The DOA-12 is a high-performance, discrete operational amplifier well suited for demanding audio applications due to it’s low noise, high slew rate, high gain capability, high output capability, and operation over a wide range of power supply voltages. It uses the standard discrete opamp 2520/990 footprint… a roughly 1”x1” device with (6) pins, a format commonly found and used in pro-audio gear.

Running at +/-24Volts supply voltage, the DOA-12 is capable of reaching +26dBu output (loaded with a 600:600 output transformer). Running at a slightly lower +/-18Volts supply voltage, the DOA-12 still achieves an impressive +24dBu maximum output.

If one uses the DOA-12 to drive an output transformer wired for 1:2, it is possible to create high-performance preamplifiers capable of reaching +32dBu output!

Each DOA-12 is designed and tested to be stable, and oscillation-free even at maximum output levels and gain settings due to careful selection of components, efficient PCB layout, design, and construction.

The DOA-12 uses double-sided, plated-through hole PCB with full silkscreen and solder masks, 2oz. copper, .062” thick FR4 boards, 1% Metal Film low noise resistors, C0G NPO capacitors and modern transistors. The two (2) output drivers are beefy, high-performance, hermetically-sealed metal case TO-39 transistors, each capable of dissipating 10 watts!


The DOA-12 operates as a Class A amplifier at low to two-thirds maximum output levels and switches to Class AB mode when operating at maximum output levels. We think this is the best balance of performance and efficiency, minimizing dissipated heat and loss energy. Current consumption is +/-16mA with or without any input signal.

The DOA-12 was tested in all FiveFish Audio preamps (X12, X72, and MX5 – API VPR Certified modules) and also tested in our Equalizer module (PEQ-503, also API VPR Certified). Performance and audio quality was stellar, delivering fast transients; big bottom end, a faithful sound reproduction with a warm, classic discrete flavor.


The DOA-12 features a very-flat frequency response extending all the way down to below 10Hz, and beyond 40Khz, as shown in the above graph. The DOA-12 is the perfect opamp for audio gear that requires high-performance. It is well suited for applications such as balanced receivers, balanced drivers, audio buffers, mic preamplifiers, instrumentation amplifiers, low and high-pass filters, bandpass filters and equalizers.