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Build your own Preamp – FABModules – FiveFish Audio Building Blocks for DIY Projects Blog ArticlesBuild. Learn. Make Audio Gear...for Students, Makers, Hobbyists and Professionals |
Here’s one of the simplest way to use our FABModules…. Hook up the following FABs together:
FAB2010 – XLR Input Module
FAB2110 – Input Transformer Module
FAB3010 – XLR Output Module
All that’s missing is Power, if you want to enable the -20dB Pad, Phantom Power and Polarity Reverse functions. Otherwise, it will still work without power applied. After all, it’s just an input transformer inserted in your signal chain.
Populated our FAB3010 XLR Output Module. There is a Logic controlled relay, used for Polarity Reverse function. All you need to do is apply a Logic “1” to the header pin (which can be +3.3V, +5V, or your V+ voltage) and it will trigger Polarity Reverse.
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.
The DOA-17 is our modern remake of a vintage discrete op amp design, using modern low-noise components and improved layout. 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 +/-18Volts supply voltage, the DOA-12 is capable of reaching +23dBu output (loaded with a 600:600 output transformer). If one uses the DOA-17 to drive an output transformer wired for 1:2, it is possible to create high-performance preamplifiers capable of reaching +29dBu output!
Each DOA-17 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.
Some people using our FAB Modules in their own DIY project may not want to use a ribbon cable for hookups. This is understandable as the usual wiring connections found in DIY boards are via solder pads.
So what we have here is our FAB9010 – Output Breakout Board. All connections on the FAB edge connectors are “fanned out” into their own individual solder pads, and clearly labeled on the Module for ease of wiring.