Warm Audio TB12 Tonebeast Mic Preamp (Discontinued)


90 out of 100. Incorporating 60+ ratings and reviews.

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Warm Audio TB12 Tonebeast Microphone Preamp
Warm Audio TB12 Tonebeast Microphone Preamp

Warm Audio describes the TB12 as a clone of the API 312 preamp, complete with premium Cinemag input-output balancing transformer. This distinct feature was normally found on more expensive units, but it is now more accessible, thanks to the increased efficiency of today's raw materials and production.

This preamp also houses multiple discrete signal paths that let you choose between two op-amps, be it the Jensen 918 (which is more transparent) op-amp or the Melcor 1731 (which is more colored).

Controls include a tone switch that changes mic impedance, 80Hz highpass filter, 20dB pad, and output attenuation. There's also a Hi-Z switch in case you want to plug-in electric guitars and basses.


  • Channels: 1
  • Mic Preamps: 1 Solid State 312 preamp with Cinemag Transformers
  • Frequency Response: 10Hz - 50kHz
  • OP-Amp: Swappable/Socketed
  • Input Connectors: 1 x XLR, 1 x TRS (with Hi-Z Switch), 1 x TRS (Receive)
  • Output Connectors: 1 x XLR, 1 x TRS, 1 x TRS (Send)
  • Controls: 20dB pad, 80Hz highpas filter, Output attenuation, Tone switch, Transformer bypass, Phantom Power, Phase Switch, Compressor
  • Dimensions : 1.75" x 5.5" x 19"
  • Weight: 5 lbs.


The TB12 is consistently lauded as being great for vocals. In addition, there are others who describe it as their all-in-one solution for capturing drums, bass, guitars, horns and many more. More experienced users are fond of the swappable op-amp feature, and its overall versatility. Many users agree that the TB12 Tonebeast is simply a real Beast when it comes to mic preamps.


There aren't that many complaints about this unit, but there was one who complained of having problems with one of their transformers.


We were recommending the Warm Audio TB12 Tone Beast until we performed a detailed revision of mic pres in February 2018. At this time we found there were more highly rated options available which we are now recommending in our guide to The Best Microphone Preamps.