midify synthesizer

[carlos]

Hi everybody,

Totally new to this board and I do hope I don't ask a stupid question...I have searched this board and a bit of the specs of the midibox...

My question is the following : Is it possible to control all the parameters of a synth like the filter resonance ADSR ... every pot that is on the board...and notes on and of of coarse. And if so could somebody give me a pointer how to start with it.

The question is also if I can use the 8 CV on the midibox to control 7 knobs or sliders and the notes? 

or are there other solutions?

anyways thanks for the time!

[Tanstaafl]

The simple answer is... YES!

  The complex answer is.... for adsr.... you are going to need a voltage controlled ADSR... they are out there on the web.

  I believe you can programatically set the outputs of the midiCV but I am only using it for gate for envelopes and voltage control of oscillators.  These being modular in design.

  Now as to being able to control YOUR synthesizer... I guess if all the knobs and controls of your synth are midi based.. like a Korg ms2000 or a Virus or Nord modular, then you could assign midibox controls to your synth.but.... does that not kinda seem like overkill?

maybe I don't quite understand what you are trying to accomplish.

a bit more info please?

gb

[carlos]

Hi,

thx for the quick answer,

I have a couple of vintage soviet synthesizers that I want to control with the computer. One of them the polivoks I had installed the synhouse midijack on and it works but still don't have control over other parameters. Another one the Aelita isn't midified yet but I want to try out this midibox if it will do what i think it could do, that is send control voltages to any parameter on the synth.

So if I get this right each parameter has to be voltage controlled...could you give me a pointer no how to know if a parameter (filter cutoff, resonance filter adsr, vca adsr, vibrato, unison) is voltage controlled or not... can you measure it with a dmm or do i see it on the schemes? are there other possibilities except voltage controlled parameters?

as you can see...a lot to learn :-)

thx!

[Modularman]

Hi,

thx for the quick answer,

I have a couple of vintage soviet synthesizers that I want to control with the computer. One of them the polivoks I had installed the synhouse midijack on and it works but still don't have control over other parameters. Another one the Aelita isn't midified yet but I want to try out this midibox if it will do what i think it could do, that is send control voltages to any parameter on the synth.

So if I get this right each parameter has to be voltage controlled...could you give me a pointer no how to know if a parameter (filter cutoff, resonance filter adsr, vca adsr, vibrato, unison) is voltage controlled or not... can you measure it with a dmm or do i see it on the schemes? are there other possibilities except voltage controlled parameters?

as you can see...a lot to learn :-)

thx!

Hi Carlos,

I used to own a polivoks and I added cv and gate inputs to mine with an external midi/cv converter and I also cloned the filter from it for my modular synth. What you are proposing would require a large re-design of many of the circuits. First the easy stuff, - it's very easy to add voltage control of pitch cv and gate, there is a circuit for this here http://www.muztech.com/eng/images/cv_gate.jpg  it is not too difficult to arrange voltage control of filter cutoff too.

To control the filter and vca ADSR and VCA vibrato would require a complete redesign of the circuitry with transconductance opamps to allow voltage control of ADSR, as there is no internal facility for voltage control. For unison switch you could use a cmos switch such as DG403 or a cmos multiplexer I think this would be a lot of work!

I have no experience of the Aelita, but it could be a similar story there.

BTW, With the polivoks it is worth changing the psu, I changed mine for an LM317 / LM337 based design and this really improved tuning stability, the original power supply is really not stable enough on these models. It works on a rather unusual +/-12.5 volts, so 7812 and 7912 based psu's don't work.

Allan

[Tanstaafl]

geez, wish i had cyrillic alphabet on my pc... a POLYVOX  !!! wow. 

a buddy of mine had one of these he got ...  i guess 5 years before the fall of the CCCP.  he had no idea what he had.... gave it to somebody that turned it into a PLANTER!!!! of all things.

I don't think you should hack into it.  Leave it as is... build new stuff if you can afford it. 

good luck

gb

[carlos]

Hi guys,

thx for the info!!,

I was afraid i would get this answer... About the cv gate, I used that scheme from the creator (vladimir...) to install the midijack, it was an fairly easy task using the scheme so I can control the polivoks with asequencer. I also think the filter would be the easiest thing to handle since it uses (at the back of the polivoks) CV to control it. Concerning the ADSR (or the rest of the knobs on the synth...), I hoped it would have about the same logic as the filter (send a certain amount of voltage) so I guess not....damn :).

It is just that I know of a guy (http://www.sms-audio.be/analogue/exp07sm.htm) that did it with an ms20 and others too and I thought it would be a bit more simple than what you described.

About the PSU...you are right about that one...tuning is a disaster...i will change that it the future for sure if it is a lot of difference (thanks for the pointer!)

Well I still dont know what i am going to do ,maybe I will give those people at smsaudio a try or ask how they do it :)

Anyways many thanks!

