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Seventh Circle Audio

Seventh Circle Audio J99-500 (SC90)

Jensen Twin Servo / John Hardy 990C-style discrete op-amp mic preamp module, 500-series format

Preamp

$499Manufacturer list price

Specifications

Type
Preamp
Description
Jensen Twin Servo / John Hardy 990C-style discrete op-amp mic preamp module, 500-series format
Topology
Transformer-coupled, discrete op-amp (Jensen Twin Servo / John Hardy 990C-style), JLM/Jensen lineage, no signal-path capacitors
Signal path
Analog
Channels
1
Channel format
mono mic/line preamp
Form factor
module (API 500-series/Rev G format)
Connection
API 500-series (Rev G) lunchbox format
DSP
false
Powered
true
Impedance (Ω)
1200 / 300 (switchable)
Country of manufacture
USA
Phantom power
48V

Details

Controls: 12-position Grayhill stepped gain switch (15-70dB in 5dB steps), gain trim (up to 6dB cut), phase reverse switch, phantom power switch, switchable input impedance (1200/300 ohm)

I/O: 500-series edge connector I/O; Lundahl 1538XL input transformer, CineMag CMOB-2H output transformer

Notes: Clones Jensen Twin Servo / John Hardy 990C-style topology (JLM/Jensen family); EIN approaching -130dB as published; up to 76dB gain at 300-ohm setting. FLAG: genuine API 500-series-compatible module, will NOT work in SCA's CH02/PC01 chassis -- distinct from the SCA-proprietary-format 'J99' classic-series module. Available as DIY kit or assembled.

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