Fixing broken chinese Ammoon Looper Pedal

Information compatible with:

  • Harley Benton Mini Looper
  • FAME Looper * Rowin LEF-332
  • Donner Looper
  • Ammoon AP-09 nano looper

I bought this little fella after I saw it listed as broken for a really low price, considering that I could make it work after updating its firmware.
The provided USB cable was faulty and I replaced it with a working one and the LooperSuite for macOS didn’t work at all. I searched both Rowin and Ammoon sites for an alternative firmware without any success.

Using LooperSuite v1.7 I tried to delete the Song 001 in vain. However, then I replaced the Song 001 with a blank WAV file and replugged the looper to my rig. To my surprise, everything was working as expected.

Considering the price it’s an awesome looper, but I have no idea if it’s going to freeze again.

Arduino as ISP checklist for someone who didn’t burn/program anything in a long time

Back in 2009, I became aware of the existence of Arduino(through TuxRadar Podcast). The idea of open hardware and open software platform aroused my interest in electronics.

I got myself a kit and built a Serial RS232/DB9 board. That was my first soldering experience and really started my relationship with electronics as a hobbyist. Soon after, I got a counterfeit Arduino Mega from China and my Serial one was put aside.

This weekend I was testing a sketch and it was incompatible with Arduino Mega. Unfortunately, I was unable to find the right drivers for my serial adapter. Enough story, I ran into a few issues and here is a checklist to avoid them:

  • Don’t forget a 10μF cap between Reset and Ground.
  • External PSU, don’t rely on the programmer’s 5V.
  • Check USE_OLD_STYLE_WIRING constant on ArduinoAsISP sketch (when not using the ICSP header).
  • Install MiniCore boards on your Arduino board-manager (Check MiniCore GitHub for more information)

Modifying my cheap guitar – Part I – The Wiring

friend lend me his electric guitar for quite a while when I determined to learn a string instrument. After a lot of months I finally got my act together and bought a cheap an inexpensive electric guitar bundle(with a 15-Watt amplifier, gig bag and strap).

After a period of time it occurred to me to experiment, modify and change some aspects of the guitar wiring. All the applied modifications were found over the internet and, as you can imagine, there is nothing innovative.

Modifications:

  1. Switch between the original tone capacitor and a new one.
  2. Hard clipping using two diodes connected in antiparallel.
  3. Neck ON Switch (David Gilmour wiring).
  4. Treble bleed mod.

Motivation

It was a cheap guitar, however its value reflects its quality. I was a bit unsatisfied with its tone, with a little research I found out some ways to improve the tone.

Schematics and part list

guitar-wiring

C1 - 0.002uF / 2nF / 2000pF
C2 - 0.047uF / 47nF / 47000pF (original film capacitor)
C3 - 0.1uF / 100nF / 100000pF (ceramic capacitor)
D1,D2 - 1N5819
R1 - 100k Ohms resistor
SW - DPDT

Switch between the original tone capacitor and a new one

Simple selector between two capacitors. The second one helps to get a darker sound and not so strident like Stratocasters usually are.

Hard clipping using two diodes connected in antiparallel

Sometimes called as “passive distortion” or even wrongly as “passive overdrive”, it’s a fun modification. Gives a harsh sound, but loses volume since it clips the sound without any boost.

Neck ON Switch (David Gilmour wiring)

This wiring, when enabled, connect the neck pickup with whatever selection in the 5-way switch. David Gilmour may be the most famous musician to use this mod. Now with up to 8 possible combinations, the guitar has so much possibilities. In my opinion, the sound is colorful now.

Treble bleed mod

When you turn the volume down on a guitar you can feel that the sound loses a bit of treble. It happens because the pickup, the volume potentiometer and the capacitance in the cable act as a low pass filter. To compensate this loss we “bleed” more treble into the signal as the volume is turned down.

Further modifications

After all that, I ordered and installed a hotrail pickup in the bridge position. Unfortunately I don’t have any pictures, but If I did it again today I would use the Gilmour/neck mod with the bridge pickup instead of neck. I customized the pickguard with an artist, that being the subject of the Part II of this post.

Conclusion

guitar-guts-and-componentsI learned a lot in the process. From something stupid like how a 5-way switch works to something unexpected like fixing to a stripped screw hole.