Category: Knobs

GR-1 production update // The old ‘bench & something new

Dear all,

Just a post to inform you of what’s going on in the world of Tasty Chips.

First of all, the GR-1 production schedule. We’ve been on time for the last 5 months. We’re still good, but we’re 1 week behind now. We’ve identified some of the slowdowns in the assembly&test program, and solved them. We should be able to produce unhindered for the rest of the year at least.

We’ve open sourced the old Sawbench hardware! Since it was always a DIY project, a schematic is welcome. We’re still selling the DIY kits, if you’d like to try. In a way this is our thank you to the open source community that fed us, and helped us to grow. Sawbench github is the place to visit of your DIYing this or perhaps making a clone.

One more thing: feel free to visit our forum to ask for help with these. Just know that we ourselves cannot supply information indefinitely to people wanting to clone parts of it. We have a business to run. Which brings us to our next topic:

Innovation! We’re producing a new Eurorack module. It’s the first of its kind: A true-stereo convolution reverb with display. On the photo you can see a prototype, of course based on the Raspberry Pi (although we may switch to another Single Board Computer later on).

ECR-1 prototype: the first Eurorack convolution reverb!

Some features:

  • Load your own responses from USB stick
  • RECORD your own responses from the inputs, and SAVE to USB stick
  • Up to 40s impulse response
  • 128×128 full color display
    • up to 4 responses
    • envelope shape
    • parameter read-out
    • WAV name
  • Separate Dry and Wet controls
  • Attack and Release controls
  • Input gain control
  • Stereowidth control
  • Predelay control
  • Audition feature to replay your responses

The software is about 90% finished. The hardware does still need a bit of work, but prototype on the photo does actually record and replay at HIFI 48 kHz quality.

Release date: March 2019, price TBA.

ST4 silkscreens, and the year 2016

Traditionally, there is good news, and there is bad news. This is no exception. So..

Good news, people: the first silkscreen painted casing arrived. See below (click to enlarge). And yes, the power switch is in the Tasty Chips logo 🙂

The first ST4 with silkscreens.

The first ST4 with silkscreens.

Bad news, people: the silkscreen quality isn’t high enough. And this means the delivery will be postponed to next year.

To explain. The silkscreen is spotty and varies in thickness over the plate. We’ll need another iteration to perfect things. Sorry, we just can’t choose to rush this. Especially not on a synth of this class. Which is to say, we will clear this up. No matter the cost!

Now that that’s out of the way. Other news!

Superbooth 2017: April 20..22, Berlin. The most interesting synth fair in Europe. We’re there to demonstrate all our stuff, including formerly classified projects!

In the meantime we’ll keep working on our projects. The ST4 still needs to support more USB keyboard languages 😉

ST4 – Electronics production done

All electronics for the ST4 kickstarter have been completed!

All electronics for the ST4 Kickstarter have been completed!

Take a good look. Yes, all those PCB’s have been assembled. And over half of them in-house. That means we just have to hook it all up and test it.

On other fronts: the firmware has progressed nicely. Apple USB keyboards are now supported, German keyboard layout is supported, and it looks like UK is up next. If you have a kayboard layout you want to see supported, you can send it to us and we’ll code it!

USB hubs are (somewhat) supported, which opens doors to new avenues like USB MIDI controllers. The tracker now features half and double speed options. The display has the feature to show multiple controls (up to 4) at the same time, and controls have set points. Huge amounts of features to control the signal path have been added: LFO sync, LFO cross modulation, frequency controllable LFO random noise, channels may be bundled in one big group (for instance, set cutoff for all channels with a single pot). Poly and mono (non-)legato modes are available. There’s now a PWM mode and LFO modulation can control it. That’s not all, LFO can also control bit crusher parameters!

We’re currently negotiating the casing with a number of factories. This is a lot time consuming as previously thought. The ST4 casing is multi-functional (desktop and 19″ rackmount), has a display and this involves a lot of details and choices to be made. When we’ve invested months and months in electronics and software, we’d like to do the same for the casing. We’ll see which ones comes out best. The cardboard box design now also has been done. The DIY manual is 95% finished and the user’s manual is about 70% complete.

In the meantime we’ll continue making the firmware better and better. Most features will be made available through the two onboard rotary encoders, not only through the USB keyboard. The goal is to have everything except sequencing and typing in names possible with on-board controls.

In short, it’s primarily casing stuff and firmware polishing from here on. Late august does seem somewhat feasible.

ST4 Production

In recent weeks the ST4 electronics production has kicked off. Many of the simpler boards have now been produced and are ready to be built into the ST4 units. These were handmade right here at Tasty Chips labs in The Netherlands, just like the Sawbench synth was.

A stash of assembled ST4 VV boards.

