[closed] Dervish: 12HP FV-1 euro FX

[gbiz]

The current run of Dervish PCBs are now sold out. I have no plans for another run, so Dervish is now closed.

I do still have uDervish PCBs etc available if you want to build an FV-1 based FX module (details here).

I will retain a few Dervish boards as maintenance spares so if you need to repair a Dervish, or want a new PCB panel, ping me an email.

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Dervish: fx module based on the Spin Semiconductors FV-1 DSP.

(If you're looking for the 8HP µDervish thread, click here)

OLED control/display & DSP boards:


Gloss black PCB panel with acrylic window in cutout:



Docs:
See this doc for links to all the docs, BOMs.

Schematics will be emailed to you when you purchase boards.
FPD & pdf dims files are available for people who want to create their own metal panels


Audio:
The hardware offers stereo in, stereo out. Level and mix control on both channels. The right hand input is normalised to the left hand input for mono in/stereo out (this configuration still provides independent level/mix adjustment for each channel).
Full stereo depends on the program running. A few are stereo in, stereo out. Many are mono in, stereo out. Some are mono in, mono out.
Suggested 32KHz crystal provides max 1sec delay times at ~15KHz bandwidth.

See the next post for example sound clips.

CV control:
The FV-1 provides three control voltage inputs. Dervish provides summed pot & external CV for each of these. External CV range is +/-5V with the corresponding pot centred.

Programs:
11 banks of 8 programs. The FV-1 can address a single bank of 8 effects/programs stored in an external i2c EEPROM. Dervish expands support to 11 banks of 8 effects (binary + text) by using a larger EEPROM & storing the extra banks above the 4KB addressed by the FV-1. An ATTiny MCU provides the ability to switch banks by copying the new bank into the FV-1's addressable space. A 4-pin connector exposing the i2c bus is provided so you can customise the content of the EEPROM.
I provide an EEPROM image that you can use immediately containing compiled versions of the algorithms available from Spin Semiconductor under their open reverb license.

Current bank number, program number, display brightness & timeout settings are persistent across power cycles


Display:
0.96" 7-pin SPI OLED display. The main runtime display shows the current effect's bank name, effect name, labels for the three CV's function (see image above). A menu provides options to select new effect bank, set optional display screensaver timeout & change display brightness.


Physical:
Width: Display board is 12HP, DSP is 8HP.
Depth behind panel: 35mm. (Could be reduced by 5mm with lower profile headers)
Current draw (measured with a long reverb program running): -12V: 26mA. +12V: 100mA with display at full brightness, most characters displaying, 92mA with display blank. Varies by a few mA depending on the program running, reverbs seem to be worst.


Component sourcing:
I can supply: PCBs; PCB panel + window ; FV-1 DSP ; Tall Trimpots ; pre-programmed ATTiny & EEPROM.
See "Ordering" section at bottom of this post for details on pricing, shipping etc.

Thonk or your favourite local equivalent: Alpha pots, Thonkiconns, Davies knobs

Mouser carts for the rest of the components.

Edit: As of Apr 2019 I've stopped supplying the OLED display. The current ATTiny code should support any 7-pin 4 wire SPI 0.96" SSD1306 compatible display, so source this from ebay/Ali or one of the more "reputable" suppliers. I currently still have M2 mounting hardware available, i'll bundle that in with the panel.


Build:
Build guides & BOMs are available for all the boards.

All the ICs are SOIC, so easy enough to solder. The passive components are 0603 SMT. Anyone who's successfully built one of the Mutable boards shouldn't have any difficulty with this.


Programming:
I have pre-programmed ATTiny & EEPROM available if you want to avoid flashing these devices. With these once the module is built & working, thats it, it's a working module. You don't need to do any programming unless you want to do some customisation of the program banks etc.

Alternatively, for those willing to do the programming themselves, i provide binaries for both the ATTiny & the EEPROM image, along with full source code.
I supply a "programmer shield" PCB as part of the PCB. This uses an ATMega32u2 that can be used as a programmer suitable for programming both the ATTiny & the EEPROM.

The control/display board has a standard 6 pin ICSP header to upload code to the ATTiny. You'll need a suitable programmer (I use an Olimex AVR-ISP MK2). If you don't have one, the i2c EEPROM programmer shield provided as part of the PCB set can be used.

The DSP board has an i2c header that you use to program the EEPROM. This i2c bus is also connected to the FV-1 & the ATTiny. The FV-1 isn't tolerant of voltages above 3.3V on it's i2c pins, so any i2c programmer you use must provide 3.3V signals else you'll kill the DSP. Code to interface into this EEPROM programmer from your desktop is provided for Linux & MacOS. Windows users are recommended to use a Linux image running in Vagrant and use the Linux code.


Customisation:
I've written a progamming environment that when used in conjunction with the "eeprom programmer" shield & companion sketch, allows you to upload/download EEPROM images, program banks or individual program binaries into Dervish. This environment is written using standard Unix tools, so whilst it runs on MacOSX and Linux, it cannot be easily ported to run natively on MS Windows. Windows users are recommended to use Linux hosted in Vagrant (this is easier than it sounds, i have a basic doc on how to set this up).

The Dervish programming environment is designed to work with Nathan Fraser's asfv1. Together this environment can be used as an FV-1 development system.

The programming environment has a full users guide, and for those unfamiliar with the command line interface, an installer script.


Expansion:
2 expander boards are available:

I2C & 3x attenuverters (4HP): Useful if you do a lot of FV-1 programming. Keep the Dervish in the rack. Plug the EEPROM programmer into this module. The i2c from this module plugs into Dervish.

UpDownTap (2HP): Provides external control of program up/down, and a basic pushbutton for use with tap tempo programs.


Ordering:
See this page for prices, options etc.

