Samson S-Max MD1 Pro - Passive mono DI box with shielded STLX transformer, −15/−30 dB pad and Ground Lift

Samson S-Max MD1 Pro - Passive mono DI box with shielded STLX transformer, −15/−30 dB pad and Ground Lift

The Samson S-Max MD1 Pro is a passive mono DI box designed to take unbalanced instrument or line signals to a low-impedance balanced XLR output , minimizing noise over long runs. It features an STLX transformer with mu-metal /Faraday shielding that guarantees a flat response from 18 Hz to 40 kHz with low distortion and excellent interference rejection. Its 3-position pad (0/-15/-30 dB) allows you to accommodate everything from guitar/bass pickups to line outputs and even speaker levels when necessary. It includes Ground Lift to break ground loops and 1/4" IN/THRU connections to route the signal to an amp or monitor while sending the XLR output to your mixer.

Constructed from 14-gauge steel , the MD1 Pro is ready for intensive live or studio use. Being passive , it requires no power (no phantom power or batteries), simplifying logistics on stages, in schools, and rehearsal rooms.

Main features

• Shielded STLX ( mu-metal /Faraday) transformer for maximum signal integrity and low noise.
• Wide frequency response : 18 Hz–40 kHz (±0.1 dB).
• Switched input pad : 0/−15/−30 dB for instrument, line and speaker levels.
• Ground Lift to eliminate hum from ground loops (disconnects pin 1 on output XLR).
• Inputs/Thru on 6.35 mm jack (unbalanced) and balanced XLR output .
• 14 gauge steel chassis , impact resistant.
• No power : 100% passive operation.

Product benefits

• Clean and consistent audio : Low-impedance balanced conversion for long cable runs without loss or noise.
• Versatility : The pad prevents clipping and allows the DI to be used from guitars/keyboards to speaker outputs in re-amping or special capture situations.
• Noise Control : STLX transformer and Ground Lift reduce hum and interference typical in complex environments.
• Easy routing : The THRU jack keeps your monitor/amp in parallel while sending a clean signal to your mixer or interface.
• Reliability : Rugged metal construction for touring and rental use.

Use cases

• Direct : guitars, basses, keyboards or electronic drums to PA/monitors with minimal interference.
• Studio : re-amping and capturing instruments with clean to balanced conversion.
• Facilities : auditoriums, churches, educational centers with long runs and multiple users.

Frequently Asked Questions

• Does it need power? No. It's passive ; it doesn't require a phantom power supply or batteries.
• Can I use it at speaker levels? Yes, using the −15/−30 dB pad depending on the amplifier's power/impedance to avoid clipping.
• Does it have parallel outputs? Yes, the 6.35mm THRU connector allows you to send the signal to your amp/monitor simultaneously.

Description for projects

Passive mono DI box with shielded STLX ( mu-metal /Faraday) transformer. Inputs : 1× 6.35 mm jack (IN unbalanced) + 1× 6.35 mm jack (THRU in parallel). Output : 1× balanced XLR. Controls : Pad 0/−15/−30 dB; Ground Lift. Response : 18 Hz–40 kHz (±0.1 dB). Max. input : +20 dBu @ 0.35 % THD. THD : <0.03 % (20 Hz–40 kHz). Dynamic range : >100 dB (balanced output). Impedances : 400 kΩ input; 250 Ω ±20 % output. Transformer ratio : 15:1. Construction : 14 gauge steel. Dimensions : 127 × 86 × 49.6 mm. Weight : 0.667 kg. No power supply required.