Vacoloco Ramblings

Well it’s all over, it was a good weekend though very hot with temperatures hitting 28 or 29 on Saturday. I did spend a large portion of the time asleep due to heat and just being tired from working some very long days recently.

I took along a couple of PicoWave prototypes, GorF and a 25 note MIDI controller. The PicoWave was well received and the feedback I was given was very useful.

I’ve uploaded my pictures to the gallery page, if anyone else would like to upload their pictures, or has a link to their picture sets, let me know and I’ll add them here and on the main synth diy uk page.

UPDATE: Michael Zacherl has posted some pictures from Cambridge on his gallery page

Well, work has me busy, but I’ve not been completely idol in the little spare time I have.

I’ve been tinkering with the code on Zira (TSKAPW - The Synth Formally Known As PicoWave), I just have the boot loader/MIDI Sysex update code to modify and test before Synth DIY. I’ll try and get around to recording some more audio examples and uploading them soon.

A few people have asked if this will trun into a kit, alas it can’t because of the use of an NJM2069 however, I do plan on using a lot of the technologies and methods to make something similar but using a none OEM filter, this will be available as a kit, but not until this is complete.

I’ve been frantically building the prototypes ready for Synth DIY. I’m building four of them and work is almost complete.

So, here’s some pictures to wet the appetite of those receiving theirs at Synth DIY UK 2010;

And just to prove they’re prototypes, no prototype would be complete without a few mods, what can I say, no-ones perfect first time -

It’s been a while since I’ve posted. I’ve been busy with work and also with QiX (and getting to grips with Linux), but I’ve also been tinkering with a new project.

Originally called “picowave” it’s now called “Zira” in keeping with my naming convention of classic 80’s arcade games.

I’ll say in advance, this won’t be made into a kit as it stands, and it’s also far from finished.

Specs:

• 2 oscillators each with 59 waveforms and de-rez
• 1 Sub oscillator (an octave below Oscillator 1)
• Hard Sync (oscillator 2 to 1)
• 2 ADSRs, one for VCA, one for VCF. Each with linear attack, and expo decay and release
• 1 LFO, Sine, Saw, Square and Random, plus key sync and single shot modes.
• Analogue 24dB/Oct VCF (Korg NJM2069)
• Analogue VCA (Korg NJM2069)
• 64 Patch memories
• Various modulation routings (to be finished)

The use of the NJM2069 means I cannot make this into a kit or production unit, sorry (i had a couple of spares and wanted to see what could be done). If a suitably small, and simple, VCF design can be found, then I’ll consider making a kit.

There’s no Audio DAC, I went all “old school” and used an R2R ladder made with 0.1% resistors (A few pennies more than normal resistors) as I wanted to see how “simple” and cheap I could make the hardware.

With this as one of the main compromises it means you cannot seperately adjust the level of the two oscillators, you can have both off, oscillator 1 on, oscillator 2 on or both on.

Also, the CV DACs for controlling the filter are only 12 bit (Micro chip dual 12bit DACs), again the idea was to make this as cheap and simple as possible, so there’s no high resolution DACs or complex analogue summing of voltages.

In a way, it’s a much slimmed down Monowave, though it doesn’t have the beefy moog ladder, 256 waveforms, no analogue ADSRs, nor refinement in attention to detail for the audio path. Neither does it have the same 1Mhz sample rate, this is much lower, around 200Khz. Also I’m using a much lower number of samples per wave, 128 instead of 256, so it’s a bit more “harsh” than the Monowave.

A picture with it next to GorF, as you can see, it’s the same PCB size, 80mm x 100mm,

So, you can see it’s the same size and concept as GorF. It runs of a DC wallwart the same as GorF (anything 6 to 18V seems fine). It’s taken a lot of messing around to get the NJM2069 to work, and I’ve learned a lot about the chip and it’s use.

Here’s some sounds of the current version (v0.24) -

• Filter tweeking and general messing around
• Velocity to Wave number

If you want to see more, come to Synth DIY UK 2010 as I’ll be showing it there, along with GorF.

