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 to fast and clear. 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 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


Customer Reviews

Based on 7 reviews
Steven Rodenbaugh
Inflates and intensifies the source

Got this with the 70s Character Duo bundle. Going DOA into TM79 and then into 15IPS on mixbus. The DOA itself with the RED25 is cool. The best way I can explain it is that it saturates/inflates and intensifies everything that goes through it. The saturation provides more volume and glue. Drums and guitars sound like they are hit/strummed harder. It was a pretty profound thing to hear for the first time. My mix immediately sounded more 3D and in your face. My understanding is that opamps provide much of the character of our favorite preamps- I bought opamps from Hairball Audio, BA512 and Raindog. They all sound different and do very cool things accurate to their descriptions. It's cool to hear them in person and understand how things like slew rate can effect the shape and vibe of a full mix. The Colour format is such a great concept, and I love that I can switch gears for different vibes on different mixes on the fly.
On the Duo, and with the material level I'm feeding it, I typically run the gain at about 12-1 o'clock before things begin to break up and distort. The RED25 is an inexpensive opamp, but sounds just as good as others 2-3x the cost. I was afraid after getting a CTX that I wouldn't use this Colour as much, but they have different sounds and uses for me. I plan on doing a more in depth video on how I use my Colours and just may well get another pair of DOA cards.

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!

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