DOA Discrete Opamp Colour


  • Full Kit
  • Step-by-Step Guide
  • Supported
  • Intermediate

Add the sound of any discrete opamp to your Palette.

Discrete opamps (DOAs), such as the API 2520, are at the heart of countless pieces of classic gear. Every DOA has it's own tone, from slow and dark (ex: Melcor 1731) to fast and clear (ex: John Hardy 990). And DOAs are largely responsible for the recognizable sound of many consoles, preamps, etc.

The DOA Colour allows you to plug any DOA into your Palette and tailor the amount of saturation you desire. You can purchase the DOA Colour on its own or bundled with the Whistle Rock Audio "RED-25" DOA.


  • Compatible with the Colour format
  • Black PCB with gold-plated pads
  • Mill-Max DOA sockets
  • Designed by Eisen Audio for DIYRE
  • Accepts any 2520-style discrete operational amplifier, including:
    • API 2520
    • Melcor 1731
    • John Hardy 990


Real analog plugins.

Colour is a new format for analog audio gear designed for and by the DIY community. We took our favorite sounding analog circuits and put them on modules that are small, affordable, and swappable.

The Colour format consists of Colours and Palettes:

Colours are ultra-compact, pluggable analog circuit blocks that impart various types of analog color. Check out our ever-growing selection of Colours. Colours can be designed and released by anyone.

Palettes provide controls, power, and support circuitry for Colours. We currently offer the Colour 500 Palette and CP5 Mic Preamp with Colour.

Customer Reviews

Based on 6 reviews
Clinton Cleveland
Handy module

This is a quick and easy build and it’s a great way to fill those extra colour slots. There are so many DOA’s available that it’s nice to have a couple of these for easy swaps.

Dag Rosenqvist
Subtle saturation

Really nice subtle saturation, adding warmth and texture. Will probably use this as a fixed part of my signal chain from now on when recording. I got the RED-25 to go with it as well, but might try to experiment with other Op-Amps as well. Easy build and very reasonably priced as well.

Daniel Vogel
Can't get enough DOAs!

This one seemed like a no-brainer - easy way to get another DOA into a signal. I put a Louder Than Liftoff Rogue 25 in it and it does what I wanted!

Luis "L-ROX" Franco
Add more Colour to your Colour

I'm just scratching the surface when it comes to learning how DOAs affect the audio that runs through them on their own. I have the RED-25 and Rogue Five DOAs and they each have their own sound. When you hit these circuits with the right amount of signal, they can give your tracks a nice amount of that sought-after analog flavor that up to this point, I was chasing in plugins. I'm starting to view saturation in my DAW completely different now that I have a few of these Colour cards. This stuff is fun to build (I've been building my own cables and doing light repairs and tinkering around for close to 30 years now, fwiw) and it's also really fun to use!

Ryan G.
For every track

I have this colour with the ML2520 in both of my CP5's. I needed to use the low gain resistors in the colour kit, otherwise it clipped with the colour about half way up. I appreciate that the low gain resistors were in the kit. I didn't want a noticeable saturation distortion or anything too colorful. I wanted a more "mid-forward" sound. This combo did the trick. This combo has some nice natural compression too. That was an unexpected plus.

Related Products

Liquid error: Could not find asset snippets/iStock-notify-me.liquid