The LaChapell Audio Model 992 is a two channel fully balanced all-tube preamplifier and instrument input amplifier. Meticulously hand assembled, every aspect of the 992 speaks of our dedication to quality of sound and solid, robust construction. Utilizing a total of eight vacuum tubes promises that the 992 will absolutely awaken your ears with its warm melodic character and rich low-end response. But, what makes the 992 such a powerful preamp is the level of control the user has over both the input and output stages. Allowing the user to actually throttle gain in or out of either the input stage (for loads of character) or the output stage (for a more clear, transparent response) by way of fully variable potentiometers secures the 992 as one of the most flexible vacuum tube preamps available in today’s market.
For the 992’s input stage we chose one of Jensen’s best microphone input transformers; the JT-115k. along with two 12AX7/ ECC83 vacuum tubes per channel; allowing a generous >74dB of raw internal gain. With over 40dB of gain deployed to the input pot alone, your ability to drive and explore the sonic potential of this amplifier becomes very dramatic. The harder you push the input stage the more harmonics are generated; even into 15~20% distortion! And, since this is a balanced amplifier (meaning both negative and positive rails are amplified internally) the distortion will sound compressed and full of energy.
The direct instrument input (Hi-Z) stage on the 992 utilizes the high performance Cinemag CM-DBX direct transformer which feeds the balanced differential amplifier input. This double balanced approach allows for an extremely quiet Hi-Z stage; renowned for it’s rich, clear, full sound- highly favored among electric guitar and bass players.
The 992’s output stage features a cross-coupled push-pull topology which includes two 12AU7 tubes in parallel with the Jensen JT-11BM line output transformer to balance the outputs. Unlike the input stage, this stage was intentionally designed to be extremely clear and ̇ difficult to overdrive. If you’re looking for a crystal clear signal for your acoustic guitar tracks or ‘airy’ vocal tracks, this is the stage to favor over the input. Output signal strength is easily monitored through an isolated Sifam back-lit VU meter. There are also five illuminated toggle switches per channel for Meter On/Off, 48v (Phantom), -20db input pad, phase reverse and Mute.
All of this is housed in a chassis that is built like a tank. Designed with reliability and ̇“on the road” stamina as a requirement, we start with high grade aluminum stock milled to a sturdy 1/4” front panel with chip resistant powder coating for the finish. All internal compo- nents are well secured using PEM type fasteners and tie-downs. And, of course, ultra-premium components are used throughout: 3/4w Vishay resistors, ASC caps, sealed premium relays … Our goal is to communicate a sense of robust sturdiness when interfacing with the 992. Each ̇ unit is assembled by hand with much care and attention to detail with the hope of preparing it to be the next center piece for any professional recording or broadcast environment. We encourage you to try one and experience for yourself what we think is a new standard of pure tube amplification.
|Frequency Response||10Hz to 100KHz|
|Max Output (1% THD+N)||+24dBu|
4 x 12AX7 / ECC83
4 x 12AU7 / 6189