Dual SSM2044 PCB Bulk Order

[Echopraxia]

Thanks seppo. I cheked it out just now. This seems like a fun project and hopefully should cost less than $100 to realize.

I was still thinking about the mbsid configuration and how many poteniometers (forgot how to spell) would be needed since I will not be using the actual sid control surface.I assume only two? I would also need a to connect an lcd yes? Sorry for ranting I am just methodical.

[Pseudo]

The filter board has been designed to be completely integrated and controlled from within the Midibox SID software. Therefore there is no need for potentiometers of any kind and all the information will be presented on the Midibox SID LCD.

[madox]

I am not sure about how the capabilities of this work:

For use with a fully featured MB-6582, with 4 stereo outputs, can I use 4 AOut modules (of whichever type), and 4 Dual SSM2044 modules, so as to have individually controllable SSM2044 filters for each half of each stereo output pair? Can the SID software handle this case?

[seppoman]

For use with a fully featured MB-6582, with 4 stereo outputs, can I use 4 AOut modules (of whichever type), and 4 Dual SSM2044 modules, so as to have individually controllable SSM2044 filters for each half of each stereo output pair? Can the SID software handle this case?

yes that's right. Just the bypass function can only be switched for the whole (stereo) filter pair, not single channels. And if you wanna use AOUT_LCs, you'll need two of them per PCB because their two CV channels can only can only control one filter channel (cutoff, res).

The MBSID software has everything you need integrated. Just activate the AOUT_INTERFACE_TYPE and (if using the bypass relay) set DEFAULT_J5_FUNCTION 3 (in the setup...asm, then recompile).

Usually you will want to 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.

S

[madox]

yes that's right...

Fantastic. Thanks for the detailed explanation.

I haven't yet built an MB-6582, though there is one in the pipe. I am thinking to either use a completely different enclosure (maybe custom built) with enough height to fit the additional boards, or possibly still house the main instrument in the PT-10, but include a bus port to connect to a separate filter box.

Has anyone got any good ideas about how to house all the boards?

Cheers

[sineSurfer]

just added myself to the list on the wiki ;)

[cimo]

or possibly still house the main instrument in the PT-10, but include a bus port to connect to a separate filter box.

this feature is already present in the mb6582

[madox]

this feature is already present in the mb6582

Ah, thanks for pointing that out. I had missed that.

Cheers

[seppoman]

Hi Filter-People :)

first thanks for the overwhelming interest in this PCB! I would never have thought that the numbers go through the roof so quickly.

As there are already quite a lot people on the list and new entries become fewer, I thought why let everybody (including me ;)) wait too long, so I've changed the deadline/last orders date from August, 10th to August, 3rd. I hope that's fine with everyone. Probably there'll be a few people missing out on the bulk order, but that will happen anyway regardless of the deadline date. I will probably order a few spares, and according to Wilba's experience a few people will probably change their minds after the deadline has passed (though I'd much prefer everyone to make up their minds before!), so even some late-comers will still get a chance to participate.

Another announcement - I thought of doing the PCBs with red parts print on matte black solder mask (background) to make them also visually special - hope you like that idea :)

And lastly, I'll be mostly(completely?) offline until this friday, so if you send me a PM with any questions, please be patient :)

S

[Wilba]

I can't believe it got this big...  :o

Looks like I'll be ordering 500+ SSM2044 chips.

However, I can't run this bulk order right now... I've got to finish off a bipolar PSU so I can connect the AOUT_NG and SSM filter PCB (prototype!) to my MB-SID and thus setup a "test rig", then perhaps get a small 100pcs quantity from the supplier just to check they're good, then buy up big... since there's plenty of demand it seems, I might not bother with a pay-up-front bulk order, I'll just sell them on demand like the 6582 SID chips, but only to those on the waiting list first.

I will only be ordering enough to supply everyone's pre-orders on the deadline of August 3rd

I cannot guarantee supply of SSM2044 chips, or give anything but rough estimations of price and expected delivery.

All I have at the moment is a quote from a supplier, not an established purchasing arrangement of known good chips.

I do know that there's heaps around, so I'm almost certain that I can get at least 500pcs from somewhere.

[Sasha]

Bit offtopic.

Is there enough room in PT10 case to accommodate 1 pair of NG and filter board?

[stryd_one]

With an MBSID too? Not a chance. Without, just as a filterbox, sure!

[Sasha]

Yes, I meant with MB6582. Thanks for an answer.

[sineSurfer]

got curious:

what would we need to make it a standalone filter box without CV or MIDI control?

and on the opposite case, fully featured standalone box with CV and midi control?

Thanks.

