Normaphone MXPre L1C



The Normaphone MXPre LC1 is a low noise, low distortion preamp to be used in the Sony MXP 3000 series console.  It is built around the Lundahl 1538XL transformer, features a low distortion fet op amp gain stage, DC servo, and output amp capable of driving 600Ω loads with ease.   

I started this project because I'm a big fan of the simplicity and elegance inherent to transformer coupled preamps.  I also needed a preamp that could handle higher incoming levels.

The Lundahl 1538XL transformer is a wonderful transformer.  It's only slightly more colored than the Jensen transformer used in my other favorite preamp built for this console, John Hardy's MPC3000.  

If you are interested, they are $425 apiece plus tax (10.25%) and shipping, with a price break for higher quantities.  







Functional Features:
  • 16 position gain switch 3dB per posion, ranging from +20 to +65dB gain, DC servo
  • 20dB pad
  • Phantom Power Switch w/dim blue led indicator
  • Gold plated switches in audio path for long term reliability
Preliminary Technical Specs:

Input Impedance -                1400Ω
Output Impedance -             25Ω
Maximum Gain -                  65dB
Maximum Output Level -     23dBu w/ 10kΩ Load, 
                                             22dBu w/ 600Ω Load
E.I.N. (150Ω Source,
non-weighted) -                  -127dB @ 41dB Gain
THD+N (1kHz) -     %0.0015 (10kΩ load, 23dBu out)
Deviation From Linear Phase =    < .5º (BW 10-20kHz)
Power Consumption          ≤ 20mA (10mA per 18v rail)