Bended MIDIbox SID engine

[TK.]

How about a "circuit bending" option in the MIDIbox SID which allows to change the characteristic of the engine?

How it could sound? See this example: :-)

http://www.ucapps.de/tmp/tb303_test3.mp3

Best Regards, Thorsten.

[MMorph]

Most interesting. So would this be traditional hardware based bending or is there a way to do the trick inside software? This truly would give more unique sounds out of the SID box! :-)

Regards, Petri

[d2k]

;D ;)

[TK.]

The software as well as the hardware is "bended" ;-)

The software got some small modifications, especially in the envelope

behaviour (for proper accent handling) and in the filter characteristic.

Oh, and in the meantime also the WT sequencer is modified - it's now a TB303

style sequencer with note/accent/slide/gate and an optional CC, up to 32

steps can be stored in each pattern, live editing and fast switch between

different sequences is possible (and this all with a small number of

additional assembler instructions at the right places)

The hardware: I added a moog filter which is controlled from the MBSID via

the AOUT module. I think for the final release it makes sense to support

also the "Low-Cost DAC" which consists of a single 74HC595, a resistor

ladder and a TL074

The new option makes also fun with the original SID filter (so that no

hardware mods are required)

Here a new example, the sequence is played by the MBSID itself, and it is

synchronized via MIDI clock:

http://www.ucapps.de/tmp/tb303_test4.mp3

Is anybody interested in beta-testing the new firmware? :-)

Best Regards, Thorsten.

[MMorph]

Hmm, been wondering if it would make any sense to make external filter unit for SID. Having few filters in it, maybe even totally different of types, and then use whatever you want via filter matrix kind of coupling. It wouldn't be too hard to make with an analog switch matrix IC's although they are not available in every electronics shops and therefore being quite expensive. Though it would be nice to have more analog outs to control them.

Then again could take some DSP chip and begin to program some earth shattering filters..! I think I still have one Freescale chip somewhere in my junkbox. Hmm.. :-)

It's just.. Where do you guys get all of your time you need for building all this stuff?  ::)

Regards, Petri

[moxi]

The hardware: I added a moog filter which is controlled from the MBSID via

the AOUT module. I think for the final release it makes sense to support

also the "Low-Cost DAC" which consists of a single 74HC595, a resistor

ladder and a TL074

Hi thorsten ,

i'm working on a diode ladder filter too, that can fit on the standard format of the midibox board!!!it's based on this one :

http://www.freeinfosociety.com/electronics/schematics/audio/diodeladderfilter.html

i'm tryin to add the resonnance feedback ,but the VCA to drive it from CV need to be on another board for the while (it's the first time i try to design a pcb ,so...)

which design did you choose for yourfilter ?

i don't look for such design ,but effect like phaser are "easy" to do ,and i think it could be great additionnal effect pcb for the SID or your other synth.

[moxi]

a phaser :

http://www.freeinfosociety.com/electronics/schemview.php?id=571

[Skunk]

Wow, what a hot link, Moxi!  8)  Thanks for this hint!

Cheers,

Skunk

[Twin-X]

The software as well as the hardware is "bended" ;-)

The software got some small modifications, especially in the envelope

behaviour (for proper accent handling) and in the filter characteristic.

Oh, and in the meantime also the WT sequencer is modified - it's now a TB303

style sequencer with note/accent/slide/gate and an optional CC, up to 32

steps can be stored in each pattern, live editing and fast switch between

different sequences is possible (and this all with a small number of

additional assembler instructions at the right places)

The hardware: I added a moog filter which is controlled from the MBSID via

the AOUT module. I think for the final release it makes sense to support

also the "Low-Cost DAC" which consists of a single 74HC595, a resistor

ladder and a TL074

The new option makes also fun with the original SID filter (so that no

hardware mods are required)

Here a new example, the sequence is played by the MBSID itself, and it is

synchronized via MIDI clock:

http://www.ucapps.de/tmp/tb303_test4.mp3

Is anybody interested in beta-testing the new firmware? :-)

Best Regards, Thorsten.

Thorsten,

I would like to beta test it but unfortunatly i am quite a sid noob.

I have finished my quad sid. Can i have 1 TB and 3 sids or 2 303 and 2 sids?

How is this implemented?

The reason i wish to beta test is because i am an active member at Lotstelle (acidcode) the 303 clone with sequencer based on MIOS ;)

They will go nuts if i tell them this hehehe.

