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This is my own version of a classic preamp, popular in the 70s and still popular today. It's not a clone since I'm using a totally different signal path and design, and different input and output transformers. But the sound nevertheless is awesome.  Big and beefy with lots of transformer mojo goodness. 

Note: This kit is my 1u rack version with on-board local voltage regulators.

Using Input and Output Transformers
12-step Gain from 22dB to 68dB, at 4dB/step
-20dB Input Pad
High-quality parts
Option to use Discrete OpAmps with the 990/2520 format
Using high-performance chipsets, currently the best chip around
Using High-speed 2000V/us, video buffer, high-current transformer line driver
Using Grayhill switch - high quality mil-spec
with output trim Bourns potentiometer - so you can overdrive the input trafo and be able to trim the output of the pre.
Null offset trimmer adjustment
LED-lighted push buttons for 48V phantom, pads, and polarity reverse
Relay Controlled Polarity Reverse
Relay Controlled -20dB Pad
Soft-start/Ramp-up 48V Phantom Power
Includes on-board voltage regulators
Professional PCB, Rohs PCB with double-sided, plated-through holes, 2oz. copper
with soldermask, silkscreen layout,
Includes everything... 5-LED VU Meter, spacers, screws, knobs

Download X-12 Mic Preamp Assembly Guide
don't forget to download too the VU Meter Assembly Guide

NOTE: The X-12 Preamp requires a Power Supply Unit. 
You can use my PSU-24448mk2 and Power Transformer Kit to power your X-12 Mic Pre.

You can also use discrete opamps with these kits. Discrete OpAmps not provided with kits. But there are lots of 3rd-party companies making and selling them.  

with a JFET-992


with APP2050 (Made in Italy)


with APP10 (Made in Italy)

 X-12 Mic Preamp with a Melcor DIY Discrete Opamp