A stash of assembled ST4 VV boards.

The more complex boards (exp, vcf, vca) are being assembled by machine in a fab nearby and should be done by the end of the month. Concerning the manual labor, we still have to do the voice and the mod boards. The DIY manual has also seen some major progress and many of the board pages are supplied with photos of all the soldering steps: ST4 DIY resource. More and more detailed information will appear on this DIY resource in the coming weeks.

In parallel, the firmware is still being worked on. Some news:
– Poly mode now works fine and is intelligent enough to allow 3 finger chords + solo.
– The ST4 tracker can now send MIDI out clock signals.
– The ST4 tracker accepts MIDI clock input (preliminary).
– Samples can now be tuned.
– Sample looping can be turned on or off individually per instrument.

The casing (graphic) design is ongoing. We’ve got an excellent graphics artist on board to help us with the silkscreens. The details of the fabrication are being negotiated at the moment.

Last but not least. We’ve had multiple requests whether the ST4 will become available to the public after Kickstarter. The answer is YES! Also, we are taking pre-orders. These are completely free of charge and the interested party is not obliged to buy in any way. Just send your name, postal address, and the version you want (kit, or built unit) to Price for built unit will be 850 eur, 550 for the kit. Units are shipped out on a first-come-first-served basis.

Kickoff t-minus 4 days

The last days we’ve been working feverishly on the ST4 Kickstarter campaign preparations. We’ve already completed a feature-by-feature demonstration last week. This week we’re focussed on making a trailer video, much like the Sawbench one from last year:

But the ST4 more than 4 times as complex as the Sawbench. The feature list is enormous and it’s impossible to even list all features in a minute-long video. So we just have to make the best possible music with the thing..

That ain’t easy, though. We discovered:

* Renoise on Mac exports signed 8 bit WAV, should be unsigned.

* We need way better lighting in the studio to make decent film.

* The ST4 prototype firmware refused to reload the samples from its song.

* Hooking up a full-blown MIDI setup takes time.

Studio demonstration of the ST4.

Studio demonstration of the ST4.

Anyway, we’re good at what we do, and we’re big boys. We’ll manage 😉

Edit: we did, thanks to 20k of filmstudio equipment and professional help!

Developing for the old woodboard, a new screen to display the full LFO MOD matrix.

Developing for the old woodboard, a new screen to display the full LFO MOD matrix.

The coming days we’ll also output some extra video’s: jam sessions and feature-by-feature explanations. There might also be a documentary about STU’s synth/chip history.

STay tuned!

Sawbench update: 120x PCB’s, casing, planning

The electronics

This week the 100 analog and 100 digital sawbench PCB’s finally arrived. We already had 20 before and these are now fully soldered and tested. The PCB’s seem fine: the silkscreens are now DIY-proof (all values are printed).

There’s one set back: the snap-in holes of the potentiometers aren’t big enough. In the past it’s been hit or miss. Either they are just right or too small. The supplier seems unable to tell us what’s up with that. Our guess is, it’s not a very accurate process. Not as critical as the rest of the PCB. The holes in the EAGLE drawings are small too. Seems like a lucky accident that they sometimes end up being bigger.. Oh well, next time we’ll change the diameters. For now, it’s manually re-drilling 1200 holes (!!!). This is a day of work, so nothing to worry about, except a sore thumb. 😉

100 analog and 100 digital boards.. arrived yesterday.

100 analog and 100 digital boards.. arrived yesterday.

The casing

The casing design will be finalized today. And we can say it looks fantastic! An early version:

Preview of the frontplate graphics.

Preview of the frontplate graphics (pots and buttons are not shown here).

The graphics will be inverse. The background will be aluminium and the font and drawings in blue. The best news is that the colour will be integrated into the aluminium skin, making it scratch-proof and solvent-proof!

Honestly, we cannot wait to get our hands on these casings, but it will have to wait for a bit. Read on..

The planning

There have been some questions about the delivery schedule..

First of all, Kickstarter informs us of a 14 day period to collect all the pledges. This would (ideally) mean we’ll have the money by April 16th.. and can then start paying for casing fabrication.

The way it looks now the bare bones kits will be able to ship this month (April). We have enough PCB’s and a small batch of potentiometers should arrive in a few days.

Casing production (of 200 units) will take 4 weeks in total, and can only start when the Kickstarter money is in: it’s the most expensive part of the product.. We’re trying to get the first 100 casings before the end of the month, but we don’t know yet if this is possible. We’ll update this post when we know more.. Worst case estimate is that we can start assembling the full units from May 14th onwards.

