Repairs

Long time no post! I have been meaning to post something for a while, but I didn't realise that it had been quite that long.

So what have I been up to? I have built a MIDIbox Seq V4 and MIDIbox CV. Neither are completely finished, but they are usable. I have also acquired some more retro toys in varying states of (dis)repair....

Only one of these actually works, so lots to do. Oh and my Juno 106 is now suffering from the dreaded 80017A VCA/VCF plague. I have removed these and will be giving them the acetone bath treatment in due course.

Effects

I still haven't got around to doing a video of the MIDIpal, but the effects PCBs finally arrived a few days ago. I brought the boards for a Gristleizer and an EchoBase delay from http://musicpcb.com. Prior to this and in need of something to occupy me, I drilled a case for the Gristleizer, mounted the pots on a piece of stripboard and did some of the wiring. I opted for small desktop format cases rather than stomp boxes.

Prepared case

Once the PCB arrived, it was quickly populated and wired up. I ordered the wrong trim pots, but they fit with some leg-bending and the LFO speed pot has the wrong taper. Anyhow, it works and I'll change the pots at some point.

The Gristleizer PCB

PCB mounted and wired

"Completed" Gristleizer. Yes I drilled a hole in the wrong place.

Having completed the Gristleizer and before starting on the EchoBase, I decided that laser cut front bezels would look good. I designed one, along with a drill template for the EchoBase in Inkscape and will do also design a new front panel for the Gristleizer.

Initial EchoBase drill template

I built and tested the EchoBase outside the case as there are several mods available that I wanted to experiment with before modifying the panel (see http://musicpcb.com/pcbs/echo-base-delay/). I went with a diode lift switch, along with substituting the value of one resistor to cope better with "hot" signals as I will be running synths through this.

EchoBase guts

Finally, the case was drilled (with the deletion of the effect LED as the LFO LED is dual purpose) and the internals mounted within.

The completed units

I intend to do several more effects and also build a power supply for them in a matching case, rather like a DIY version of the Boss Micro Rack series from the 1980s. In the meantime I'll get the bezels made and build the Shruthi-1.

MIDIpal

This wasn't supposed to be my next project, but I am still waiting on parts for the audio effects units.

I have intended to get a MIDIpal for a while now, but was put off by the surface-mount soldering involved. I finally bit the bullet and ordered one and built it over the last few evenings.

The MIDIpal is a tiny MIDI processor, which can serve as an arpeggiator, a simple step sequencer and delay, among other functions. It is Open Source hardware and available as a kit from Mutable Instruments.

This was my first experience of surface-mount soldering and it actually turned out easier than expected, though I applied too much solder to the ATMega328p MCU, resulting in a short between VCC and ground. Solder wick fixed the short, but left rather a lot of burnt flux behind. As for the resistors, LEDs, diodes and capacitors - soldering was actually quicker than with through-hole parts.

The completed MIDIpal in it's transparent case. Despite the mess around the MCU, it works!

Uploading the firmware using a USBtiny ISP.

I'll post a video once I have had a chance to play with it.