Description

Design Criteria for the MC PRE PRE:

• No coupling capacitor at the input because of the extremely fine input signals.
• Noise contribution to be very low. Typical goal >70dB S/N ratio @ 0,5mV input signal.
• No opamps or anything needing Negative Feedback.
• A nice linear tube without negative feedback would be optimal, but they generate too much noise for these low signal levels.
• A J-FET at the input, it works very much like a tube in MU-Stage configuration

It is a fully, assembled SMD-Board with custom Gain setting (Done by me with an AP2333 Audio Analyzer)

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The gain will be set by me personally and is by choice of the customer.
I will contact you to agree on the desired gain setting.

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Final specifications:

Gain	5 to 25 (will be factory set on demand)
Input Impedance	1k Ohm *)
Output Impedance	Aprox. 200 – 500 Ohm
Bandwidth (within 0 – 1,5dB)	0 – 200kHz
Distortion at 10mV signal input	d2: 0,1% d3: 0,0025%
Output noise with inputs shorted (i.e. amplifier noise contribution)	~20nV / SQRT(Hz)
Size	58 x 73 mm (Mounting holes 50 x 65 mm – Dia. 3,5 mm)
Power supply (DC)	~15V DC >100mA (per board) Audio Grade recommended. Minimum 13.0V for proper functioning of embedded Tent Shunt Regulator