Sign in to follow this  
Followers 0
Phattline

CV+TB303 VCO- working?

41 posts in this topic

Hi, my plan is to build a:

TB303 clone, almost controlled by the SID-CV

VCO-VCF-VCA=> Analog

ENVelope LFOs and controlles=> Digital (transformed in CV)

If anybody knows the right Voltages and Lin/log of the 303 CVs....tell me.

I have made a Excel sheet, and saved it as Html, here you are:

http://www.phatline.at/XOXBOX/SID-303evaluierung.htm

If something is not right, or somebody have the answeres. please let me know.

Parts List for Germany:

I have already the Rare Parts (but this is a secret, until I have my parts  :-* )

http://www.phatline.at/XOXBOX/XOXBOXparts.xls

(this list is now not uptodate, since the whole project is in planing, but later, if it is finished, this list will be the final part list  ;) )

The first shematics:

The orginal circuit (303)

http://www.phatline.at/XOXBOX/303.gif

The V-ca Section

MB-CV-VCA.png

Here is this is the inner circuit for the VCA chip:

BA6110Shem.png

Share this post


Link to post
Share on other sites

anmerkung am rande: es heißt "to delete"  ;)

Share this post


Link to post
Share on other sites

i'm interested in this but for now i don't know much, i will report my infos.

Share this post


Link to post
Share on other sites

I'm totally out of my area here, so I'll just watch and smile. Good luck phattline, this is a cool idea!

Share this post


Link to post
Share on other sites
I dont understand a part of the VCA and gate---ääähm. What does Gate? Is gate a own Signal, or is it in the same signal path as envelope?

Gate is a simple On/Off - signal which is normally sended along with the CV. It is a "own signal".

For example: If you press a key on a (analog) synthi it sends the CV on the CV-line and a ON on the GATE-line to the synthi. If you release the key Gate sends off. This signal is then used for signal forming stages, for example a ADSR to form the envelope. Or as a simple start/stop signal.

It is a simple control-signal.

Hope this helps.

greets

Doc

Share this post


Link to post
Share on other sites
In normal use the envelope is generated when the module receives a gate pulse or is triggered by a specific input.

Ok I think its like that:

If on the Gain of the VCA is no Voltage, the VCA outputs no sound.

The Gain of the VCA, is controlled via the Envelope

The Envelope:

You press a key, and the keyboard send a "Gate on" Signal.

With this Signal the envelope starts (triggers):

Attack comes and the Voltage get higher, until Decay is reached.

Decay hold this Voltage as long a new Gate Signal comes.

If this is a "Gate off Signal":

The Suistain comes, it gives a static signal, until Release comes (and acts like the decay)

Then the Release comes, and the Voltage goes down. (Release acts like Attack only invertet)

If this is a "Gate on Signal":

I am not sure.

But if this so works, I think midibox SID can handle this. The ENV output on the CV board, have already integratet this. (correct me if I am wrong please)

Because the Midibox ENV is software based (?) and it already triggers the envelope with the gates? So I dont need any Gate signal on my layout because I use the digital ENV for my TB303.

2nd need is the Resonance Pot, I want it to CV. Since it is Stereo Pot. And feedbacks Signals, I need a simply dual VCA, or a simply VCR (voltage controlled resistor) which can handle this.

The one part of the Stereo part, mixes extra Accent to the VCF. The Other part of the Stereo Pot Feedbacks the Filteroutput to the Filter input or whereever :-).

So maybe the Resonance Pot-problem, can make with a single VCA, which only feedbacks the signal, the extra accent can be emulatet, since the Single VCA is driven via CV over the Midibox, it must be possible to add, by turning the RES-Encoder on the SID - to add a bit Accent to the Velocity CV-Out...but Since I am a analoge human I dont know if this possible, and if it is possible I dont can programm that :-\.... So This must be a Dual VCA (op amp or what ever...)

Cool Idea is the

MB-sidechain

You take the basedrum amplify it, connect it with a yellow LED, and put on the LED a LDR, the output of the LDR must be amplifyed too, ant then you go in a MB-AIN.

Here you can duck the MB-SID-Volume-Envelope, and you have a sidechain VCA, between: good sidechaincompressors outthere working with VCAs!

The point where the Sidechain in the SID-application must be, is, always on last position!,

Meens:

If you route a LFO a Envelope and the Sidechain to the Cutoff of the SID.

the Sidechain, can reduce the Controll-voltage, to the minimum, elswere, the LFO would amplify it agin  8)

But this of course is in first thing a programming thing  :P , the analog circuit, would be so easy.

