Value- and Performance-packed 2-channel Pre from SPL

Delivering exceptional audio quality, impressive flexibility, and outstanding value in equal measure, the SPL Pre One dual-channel microphone preamplifier upsets the price-performance ratio that, for the most part, governs affordable pro audio gear. But SPL is no stranger to pushing the envelope, as its decades-long history of groundbreaking products bears out. Featuring SPL’s discrete transistor circuit design, the Pre One is cut from the same cloth as SPL’s upmarket Channel One Mk3, processing sources with a beautifully transparent and open sound. Meanwhile, the second channel retains a rear-panel hi-Z DI input for electric guitar, bass, or keyboards.

Impressive versatility

The wide range of the Gain control (8dB–62dB) gives you broad latitude when using the Pre One. It has ample gain to handle low-output passive ribbon mics, yet you can crank down the gain enough to accommodate line-level signals. Each channel of the Pre One provides the features you would expect of a professional preamp from SPL. There’s 48V phantom power for your condenser mics and a rear-panel 20dB pad to facilitate healthy gain staging. An 80Hz, 6dB/octave highpass filter lets you quickly strip any unwanted/unneeded low-end content from your signals. A polarity reverse switch completes the per-channel accoutrement — almost.

Enhance signals with Flair and Contour

Among the quartet of switches straddling the large Gain controls of each of the Pre One’s two channels is one labeled Flair/Off/Contour. We realize that these proprietary SPL circuits probably require some explanation. Flair imparts a scrumptious range of silky highs to the signal. Contour, on the other hand, does something entirely different: it compacts the signal while retaining its natural presence and strength. Each, in its own way, is so effective that, in the opinion of many Sweetwater engineers, these features alone are worth the price of admission!

Convenient connectivity

The two rear-panel mic inputs of the Pre One are equipped with rear-panel Neutrik XLRs with gold-plated contacts. Signal transmission is electronically balanced at a nominal level of 0dBu. The second channel of the Pre One also features an ultra low-noise hi-Z DI input on the rear panel. If an instrument is plugged into the instrument input, the microphone input is deactivated. Each of channel has a separate line output on balanced TRS jacks, facilitating convenient connection to a wide range of popular audio interfaces. Lastly, the Pre One comes with an external 12V DC power supply that works in concert with a secondary internal power supply, generating +/-17 volts for the Pre One’s analog audio sections. This ingenious solution produces professional levels of up to +22.5dB.

SPL Audio: supercharged audio products

Formed in Germany in 1983, SPL — Sound Performance Lab — has been at the forefront of the pro audio industry since its inception. From the renowned Transient Designer, TwinTube, and Vitalizer MK2-T to professional mastering tools such as the Passeq, SPL gear is found in top studios and mastering facilities worldwide. After developing proprietary 120V Technology in the ’90s, SPL decided to make this groundbreaking invention the heart of its high-end products. SPL meticulously crafts its equipment in its Niederkrüchten, Germany-based factory using discrete, top-drawer components and through-hole circuit designs. There, the company conducts its R&D, which includes real-world subjective listening tests as well as stringent bench testing to the strictest tolerances. Sweetwater is proud to offer audio professionals SPL’s distinguished lineup of innovative products.

High-pass filter

A high-pass filter with 6 dB per octave is available in both preamp sections and reduces subsonic noise below 80 Hz when activated. This low-cut filter can be used for the microphone inputs as well as for the instrument input on the second amplifier.

48V

Both preamplifers have a 48V switch. This switch activates the required phantom power of 48 volts for the use of condenser microphones.

Ø

The phase reverse function of every preamplifiers reverses the polarity of the signal. After pressing the switch, the phase is reversed by 180°.

Power Supply

Good sound always starts with the power supply. This is where you lay the foundation for the performance of
the entire device. Although we “only” supply a 12 V plug-in power supply unit, the secondary power supply inside generates a voltage level of +/-17 volts for the analog audio sections with which professional levels of up
to +22.5 dB can be achieved!

An elaborate low-drop operating voltage regulation provides more “juice” and regulates cleanly
even when the maximum operation voltage is reached.

Features

2-channel microphone preamplifier
Discrete transistor circuit design
Per-channel balanced XLR inputs, line outputs on balanced TRS jacks
Per-channel 20dB pad, polarity reverse, 48V phantom power, and 80Hz, 6dB/octave HPF
SPL’s proprietary Flair and Contour circuits, per-channel
Internal power supply: +/-17 volts
External 12V DC power supply
Meticulously crafted in Germany