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Manley TNT Microphone Preamplifier

The dual-channel Manley TNT is loosely named after its “Tube ‘n No Tube” channels. But I contend that it could also refer to “Tweak ‘n Tweak,” as that’s what you’ll be doing with this $3,000 preamp’s wealth of interesting options.

The dual-channel Manley TNT is loosely named after its “Tube ‘n No Tube” channels. But I contend that it could also refer to “Tweak ‘n Tweak,” as that’s what you’ll be doing with this $3,000 preamp’s wealth of interesting options.


According to the manufacturer, the TNT was born out of many users’ requests for the tube mic amps of the Manley SLAM! (Stereo Limiter and Mic Preamp) without the other features. In addition, with so many engineers having access to unlimited (or at least very high) track counts, multiple mics on one source is (nearly) a norm … and those mics often require different preamp topologies with which to “paint.”

For the TNT, the “Tube” side is based on a JFET/vacuum tube triode cascode circuit. The solid state side was created with a mix of discrete and op-amp amplification, as well as the Rapture Amp as the final line driver; Manley calls this channel the “Cool” side of the TNT.

Both sides offer independent phantom power, a polarity reversal, a high pass filter (80 Hz for Cool, 60 or 120 Hz for Tube), stepped gain controls (+20 to +70 dB), gain trim (from -10 up to +10 dB, allowing up to +80 dB gain overall) and impedance selection; each side offers numerous values (600, 2400 and 10 kilohms Tube; 2 MEG, 2000, 600 and 300 ohms Cool) and neither suffers from volume changes (an aid in making valid comparisons). Settings on the Cool side are actually achieved by switching between (or combining) two different stages of the solid-state amplifying circuits.

The Cool side also benefits from a Color switch, offering ‘60s and ‘70s settings. These switches engage additional circuitry, which simulates tape and guitar amp clipping of a light variety. The Cool side also allows control of its output transformer via the Iron control. This knob adjusts the audibility of the transformer from an exaggerated +3 to “bypassed” at 0 to the “opposite” of a transformer at -1.

Fast FactsApplications
Studio, project studio

Key Features
Discrete tube and solid-state channels; phantom power; a polarity reversal; high-pass filter; stepped gain controls; gain trim; impedance selection; various other unique controls


Manley Labs | 909-627-4256 |


  • Multiple topologies and signal path options
  • Wide range of useful and creative features
  • Quality construction and thoughtful design


  • Expensive, even if warranted
  • Limited metering
  • Requires ample cooling in rack

Although it’s $3k, Manley’s TNT is a bargain by its expected longevity, resale value, quality and flexibility.Metering is provided from two sets of four LED’s indicating signal presence, +10 dB, +22 dB and overload. Input/output is provided on XLR connections (except for front panel 1/4-inch DI inputs), with additional 1/4-inch outputs. Output level can be switched from the rear panel, offering -10 dBV unbalanced and +4 dBu balanced or unbalanced modes.

In Use

With only a vented panel for top and bottom, the TNT’s insides called for a closer look. I marveled at a beautiful layout and quality components throughout (12AT7 and 7044 tubes, multiple Lundahl transformers, rugged switches, sealed relays etc.). I proceeded to throw a little bit of everything into these circuits over the next few months, including close and ambient drums, amplified instruments, acoustic instruments, percussion, piano and vocals.

The TNT took each application with grace, revealing nuances of mic selection and placement without any signs of sluggishness, distortion or compression. Both sides offered unrestrained dynamics, openness and headroom, exhibiting linearity at nearly all gain levels. These qualities, and the TNT’s quality construction, are to be expected from Manley’s tradition, and are delivered here. The pleasant surprises truly lie in the additional features.

Seasoned pros know that “tube” does not always equal “fuzzy,” and the tube side is wonderfully clear and clean. I found its impedance selection to be my paintbrush, with higher settings typically sounding more open and crisp (due to the lighter load) and lower settings affecting the bottom end and its tightness. In use, the subtle (and no so subtle) differences from mic-to-mic called out for much experimenting; sometimes the textural differences were merely academic, while at other times theere was significantly altered balance and transient response. At times, impedance changes made me reposition my mic … tweak ‘n tweak.

The Cool side is truly the perfectionist’s delight, however. The two HPF settings were useful, with the non-traditional 60 Hz setting being a welcome addition. The wide range of impedance settings dominated my curiosity with a great variety of possibilities, especially the 300C setting (this setting bypasses the preamp mixing circuit, a purist setting if you will). When using the 1/4-inch instrument DI input the impedance switch selects a different range of values for that input. The Cool side offers five impedance choices from 100K to 10 Megohms, allowing compatibility with everything from old-school single-coil pickups to modern humbuckers to line level-type sources … more tweak ‘n tweak.

The Color switch proved itself to be powerful, but not frequently called for. Both the ‘60s and ‘70s settings were fairly dramatic, altering frequency response and dynamics in obvious ways. Although I’ve been doing a lot of clean work lately, those of you who do highly stylized productions and work relying on grit and grain will utilize this feature on a daily basis. Combined with driving the input hard, the output trim and impedance settings, I found myself doing lots of long experimental soundchecks. Tweak …

Topping it all off: the Iron control. Seasoned pros know that “transformer” does not always equal “fuzzy,” either, so this control should not be expected to be some sort of overdrive. What it does do is impart subtle transformer coloration in the form of low frequency level and its distortion, high frequency level and its dynamics. I found myself split on the use of Iron, sometimes rounding out harsh aggressiveness, sometimes getting out of the signal’s way to retain clarity. Sometimes this control made me reconsider mic issues again … you know by now.


Manley quality does not come cheap, but this unit is still a bargain due to its expected longevity, resale value, quality and flexibility. Engineers who travel with gear will value its portability vs. versatility ratio. Engineers who like to double mic sources and track either similar or dissimilar options will revel in its inherent flexibility. Engineers who like to make quick decisions and aren’t concerned with colorful options take heed; you may require blinders to block out features vying for your scarce attention … my initial re-naming “tweak” is amply supported.