  • April 15th: barebones kits start shipping
  • April 15th: first batch of potentiometers should arrive
  • April 16th: Kickstarter money should be transferred
  • April 16th: start of casing production
  • April 30th: (POSSIBLY) first casings should be available
  • April 30th: (POSSIBLY) the first 10 cased units may be shipped out!
  • May 8th: final batch of potentiometer knobs should arrive
  • May 14th: casing production done
  • May 19th: final batch of potentiometers should arrive
  • May 20th: shipping of kit+casing and full unit should commence

Autumn update: Superpiggie follow-up and “ST4”

Time for a little update after many months of silence on the blog.

Tasty Chips Electronics are still going strong. All the original Piggies have been sold and so we’re going to do a follow-up 😉

The Superpiggy prototype will be a blueprint for this device, although it’s likely it will feature a real VCF instead of a manual filter, along with some other features. The goal is to keep as high a fun-factor as possible, yet also usable as a serious analog monosynth. The product name is not known yet, but there is some idea about the release date: early next year. Also, we will opensource the original Piggy hardware (software was already open), as a sort-of thankyou to the whole Arduino community. 🙂

Meanwhile, the big polyphonic synth project is still ongoing and the prototype is now being integrated with everything on it:
– 3.2″ display
– about 50 knobs
– 4x multi-mode VCF’s
– 4x stereo VCA and mixer
– countless leds and buttons
– MIDI, SRAM, headphone and all other stuff

The ST4 breadboard. Well, part of it..

The ST4 breadboard. Well, part of it..

The SAM3X8E, the micro controller in the Arduino Due, is not powerful enough to control all the analog hardware on its own. A whopping 16 Control Voltages (CV’s) are necessary to control all analog units such as VCF and VCA. So additional PWM IC’s along with output filters were added to the design: these can be controlled by SPI, so the amount of Due pins used there is not high.

Also the display took a huge number of GPIO pins: 21 in total. And all the other devices such as button, potentiometer and led control required many other GPIO pins and analog inputs. All-in-all, the Arduino Due hasn’t got any more pins.. And that’s how we like it: really using the hardware to the fullest, yet keeping it completely transparent for the musician.

Overall, the SAM3X8E and analog electronics now feel like home, just as much as the Atari ST and Falcon once did. This synth, codenamed the “ST4”, will be an ode to those machines of yore. Straightforwardness, directness, fun factor and reliability are the first things we considered. We merge these things we appreciated so much from the early days of computing and computer music with the characteristic beauty of analog audio circuitry; The multi-mode VCF is our own unique design and is very smooth and warm. You’ll love it! 😀

Polysynth development and the Arduino Due, part due

So much has happened in the recent weeks.. Where to start?

First off, we’re making a new synth. A full-blown polyphonic, with loads of special features you’re unlikely to encounter in any other device. This time not only intended as a demonstrator, but as a unit suitable for mass production, and as portable and sturdy as you can imagine. This project is a collaboration between Tasty Chips and STU.

We don’t want to reveal too much, but we can say it’s getting there. We’re building all of this around the Arduino Due, much like the TCE-1M. The Due is so powerful that it can do 8 polyphonic voices with multiple oscillators per voice. For this synth, though, we want to keep it limited to 4 and leave some room for other more exotic features.

PWM + low-pass filter = DAC

The Due has PWM, which is faster and potentially has more resolution than the Uno. As told in previous posts it’s no problem to crank it up to 300 kHz 8 bit.. or 20 kHz 12 bit. Combining two PWM pins using carefully picked resistors, it’s possible to make 2 x 8 = 16 bit DAC’s, using a simple analog anti-aliasing filter behind it.

The Due’s SAM3X micro controller is a true powerhouse. Almost all of its pins are multiplexed, which means they have multiple functions. It turns out you can have way more than the 12 advertised PWM’s. In reality, you can have 4 more.. and now comes the best part.. all of them have complementary pins. That’s normally used for H-bridges and power electronics control where pulses should be complementary but non-overlapping.

Complementary PWM signals with “dead time”.

This non-overlap is controlled by so-called “dead time”. And this dead time is a user-specified variable per pin. So, just set your PWM complementary pair to 50% and vary the dead time on both. you lose 1 bit of resolution, but you gain 14 additional PWM pins. This means you can have a total of 15 audio DAC’s excluding the two already onboard DAC’s. How’s that for a digital oscillator bank!

Of course, all of this should be tested in detail. Using the PWM DAC’s in 8 bit mode was a
success, but there might still be problems with making it 16 bit. We’ll just have to see.

In any case, the SAM3’s PWM power is the reason we stayed Atmel/Arduino, instead of going for the hugely popular STM32. STM32 is multiplexed in a way that does not allow usage of SPI alongside PWM. Very disappointing for an otherwise great micro controller. You just need PWM’s if you’re going to do anything with analog synthesizers. There’s just no way around it.

