Analog Prairie True North Passive Transformer Based Stereo Processor
True North is a handcrafted, fully passive stereo color box built around a matched pair of Hammond 1140 transformers, precision-made in Ontario, Canada.
It captures the calm, balanced tone of the north — clean and open at low levels, colorful with slight compression like behavior when driven. Front Panel potentiometer attenuates the signal on the transformer secondary (output)
Features
Dual Hammond 1140 nickel-core transformers (1:1 ratio, 600 Ω : 600 Ω)
Single stereo COLOR potentiometer that varies impedance, transformer drive, and harmonic texture
Fully passive design — no power, no op-amps, no added noise
Balanced XLR inputs and outputs
1 U rackmount chassis with matte-graphite finish and white engraving
Tone & Character
The Hammond 1140-LU-B transformers are renowned for their smooth, open character and gentle saturation curve.
Higher Impedance / COLOR Up: wideband clarity, linear phase, extended top end
Lower Impedance / COLOR Down: thicker harmonics, soft transient rounding, and “iron glue” cohesion
Specifications
Transformers: Dual Hammond 1140 (nickel-core, made in Ontario, Canada)
Ratio: 1 : 1 (600 Ω : 600 Ω)
Topology: Fully passive, balanced stereo design
Control: Single stereo potentiometer varies impedance and transformer drive
Frequency Response: 20 Hz – 20 kHz ± 0.5 dB typical
Insertion Loss: 1 dB @ 1 kHz
Distortion (THD): < 0.05 % @ +4 dBu, 1 kHz
Maximum Input Level: +21 dBu @ 20 Hz (.150 % THD @ 20 hz)
Common-Mode Rejection Ratio: > 100 dB @ 60 Hz
Output Impedance: ≈ 600 Ω (variable via COLOR control)
Connections: Balanced XLR In / Out (Left / Right)
Chassis: 1 U aluminum rack (17″ × 8″)
Finish: Matte graphite black with white engraving
Weight: ≈ 2.5 lb (1.1 kg)
Power: None required — fully passive
Applications
Mix-bus or mastering transformer stage
Stereo tone-shaping before or after summing
Parallel analog color path for synths, vocals, or drums
FOH/IEM signal conditioning
Studio line-balancing or isolation
A passive reflection of the northern sound: clear, balanced, and naturally harmonic.
True North is a handcrafted, fully passive stereo color box built around a matched pair of Hammond 1140 transformers, precision-made in Ontario, Canada.
It captures the calm, balanced tone of the north — clean and open at low levels, colorful with slight compression like behavior when driven. Front Panel potentiometer attenuates the signal on the transformer secondary (output)
Features
Dual Hammond 1140 nickel-core transformers (1:1 ratio, 600 Ω : 600 Ω)
Single stereo COLOR potentiometer that varies impedance, transformer drive, and harmonic texture
Fully passive design — no power, no op-amps, no added noise
Balanced XLR inputs and outputs
1 U rackmount chassis with matte-graphite finish and white engraving
Tone & Character
The Hammond 1140-LU-B transformers are renowned for their smooth, open character and gentle saturation curve.
Higher Impedance / COLOR Up: wideband clarity, linear phase, extended top end
Lower Impedance / COLOR Down: thicker harmonics, soft transient rounding, and “iron glue” cohesion
Specifications
Transformers: Dual Hammond 1140 (nickel-core, made in Ontario, Canada)
Ratio: 1 : 1 (600 Ω : 600 Ω)
Topology: Fully passive, balanced stereo design
Control: Single stereo potentiometer varies impedance and transformer drive
Frequency Response: 20 Hz – 20 kHz ± 0.5 dB typical
Insertion Loss: 1 dB @ 1 kHz
Distortion (THD): < 0.05 % @ +4 dBu, 1 kHz
Maximum Input Level: +21 dBu @ 20 Hz (.150 % THD @ 20 hz)
Common-Mode Rejection Ratio: > 100 dB @ 60 Hz
Output Impedance: ≈ 600 Ω (variable via COLOR control)
Connections: Balanced XLR In / Out (Left / Right)
Chassis: 1 U aluminum rack (17″ × 8″)
Finish: Matte graphite black with white engraving
Weight: ≈ 2.5 lb (1.1 kg)
Power: None required — fully passive
Applications
Mix-bus or mastering transformer stage
Stereo tone-shaping before or after summing
Parallel analog color path for synths, vocals, or drums
FOH/IEM signal conditioning
Studio line-balancing or isolation