[Davo]

I see those synths on Ebay all the time.  What are they like?

[carlos]

Hi,

IMHO the polivoks could be commpared with ms 20, raw sound and good for fx.

Aelita is something is more difficult to describe is also raw and sometimes subtle. the unison feature is great, On ruskeys.net you can hear some samples.

cheers

[lovesickdog]

If you know more about the PolyVox maybe you would mind giving the people over at Synthmuseum.com a shout. They have this little article, but also ask for more infomation on the manufacturer here

[Analog]

Hello friends, 

I am new in this forum and I am right of I found the ideal place to obtain help, 

I notice that aquí has people very understood in the subject. 

I am building an alaog monophonic synth with 37 keys, 

MIDI Keyboard with Velocity sensing 

with a total of: 

30 potentiometers 

13 SPDT on/off/on toggle swithces 

7 rotary switches 1pole 6 positions 

2 rotary switches 1pole 4 positions 

(See circuit in included PDF) 

I can implement my synth with a sytema MIDI and with presets memory using a MIDIbox. 

I need to know which MIDIbox is more appropriate to my project, 

MIDIbox CV or MIDIbox64. 

Thanks 

See my diagram in block below

MIDI Analog Synth.pdf

[stryd_one]

Hi Analog, welcome aboard  :D

I'm working on something similar with FX also.

There are two ways to go with this... One way is to make a voltage controlled synth (IE, it will have CV inputs) and use the AOUT modules to drive that with a MIDIBox CV, the other way is to build the synth as if it were going to be controlled with pots, and use digital pots, controlled by MIOS. I find that the 2nd option is my preference, as it is far cheaper and more flexible, because you can still have analog inputs with this model, where the CV ins would go to an AIN and then onto the core, and out to the digipots - but those inputs are then freely assignable to different digipots (mod matrix style). But be warned that the second option is not proven, it's a works in progress, where the CV control has been done before and is known to work. The digipot system best suited to synths designed from the ground up to be MIDI controlled like yours.

Have a look on the wiki and the recent threads on the forum about MBFX for some ideas...

Cheers!

[el-bee]

What about replacing the pots with digital potentiometers (ie. DS1803, http://www.maxim-ic.com/quick_view2.cfm/qv_pk/2779) where applicable (suitable sizes available etc)? Anyone tried this? Using these would probably need some code on the midibox side and the panel controls of the synth would be rendered useless :(

[illogik]

hi;

http://www.midibox.org/dokuwiki/doku.php?id=midiboxfx_-_midifiying_analog_gear

of course still "under construction"  ;D

The AOUT is also implemented for MB64; this app features a "patch mode"; >>if you make a sound you like using the mb64 controllers you can save your patch!

[stryd_one]

What about replacing the pots with digital potentiometers

Look up :)

[el-bee]

Yeh just came across some other posts about digital pots :)

[Analog]

Hi,

Can I use a MUX to increase AIN in MIDIbox CV? 

or is this only possible with MIDIbox64?

Cheers.

[moebius]

No AINs are supported by MIDIbox CV (those are for analog inputs).

If You mean MUXing AOUTs - SHX8 module is not currently supported by MB CV and it's also hard to find Sample & Hold chips used in it.

Moebius

[Analog]

It would like multiplexar the analog inputs A0..... A8 of the CORE to connect 32 pots in the AINS. 

See the diagram below in block

Thank

MIDI Analog Synth.pdf

MIDI Analog Synth.pdf

[illogik]

Yeah if you go the cv route;

you have 32 (pot) parameters for your synth?

you could build a mb64 with MBcv attatched, maybe worth to look for the S&H ic's (maybe mouser?) if you have 4 you'll have 32 cv outs controllable with mb64's 32 pots

cheers

[Analog]

Hi all,

Is it possible to build a MBox64 and to add the features of MBoxCV?

[stryd_one]

Have a look around and see if you can find the answer :)

[Analog]

Hi,   

Somebody already used these types of keys     

with the module AIN4 or DIN4?     

(see picture below)

Because I cannot use the original Buttons of the project in all my analog synth

Thanks

[illogik]

hey,

so basically you want everything on your synth midified..nice

but know that you will have to find out a lot of things yourself, or be very very patient and hope someone here finds the time for it 

for the switch thing, only some initial ideas have popped up here recently but i think nobody is really busy with this at the moment

you can make switches with cmos ic's which can be controlled by a pulse (coming from the midibox), there are switch matrix ic's that can be controlled directly by microcontrollers etc. i also saw some interseting posts from smash on switching audio with optos/relays but haven't read them properly yet

anyway if you find a suitable solution, you will then also have to do some programming for implementing everything with a midibox

as for midifying the pots, you have had some suggestions in this thread; digipots, vc resistors but still these ideas are still quite basic.

if i havent discouraged you  ;) read up on all the reated bits and start experimenting!!

cheers, marcel