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[Old version] "Waverider" - Electric Druid VCDO
MUFF WIGGLER Forum Index -> Music Tech DIY Goto page 1, 2, 3 ... 12, 13, 14  Next [all]
Author [Old version] "Waverider" - Electric Druid VCDO

frequencycentral

EDIT 15th June 2013

New version of Waverider now available with fabbed PCBs and panels:


https://www.muffwiggler.com/forum/viewtopic.php?t=84728

_____________________________________________________________



Here we are! Waverider is ready to go! Tom is fully loaded with programmed PICs, of which I will be ordering a substantial amount shortly.

Tom has a draft PDF on his website right now (see page 8 of this thread).

Preliminary build doc, I'll probably flesh it out with a few photos...

https://dl.dropbox.com/u/967492/ED%20VCDO/Waverider%20Build%20Doc.pdf

______________________________________________________________________ __________________________________________________

Original OP for posterity:

I've been messing around a lot with the Electric Druid VCLFO recently (well actually the TAPLFO2) see 'the other thread': https://www.muffwiggler.com/forum/viewtopic.php?t=49661 It's a superb VCLFO and a huge bang for the buck compared to building a similarly spec'd analogue (would be a huge circuit) VCLFO.

It's got me thinking, what a great feature set it has, loadsa waveforms, CV input for frequency, Cv input for waveform, CV input for PWM, oscillator sync input. Wouldn't it be nice to attempt an audio oscillator version? Surely it shouldn't be too difficult to tweak the coding a little and make it run at audio frequencies......then if it could be coaxed to operate at 1v/oct it would be a superb digital VCO....

So, being the glutten for punishment that I am, I'm about to pull the trigger for a PIC programmer and a bunch of blank PICs....

I know some will look down their noses at a digital VCO, but.......it would be a really easy build as all the work would be in the coding, it would be a quick and easy way to increase your VCO count too. Might not be your only VCOs, but run alongside some regular analogue VCOs? And the fat subtle 'drift' we all love in analogue could be patched in with some really gentle, slow LFO modulation.

Tell me I'm insane!



stk

I'm all about digital VCOs, love em.
However, this:
Quote:
Using an external crystal with the PIC allows the chip to run at its maximum clock speed of 20MHz, and this means that the PWM module is able to produce a 19.5KHz sample rate at 10-bit accuracy.


whilst ok for an LFO is likely to be not very hifi in audio range, I think?


brother303

Hi,

stk wrote:
I'm all about digital VCOs, love em.


Same here. Love my Piston Honda,Hertz and Tabula Rasa. thumbs up


stk wrote:
whilst ok for an LFO is likely to be not very hifi in audio range, I think?


Hm,could be even more nasty (translate -> interesting) combined with a bit reducer/shaper or some Plague Bearer-like stuff...

hmmm.....

Cheers
Greg


Rod Serling Fan Club

Sounds very interesting. I would likely purchase one.

Reminds me a bit of the hertz donut with the waveform distortion thing. I wonder if the sync could be made to work like the donut, where there is selectable slower "tracking" between the oscillators.


gwaidan

Sounds interesting!


samuraipizzacat29

Anything unique is for me nanners


wmonk

stk wrote:
I'm all about digital VCOs, love em.
However, this:
Quote:
Using an external crystal with the PIC allows the chip to run at its maximum clock speed of 20MHz, and this means that the PWM module is able to produce a 19.5KHz sample rate at 10-bit accuracy.


whilst ok for an LFO is likely to be not very hifi in audio range, I think?

But there are a lot of interface pins on PICs, so you could use an external DAC. 8_)


J3RK

The Atmel AVR series seems a bit more powerful, (at least in general.) I know there are some PICs that are pretty powerful (like the ones in the e350, but those have some DSP functions.)

General purpose uControllers should be enough to do some phase accumulation oscillators like in the SID chip, which would also lend themselves well to wavetable applications. (which I guess is more or less what a PA Oscillator is anyway) Probably not powerful enough to do really effective aliasing correction, but that may not be important anyway.

I've got a bunch of AVR dev kits (Dragon, and AtMega,) and have been waiting for some magical extra time to present itself to start tinkering with something like this. However, after seeing the Cylonix Cyclebox using the eval boards for the Cyclone CPLD, this has started intriguing me a bit more than using the Atmel stuff. A bit more expensive, but a lot more powerful.


