Hi-End DI – Flagship Mono DI Box (Advanced J-FET, Class A)

For mastering, archival recording, and uncompromising reference-grade applications.

The Hi-End DI represents the pinnacle of Simple Way Audio’s engineering philosophy. Built with our most advanced discrete J-FET topology and operating in pure Class A without global negative feedback, this flagship device delivers absolute transparency for the most demanding professional applications.

Sound Quality Characteristics

Spectral Uniformity: The Hi-End DI achieves the ultimate in tonal neutrality with THD <0.0009% @ 0 dBu across the entire audio spectrum. No coloration, no frequency-dependent character—only mathematically pure signal conversion. Your instrument’s voice remains completely unaltered from input to output.

Transient Response: Extended bandwidth to 200 kHz captures every microsecond of transient information. The initial attack of a plucked string, the articulation of a bow stroke, and the shimmer of high-frequency percussion are reproduced with reference-grade precision. Phase linearity across the audio band ensures transient events are captured without ringing or smearing.

Dynamics and Distortion: Ultra-low distortion of 0.0009% (typical 0.001%) at 0 dBu preserves the full dynamic range of your performance from pianissimo to fortissimo. Maximum input headroom of +34 dBu (PAD on) accommodates the hottest line-level sources without clipping. No compression, no strain, no glare—just pure, uncompressed dynamics.

Pianissimo Clarity: Noise floor of −110 dBu ensures that the softest musical gestures remain perfectly audible. Low-level detail—finger slides, breath sounds, subtle pedal work, and ambient room reflections—emerges with pristine clarity. This exceptional signal-to-noise ratio (exceeding 120 dB) makes the Hi-End DI ideal for mastering-grade recording where every nuance matters.

Ambience Reproduction: Superior noise performance and vanishingly low distortion combine to preserve reverberation tails, room reflections, and three-dimensional spatial information with studio-reference quality. Sound-stage imaging, depth perception, and localization specificity are maintained through the entire signal path.

High-Impedance Source Compatibility: Input impedance >4.7 MΩ provides optimal loading for passive guitar pickups, vintage keyboard outputs, and modular synthesizer signals without tone loss or loading effects.

Reference-Grade Performance: The Hi-End DI is designed for critical applications where transparency is non-negotiable: mastering studios, archival recording, broadcast facilities, and high-resolution audio production.

Technical Specifications

• Circuit: Advanced discrete J-FET transistors, Class A, no overall negative feedback
• Input Resistance: ≥4.7 MΩ
• Input Impedance (PAD on): 47 kΩ
• PAD Attenuation: 20 dB
• Bandwidth: 20 Hz – 200 kHz
• Noise Level (unweighted, 10–20 kHz): <−110 dBu
• Signal-to-Noise Ratio: >120 dB
• THD @ −20 dBu (guitar level): <0.001%
• THD @ 0 dBu, 1 kHz: <0.0009% (typical 0.001%)
• THD @ 0 dBu, 100 Hz: <0.0009% (typical 0.001%)
• Max Input Level (<3% THD, PAD off): >+14 dBu
• Max Input Level (<3% THD, PAD on): >+34 dBu
• Output Impedance (XLR balanced): <33 Ω
• Power: 48V phantom power
• Ground Safety: LED warning indicator for dangerous ground faults
• Construction: Precision machined aluminum enclosure
• Dimensions: 95 × 147 × 47 mm
• Weight: 0.35 kg

Key Features

Advanced J-FET Input Stage

The Hi-End DI utilizes carefully matched discrete J-FET transistors selected for the lowest noise and highest linearity. This topology provides natural, musical input buffering with ultra-high input impedance—perfect for passive pickups and high-impedance sources that demand optimal loading.

Class A Operation Without Negative Feedback

Operating in pure Class A without global negative feedback eliminates phase anomalies and transient smearing that plague conventional designs. The result is microsecond-level transient accuracy and natural sound reproduction without electronic artifacts.

Ground Safety Monitoring

Unique to Simple Way Audio, the integrated LED indicator provides visual warning of dangerous ground potential differences, protecting performers from electric shock hazards during live performance and studio sessions.

Precision Construction

Machined aluminum enclosure provides electromagnetic shielding and robust mechanical protection. Despite professional-grade construction, the Hi-End DI weighs only 170 grams—ideal for touring musicians who demand uncompromising performance without added weight.

Recommended Applications

Critical Recording

The Hi-End DI is the reference choice for engineers and producers who demand the mastering grade quality at very first recording stage. The lowest noise floor and highest transparency. Ideal for:

• Direct recording of acoustic instruments via pickup

• Vintage synthesizer and keyboard recording

• Bass guitar direct tracking for mixing flexibility

• Any application where the recorded signal will undergo extensive processing or dynamic range expansion

Archival and Preservation Recording

Museums, archives, and institutions trust the Hi-End DI for preservation-quality recordings where absolute fidelity to the source is mandatory.

High-Resolution Audio Production

For hi-res formats (24-bit/96kHz, 24-bit/192kHz, DSD), the Hi-End DI’s 200 kHz bandwidth and −110 dBu noise floor ensure the full resolution of the format is utilized.

Vintage Instrument Recording

High-impedance vintage synthesizers (Moog, ARP, Rhodes), vintage electric pianos, and classic guitar pickups benefit from the Hi-End DI’s optimal input impedance and ultra-low noise.

Reference Monitoring and A/B Testing

Recording engineers use the Hi-End DI as a known-transparent reference when evaluating other equipment or conducting listening tests.

What Sets the Hi-End DI Apart

Compared to Standard DI Boxes:

• 10–20 dB lower noise floor

• 10–100× lower distortion

• 2–4× wider bandwidth

• Superior transient accuracy and phase linearity

• Professional ground safety monitoring

Compared to Simple Way Audio J1mini:

• Identical core specifications (both use J-FET topology)

• Enhanced component selection and matching

• Premium construction and finish

• Flagship positioning for most demanding applications

The Hi-End DI Difference:
Where the D-series provides professional-grade transparency for touring and studio work, and the J-series delivers reference-grade purity for critical recording, the Hi-End DI represents the ultimate expression of Simple Way Audio’s design philosophy: absolute transparency without compromise.

Every Hi-End DI is:

• Hand-assembled in Latvia using selected discrete components

• Individually tested and measured for specifications compliance

• Backed by our commitment to lifetime support and service

• Designed to deliver decades of reliable, transparent performance

Whether you’re capturing the nuances of a priceless vintage instrument, creating masters that will define your catalog, or simply demanding the finest signal conversion available, the Hi-End DI ensures your sound remains objectively, measurably, and perceptually yours.

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Comparison: Hi-End DI vs. Product Line

Choose D1mini for: Professional touring, live sound, general studio work at excellent value
Choose J1mini for: Critical recording, high-impedance sources requiring lowest noise
Choose Hi-End DI for: Flagship performance, archival work, reference-grade transparency where no compromise is acceptable

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The Hi-End DI: Where measurement meets musicality, and transparency becomes truth.