ART Mic Preamp: Affordable Favorite
by Barry Rudolph
Updating the Original / What's New?
Thanks to a new output limiter and analog-style metering, the ART Tube MP Studio is a worthy upgrade to the original compact ART Tube Mic Pre.
Ease of Use: 5
Applied Research and Technology (a.k.a. ART) is at it again. The original Tube MP put a tube microphone preamplifier in the hands of musicians everywhere. And I mean that literally: this little unit, not much larger than a guitar stompbox, fits right in your palm. Just make sure to keep it on your desktop and not under foot! But size was only part of the MP's appeal: a 12AX7A dual triode vacuum tube helped shape the little pre's unique sound, and its price was in reach of even the most modest studio mogul.
Like the original MP, the MP Studio is a one-channel microphone preamplifier with both XLR and 1/4" input and output connections. Powered by a nine-volt AC wall-wart, the MP Studio is all you'll need to record any microphone or instrument directly to your tape deck or hard-disk computer recording system.
The Tube MP Studio adds two new features to the original design. There's a lighted VU meter, which monitors output level. The meter also tracks the action of the second new feature, the Output Peak Limiter circuit (or OPL).
The MP Studio's control layout is pretty basic. Input Level sets gain from +6dB to +40dB. The Gain switch adds a 20dB boost, bringing the input range up to +26dB through +60dB. It's good to know that there is up to 60dB of gain for boosting low-output mics and recording very quiet sounds. The Equivalent Input Noise (EIN) is -129dBu (A-weighted).
Additional controls include +48volt phantom power (required for powering condenser mics and some direct boxes) and a Phase-Reverse switch. The latter --- a common feature on "pro-level" devices -- can come in handy when using the Tube MP Studio in a multi-miking setup.
The OPL uses an FET (Field-Effect Transistor) -based circuit to guarantee full control over output peak levels. This is an insurance policy against overloading and clipping your recorder's inputs with a signal that's too hot. When the OPL push-button is engaged, the output level is limited to 0dBu at the unbalanced 1/4" output jack, and +6dBu at the balanced XLR out. Attack time is program-dependent, ranging from less than 1ms up to 30ms. Release time is also variable with the shortest time set to 200ms. These presets work well for most situations.