I am sorry to say the last GorF PCB has been sold. I’m also sorry to say that I won’t be making further PCBs or Kits, but the Eagle files required to make the PCB are available on the GorF web pages, under the downloads section.

I’m taking a short break and when I return I plan to continue with QiX, Defender and other projects.

I would like to thank everyone who purchased a GorF Kit for your support and encouragement. I have really enjoyed developing GorF and I am still in awe of the response, and attentionn, my “test sequencer” received.

Paul

We’ve got dates ready for Synth DIY 2010. This year the date for the main event is the 10th of July. A lot of people will arrive on the 9th of July and leave on the 11th, and Neil Johnson has put up his room booking page.

I’ve updated the main synth diy uk page here - http://www.diy.synth.net/uk/ and I’m going to start asking for donations for raffle prize. Last year we raised over 175 pounds for charity which was the Drake Music Project. Thank you to every one who contributed by buying a ticket or donating a prize.

Galleries of previous events can be found on the Synth DIY UK Gallery page.

So why not come along, bring some things you’ve built and meet like minded people.

Well, I’ve put together 10 more kits, of the people who contacted me and gave me their email address five have bought kits.

This leaves 5 4 3 2 1 no more of “kit 6″ to be sold, sorry. These were the last full kits I will make and will leave me only 4 or 5 GorF PCBs left to sell.

Kit 6 includes the following

• 1 x PCB
• 1 x PreProgrammed Micro
• 12 x Switches
• 12 x Switch Caps
• 4 x Seven Segment Displays
• 1 x 16Mhz Oscillator
• 1 x 5V Regulator
• 8 x Potentiometeres
• 1 x I2C EEPROM
• 2 x MIDI Sockets

The price is 80 GBP plus shipping (2.00 GBP to the UK, 4.00 GBP to Europe, 6.00 GBP to the US, 7.00 GBP to anywhere else). All you’ll need to find is 8 x step LEDs, the resistors, diodes, capacitor and time to put it together.

If you want one, email me - yo (at) vacoloco.net and I’ll pass you details of my paypal account details.

Is there anyone in the UK that would be willing to work with me making a case for Defender?

My previous efforts (below) at wooden cases sort of suck. What I really want is an angled front panel with the keys in the bottom, a bit like a minimoog with it’s panel angled, but not adjustable, just angled up all the time. The keyboard is only 3 octaves and is the same length as the panel.

If you’re interested, let me know, I’m happy to pay for wood and some time, but I’m not loaded (who is these days?).

No, don’t panic, the panel layout is staying the same. What is changing is the backend for the panel, I had numerous problems with the first revision of the panel control board, mostly with it talking to the main CPU board and then the voice.

So, I’ve shrunk things, the panel board now controls the voices, handles MIDI and will handle patch storage. This all fits onto a 100 x 80 mm PCB (I love surface mount). Below is the PCB almost assembled (I’m missing the pull ups for the switches). I have two of these and I’m sure the other will come in useful soon for something.

Below is the current PCB in situ, I plan to rewire this to the new panel PCB soon.

Well, I know it’s been a while since I mentioned QiX, and we’ve gone through a lot of changes.

We’ve settled on an ARM 9 based CPU (i.MX233) and a DSP56720 (dual core 400MIPS) as starting points. Both of these are available in QFP formats, so the cost of prototyping is low (which is always a good thing).

To this end, I’ve got one of the i.MX233 development board, and getting Linux up and running was a no brainer, it came with it. Hooked up a screen typed a few command lines and bingo, pictures below. What this does mean is that Freescale have a BSP for it, so a large portion of the work is already done. It will also boot from SD card, so that’s my next step, building a Linux kernel on SD.

I intend to get this talking to the SoundBite board I also have from Freescale, so I can get a pretty powerful DSP development system.

I have the parts arriving for 10 more kits.

I’ll call these “kit 6″, and they will contain:

• 1 x PCB
• 1 x Micro (pre programmed)
• 12  x Switches
• 12  x Switch Caps
• 4 x 7 Segment Displays
• 1 x 16Mhz Oscillator
• 1 x 5V Regulator
• 8 x Potentiometers
• 1 x I2C EEPROM
• 2 x MIDI Sockets