[tatapoum]

Hi all,

Why not working on a dedicaded analog filters unit based on MIOS ?

ludo, my SID box is full... ;)

[TK.]

More informations about the filter that I've used in the first example can be found here: http://69.56.171.55/~midibox/forum/index.php?topic=2821.0

A "filter box" would be a great idea, not only for the MBSID, but also for MBFM - I would build one!

But unfortunately I'm not an analog expert, therefore such a project should be driven by somebody with experiences in this area.

Twin-X: I will send you a snapshot this evening. Yes, you can mix the firmwares like you want - sooner or later I will change the TB303 feature to a soft-selectable option, which means that you can use the same firmware for both engines

Best Regards, Thorsten.

P.S.: currently I'm thinking of an optional TB303-like keyboard for better editing capabilities. I hope that there is enough space in the flash for this useful feature, if not this option will only be available when anything else is disabled (e.g. some menu items which are not related to the typical TB303 sound)

P.P.S.: maybe I should mention here that Matze (the creator of the acidcode.de box) gave me a lot of useful hints about the TB303 behaviour and the schematics :-)

[moebius]

P.S.: currently I'm thinking of an optional TB303-like keyboard for better editing capabilities. I hope that there is enough space in the flash for this useful feature, if not this option will only be available when anything else is disabled (e.g. some menu items which are not related to the typical TB303 sound)

Wow!

It's so nice to see, You're still having FUN!!

Bye, Moebius

[airmailed]

i think the 303 style keyboard is a great idea.. i had been wanting to put such a thing in my sid but wasn't sure if i could handle the programming.... i think a useful feature might be using the keyboard to control the arpeggiator... and maybe have a "latching" mode, where the keys could be pressed once and send a continuous note on to the arpeggiator (so that they would not need to be held down)... i know it's unsure whether there is room in the firmware for this but it might be a nice touch if it's possible...

i have bought some of ken stones steiner vcf boards for my mbfm.. they run on +-12v,

http://www.cgs.synth.net/modules/cgs35_syntha_vcf.html

i might just include these in the fm without any voltage control.. (just knobs for cutoff and q) i have to see how much 12v stuff i can run from a 250ma supply.. the plan is to include separate input sockets for the vcfs so that external signals can be run through them, i might also include  rotary switches so that i can switch the outputs from the fm between each filter input (hp, lp, bp) and also bypass the filters if i want to....

for anyone wanting a filterbox i think these look great for that (i didn't build them yet but have built ken stones passive ringmod which i really like, the mod input is direct coupled so that very low signals... like 0.01hz can be used to modulate the audio)... ken delivers the boards very quick...  thats my recommendation ;-)

[jdutcher]

perhaps i'm a complete moron, but i don't quite understand what's being discussed here.  what exactly has been done to the MBsid?  sorry...i'm very intrigued but a bit confused.

[Twin-X]

perhaps i'm a complete moron, but i don't quite understand what's being discussed here.  what exactly has been done to the MBsid?  sorry...i'm very intrigued but a bit confused.

TK has written software for the MBSid so that it emulates a Roland TB-303. (thats it a bit explained globally). It also discusses about adding external filters to your MBSid since the mp3's posted use external filters for fattening up the sound.

[rebb]

Is anybody interested in beta-testing the new firmware? :-)

Interested? Yes, very. I already did some tests thru Doepfer wasp filter. Sequencer part

on mbsid firmware :o Hmm is it possible to put batteries on mbsid ;)

[moxi]

Why not working on a dedicaded analog filters unit based on MIOS ?

Hi tatapoum ,just wait ,i' m building an "OAKLEY FILTREX" ,in a stereo version ,and for the while i'm waing for the last part (reichelt is very long to send things!!)

what i'm tryin to do :

-a midification of this filter : the cutoff still have a CV input ,so it easy ; i'm building two VCAs for the rezonnance ,two more for the other parameter (fuzz\smooth) ,and a sync for the LFOs

-a step SEQ ,using the TK SEQ ,that can be used to trig the envellope (it have already his gate input) and can modulate at least the CUToff and the rezo (each parameter ,assigned to a track will be "mutable" individually)

-a little tube distortion on the output (as you can find on the ELECTRIBE box, or in guitar effect).

the first PCB is already mounted , i'm waiting for the parts for the VCAs ,and for the lamp...

