MDP-1 Vacuum Tube Mic/DI Preamp

The Ultimate Front End for High Resolution Recording

The MDP-1 is a modern two channel vacuum tube Mic/DI preamp designed to be the ultimate way to get your mic or source directly to tape or hard disk. Unlike vintage or hybrid designs, the MDP-1 uses a pure tube, class A high voltage circuit topology with a transformerless output stage to deliver an open, intimate sound with a level of detail that meets the requirements of the most demanding recording applications. Our short signal path design excels in audio performance, delivering extremely wide bandwidth, low noise, and high headroom.

A key component of the sound of a tube mic preamp is the input transformer. It's here that we let your select how you would like the preamp to sound. The MDP-1 can be ordered with your choice of two low turns-ratio transformers depending on your requirements: a Jensen 13K7A for a full, open sound with plenty of sparkle in the high end and a deep low end - perfect for recording all sources, especially instrumental music; or a custom-wound transformer for a more 'focused' sound, with extra presence and clarity in the midrange - ideal for a vocal sound that easily distinguishes itself in a mix.

The MDP-1 also has all the things you'd expect in a full-featured mic preamp; phantom power, phase reverse, -20dB input pad, a lo cut filter with 10 frequencies and large, illuminated VU meters. The DI signal path is completely transformerless, with a selection of three input load impedances: 10M for piezoelectric acoustic instrument pickups, 1M for magnetic pickups, and 100k with a 20dB pad for line level sources such as keyboards or other -10dBV equipment.

Specifications

Circuit Type: Class A vacuum tube signal path with transformerless output
Meter: selection of output level (0VU = +4dBu) or tube gain (0VU = +20dBu)
Phantom Power: +48Vdc applied to pins 2 and 3
Mic Pad: -20dB pad at the primary of the mic input transformer
Mic Phase: inverts the phase at the secondary of the mic input transformer
Mic Lo Cut: 6 dB/octave rolloff from 20-180Hz in 10 steps
Polarity: input and output XLR connectors are pin 2 hot
Vacuum Tubes: (2) ECC83/12AX7A, (2) 6922
Power: 120Vac, 30W (240Vac optional)
Power Supplies: +300Vdc and +12.6Vdc, fully regulated with soft-start warm-up

Mic Preamp

Input Gain: +33 to +63dB in 3dB steps
Input Impedance: 1500 ohm, transformer balanced and floating
Frequency Response: -1.0dB 6Hz and 65kHz with 10Kohm load, +45dB gain
Noise: EIN less than -125dBu with 150 ohm input load, unweighted (Jensen 13K7)
Distortion: THD+N less than 0.03% from 100Hz-10kHz, less than 0.07% at 20Hz, measured with -20dBu input, +10dBu output, +45dB gain

DI Preamp

Input Gain: +20 to +50dB (Instrument), 0 to +20dB (Line) in 3dB steps
Input Impedance: 10Mohm or 1Mohm (Instrument), 100Kohm with 20dB pad (Line)
Frequency Response: -1.0dB 5Hz and 250kHz with 10K load, +20dB gain
Noise: EIN less than -116dBu with input shorted, unweighted
Distortion: THD+N less than 0.04% from 20Hz-10kHz measured with +10dBu output, +40dB gain
Output Level: +35dBu into 10Kohm load, +25dBu into 600 ohm load, Output control at maximum

Dimensions

2U Enclosure: 19" x 3.5" x 12.5" (48.2 x 8.8 x 31.8 cm)
Weight: 14lbs (6.4kg)

Fast Features

All tube, short signal path design · Pure class A, high voltage circuitry · Transformerless tube output stage capable of delivering +35dBu · Low noise, wide bandwidth and superior transient response · Choice of mic input transformer for 'full' or 'focused' sound · 30dB gain range in 3dB steps · Fully transformerless DI with 100k, 1M and 10M input impedances · Ten position mic lo-cut filter (20-180Hz) · Gold-plated switch contacts, I/O connectors and tube sockets · Polypropylene caps and metal film resistors (pairs matched to 0.1%) · Fully regulated high voltage (300V) and filament power supplies with soft-start warm-up and muting · Custom toroidal power transformer with shield for minimum hum · Handcrafted in the USA

Notes:
0dBu = 0.775 Vrms
All noise measurements are unweighted, 20 - 20,000 Hz bandwidth
All Specifications are subject to change without notice