Electric Druid

With a bit of prodding from FrequencyCentral, and a good amount of help and feedback too, I've been developing a prototype digital oscillator based on the PIC 16F1847.

http://www.electricdruid.net/images/VCDO.mov

(24MB file)

It's got 16 main oscillator waveforms arranged as a wavetable. There's a Wave CV input for scanning through the wavetable. Intermediate waveforms/points are interpolated to give a 256-entry wavetable.

There's a fine tune control (+/-1 semitone) and a frequency modulation CV input (+/-8 semitones).

Since the video was done, I've added a suboscillator with 8 waveshapes, all available either -1 octave or -2 octaves. Four waveforms are shared with the main osc. The other four are sub-osc only.

It also has portamento/glide. It's a constant-rate glide, so it takes longer to do an octave than a semitone. If that isn't right for you, sorry. There are some limitations!

The output is 8-bit at 125KHz, so the audio quality isn't bad. If you want it bad, it has a "Bitcrush" control that goes from 8-bit down to 1-bit to reduce everything to utter mush!

I'll probably post more on this soon, but I'd be interested to hear people's ideas or feedback on what I've got so far.

Thanks,
Tom


roglok

awesome!!!1

on board portamento and sub oscillator sounds dope...


J3RK

Wow! Sounds like a lot of fun! I'd still like to work on something like this as well at some point, but my programming skills are just a step or two above nothing.

This VCO sounds very nice! Has a nice hint of PPG/Waldorf in it.


reignbear

this sounds great!
SlayerBadger!


frequencycentral

I'm super excited about this project, Tom's worked in some great features. I'm fit to burst to actually build a couple, as Tom has been teasing me with tasty tidbits of info for weeks. If all goes as planned I'll be offering a run of PCBs + programmed PICs once the project reaches completion. Fun times ahead!


NV

If the circuit remains rather simple and easy to build I would certainly be in for a few (board mounted pots, small part count, etc - much like the VCLFO). A quick and easy way to make a multi-VCO module would be the draw for me.


Rod Serling Fan Club

I'm happy more digital oscillators are entering the DIY realm.


mckenic

Watching this with great anticipation!

Frequency Central & Electric Druid are shaping up to be quite a team!

thumbs up


aladan

DO WANT! hyper


zomgw00t

Electric Druid wrote:
It's got 16 main oscillator waveforms arranged as a wavetable. There's a Wave CV input for scanning through the wavetable. Intermediate waveforms/points are interpolated to give a 256-entry wavetable.


Sweet! Any chance you might include the ability to output the waveform number to a series of LEDs? I love my digital modules to have lots of blinkenlights!

screaming goo yo

Electric Druid wrote:
The output is 8-bit at 125KHz, so the audio quality isn't bad. If you want it bad, it has a "Bitcrush" control that goes from 8-bit down to 1-bit to reduce everything to utter mush!


I'm particularly excited about the idea of a "bitcrush" control. I'm assuming it will control bit depth? It'd also be cool to have a bit rate reduction control for some serious resolution mangling.


~Chappie


ossi_fx

I definitely want one!


Luka

Nice

I always thought it would be cool if my druid lfo would go audio rate

Is it possible to just change the code to increase the range?


Electric Druid

Luka wrote:
Nice

I always thought it would be cool if my druid lfo would go audio rate

Is it possible to just change the code to increase the range?


Not really, no. There's more fundamental changes required, which is why I've never done a PIC digital oscillator until now. It's not that it isn't possible, just that I was never happy with the limitations.

Microchip have released some new chips which go about 50% faster than previous ones. This gave me the extra power to do a decent job of it.

Obviously with chips at this level (cost £1.20 or so) there *are* limitations, but it's surprising what you can squeeze into them. And getting more out of less is the fun part!

Tom


brother303

Awesome!

Want!

SlayerBadger!


Funky40

Electric Druid wrote:


Obviously with chips at this level (cost £1.20 or so) there *are* limitations, but it's surprising what you can squeeze into them. And getting more out of less is the fun part!

Tom


why not using something more powerful that might cost some $ more ?
10 or 20 or 30$ wouldn´t be much, not ?
IMHO the main investment ist the buildtime


theabsent

Interested!


Sebo

Great Project!!!
I want one!!!

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