[arumblack]

You would have to have CV, but it may not be an external CV. You would need some pots for cutoff and resonance, maybe some resistors to scale the voltage.

With CV and MIDI control I suggest a core running mmidibox cv and an aout of your choice.

Correct me if I'm wrong...

[Peake]

Increased my order size- remembering that SIDs can do resonating HP sweeps- combining an LF HPF resonant sweep with an HF resonant sweep provides two resonances moving independently. There is a lot that can be done with such a configuration... THANKS!

[asafnetzer]

combining an LF HPF resonant sweep with an HF resonant sweep provides two resonances moving independently.

Care to explain more  ???

[sineSurfer]

You would have to have CV, but it may not be an external CV. You would need some pots for cutoff and resonance, maybe some resistors to scale the voltage.

so it means no Core or AOUT_NG, AOUT_LC or an AOUT would be needed, just the CV ins and/or cutoff/resonance pots and IN/OUT jacks... and the bipolar psu?

[arumblack]

of course I did not design this board so I can't say for sure. I did just notice on the Wiki page (link at the first post of this thread) that the "CV" is not a standard V/Octave, and an additional circuit is required for this to work properly.

The control summer found in all the documented designs on the web was removed. The frequency input of the 2044 expects an input of about -100..+100mV. The mentioned cirquit adapts that onto the standard V/Oct CV range. But this also means you would first need to adjust offset and gain of this cirquit to make the SSM input conform to that standard and then calibrate the output of your AOUT module to also comply with this standard. V/Oct is certainly important in a completely analog modular synth where several analog control sources are mixed and fed to that input, but in a situation where the AOUT is the only source, this conformity is not good for anything. So removing this stage of complexity reduces size and cost and takes away another level of necessary calibration.

The consequence of this is: If you want to use this module together with “non-AOUT†CV sources, you will need to add the control summer cirquit externally (I’ll publish a schematic for it soon). And, if you’re using the module together with the classic AOUT module, you will need to add the bipolar option (as documented on the AOUT page) at least for both frequency channels (normally AOUT1 and AOUT3).

So to use external CV you would need this extra circuit. to just have some pots you would need to give an input of -100mV to +100mV for the frequency CV. some additional circuitry will probably be needed here as well, but it should be doable.

Seppoman, can you comment on this?

Edit: Fixed quote.

[Peake]

Care to explain more  ???

The SID can do a resonant high-pass filter while the SSM adds an LPF resonant characteristic as well. Like cranking up the resonance on an MS20's two filters, but then being able to move each independently via modulation...should produce some nice sounds, moreso than simply using the SSM to do LPF of the SID oscillators alone... There is much to consider :)

[arumblack]

Sine surfer:

I went home and tried this (see attachment), and it gave me a bipolar voltage at the wiper of the pot.Now the extra resistors were to scale the voltage to fit the pot I had and it didn't go to quite +/- 100mV, igot around +/_350mv with a 100K pot and 2.2M resistors, using a +/- 15V supply. anyway, if you do some experimentation you should be able to get the voltage needed. I would add some trimpots too because the voltage wasn't "centered" Right due to the tolerance of the components. Oh, and a linear taper pot is what you would want. The load resistor would be your SSM filter CV input.

Now I'm not the most experienced guy here, so does anyone see something wrong with this method?

[sebiiksbcs]

Yo, I just added my stuff to the list. Do we need exactly n*500 PCB orders?

[madox]

I went home and tried this...

There are various ways one could achieve the result, and what you have done is not wrong. If you were to use trim pots, they could replace the fixed R2,R3.

Even with expensive, low tolerance fixed resistors, you may not get the precision you would like, as the +/- 12V are also subject to error with respect to the 0V ground.

As you are doing the circuit by hand, in low volume, there is no real problem with using trim pots to set the range. You can use a spot of adhesive to fix the pot positions once correctly set.

If you are concerned with precision, then you may also like to keep in mind that the potentiometer R1 may also not provide a full range swing on the wiper resistance. For example, your minimum resistance may be 0.01 x R1 and max may be 0.92 x R1. All the resistances will also be subject to some level of drift, though this is rarely a problem for this kind of application, and in practice, high precision is rarely needed.

If you would like to calculate component values, you can look up the 'resistor divider' relationship.

[arumblack]

Thanks Madox. I was just trying to give a proof of concept using whatever I had lying around, didn't bother with the math. When I have a board in hand then I can give better instructions, or maybe sinesurfer can figure it out himself with the info given.

Sorry if this has hijacked the thread....

AB

[seppoman]

Do we need exactly n*500 PCB orders?

No of course not - I can order any number of PCBs :)

S