The HD REFERENCE Microphone Preamplifier can be described as unique, revolutionary, and among the best performing mic pre's of all time.
Well almost unique. The internal topology was first introduced in the 500 Series Fredenstein HD PRE which features the new current mode, true class A, zero negative feedback, 100% balanced circuit that uses 54 discrete premium transistors for gain. The HD REFERENCE goes a step further with 72 transistors and a +/- 24 volt power supply. The HD REFERENCE is also designed to be remote controlled (or not) and offers 1 dB gain steps shown clearly on the front panel.
 
Technical performance can only be described as extreme or exceptional. Extreme low noise (EIN - XX dB), exceptional low distortion (.XX% at 60 dB of gain), extreme bandwidth (-3dB down at 900kHz) and is can deliver +30 dbu at the outputs. And while it sports the holy grail, grand combination of high end specifications, The HD REFERENCE also out-performs typical tube pre-amplifiers in the area of smooth transition into saturation, due to the absence of negative feedback and the fast recovery inherent in the topology. In other words, it goes from pristene to 3 dimensional through rich and then power house depending on how hard one drives it.
 
Features include 1 dB stepped gain from 0 dB to +64 dB (using high reliability relays) indicated with a large 7 segment LED display. 3 high pass filter frequencies, 3 impedance settings, phantom power and polarity switching. Details like, automatic muting while phantom power is changing, to prevent thumps and damage to monitors is built in. There are also a pair of Direct Inputs for instruments with low noise discrete JFET inputs (2 meg ohm) and 0 to 40 dB of gain.
 
And then by adding the COMMANDER remote control we can reap the benefit of keeping the mic pre close to the mic, while still keeping control of all the features the HD REFERENCE provides. By keeping the cable between the mic and the REFERENCE HD short, we can preserve the fragile mic level signals and send a robust line level signal any reasonable distance to the converter, console or compressor. The Commander and REFERENCE HD connect with a standard mic cable. The COMMANDER additionally has a LOCK button that can prevent tampering at the remote preamp.
 
The Features 
- 2-channel microphone preamp with 64dB of gain
- Fully discrete signal path and Class A balanced output stage achieves a true-to-life sound
- Current amplification circuit eliminates internal transistor capacitance, providing 920kHz of bandwidth
- Experience warm, natural sound via zero-negative-feedback topology
- Transformerless design won't color your sound
- Digital displays allow you to set your gain level in accurate 1dB steps – great for setting up stereo pairs
- 7-segment LED meters make monitoring your levels easy
- 3 impedance settings optimize the preamp for your mic
- 3 highpass filter frequencies eliminate unwanted low-frequency rumble
- Phantom power and polarity reversal
- Discrete JFET inputs for your guitars and other high-impedance sources
- Optional HD Commander remote control is available for keeping the preamp close to your mic (sold separately)