LaChapell Audio 992EG Tube Microphone Preamp

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. The 992 TLS features a transformer-less balanced differential microphone input utilizing two USA made 6072A’s per channel. Our technique of using large matched capacitors with the 6072’s to balance the input instead of a transformer is unique and indeed a vital design requirement for capturing the essence of the coveted 6072. With the 992 TLS, the full burden of generating gain falls on the input tubes themselves, isolating the 6072s as the primary source of character. In addition to the TLS and, wanting to answer the call for more gain, we dug deeper and developed a second variant; the 992 EG (extended gain). By replacing the input caps with the Jensen JT-115k transformer and exchanging the 6072’s for the timeless 12AX7/ECC83 this variant is able to provide a generous >74dB of raw internal gain. With over 40dB of gain deployed to the input pot alone your ability to explore the sonic richness of each stage becomes even more dramatic than that of the 992 TLS. The direct instrument input (Hi-Z) on both variants utilizes a high performance Cinemag direct transformer which feeds the balanced differential amplifier input. 

From there the signal reaches the cross-coupled push-pull output stage where we’ve place two 12AU7 tubes in parallel along with the Jensen JT-11 transformer to balance the outputs. The balanced class-A circuitry used throughout this amplifier provides twice the headroom of single ended designs as well as low noise performance. With the use of four tubes per channel, the 992 easily delivers performance well beyond the limits of audibility. 

In operation, the user has individual control over the input and output gain stages of each channel. This provides uncommon flexibility to delve into the 992’s broad sonic pallet making it one of the most versatile preamplifiers in any environment. Push the inputs hard and capture that elusive air that can only come from fully balanced tube gain. Or, pull the inputs back and favor the output stage for a cleaner, more linear signal - the choice is yours. 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 components 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. 

Features:

• Amplifier isolated VU meters
• Eight total vacuum tubes
• Fully variable input/output control
• Robust construction
• Balanced circuitry throughout
• Hi-Z instrument input
• Premium tubes components
• Jensen JT-11 output transformer
• Individual channel mute function