Weight Tank WT-72

The WT-72 is a tribute to the iconic V72 modules originally crafted for the German radio network. With its design inspired by these vintage modules, the WT-72 captures the essence of their sound while offering enhanced functionality. While the original modules provided 34dB of gain, the WT-72 takes it a step further with an additional 22dB of gain, achieved through careful circuit adjustments that preserve the beloved sound and character.
To deliver performance and character reminiscent of its vintage inspiration, the WT-72 incorporates custom input and output transformers, as well as an output plate choke. These components play a crucial role in shaping the overall sound and ensuring a faithful representation of the original design.
Staying true to the all-tube tradition, the WT-72 maintains an authentic vintage design by utilizing both AC and DC voltage feedback. This approach not only provides the appropriate gain but also ensures the necessary stability for optimal performance.
A distinctive feature of the WT-72 is its silent gain-switching mechanism. Traditional DC feedback switching can introduce loud thumps, risking monitors and hearing. To address this, the WT-72 employs a special muting system that briefly silences the output during each gain-switching step. This eliminates loud transients and allows the tubes to settle before the output is re-engaged, providing a smoother and more user-friendly experience.
The WT-72 incorporates a hybrid switching system that combines an 11-position rotary switch with mechanical and photo relays. This design allows for flexible control over the amount of gain, offering versatility to suit various recording scenarios. The gain knob settings on the WT-72 are divided into two sections. The 36dB range is achieved by attenuating the signal to the first EF86 tube, while the remaining 20dB of gain (36-56dB) is switched by altering AC and DC feedback. This approach minimizes noise at lower gain levels, providing a cleaner signal. For example, at 36dB of gain, you can expect 20dB less noise compared to 56dB of gain. The WT-72 strikes a balance between gain flexibility and optimal noise performance by leveraging attenuation before gain stages.
Transformers play a vital role in shaping the sound of the WT-72. With transformer-balanced input and output, the unit preserves the character and qualities of the original design.
In terms of circuitry, the audio signal passes through two EF86 tubes, providing a total of 56dB of gain. The signal path remains purely tube-based, with no solid-state components in the chain, ensuring a true vintage tube sound.
To accommodate line-level signals, the XLR IN switch features a "Line" option. When selected, a 36dB pad is applied before the input transformer, allowing for seamless integration of line-level sources.
In summary, the WT-72 pays homage to the iconic V72 modules while introducing enhancements and features for modern recording needs. With its attention to detail, silent gain switching, all-tube design, and thoughtful gain control, the WT-72 offers flexibility, vintage character, and improved performance for capturing and shaping audio signals.

Specifications

Mic/Line input (XLR) and high impedance DI
DI disables XLR input when plugged in
Two EF86 equivalent tubes
56dB of gain
11 position gain rotary selector
Polarity reverse switch
36 dB pad switch (line select)
48 volt phantom power switch
XLR Input and Output connections
American made input and output transformers and plate choke
White LED indicators for phantom, power and output present (-12dBu 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
Input load impedance in mic mode: ca. 4kΩ
Input load impedance in line mode: 9550 Ω
Output impedance: < 100Ω
1/4" DI impedance: 500 kΩ
56dB of gain
Frequency Response: 20Hz-20kHz
Maximum output level: +24dBu
THD+N: <1%
S/N Ratio: >70dB
Dimensions: 19" w x 3.5" h x 10" d (2u rack space)
Shipping Weight: 15 lbs.
Power Consumption (120/240VAC): 25 watts