.

Three eight-channel converters

A common way to feed the 24 channels of the Neos would be to use three eight-channel D/A converters. As a rule, one converter is defined as the main converter and the two others are connected in chain. As long as the converters have the same DB25 connectors the connection is straight forward and the channel assignment corresponds to the one in the DAW’s setup.

A high-quality two-channel converter might the best option to record the signal of the Neos’ Rec. Out. The A/D stage could also be integrated through the S/PDIF inputs of the main converter. The recorded signal can be routed to the two-channel converter through the S/PDIF outputs of the main converter, whose D/A output would then be connected to the Tape Return of the Neos.

Converters with separate outputs

If the analog outputs of the converter are available as separate XLR and jack connectors, a clever channel assignment could save converter channels. Typical sessions have usually four mono channels (vocals, snare, kick, and bass) while the rest of the elements are available as stereo stems in the DAW (keyboards, guitars, backing vocals, overheads, toms, etc.). In this scenario you can make the final mixdown with the Neos. Nevertheless, do take into consideration that the more channels available for a production, the better.

Here is an example of such a session: once again we have three eight-channel converters, however this time they have separate outputs connected via eight XLR/jack-to-D25 snake cables. In the DAW, route the four mono channels to outputs 5, 6, 7, and 8 of the first converter. Afterwards, connect the converter outputs with the Neos DB25 inputs 1, 3, 5, and 7. That way, the mono signals are now controlled by the first faders of the Neos — and considering that the input paths are stereo, whenever you use mono signals one of the channels is free (in this example, DB25 outputs 2, 4, 6, and 8). All other stereo stems from the DAW should be routed to the Neos through the two other converters. On the first converter you still have four output channels left, which you can use for the Tape Return input of the Neos and a headphones mix.

The Sound

120V Rail Technology is our reference technology developed and manufactured to run on an operating voltage of 120 volts, which corresponds to twice that of discrete operational amplifiers and four-times that of semiconductor operational amplifiers.

120V Rail Technology reaches outstanding technical and sonic performances. Technically especially in terms of dynamic range and headroom and sonically especially in reproducing the finest details and delivering a totally relaxed sounding audio experience. Music sounds absolutely natural and hearing fatigue is drastically reduced.

Even the best audio measuring equipment arrives at the boundaries. In same situations we ended up just measuring the Audio Precision Cascade 2 measuring device and we cannot say how good the 120V Rail Technology actually performs.



These diagrams show how our 120V Rail Technology compares to other circuits.

The direct relation between operating level and maximum level is fundamental for the classification: the higher the operating level, the higher the maximum level a circuit can handle. And since virtually all essential acoustic and musical parameters depend on this relation, a higher operating voltage also has a positive impact on the dynamic range, distortion limit and signal-to-noise ratio.

Do bear in mind that dB scales do not represent linear but rather exponential increases. A 3dB increase corresponds to doubling the acoustic power, +6dB correspond to twice the sound pressure level, and +10dB correspond to twice the perceived loudness.

When it comes to volume, the 120V Rail Technology exhibits a performance, in regard to maximum level and dynamic range, that is twice that of common components and circuits given that its values are approximately 10dB higher.

THD measurements of the 120V op-amp show a difference of more than 3dB compared to the OPA134 at 36V — in terms of sound pressure level, that corresponds to an improvement of more than 50%.

The operating level most commonly used for audio equipment is 30 volts.

The 120V Rail Op-Amp Generations