The Teegarden Audio Fatboy Tube DI features an Electo-Harmonix 12AY7 tube.

The Fatboy ($695 direct)—about the size of a thick paperback book—employs an Electro-Harmonix 12AY7 tube (comparably, with a little less gain than a 12AX7 and a warmer “bluesier” tone, which Teegarden notes was chosen for its almost non-existent microphonic characteristics, allowing placement next to loud instruments, like drums, in live applications); a Cinemag CMOB-2S transformer; a large in-line 24 VAC power supply (Food); typical quarter-inch in (Push) and thru; a large, unstepped attenuation knob (Beef); and ground lifts and dual outputs (labeled Pull—one at mic level, one at line level +18 dBu max.). Apparently company founder and accomplished Nashville-based recording engineer Bret Teegarden has a sense of humor.


The frivolity ends once you plug-in and crank up—and yes, this box sounds “tube!” Plugging my vintage ’60s passive bass into the Fatboy, I received back a thickness, smoothness and lack of high-end harshness that’s clearly old school: that classic round tone that discriminating bassists seek to fill the pocket and never poke out of it. Its highs were clean, airy and pleasant, with a touch of compression that helped keep all notes even. (Check out my audio webclip of this example at Considering Teegarden’s beginnings as a session bassist, it makes sense that the Fatboy excels when applied to bass tone.

A peek inside the Fatboy Tube DI.

The line-level out provided enough level to either hit my DAW’s converters or drive a compressor. I also used the mic-level outs; I must say that the tone seemed a little more “pure” when I skipped a mic pre and patched into a compressor. Watch out, though: Hot, active instruments will likely cause that tube to bark rather than growl—not a particularly useful distortion sound. Electric guitar DI proved this out, as the Fatboy is no substitute for an amp; I did achieve some “chicken pickin’” clean sounds that were nice, yet roll back that Beef attenuator and you will gain some nice texture and musical harmonics for better virtual amping in your DAW.

Acoustic guitar DI was rather similar. Full disclosure: I absolutely hate DI’d acoustics. Though Fatboy is no substitute for a nice mic or two, it definitely helps achieve some smoothness and remove some stark boxiness—performance was way better than a typical DI, particularly appealing to me for some basic tracking and on scratch tracks.

Synths and keyboards were quite interesting when “Fatboy’d,” affording some pretty tasty crunch out of drum (machine) sounds, buzzy synths and general electronica mangling with line inputs; to my ears, it’s a sound similar to Thermionic Culture’s Culture Vulture, a standard amongst Mr. Reznor (Nine Inch Nails) and other discriminating sound smashers. That’s dramatically nice and all, but the Fatboy does a fine job of gently warming up synths, too; dial back that Beef attenuator and fine-tune just how much plumpness or beard you desire.


At $695 direct, the Fatboy isn’t a DI for cheapskates. It’s also a completely different flavor than a Countryman Type 10, my current standard bearer. Potential buyers should consider that the Fatboy allows variable tube saturation on basses that is hard to replicate (especially with such musical subtlety), some marginally useful warming of guitars, a nice harmonic beauty to synths and the ability to artfully mangle line inputs to taste. These applications, its worthy components and an overall elegant design lead me to give the Fatboy a “thumb’s up” rating. The Fatboy also comes in two rackmounted versions—arguably even more compelling than the “box” version—in mono and stereo models, the latter of which is ideal for synths.

Teegarden Audio