Built modules are occasionally available from me, free time permitting. Please PM or email me for details. There are other builders who can also provide built modules for customers.

[gbiz]

Links to example sound clips, videos ...

Links on my soundcloud ...
* Nein-oh-nein kick through reverse reverb and
* through various reverbs
* Elements with various reverbs, no Elements builtin reverb used.
* Radio Music into MS50-ish filter into Dervish with 2:1 clock sync pingpong (2:1 means pong is half the delay time of ping)
* pitch shifter w/feedback
* Shimmer based on Dattorro reverb
* various drv103 programs (drv103 is my attempt on a tape delay)
* clocksync 2:1 drv103 used in a demo of my System100 filter

Other examples by builders posted in this & the µDervish threads...

* Awesome youtube video tutorial (in Russian). By temaniak
* 'huge reverb wash'. By TimoRozendal
* Reverb. By toneburst
* jam using 3 x µDervish. By ImportJingles


(I know i could use the embedded soundcloud & yt options, it takes too long to load IMO).

[Altitude909]

Yay! Build thread!

Let me kick it off:

for the USians:

http://smallbear-electronics.mybigcomme ... semi-fv-1/

[Dogma]

theres a guy around who said he had cooked up a bunch of fv1-spin programs - he might be good to get in contact with as he said hes put a lot of work in but is a bit afraid to show his work....
a set for me please

[oberkorn]

looking good! I'll take a set when available.
(if anyone in Europe is ordering from OSHpark i'll join in)

[SoundPool]

interested for the future, but will hold off for now due to huge backlog. but given how many folks seem interested right off the bat I would suggest looking into getting your PCBs done somewhere other than OSHPark. its great for small runs and proto, but if you are going to bother doing larger batch production rather than just sharing project files you could probably get much better pricing per-unit from somewhere else.

[gbiz]

interested for the future, but will hold off for now due to huge backlog. but given how many folks seem interested right off the bat I would suggest looking into getting your PCBs done somewhere other than OSHPark. its great for small runs and proto, but if you are going to bother doing larger batch production rather than just sharing project files you could probably get much better pricing per-unit from somewhere else.

My reason for sticking with OSHPark, i'd know the boards would be same as ones i've tested. But others have suggested the same as you, so i'm looking at alternatives.

[Altitude909]

Just for reference, OSHpark are ENIG (aka immersion gold) plated. Decent for leaded or unleaded solder. Avoid the silver stuff (IAg), tarnishes quickly and hard to solder to.

I like leaded HASL if that's permitted for you (easiest to solder), I'd say avoid unleaded HASL

[lamouette/rck]

Add me to the list !

[anto32]

Awesome project!

The calibration for external cv is located into the code?

thanks

[gbiz]

The calibration for external cv is located into the code?

I'm not sure what you mean by calibration ?.

[gbiz]

Just for reference, OSHpark are ENIG (aka immersion gold) plated. Decent for leaded or unleaded solder. Avoid the silver stuff (IAg), tarnishes quickly and hard to solder to.

I like leaded HASL if that's permitted for you (easiest to solder), I'd say avoid unleaded HASL

I have no objections to lead.

Looks like PCBWay are trialling ENIG. They had an option for it, supplied at their discretion, with HASL if you don't get it.

[sammy123]

Add me to the list please.

[mothertongue]

I'll jump on the list too!

[horstronic]

I'm in for one!
Nice project!

[d.simon]

I am interest for one set

[Eloc]

I'd be down for a PCB set, and panel probably too.

I have no objections to lead.

Looks like PCBWay are trialling ENIG. They had an option for it, supplied at their discretion, with HASL if you don't get it.

I've had ENIG done by PCBWay for Panels. In fact I didn't ask for it on one design to save money and they mistakenly did it gold anyway... I didn't complain...

[gbiz]

Ah yes. Panel. Not something i've ever really done properly for my own designs before. Cost of decent metal panels from FPE/Schaffer coupled with a likely hit for UK import duty always put me off. I've never been a massive fan of acrylic or PCB panels. I can live with a rough looking DIY panel that i've done. But i suppose this one should be done properly.

I already have .dwg & .svg files that i used as drill templates to create the panels i'm using now. And i've put together a PCB layout for a PCB panel, though that needs some graphics for the text. So most of the hard work is done. I'll include both in the upload to github.

[BARE BONES]

do you have a link to your github please?

[grizzle]

I'm in for PCB's and a panel if it gets offered!

[gbiz]

I'll upload to github once i'm happy the current gerbers don't require rework. I'll add a link to it in the OP then. When that happens depends on when i get my latest prototype PCBs back from OSHPark.

[woodster]

So happy to see this is happening, Good skills gbiz !

[anto32]

I'm not sure what you mean by calibration ?

Ah sorry! I want to use the cv inputs with a 0/10v signal. So maybe i could shift the -5/+5v?

[gbiz]

I'm not sure what you mean by calibration ?

Ah sorry! I want to use the cv inputs with a 0/10v signal. So maybe i could shift the -5/+5v?

Ah, i see what you mean. (I had visions of you wanting to calibrate it to a nicely linear 1V/Oct ).

The +/-5V CV input provides full voltage swing at the FV-1 POT input with the corresponding control pot centered. You can get a similar full swing with a 0-10V CV with the control pot fully counter-clockwise, but then you lose the ability to set a offset with the control pot & drive the POT input in a negative direction with the CV. Theres no way round that in the module unfortunately, at least without some rework. You'd need external voltage processing of your CV.

Attenuverters & level shifters work well with these CV inputs. I did think about adding them. But the panel would have ended up at 16-20HP. There's probably the case for a 8HP companion module for this that provides attenuverters, level adjusters for the CVs, input mixers that make it easier to add feedback etc.

[jhulk]

im in for pcbs put me on list please