MB_Sid with AOUT and external filter

MIDIbox SID
1

I’ve ordered up all of my PCB’s and pics from Smash TV and I’ll be starting to build my MB Sid with full control surface and 4 sid chips very soon :). I’ve had a good read of lots of forum posts and changelog and (surpise!) still have a few questions…

I was hoping to use it with an external VCF and the Oakley Superladder http://www.oakleysound.co.uk/super.htm looks an ideal contender to me, for the following reasons:-

1 - It can be built either as a Moog ladder filter or as a TB303 diode filter

2 - It has 4 pole, 1 pole and bandpass outputs - nice complement to the Sid 2 pole filters

3 - It is very near to original moog filter in sound, but has added resonance gain circuit so that the level does not drop as resonance is increased, which was a problem with the original. It will also self resonate and track just like the moog.

4 - It has voltage control of resonance and envelope modulation as well as frequency

5 - It has 4 inputs, so 4 sids could easily be connected to it, and if opamps were added to Sid outputs then the input of the filter could be overloaded too, just like a Minimoog :slight_smile:

It can be bought just as a pcb from Oakley, I’ve built a couple of them for my modular synth they work really well.

I know that the AOUT is still in beta, just trying to get a feel for what is possible - I can’t find any mention of a 1v/oct pitch output  from the sid via the AOUT module, this is really needed for filter tracking - also, will filter resonance as well as cutoff frequency be available from the AOUT? Is everything from modulation matrix is available to the AOUT module?

Now for a completely different question -  with the 4 Sid  chips sounding in unison on the same patch, is it possible to fine tune each Sid machine to get a big fat unison sound? I’m just wondering if there is a global fine tune for each sid machine or does this have to be done by fine tuning each vco, which would mean seperate patches for each Sid otherwise they would all be the same fine tune offset. With them being DCO’s rather than VCO’s just wondering how this is acheived?

I know nothing about programming, but I’m building the MB_Sid in the hope of learning some coding so I can hopefully add to the community, up until then until then I’m a bit of a drain on it    :-[

Allan

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Allan, I think that the AOUT on the MboxSID is either derived from the software lfos’s and EG’s or incoming CC’s.  So you can connect the RES, the Cutoff, and whatever else you wanted to the AOUT ports.  Im in your shoes (not yet built) and have questions myself, but plan on getting one goin then adding the rest and then going for the AOUT.  I think there will be an “Official” release of the AOUT for SID (low cost R2R ladder DAC board) and until then Im holding tight here. 

Check down the list a few posts and youll find info about all of this, really.  do a bit of digging.  I read it all, forgot it the next day and then posted a question about it all the day after.  DUH should have reread it.  Sorry TK!

BTW, mind sharing ideas about how you are going to enclose your MboxSId?

have fun.

~Steve

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Allan, I think that the AOUT on the MboxSID is either derived from the software lfos’s and EG’s or incoming CC’s.  So you can connect the RES, the Cutoff, and whatever else you wanted to the AOUT ports.  Im in your shoes (not yet built) and have questions myself, but plan on getting one goin then adding the rest and then going for the AOUT.  I think there will be an “Official” release of the AOUT for SID (low cost R2R ladder DAC board) and until then Im holding tight here. 

Check down the list a few posts and youll find info about all of this, really.  do a bit of digging.  I read it all, forgot it the next day and then posted a question about it all the day after.  DUH should have reread it.  Sorry TK!

BTW, mind sharing ideas about how you are going to enclose your MboxSId?

have fun.

~Steve

Thanks for the info Steve, I think the low cost dac will be a very good solution for filter control, absolute precision is certainly not necessary. Found the other posts on AOUT - oops! Do hope its possible to get a 1v/oct signal for filter tracking.

I was thinking of mounting my MBsid in a 3U rack case (which I already have), and having a 3U front panel made by Schaeffer, with panel legends done on clear Lazertran. Still in the planning stage yet though…

Hey, All of my pcb’s and parts arrived today ;D Excellent job by SmashTV, I’m most impressed. No excuses left now, gotta get on with it!

Cheers,

Allan

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Hi Allan,

I know that the AOUT is still in beta, just trying to get a feel for what is possible - I can’t find any mention of a 1v/oct pitch output  from the sid via the AOUT module, this is really needed for filter tracking - also, will filter resonance as well as cutoff frequency be available from the AOUT? Is everything from modulation matrix is available to the AOUT module?

currently you can forward any parameter you want to any number of AOUT channels you want… because the routing is hardcoded :wink:

A user-configurable option will be available sooner or later, but since there are so much possibilities, this is currently a “low priority” feature for me.

Now for a completely different question -  with the 4 Sid  chips sounding in unison on the same patch, is it possible to fine tune each Sid machine to get a big fat unison sound? I’m just wondering if there is a global fine tune for each sid machine or does this have to be done by fine tuning each vco, which would mean seperate patches for each Sid otherwise they would all be the same fine tune offset. With them being DCO’s rather than VCO’s just wondering how this is acheived?

The CS allows you to modify parameters of all selected oscillators at the same time. It doesn’t matter which oscillator is selected.

So, let’s say you are using OSC1 and OSC2 for a nice saw sound, and OSC3 for percussions. Then just select OSC1 and OSC2 (both LED should lit), and tweak the Finetune parameter. Then select SID 2, do the same, and so on…

It’s even possible to select multiple oscillators and SIDs at once — since the oscillators are not synchronized (by default) you will get a very fat sound (by default ;-))

You see, the control surface allows such a quick usage, that you don’t really need such special features like global finetune. In my oppinion it would complicate the menu structure too much.

Best Regards, Thorsten.

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It’s even possible to select multiple oscillators and SIDs at once — since the oscillators are not synchronized (by default) you will get a very fat sound (by default ;-))

You see, the control surface allows such a quick usage, that you don’t really need such special features like global finetune. In my oppinion it would complicate the menu structure too much.

Many thanks for the help TK, I can now see how easy this is to do from the control surface and you’re absolutely right about a global fine tune being unnecessary.

Didn’t realise the AOUT routing was quite as flexible either - the midibox SID step C really has some very powerful features!

Makes me want to get mine finished ASAP :slight_smile:

Best regards,

Allan