J99 Microphone Preamp Module
Available without opamps (Add your own) or buy with John Hardy 990C's included! (SC99 no longer available)
The SCA J99 is a flexible, high-gain, low-noise, low-distortion microphone preamplifier, based on the classic Jensen Twin Servo design. This is a great preamp to use when a neutral sonic character is required, but the slightest amount of euphonic transformer coloration is desired.
CH02-SP-J99 subpanel must be ordered separately.
The J99B can provide 70dB of gain which includes the voltage step-up provided by the input transformer. Jumpered for 300 ohms input impedance, the maximum gain available is not quite 76dB.
With an EIN approaching -130dB, the J99 is quiet enough to use in virtually any recording application, especially with low-output ribbon mics.
Dual DC Servos
The J99B has a DC servo for each op-amp and uses no capacitors in the signal path.
Stepped Gain Control
A 12 position Grayhill switch provides accurate and repeatable gain settings in 5dB steps from 15dB to 70dB.
Since 5dB is often too big a gain step, the A12 also has a gain trim control, which provides up to 6dB of cut at any gain setting. This allows very fine adjustment of gain between steps.
Inverts the signal phase.
Slow-rise phantom power minimizes pops and thumps.
High quality PC mount connectors eliminate cabling and ease assembly.
Lundahl Input Transformers
The J99 uses a Lundahl 1538XL to couple the microphone signal to the amplifier. This transformer is used in a number of high-end preamps and it provides superior performance in a compact package.
Cinemag Output Transformer
The CineMag CMOB-2H output transformer provides a balanced, floating output with extremely low distortion and wide bandwidth.
Flexible Power Supply
On-board voltage regulators can accommodate power supplies from +/-27VDC up to +/-35VDC, allowing the use of op-amps with +/-24VDC requirements. Potentiometers allow easy voltage adjustment, making experimenting fast and simple. Local regulation also keeps inter-channel crosstalk extremely low when multiple preamps share the same power supply.
Built-In Op Amps
The J99B has two high-performance discrete op-amps laid out directly on the main circuit board. These MAT14-based amplifiers have better noise performance than our SC99 amplifier modules.