And If you want the sidehain to be mor linear:

You must take instead of LED and LDR, Transistors!

Amplyfiy it Rectify it,- put it in the AIN (but more of this later)

The Other Idea, would be take, the sidchainsignal, and trigger the envelope with it, but the upper idea is much smoother

anybody can explain what a audio buffer is? is this done with simply building a OPamp - amp???  ???

Share this post


Link to post
Share on other sites

[me=stryd_one]clueless[/me]

Share this post


Link to post
Share on other sites

more question about the midibox SID-CV:

Is there any preset setting in the SID what says: CV1=Cutoff CV2=Resonance usw....???

Or it doesent matter, because, it easy to edit in the SID-Application????

When I use digital switches (dout modul remotes a switch, and the switch ---switch audio)(8 are supportet?) which switch could that be?

What Voltage Controlled Resistor can I take? (aviable in the EU- germany-austria...) and has anybody have a shematic for that--thankz

Share this post


Link to post
Share on other sites

Is there any preset setting in the SID what says: CV1=Cutoff CV2=Resonance usw....???

That should probably be routed via an AOUT module, you can see more discussion about that in the current thread about the ssm filter.... but uhm... I thought you were doing a VCO?

When I use digital switches (din modul remotes a switch, and the switch ---switch audio)(8 are supportet?) which switch could that be? I simply wire it on a din module? (maybe with a resistor between-yep..)

Momentary ons. You should really search the forum and wiki if you're not sure on such things ;)

What Voltage Controlled Resistor can I take? (aviable in the EU- germany-austria...) and anybody have a shematic for that--thankz

Search for 'mbfx' (don't forget to follow and where necessary add tags) to find info on this.

Share this post


Link to post
Share on other sites

That should probably be routed via an AOUT module, you can see more discussion about that in the current thread about the ssm filter.... but uhm... I thought you were doing a VCO?

no no no you dont understand me  ;)....I am still talking about CV and the TB303....so: Is there any preset setting in the SID what says: CV1 from the AOUT-MODULE

=Cuttofff---->

The SID application has already a preset setting for the encoders and the DIN modules for it  ;) ----> is there a preset setting for the AOUT in the MB-SID Firmware????  ;)

I know that I need the aout module  ::)

The Tread titel is named CVTB303 VCOworking? because- my first question was, can handle the MB the current that a 303 needs? I think yes. But I have to CV the whole 303, except from the Envelope---that will do independet for VCA and VCF the SID envelopes and LFOs  ;D

When I use digital switches (din modul remotes a switch, and the switch ---switch audio)(8 are supportet?) which switch could that be? I simply wire it on a din module? (maybe with a resistor between-yep..)

Momentary ons. You should really search the forum and wiki if you're not sure on such things ;)

No my fealure... I meant of course the DOUT modle. So I was talkin about the little small DIP-form- devices---the digital switches, that are switching, if they get a current---for exemple bya DOUT module. Of course I know what momentary switches I take.

Search for 'mbfx' (don't forget to follow and where necessary add tags) to find info on this.

Thankz I will search

Share this post


Link to post
Share on other sites
so: Is there any preset setting in the SID what says: CV1 from the AOUT-MODULE

=Cuttofff---->

Sorry my bad!

Yes, that's the one in that thread about the ssm I mentioned...This one :)

-the digital switches

Ahh my mistake again! Yeh, what kind do you need? What signals are going through them? There are lots of different flavours. I guess the 4066 is the standard, but there are many types that are intended especially for audio.

Of course I know what momentary switches I take.

You would not have been the first person to ask ;)

HTH!

Share this post


Link to post
Share on other sites
MBSID software:bJust activate the AOUT_INTERFACE_TYPE and (if using the bypass relay) set DEFAULT_J5_FUNCTION 3 (in the setup...asm, then recompile).

use the F2A function (found in the EXT menu of the Ensemble).

This routes everything you do with the SID filter(s) to AOUT channels 1-4.

Connect the Bypass input of the SSM module to one of the J5 gate outs.

This way you can set the filter active/bypass by checking/unchecking the respective option of the patch's EXT page (S#1..S#8 depending where the bypass is connected).

The bypass state will also be stored within your patch, so when playing stored patches you can have patches using the ssm or the SID filter or both, without changing any wiring or patchbay or other kind of action.

