Warm Audio TB12/500 Microphone Pre Amplifier

The 500 series “lunchbox” version of the Warm Audio TB12/500 – Tone Beast Microphone Preamplifier is a single-channel mic preamplifier this is designed to provide a wide range of tonal options for mic, instrument, and line-level sources. It is capable of up to 71 dB of input gain, and employs an output attenuator, allowing you to drive your input signal harder for color and saturation while keeping your signal from peaking.

The device lives up to its name by allowing you to select between two different discrete op amps, two different steel and 50% Nickel CineMag output transformers that can be bypassed altogether, two input impedance settings for dynamic, condenser, or ribbon mic optimization, and two different capacitors. The preamp is capable of producing colored, vintage-style tones with early break up and clean, transparent modern tones. Thanks to its front-panel instrument input, the preamp can be used to record DI tracks, while the front-panel 1/4″ line input allows you to use the TB12 to provide color or warm up previously recorded tracks.

The unit features 48V phantom power to its front-panel XLR input, a high-pass filter at 80 Hz, a 20 dB pad, and a polarity reverse switch.

Op Amps Switch

This switch allows you to choose between 2 completely different discrete analog operational amplifiers. One of the op amps is built to the schematic of the classic 1731 style op amp, using a Melcor 1731, and the other to the schematic of the 918, employing Dean Jensen’s 918. The 1731 has a more noticeable “vintage tone,” breaking up faster and providing a more colored sound. The 918 is more linear/transparent, and does not break up as quickly.

Both op amps are socketed and use the classic 2520 6-pin footprint. This allows users to remove the op amps easily (without soldering), and replace them with their own op amps of choice.

Output Transformer Switch

This feature allows you to switch between 2 CineMag output transformers of different tone/make. The 100% steel core transformer sounds more “vintage” with a “mid-forward” tone. The 50% nickel-core transformer has a “cleaner” tone than the steel, providing more highs and lows, and was custom designed by CineMag specifically for the Tone Beast.

The nickel version uses a laminating method that gives the signal a more linear response than the steel option, but still treats the signal slightly, giving your signal a smoothness.

The Output Transformer Bypass Switch removes both the nickel and steel transformers from your output signal, and provides a transparent tone. Please note bypassing the output transformers will result in an 8dB drop in level.

Tone Switch

When engaged the input impedance of the Tone Beast is 150 ohms. When disengaged the input impedance of the Tone Beast is 600 ohms. The 150 ohm (switched-in) setting increases the gain of the Tone Beast by +6db changing the maximum gain from +65 to +71db. This feature will make a noticeable tone change to most microphones and instruments. The microphone, line and Hi-Z inputs are all altered by this feature.

The 600 ohm impedance setting is recommended for condenser and dynamic microphones, and 150 ohms is recommended for ribbons. This switch is labeled “Tone” for a reason though, so experiment with both settings on all sources to find the best possible tone for your mixes.

Capacitor Switch

This switch changes 2 capacitors in the circuit from Tantalum to Electrolytic. The “vintage” setting is for tantalum capacitors, the “clean” setting is for electrolytic. Of all the tone features provided in the Tone Beast this option is the most subtle but still noticeable to many ears depending on the source being treated.