Extremly transparent, truest instrument preamp / DI

Direct Box

Deliver your tone without coloration. Hear unvailed tone produced by your instruments and play

  • Frequency Response

    Green:Hot Red:Cold
    Exactly identical between hot signal and cold sigmal from 1Hz to 4MHz and higher.

  • Slew Rate

    Positive and negative symmetry from 0V. No error in speed of rise and voltage value (output level).

  • Instrument preamp / DI for current recording enviroment

    This is a Instrument preamp / DI that delivers the wide bandwidth and ultra-fast response required in today's high-resolution recording environment.
    Sound quality problems such as "unclear pitch" on basses with conventional DI are due to the lack of frequency bandwidth and response performance of the DI and preamp. This is more pronounced in the low frequencies and is a challenge for basses, especially multi-string basses and synth basses that produce low B and even lower G flat.

  • True to your expression

    The SP-DI500 follows the technology of the SP-MP series of microphone preamplifiers, which are highly acclaimed by top engineers and creators for their excellent fidelity to the original sound with an extremely wide frequency response and ultra fast response in nanoseconds.

    The ultra fast response and frequency response that covers not only low B (30.87Hz) and G flat (23.12Hz), but also the lowest note (16.35Hz) of 88-key pianos such as Bösendorfer Model 290 Imperial, one octave further down the range, produces clear, stable pitch and tight The high frequency range also covers the range of the instrument.

    The high frequency response is also flat to 4 MHz, well beyond the range of musical instruments. Even sampling rates as high as 784 kHz can be faithfully converted to AD. Reproduces even the previously imperceptible resonance of strings. The original timbre of the instrument and the tones and nuances created by the player's performance can be recorded without any loss of expression."

  • Pure and transparent sound

    SP-DI500 uses less than 1/3 of components compared to standard preamps. SP-DI500 utilizes only finest components such as feedback resisters that are more expensive than standard tip resistors. We strictly pay a closest attention on every tiny detail to keep signal uncolored. It featurs flat frequncey response even lower than 1Hz and higher and 300kHz. Ultra low end produced by synth bass, 5 string base are delivered as they sound.

  • 3 step Input impedance Selector ( 2M, 100k, 10k)

    Input impedace has 3 options to optimize to the souce instrument from vintage bass guitars with passive pick up to synthsizer with high output etc. Also, can add character with chosing an impedance.

  • Hi-Cut filter for balanced output ( OFF, 2kHz - 24kHz)

    Hi cut filter reduce noise heard in high-frequency such as string nosie. Cut of frequency can be set from 2kHz to 24kHz.

  • 3dB step gain selector

    Gain selectors with fixed resistors for each gain settiings are used for audio quality in stead of potentiometers which degrades sound.

  • 33dB of gain ( balanced )
  • Input impedance Selector ( 2M, 100k, 10k)
  • 3dB step gain selector with fixed resistors
  • No coloration even ultra low end for bass instruments
  • Hi-Cut filter for balanced output ( OFF, 2kHz - 24kHz)
  • Unbalanced output to instrument amp ( Gain: 0dB, +6dB, +12dB)
  • Instrument input on front panel ( Priority )
  • Perfect equality between hot and cold of balacnce output signals
  • Best for direct recording for bass, syntheizer, synth bass, guitar etc
Minimum Gain (Balanced) 0dB 3dB per step, 12 steps
Maximum Gain (Balanced) 33dB 3dB per step, 12 steps
Minimum Gain (Unbalanced) 0dB 6dB per step, 3 steps
Frequency Response 0.1 / -0.1dB sub 1 Hz to beyond 300 kHz
Total Harmonic Distortion + Noise < .0006%, Typ 12 dB Gain, DC block Hz - 22 kHz bandwidth, +4 dBu In
Intermodulation Distortion < .0007%, Typ (50 Hz & 7 kHz) 12 dB Gain, +4 dBu In
Phase Response < 6 degrees deviation 12 dB Gain, 1 Hz - 100 kHz bandwidth, +4 dBu In
Slew Rate > 160 Volts per microsecond 0 dB Gain, +18 dBu Out
Maximum Input Level +18 dBu no attenuator pads required
Maximum Output Level (Balanced) +24 dBu
Maximum Output Level (Unbalanced)
Output Impedance < 150 ohms ±7.5V Minimum Output Swing with 120mA

Need to be installed in the 500 series chassis.
Specifications are subject to change without notice.

  • SP-BP500: 1 space blank panel for 500 seris (option : Sold separately )

    Single slot blank panel for 500 series. Beautifullty machined aluminum panel manufactured by Iriso.


Marc Urselli

Recording Engineer/ Grammy Winner

The sound is absolutely transparent and it is the kind of pre-amp you’d use when you want no coloration and you want to hear EXACTLY what comes in, without any kind of alteration of the sound, without any added sonic characteristics, basically the TRUE sound that is being picked up by your microphones

Jim Anderson

Recording Engineer/ Producer / Grammy Winner

My initial impression was a very good one. The sound is clean, clear and transparent, but with a nice punch. It’s a welcome addition to the world of first-class microphone preamps.