new blog post
authorrekado <rekado@elephly.net>
Tue, 29 Jan 2013 14:16:33 +0000 (22:16 +0800)
committerrekado <rekado@elephly.net>
Tue, 29 Jan 2013 14:16:33 +0000 (22:16 +0800)
images/posts/pcb-1.jpg [new file with mode: 0644]
images/posts/pcb-2.jpg [new file with mode: 0644]
posts/2013-01-27-preamp-board-arrived.markdown [new file with mode: 0644]

diff --git a/images/posts/pcb-1.jpg b/images/posts/pcb-1.jpg
new file mode 100644 (file)
index 0000000..b2b1699
Binary files /dev/null and b/images/posts/pcb-1.jpg differ
diff --git a/images/posts/pcb-2.jpg b/images/posts/pcb-2.jpg
new file mode 100644 (file)
index 0000000..1cb04ab
Binary files /dev/null and b/images/posts/pcb-2.jpg differ
diff --git a/posts/2013-01-27-preamp-board-arrived.markdown b/posts/2013-01-27-preamp-board-arrived.markdown
new file mode 100644 (file)
index 0000000..6e03105
--- /dev/null
@@ -0,0 +1,40 @@
+---
+title: Stick preamp PCB arrived
+tags: audio,pcb,DIY,preamp,chapman stick,free software
+---
+
+![One of the boards](/images/posts/pcb-1.jpg)
+
+Today I received a package from Shenzhen containing ten printed circuit boards.
+I ordered a single board through [a taobao store](http://taobao.com) for only
+100&nbsp;RMB (about USD&nbsp;16), but I suppose there is not much of a
+difference between the production costs of ten boards and that of one.
+
+The board is the heart of my two-channel Chapman Stick preamp / signal router.
+It includes a cross-over circuit for the bass side, so that I can partition the
+bass signal into two frequency ranges that can be routed and processed
+independently. It has three very simple effect inserts (high bass, low bass,
+and melody), two buffered outputs (both signals mixed down to mono or dual
+mono), and a tuner output (which could be used for an on-stage monitor).
+
+The circuit and the board were designed using the
+[free](http://www.fsf.org/about/what-is-free-software) programs `gschem` and
+`pcb` of the excellent [gEDA suite](http://www.geda-project.org). (For some odd
+reason `pcb` is not available through the official Archlinux repositories; I
+installed it through the Arch User Repository.) You can get my circuit
+diagrams, the PCB layout, and custom footprints through the [git
+repository](https://github.com/rekado/stick-preamp) I set up for this project.
+
+![Oops.](/images/posts/pcb-2.jpg)
+
+The manufacturer only received the exported Gerber files that I checked with
+`gerbv`. Sadly, I didn't realise that the silk screen layer would be printed on
+the bottom side of the single-layer board, so the text on all ten boards is
+mirrored. (I suppose I could get used to saying "TЯƎƧИI", but "YᗡO⅃ƎM" just
+sounds weird.) Now I will have to carefully check the orientation of the
+transistors before soldering them onto the board because I'm not sure whether
+they have been mirrored when I designed the board.
+
+I'm still missing two or three parts (different component packages and power
+line filtering), but I'll start soldering the first components to one of the
+boards tonight.