Copyright (c) 2014 Xav Paice
Version 0.1 - initial prototype
Based on the circuit by Rogers Gomez at http://diyaudioprojects.com/Solid/12AU7-IRF510-LM317-Headamp/ I have made some modifications, using a laptop power supply and IRF540 rather than IRF510, plus added a rudimentary crossfeed network.
This is an Open Hardware project. For details about OSHW, go to: http://freedomdefined.org/OSHW
All documentation and drawings are covered by Creative Commons Attribution 4.0 International License.
Hybrid Headphone Amp by Xav Paice is licensed under a Creative Commons Attribution 4.0 International License.
Based on a work at https://github.com/xavpaice/hybridheadphoneamp.
The schematic and PCB are all drawn with Kicad (http://www.kicad.org/).
The PCB is easily etched at home, however I did find the pads way too small to successfully drill using a 1mm bit and dodgy battery drill. Additionally the silk screen is backwards and I've got my Kicad layers totally mixed up.
The current PCB (just) fits in a Hammond 1590 with the aid of some tiny heatsinks however the box heats up a lot and it's not an ideal build by any stretch.
- fix the silk screen and PCB layers so it prints correctly
- make the PCB pads bigger and space things out better
- use bigger heatsinks and account for that space on the PCB
- the crossfeed doesn't seem to do a lot, and the switch is largely useless
- there's hiss, and power supply crackle.
- Please do.
- Please submit pull requests, I'd love some help