X-72mk500 with UK/Carnhill Trafos

What if you could take the best features from different preamps, and combine them into one Super-Frankenstein Hybrid preamp?

And that's exactly what I did. Welcome the FiveFish Audio X-72mk500 Mic Preamp, designed for API 500 Rack Series Lunchbox.

An ultra-low distortion, low noise, operational amplifier optimized for high performance audio is used in the circuitry. Imported Carnhill/UK Input & Output Transformers are used to interface with the outside world.

You can also outfit the X72 Mic Preamp with optional Discrete 2520/990 type op amp*, and Millmax sockets.

* Available separately, extra charges may apply.
What about the sound? The X72 sound is BIG, PUNCHY, and HUGE. It adds a deep, nice, WARM coloration to the overall sound. Really deep-sounding huge. And low frequencies come out punchy and TIGHT.

FiveFish Audio and the X-72mk500** Mic Preamp is part of the API VPR Alliance.

The VPR Alliance is a program of standardization and consistency guidelines set by API Audio for manufacturers, to make our products physically fit and electronically conform to API's 500 series rack specifications. As stated on API's website, "Customers benefit from the VPR Alliance through the elimination of any confusion as to which products are endorsed for placement in API racks. Customers also benefit from a wider range of module choices for their racks, safety in the knowledge that the specification of the third party unit is correct, and that there is no risk of damage occurring. "

** X72mk500 with the RED Carnhill Output Transformer, API VPR Certified


Gain control is provided by a high-quality Mil-spec Grayhill 12-stepped rotary switch, and a separate Output Trim knob gives you fine control over this preamp. Lighted push-button switches gives a visual indicator of the status of your preamp even from far away. It also features 48V soft-start phantom power, that applies 48Volts gradually to avoid any loud popping sound when you turn on Phantom Power. There is also a -20db Pad and Polarity Reverse function, provided by switched Relays.



  • Using UK-made Carnhill Input and Output Transformers
  • 12-step Gain from 22dB to 68dB, at 4dB/step
  • Output trim control
  • LED-lighted push buttons for 48V phantom, pads, and polarity reverse switches
  • Relay Controlled Polarity Reverse
  • Relay Controlled -20dB Pad
  • Soft-start/Ramp-up 48V Phantom Power
  • 5-LED VU Meter
  • Using high-performance chips, and quality components
  • Option to use Discrete OpAmps with the 990/2520 format

BUY NOW - X72mk500 Mic Preamp

For USA Buyers
For INTL Buyers



X-72mk500 PAIR
(2 modules)




$60 - Discrete OpAmp + Mill Max Sockets installed
Mill Max sockets and Discrete OpAmp installed

$15 - Set of Mill Max sockets installed
if you plan on installing Discrete Op Amps in the future.

$10 - Set of Black Knobs

$50 - Custom Color Panel
Email us with your color preference.

Audio Samples

Click here for Audio Samples


More Photos