Atmel SAM3X – The Powerhouse

The SAM3X never ceases to amaze us. While it has bad sides (which are also amazing ;)) like pins that burn out a bit too easily, it has so many good things to make up for it. And each day we discover more. For instance.. instead of the Arduino’s digitalWrite() call to set a pin high or low, you can just write:

// digitalWrite(13,HIGH);
PIOB->PIO_SODR = 1<<27; // digitalWrite(13,LOW); PIOB->PIO_CODR = 1<<27;

A digitalWrite() call is typically 1 microsecond (!) It's direct replacement, however, is only a few cycles!! As you can see these are writes to 2 different registers. One is the Set register, the other the Clear register. This allows the programmer to use only a single write access to the bus instead of the typical read-modify-write.

DMA is the other thing that the SAM3X excels. DMA, or Direct Memory Access, was considered a luxury for a long time in the world of the PC, and for an even much longer time in the embedded world. It's an ideal solution to copy data to/from peripherals without using up costly CPU and also avoiding complex interrupt prioritization designs where timer ticks go missing and all manner of nastiness might ensue.

The SAM3's DMA comes in two flavors:
- DMAC, the standard DMA Controller: extremely flexible and fast
- PDC, the Peripheral Device Controller: slower, but very easy to use

Just about anything can be transmitted over the DMAC, and it also has 6 channels. If you want to periodically send out 32 GPIO inputs to a serial bus or dump them to a memory block. It can do that for you. If you want to send out periodic SPI commands and read back their response.. it can also do that. It can do everything. It can even do linked lists.. running a sequence of transfers completely without CPU intervention. The DMAC is just extremely powerful. More akin to what you'd like to find in your mobile hardware, than on a cheap embedded device.

The PDC is simpler and is specialized for cyclic transfers. While the DMAC is always disabled after transfers complete, you can just pass the next source and destination to the PDC in an interrupt handler. It will continue to these next addresses without any bump or delay. It is slower, but can still do a few megabyte per second. It can be used to read out the ADC periodically, drive the DACs in the same way and also to read out USB at relatively high speed.

Hardware development

Next to the digital oscillator engine, there's the design of all the hardware. 2 out of 4 PCB's have already been laid out and are being feverishly tested and coded on. The focus is on hands-on control. Getting a good, solid and direct user experience as early on in the project. In those terms, some PCB's are easier than others. One contains only a bunch of potentiometers, while others contains a host of buttons, LEDs, rotary encoders, and even a display.. yes..

The Voltage Controlled Filter (VCF) is analog. Yes, this is a hybrid synth after all. We chose to abandon the mutated Steiner-Parker filter from the TCE-1M for a new design that is
very close to signal processing theory and has everything voltage controlled: even the resonance. And of course, it is multi-mode (lo, band, hi, possibly even more). The core is realized on breadboard and it sounds fine. It can be really really resonant without going into self-oscillation. But also, it could be able to do self-oscillation for all the analog nuts out there.. if you really push it. But this is something we need to work on, still.

All-in-all, we estimate it should still take a month before a workable prototype emerges. We'll keep you updated!

More reading:
The rather excellent SAM3X user guide is available here: Atmel SAM3X User Guide

Synths in casings + new synth!

Last weekend the first fully cased Tasty Chips synths were demonstrated!

The Super Piggy, an experimental follow-up of the Piggy, was cased by Matthijs, allowing all the potentiometers to come out while safely housing both the Arduino and the Superpiggy. Next to this there were the first attempts at display modules using super-sharp and vibrant OLED displays.

This sets the general direction for Tasty Chips: Synthesizers usable out-of-the box. Fully cased and ready to be played and of course, loads of parameters hands-on available.

In this vain, the new prototype was also designed. The TCE-1M is a monophonic analog synth with the VCO and VCA sections of the Superpiggy, combined with a multi-mode VCF + loads of features.

From top-left to bottom-right in the picture:

  • Saw and rectangle VCO with adjustable duty cycle
  • Loopable ADSR envelope
  • LFO (0.05 Hz -> 50 Hz) with Pitch and VCF cut-off integration + 3 waveforms
  • Multi-mode VCF (low, band, hi) which multiple modes selectable at the same time
  • Filter sweep profiles, speeds and directions, and of course keyboard tracking

The TCE-1M is definitely the future for us. It was demonstrated and subsequently experimented on with great interest from the public. Hence, the choice was made to slowly move away from the Piggyback devices in favor of the more hands-on controllable powerful synths.. even more powerful than the TCE-1M..

Check out some photos below:

TCE-1M Monophonic Analog

TCE-1M Monophonic Analog in aluminium fronted casing.

961313_10152210383799735_324644534_n (1)

Superpiggy in its own special casing + a little OLED display (photographed in its natural habitat, obviously)

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