russell mcclellan

musical hardware and software

Eurorack Headphone Amp



Continuing my slow but steady progress on my DIY modular synthesizer, I've just finished my second module: an inexpensive headphone and line-level amplifier.

The humble purpose of this module is to bring signals from eurorack levels to both headphones and other audio equipment.

Electronic Design

Like my previous multiple module, the design doesn't contain anything novel or at all difficult. It's a totally standard amplifier, with levels set to the eurorack standard. One thing I was careful to do was use a socketed op-amp with a standard dual pinout, so users with discerning tastes can replace the "jellybean" LF353 with a more "smooth" or "laid back" chip.

For the board layout I again used EAGLE, which is free for non-commercial use. This time, most of the design was SMT, with the exception of the previously mentioned op-amps.

Again, all of the design files for the project, including a list of all parts required, are on GitHub under a permissive license.

Board Fabrication


Like last time, The board was fabricated by OSH Park.

I'll write a future post on the SMT soldering technique I used, which involves lasers, toaster ovens, and a home-made stencil rig that I designed with my friend Brendan.

Front Panel

completed buffer

Again, the panel was lasercut out of acrylic from Inventables at a local lasercutting shop. The design files were done in InkScape.

All images and text are licensed under a Creative Commons Attribution 3.0 United States License, except as noted. Linked code, and embedded code examples are licensed separately.