Build your own Preamp – FABModules – FiveFish Audio Building Blocks for DIY Projects Blog Articles

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FAB4312 – Non-Inverting Amplifier Module (Discrete OpAmp, PDIP OpAmp)

This is our FAB4312 Non-Inverting Amplifier Module.  You can use any single opamp, 8-pin PDIP package like an LME49710, NE5534 or equivalent. It also features Mill-max sockets if you want to mount a 2520-style discrete opamp, like our DOA-12, DOA-17, 990C, API 2520, or compatible discrete opamp.

A trimmer is also provided to let you adjust DC offset to zero volts (0V). A 2-pin header is provided for connection of your gain control potentiometer (or selector switch, or digital potentiometer, or switched resistor ladder network).  In the future, we’ll be providing FAB modules that will offer these different options for controlling the gain of your amplifier.

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FAB3110 – Output Transformer Module Prototype

Here’s a photo of a fully assembled FAB3110 Output Transformer Module.

You can use any API-type output transformer on this module. Shown here is an EA transformer, but you can also use transformers from Cinemag, Crimson Audio, etc…

There is a Logic control on the FAB module, allowing you to switch your transformer ratio from 1:1 to 1:2 (+6dB gain). Just apply any +3.3V, +5V or V+ voltage on this logic pin.

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FAB9001 – FAB to Cable Crossover Adapter

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FAB Modules, FAB9000 Utility Modules
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This is the FA9001 – FAB to Cable Crossover Adapter .

Normally, you hook up or connect one FAB Module to another FAB Module directly by mating their corresponding male/female headers together.

If you do not wish to do that, for one reason or another, you need to use this FAB to  Cable Adapter to connect the two FAB modules together.

What this FAB9001 adapter does is convert the Female input port of a FAB Module to a Male connector.  After the conversion, now you can use a plain ordinary 10-pin ribbon cable (with female/female connectors on both ends) to hookup the two FAB modules together.

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FAB3130 – Edcor Output Transformer Module, PC Series

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FAB Modules, FAB3000 Output Modules
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This is our FAB3130 module for the Edcor PC Series output transformers. These output transformers are inexpensive, but I find they have a flavorful sound. The PC Series though has a limited headroom and saturates early… maybe that’s the reason for the flavored sound?  I find that these Edcor transformers add thickness and body to the sound. You’ll definitely notice it. Inexpensive, but effective!

Just like our FAB3110 Module, there is a Logic Level control input so you can select either 1:1, or 1:2 ratio with the output transformer.

UPDATE: Made a Rev.B FAB3130 board, increasing the size of the PCB to match the dimensions of our FAB3110 Output Transformer Module (for Cinemag, Crimson Audio). Tonight, I sent the boards out  to the PCB manufacturer… we should get our finished prototype boards sometime next week.

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