-as it will be two filter ,it will be possible to switch between 2xMONO ,1xSTEREO or serie link (2x4 poles= 48dB\octave, not sure that is really usefull ,but as is just some switch to add..

[d2k]

moxi - sounds great :) is this stereo filtrex ur own pcb layout or are you using bought ones from the oakley site? Will you be putting the mods ya made on a webpage when ur good n ready?  ;)

[moxi]

Yes ,i will share all of that as soon as it will be fully working!

I've used the PCB that oakley sell ,they are double sided ,so difficult to repplicate ,and are about 35*10 cm! Its why i'm trying to do a simple filter that can be build for cheaper on the stantard vector boards (one for the filter ,one for VCAs , combined with an AIN*1) .

i've said to the OAKLEY guy that i will send him the mods ,so its will be on the oakley site if the man find them fine .As Oakley decide to give their schematic only to those who buy to them the PCB ,i don't want to share them, by respect for their choice ,but is easy to find moog style filter schematics on the web .

But i'm working on different things at this time ,and try to finish first the french translation of Ucapps first ,so don't expect something before at least two or three weeks .

[jdutcher]

TK has written software for the MBSid so that it emulates a Roland TB-303. (thats it a bit explained globally). It also discusses about adding external filters to your MBSid since the mp3's posted use external filters for fattening up the sound.

ahhh, exactly the clarification i needed.  thanks twin-x!!

thorsten, excellent work as always...very interested in trying it out when i finish school.  too bad i already built an analog 303 clone!!! ::)

[tatapoum]

Hi tatapoum ,just wait ,i' m building an "OAKLEY FILTREX" ,in a stereo version ,and for the while i'm waing for the last part (reichelt is very long to send things!!)

what i'm tryin to do : ...

Hi moxi. This look amazing but maybe too much (for my own use). It will also be a little bit expensive, isn't it ?

However the Oakley Filtrex looks fine.

I'm thinking in a Mooger fooger MF101 controled by the SEQ...

ludo

[moxi]

This look amazing but maybe too much (for my own use). It will also be a little bit expensive, isn't it ?

Yes ,is too much ,maybe to expensive if you build it with oakley PCB ,it's just cause i want a great great filter,just to have a beautifull thing , and cause it's one of the thing i must often use when playing .And it's why i try to do one with more simple schematic ,that you can build without buying special PCBs .

I'm thinking in a Mooger fooger MF101 controled by the SEQ...

you can easily find schematic for this one (or similar) ,there is some link before on this topic, but i don't know the difference with the filtrex one ,all are based on the same design .

on this page you will find the schematic for the VCAs you can use to drive the rezo and an envellope generator ,but i found the filtrex not really expensive ,as it already include the enveloppe and two LFO ,and building each of them separatly can cost more!

http://www.musicfromouterspace.com/analogsynth/vca.html

(thank to the one here that give the link! ;))

[cheater]

Hey guys,

just wondering... has anyone tried this with a 303 filter?

Seems cheap to make.

[srmaietta]

Thorsten,

  Glad to see the SID continually updated!!    I'm still awaiting my PCB's and parts, but this gives me time to think about panel layout and features etc.  I'm still digesting your recent "Analog Input" update, and now this!!  I vote for making it a switchable mode in software, on a per-sid basis.  The keyboard would be nice, but only if it also was useful and helpful in the normal wavetable mode.  In other words, who wants a row of buttons on their control surface when youre not using them for anything half of the time?  Having a dedicated built-in sequencer on the Midibox SID would be awesome for sure!!! 

~Steve M

[TK.]

Hi Steve,

in the meantime I'm not sure if a seperate keyboard for the TB303 sequencer would really improve the usability, therefore building this interface is a "low priority" topic in my ToDo list now.

I'm using the new "note entry" feature of the MBSID editor instead, which handles WT sequences like a tracker:

Another point is, that after heavy code optimization in the control surface routines (1k more flash memory available now!), I was able to add a soft-option for TB303 mode. Means: it's possible to use the same firmware for common MBSID and TB303 mode:

(as you can see, there are 6 remaining flags free for future options :)

A new feature of the MBSID is a low-cost AOUT driver. The upcoming AOUT_LC module mainly consist of 2 * 74HC595, 36 * 10k resistors and one LM324. The part costs of this "selfbuilt" DAC are around 4 EUR - a nice starting point for everybody who wants to control external analog filters :)

Best Regards, Thorsten.