Locomotive Audio WT-72 – Weight All-Tube Mic Preamp
OVERVIEW
The Sound of the Original V72 Modules
The Locomotive Audio WT-72 brings the unmistakable tone of the original German V72 modules into a modern preamp design built for today’s studios. While the vintage units offered just 34 dB of gain, the WT-72 extends that range to 56 dB by carefully refining the circuit, giving engineers more flexibility without sacrificing the thick, harmonically rich character that made the originals legendary. With transformer-balanced input and output, a plate choke for low-distortion headroom, and an all-tube signal path featuring dual EF86s, the WT-72 delivers the warmth, depth, and authority, making sources stand out in a mix.
True to the Original All-Tube Design
Unlike vintage modules, the WT-72 incorporates a modern hybrid switching system that allows for quiet, pop-free gain adjustments. An 11-position rotary switch combines mechanical and photo relays, while a built-in muting system eliminates transients during gain changes, protecting your monitors and ears. With mic, line, and DI inputs, a 20 dB pad, polarity reverse, low-noise performance, and phantom power, this preamp is as practical as it is musical. Hand-built in the USA and crafted to last, the WT-72 is the perfect fusion of timeless tone and modern engineering.
QUIET GAIN SWITCHING:
The all-new WT-72 sets gain with attenuation and altering AC & DC voltage feedback. DC feedback switching would normally introduce large pops, causing harm to your monitors, or even worse, your hearing. The user would need to manually lower the monitor volume before switching gain, making for a frustrating experience. A special muting system in the WT-72 performs a brief mute of the output between each step of gain. This mute eliminates the loud transient and allows the tubes to stabilize before the output becomes unmuted.
HYBRID SWITCHING SYSTEM:
An 11-position rotary switch utilises both mechanical and photo relays to change the amount of gain, offering great flexibility.

HOW IT’S DONE:
Gain knob settings Off – 36 dB are switched by attenuating the signal to the first EF86, while the remaining 20 dB of gain (36 – 56 dB) are switched by changing AC & DC feedback.
WHY IS ANY OF THIS IMPORTANT?
By changing the gain with voltage feedback (gain knob at 36-56 dB), there is less noise at less gain!
For example, at 36 dB of gain, you will have 20 dB less noise than at 56 dB of gain. We are limited by the amount of voltage feedback to change the gain because there is a “sweet spot” for stability and frequency response. Therefore, using attenuation before the tube gain stages (gain knob at Off – 36 dB) allows the WT-72 to have the most gain flexibility and best noise performance possible.
KEY HIGHLIGHTS
TRANSFORMERS:
Transformer balanced input and output give the WT-72 the character of the original.
TUBE CIRCUITRY:
Audio passes through two EF86 tubes, giving 56 dB of gain. The signal path contains no solid-state components.
OUTPUT HEADROOM:
A plate choke feeding the output EF86 provides large output swings at low distortion.
LINE INPUT:
When “Line” is selected from the XLR IN switch, a 36 dB pad is placed before the input TX.
FEATURES
- Mic / Line (XLR) and High Impedance DI Input​
- DI defeats the XLR input when plugged in
- Two EF86 equivalent tubes
- 56 dB of gain
- 11 Position Gain Rotary Switch
- Polarity reverse switch
- 36 dB pad switch (Line Select)​
- 48-volt phantom power switch​
- XLR input and output connections
- American input and output transformers and plate choke​
- White LED indicators for phantom, power on, and output signal present (-12 dBu minimum for illumination)
- Hand-built in the USA​
- 115v/230v AC mains option on rear
- Internal power supply
- 2-year warranty on parts and labor
TECHNICAL SPECS
Microphone Mode Input Load Impedance: Approx. 4k Ω
Line Mode Input Load Impedance: 9550 Ω
Output Impedance: < 100Ω
1/4″ DI Impedance: 500kΩ
52 dB of Gain
Frequency Response: 20Hz-20kHz​
Maximum Output Level: +24 dBu
THD+N: < 1%
S/N Ratio: > 70dB
Power Consumption (120/240VAC): 25 watts
Dimensions (2U Rackspace):
- Width — 19″
- Height — 3.5″
- Depth — 10″
Shipping Weight: 15 lbs.