Cutoff/resonance are controlled just like the normal filter, i.e. if you turn the cutoff/res encoders or, for example, if you set your modulation matrix to modulate cutoff from an LFO or envelope, this will affect both internal and external filter the same way. So the usage in all standard applications is transparent.

Why 4CVs for a Filter  ???

The switch is to select sqare- or saw-wave.

I want to do this via the Midibox, to store the setting for presets...but ok thats future sound...for this I must program a little I think... and I cant  ::)...but there is already a function in the sid for this... the waveform selecter switch...

The Voltages are:

VCO-voltage.png

12V and 8V  ;) I switch audio, but of course powerfull audio  ;D

Hm the use who made the filter PCB- took a relais for his bypass-switch. With a Relais its easier to do, since you only need a dout-out-and nothing else. The sound will be untouched!http://parts.digikey.de/1/1/122391-relay-smt-dpdt-1a-5v-gullwing-g6k-2f-y-dc5.html

Omron__G6K-2F-Y-DC5__0.thumb.jpg

With that shematic: http://www.uni-bonn.de/~uzs159/switching.png

You have a CMOS or whatever switch, With that shematic, the distortion or the colouring of the sound will be hard limmetet.

They say: if you switch the whole current thru the cmos, the sound will coloured! So the need a big circuit for one switch:  :o

switching.png

of course with the Railais I have the orginal sound! But its mechanical  ::) , one error change more  >:( , but ok, its much easier, and cleaner.

Share this post


Link to post
Share on other sites

4 filter CV = 2* cutoff, 2* resonance (it's for stereo pairs I guess!)

You might like to look at the TI and AD sites for audio switches.

Share this post


Link to post
Share on other sites

Hi, I did not read all of your post so maybe i'm talking bullshit, but

if i'm correct you do not use the an6562 opamp as powersupply. There is nothing wrong with that, but many people think that the crappy powersupply in the tb303 is the reason the thing sounds so squelchy. Your tb clone might more clean than you like. Second, for switching the audio you can use a cd4066 of 4016, they do that in many synths, i think also in the tb. I attached a piece from the prohet 5 schematic where they switch each wave independent from each other with a cd4016.

p5.JPG

Share this post


Link to post
Share on other sites

Hi, I did not read all of your post so maybe i'm talking bullshit, but

if i'm correct you do not use the an6562 opamp as powersupply. There is nothing wrong with that, but many people think that the crappy powersupply in the tb303 is the reason the thing sounds so squelchy. Your tb clone might more clean than you like. Second, for switching the audio you can use a cd4066 of 4016, they do that in many synths, i think also in the tb. I attached a piece from the prohet 5 schematic where they switch each wave independent from each other with a cd4016.

cool thankz. that is good that I only need one part(and its not mechanical--yes!)

A qestion to this, I should use the 4016? or I can use both(the 4066)?

And a 4016 can only switch one? or more?---The reason why I ask this:

The SAW and SQARE Wave OSCillators cannot be mixed (without audiobuffering....and with two VCOs that would be 2x2=4 audiobuffers-to much PCB-place would be needet), so I need a toogle switch.... If this not exist I must take 2 but I am happier with one  ;)

To the supply, I will take the orginal.

But the Rectifier Diodes will be stronger, because, I also drive there a 78S12 79S12 78S09 78S05 .....  ;D

A fiew persons meant that when the 12V stage and the 5.333V stage are in the same OP-amp- the Temperatur drive whould be eliminatet, so if it drives, it drives alwasys together... or so...

Share this post


Link to post
Share on other sites

You can use either.

There are 4 switches in one package.

But there is already a cd4066 in the x0xbox, maybe there are switches left in it.

Look a the datasheet: http://www.fairchildsemi.com/ds/CD%2FCD4066BC.pdf

To toggle; you'd have to toggle the 4 switches in the 4066, no problem if you have enough dout lines from the midibox.

But if you have no space for a quad opamp and some resistors to make 4 simple summing amps, then I doubt you have space for a 4066.

Share this post


Link to post
Share on other sites

I now already use 2 buffer amps, to mix the VCO1 and the VCO2 (since I build two TB303 VCOs) I thougt I will mix them with CV like on this shematic:

Bufferd-shematic.png

Signal A is the switched VCO1 with SAW or WAVE...Signal B  is the same only for VCO2

It is a cool Idea to switch the seperatly, but then I must have 2 more puffer amps....

