The Ruby Practice Amp
There are quite a few circuits out
there for building VLP (very low power) guitar practice
amps.
The Ruby circuit from runoffgroove.com has to be one
of the simplest designs and is very easy to build. The Ruby Amp:
-
uses the LM386 opamp and puts out about 1/2 a watt of power
-
has controls for volume and drive
-
with both knobs cranked, it puts out
a nice little solid-state distortion that is quite
smooth and tasty.
-
runs on 9-12vDC
-
can power a 2x12 cab at decent
practice volumes
 |
Gather round the campfire dudes. Here's
a
clip of the ruby, complete with my
riveting narrative
and shitty playing. |
|
|
Building
It
I ordered a
PCB from
General Guitar Gadgets and the parts from
Mouser.
For an enclosure, I used the LMB Heeger MDC-432 aluminum
box which measures in at 3" x 4" x 2" which provided
plenty of room for all the parts and a 9v battery. Build
was pretty simple, but debugging was a chore. After
powering it up and connecting it to a guitar and cab, it
just howled. I checked every component again, checked
for cold solder joints, and only after looking really
carefully found a small solder bridge. Fixed that with
an xacto knife and it worked like a charm.
What Does it Sound Like?
Not bad for a super-simple solid state
amp. Take the power supply up to 12 volts and it
provides a bit more clean headroom. Dial in the drive
and you can get a nice meaty distortion. All in all, the
Ruby is an easy build and fun to play around with a
practice amp.
Build Your Own
|
