Locomotive_Audio_MODEL_40AM-1_-_500_Series_Stereo_Octal_Tube_Preamp_1

Locomotive Audio MODEL 40AM-1 - 500 Series Stereo Octal Tube Preamp - Image 2

Locomotive Audio MODEL 40AM-1 – 500 Series Stereo Octal Tube Preamp

Name: Locomotive Audio MODEL 40AM-1 - 500 Series Stereo Octal Tube Preamp
Brand: Locomotive Audio
SKU: LOC-40AM-1

$1,969.00

500 Series stereo octal tube preamp inspired by legendary 1940s American designs. With its thick, heavy, and harmonically rich tone, it delivers the classic character of RCA and Gates tube gear while offering modern flexibility. From subtle vintage warmth to bold coloration, the Locomotive Audio MODEL 40AM-1 captures the essence of a bygone era with premium transformers, dual 6SJ7 tubes, and versatile controls that shape your sound with ease.

SKU: LOC-40AM-1 Categories: 500 Series, 500 Series Preamps, 500 Series Preamps|OUTBOARD, 500 Series Tape/Tube/Distortion, OUTBOARD, Preamps, Preamps

Brands: Locomotive Audio

Brand: Locomotive Audio

Description

Audio MODEL 86B-1 – 500 Series Mono Tube Preamp

OVERVIEW

Heavy 1940s American Tube Gain for Big, Thick, and Compressed Sound

The Locomotive Audio MODEL 40AM-1 brings the legendary sound of 1940s American tube preamps into the modern studio. Inspired by classics like the RCA BA-11A and Gates SA-70, this stereo octal preamp delivers the big, heavy, and harmonically rich tone engineers love for adding depth and weight to recordings. Its dual 6SJ7 tubes, premium in-house wound transformers, and heavy steel chassis provide an authentic sonic footprint that recalls the golden age of tube recording.

With features such as a 5-position Response switch, selectable input impedances, 20 dB pad, 85 Hz low-cut filter, and a high-impedance DI, the 40AM-1 offers both vintage character and modern flexibility. Whether you want smooth tube warmth, punchy thickness, or saturated harmonic coloration, the 40AM-1 gives you a powerful tool for shaping vocals, instruments, and full mixes. Built in the USA and backed by a lifetime warranty (excluding tubes), it’s a must-have preamp for producers and engineers seeking bold, unmistakable analog tone.

Set the Sound You Want

RESPONSE KNOB:

A 5-position Response Switch gives you complete control over the frequency response and harmonic footprint of any material processed through the 40AM. Position 5 enhances high and low frequencies, delivering a rich sound while minimizing distortion. Conversely, position 1 softens the highs and attenuates the lows, emphasizing the mid-range and adding subtle harmonic character. For the most neutral sound, we suggest position 4 as a starting point. The Response switch allows you to tailor the sound to your taste.

LEVEL KNOB:

The Level knob provides users with the flexibility to make precise signal level adjustments. It’s important to note that it interacts slightly with the response knob based on its setting. As the signal is attenuated, users may notice a subtle darkening of the sound. However, by working in tandem with the response knob, adjustments can be made to compensate for any changes in tone.

40AM Inspiration

Combining vintage circuits requires time and patience to achieve the perfect balance. However, when executed correctly, you can harness the strengths of each to create an exceptional hybrid. The RCA BA-11A pentode input paired with its triode output and the feedback structure of the Gates SA-70 come together to produce the rich, compressed sound of the 40AM, beautifully complementing its 86B and WT-72 siblings.