But a qestion If I use 4 switches and 4 Buffer amps, where I can mix them.... it is the same shematic wright? only with 4 buffer amps...in thwo groups, yes of course Signal A=switchabel SAW and SQAURE...The REason I cant fade them, is, that I have only 8CVs and they are still to "unzureichend" "insuffizient"  :-[

Share this post


Link to post
Share on other sites

the 4066 is the standard

4066 is an improved 4016... If you're going to go this route (As I said, I'd check out the analog devices stuff too, as they're specifically designed for carrying audio, but anyway...) then you may prefer the 74HC4066 over the CD4066 as it is much cleaner.

Phattline: Any chance you could shrink the pics a bit? :)

Share this post


Link to post
Share on other sites

Phattline: Any chance you could shrink the pics a bit? :)

done  ;) the whole topic is cleared up (from my side)  8)

Here the pinout of the 4066

4066.png

Share this post


Link to post
Share on other sites

I'm no electronics guru, but i guess you could mix the signals in a simpler way.

See: http://www.wisc-online.com/objects/index_tj.asp?objID=SSE3403

Notice that the signal is inverted, but that should not matter.

You'd have to reduce the output of the summing stage, or you'll get overload in the next tb303 stage.

Also, you do not need a cv to switch the cd4066, you can use a din out from the midibox. I made a simple drawing to show it.

For the din out's, I'm sure stryd_one knows more than me about it.

Another thing, the opamp you use is pretty fast, they oscillate pretty easy. I'd stay in tb style and use a 4558, tl07* or a ne553* if you are more into hifi.

sum.JPG

Share this post


Link to post
Share on other sites

For the din out's, I'm sure stryd_one knows more than me about it.

You're doing fine I'm happy to watch ;)

I think you mean the "DOUT"s though ehheheh

Share this post


Link to post
Share on other sites

I'm no electronics guru, but i guess you could mix the signals in a simpler way.

See: http://www.wisc-online.com/objects/index_tj.asp?objID=SSE3403

Notice that the signal is inverted, but that should not matter.

You'd have to reduce the output of the summing stage, or you'll get overload in the next tb303 stage.

Also, you do not need a cv to switch the cd4066, you can use a din out from the midibox. I made a simple drawing to show it.

For the din out's, I'm sure stryd_one knows more than me about it.

Another thing, the opamp you use is pretty fast, they oscillate pretty easy. I'd stay in tb style and use a 4558, tl07* or a ne553* if you are more into hifi.

cool-thankz for the picture!

In the XOXBOX Forum, they said me, If I want to use one OPamp for two operations, I should take the tlv2372....I bevore hat taken a AN6562, but they said "it dont go @ the top of his rails" (i understand the technical english not very much  ;) )  or something like that, I dont know waht that meens, but the AN6562 is not the right OP-amp for this operation ( to take the ouput of the op amp and get it into the negativ input---and that with the 2 inline op amps in the chip....)

But for summing the differnt sources I should take a tl071? ---but a question, why I do nee the here a summing amp? (I cant mix the 4 sources---because the SAW and SQARE of one and the same VCO cant be Mix togehter, that because, the OSC will be coloured ---because of its shematic....why exactly---I dont know- but I have to buffer them---thats what I know!)

Share this post


Link to post
Share on other sites

why I do nee the here a summing amp? (I cant mix the 4 sources---because the SAW and SQARE of one and the same VCO cant be Mix togehter, that because, the OSC will be coloured ---because of its shematic....why exactly---I dont know- but I have to buffer them---thats what I know!)

You could always buffer them before the mix ;D

Share this post


Link to post
Share on other sites

I am proudly presents my volumeconstant Waveformswitcher&Mixer :P ... if there is a better way to do that---tell me  ;)

Waveformmixerswitcher.png

How it should work:

If we look at the IC9A & IC9B:

IC9 Switch the Waveforms

IC12 Switch the Resistors (this SWITCH must be Turn off if it gets Voltage!----which SWTICH can this????)

If a Waveform is switched on (input IC9 gets voltage)

=>The Resistance of Parallel circuit get high. (The 2nd Resistor of the parallelcircuit is switched off---its now a high OHM serial Resistor!)

If a Waveform is switched off (input IC9 gets no voltage)

=> The Resistance of the Parallel circuit get low (its now a parallel circuit, the Resistance is setuped with the Trim-pot)

Share this post


Link to post
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!


Register a new account

Sign in

Already have an account? Sign in here.


Sign In Now
Sign in to follow this  
Followers 0