iCON Pro Audio UFO Class-A Tube Microphone Preamplifier with 4 Swappable Tubes

iCON Pro Audio UFO: Put Tube Color on the Signal at the Source

The iCON Pro Audio UFO is a discrete Class-A tube microphone preamplifier with up to 68 dB of gain and a tool-free swappable tube holding one of four included vacuum tubes. The idea is to add analog character on the way in, before a signal ever reaches the converter, where that color becomes part of the recording rather than a plugin bolted on afterward. It takes a mic on a 3-pin XLR input or an instrument on a 1/4" Hi-Z input and passes both across a 131 dB dynamic range. For a producer chasing warmth at the front of the chain, one box holds four distinct tube voices.

A Fully Discrete Class-A Path

Inside, the UFO runs a fully discrete Class-A signal path with no integrated circuits, built on low-noise metal-film resistors and polystyrene capacitors. That construction yields an EIN of -130 dB into a 50-ohm load and THD of just 0.005 percent - numbers that describe a very quiet, very clean stage. On a delicate vocal take, the result is warmth and detail rather than a bed of hiss underneath it. Class-A biasing keeps the response linear even at the low signal levels a soft source produces.

Four Tubes, Swapped in Seconds

A spring-mounted transparent cover pops off by hand so a fresh tube seats in seconds, with no tools involved. The UFO ships with four of them - an Electro-Harmonix 6922EH preinstalled, plus a 12AT7EH, a Sovtek 12AX7LPS, and a Sovtek 12AX7WA - spanning transparent, saturated, and vintage-midrange voicings. An engineer can audition a clean tube for a pop vocal, then drop in a saturated one for a gritty guitar without leaving the session. That turns a single preamp into a small palette of tube colors on demand.

68 dB of Gain With Headroom to Match

Up to 68 dB of gain pairs with a 131 dB dynamic range and a 10 Hz to 100 kHz response to give the UFO the reach to drive almost any source. That much gain is what feeds low-output ribbon and dynamic mics that leave smaller preamps sounding starved, while the wide bandwidth passes both air on top and weight down low. A balanced transistor-ladder stage holds crosstalk between input and output in check. The noise floor stays well out of the way of a big, open sound.

Full Control Over Mic and Instrument

Connection is straightforward: a 3-pin XLR mic input, a 1/4" Hi-Z instrument input, and a 3-pin XLR line output tie the UFO to an interface or console. Its controls cover switchable 48V phantom power, a mic/instrument selector, a -20 dB pad for hot sources, and a polarity reverse for phase alignment. A guitarist can plug straight in for a warm DI, then a vocalist tracks through the same unit minutes later. A large gain knob and an illuminated VU meter make setting level fast and visual.

Power, Build, and Who It's For

An external AC adapter feeds the UFO through a secure mini-XLR power cable, a design that keeps mains noise off the audio path. The all-metal enclosure glows with the tube's light and is built to hold up in daily use. Vocal producers, guitarists, and home-studio engineers who want analog character available on tap treat it as a permanent front end. The box includes the UFO, all four tubes with one preinstalled, the mini-XLR power cable, and the power supply.