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NorthernLightX

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Posts posted by NorthernLightX

  1. Hi Scifo,

    AFAIK SmashTV is the only one offering the MB6582 PCBs. You can buy a part kit from him as well or just the PCBs, and then order the parts in europe, for example from Reichelt (they should have everything you need). If you are afraid of import taxes Smash offers a special low value order procedure for PCBs only, but I don't know if the MB6582 PCBs are part of this deal, look at his shop for more details.

    Good luck building!

    P.S.

    Keep an eye on the fleamarket over here for additional stuff you might need, such as LCD, PacTec PT-10 case, and a set of panels for the PT-10 case.

  2. But I also I recently discussed this with a local Eurorack owner and he referenced this module:

    http://www.analoguehaven.com/intellijeldesigns/uscale/

    which specifically deals with a 10V pitch range CV.

    Funny enough there seems to have been a revision of that module and it now has a switch for the CV input that lets you select linear or bipolar CV.

    I'm working on a few other projects right now and expect some front panels for those to arrive soon. When I have the MB6582 finished (or earlier if I get a pressing request, for example from TK who needs the module for testing with the MBCV2.0 project) I'll have a prototype made.

  3. So in your opinion, given a single mb6582 setup, (I've seen your videos, very nice studio space!) is there nothing to be gained by using these AINs?

    I'm not sure to which videos you're referring, because as far as I know now video's of me or my home exist on the net. :angel:

    For my application I won't use CV in on the MBSID. I'll use analog CV modulation for example on the SSM2044 filters; MBSID will send audio out to the filters and CV can be modulated from a different source than the MBSID. I plan to implement a companion board for the SSM2044 filters that will add a second CV input for the frequency, and bring both the frequency and resonance CV input to respond to +/-5V (now frequency responds to +/- 2,8V and resonanve to 0V-10V).

    I can't say that there's nothing to be gained; I just haven't imagined a need. If you have a crazy envelope or LFO you want to use, or have other CV equipment that does tricks that the MBSID cannot do, it could be interesting.

    I suffer from a total lack of 'hands-on-it-ness'.

    See point above. If for you it's easier to grab a patchcable than to press a few buttons and turn a few knobs then go for it. It's your box. Buttons and knobs do introduce recall though, and that's hard to achieve with patchcables.

    On a related point concerning your efforts with the AOUT, do you see a need for singal conditioning to allow for bipolar inputs? I think that as a min, a pull down R and a 5.4V Zener to protect the AD inputs. Maybe an ext. op amp bridge if needed. I'll look closed at the mb64 as an example.

    This might be one other downside of the Core8 CV in option; it only responds to 0V-5V, which is only half of proper CV resolution. I have little experience with CV in, this is territory you need to navigate yourself I'm afraid. If you have modules that output very hot and/or negative signal it's wise to implement some form of protection on the CV inputs; how you do that you'll need to figure out yourself, I can only give some theoretical pointers:

    Imagine you have 2 CV inputs for one CV function; one for bipolar and one for linear. You need to use switching jacks for this idea. The bipolar jack switch is connected to GND, so when no jack is inserted this input is at 0V. The linear jack switch is connected to +5V so the input is at 5V when no jack is inserted. Both inputs are summed with an opamp. The sum is then halved with a voltage devider and fed to the CV input.

    When a -5V signal is received on the bipolar input and nothing is in the linear input the +5V from the switch will cause the sum of the signals to be 0V. When this is halved it will stay 0V.

    When a +5V signal is received on the biplor input and nothing is in the linear input the sum will be 10V, 5V after halving. a +/-5V signal will thus be converted to a 0V-5V signal which is the perfect range for the AIN.

    When a 0V-10V signal is received on the linear input it will disconnect the +5V switch and since nothing is on the switch of the bipolar jack the only thing that will happen is the voltage get's devided, so again the signal will be converted to a 0V-5V signal which is the perfect range for the AIN.

    You can't use both inputs at the same time though, since the bipolar signal needs to be summed with +5V to end up between 0V and 5V. If your input is more than +/-5V this will be dangerous, as -6V will give a sum of -1V which could damage the AIN (not sure if this is the case but IC's not designed for negative voltages usually have a very low tolerance for it). Also, with an input of +/-10V you will end up with a voltage of 7,5V which could be too hot.

    My best advise would be to make sure the output of all your modules falls in the same, safe range (maybe you need to add companion boards on the ouputs of certain modules to get the voltage to specification), and then use companion boards on the inputs of modules that need adapted CV as well. This way you can safely hook anything to anything withous letting out the magic smoke.

  4. Is it needed, no. Is it complicated to add, no. So for me, its a fun feature of the great software that I might use every once and awhile.

    Sure, it's fun! That alone is enough reason to build it.

    I can see using a pedal; adding drum pads, maybe (but i'm not much of a drummer); being able to add a unique analog controller would be a option. Maybe an interface for my Theremin. Don't know how many LFOs or ASDRs I need/want but that's kind of the point of all this; messing around and finding something new ;) The demo TK did with a 3 LFO summer into a CV, was cool (I wish I could find the link to that page again), can it be done with the standard CS, I guess.

    All that can be done using MIDI, no CV needed. Adding external MIDI control is a very logical expansion (for example adding another midibox based module to the equation).

    How hard is it to add a tap tempo to the sid's LFO? Just seems that the AINs add to the range of options. True analog control is very hard to replicate in the digital domain. This interface is limited to 10 bits so it will never capture the the full range from 0-5v but a range of 1024 can be expressive.

    You do realise that the CV in will actually be translated into the digital domain, and thus be no more precise than the internal control messages?

    I'm not planning for a PAC TEN case so I can afford more panel space. Guys, for me DIY is the point. It's fun to fire up the DAW and load a VST to have any instrument I want, just not as satisfying. Isn't that why we're all here burning PICs and breathing solder fumes?

    Of course. I'm just trying to give you feedback so you don't end up spending a lot of time reasearching and building something that will not behave according to your wishes. :flowers:

  5. It will be not exactly hole but "D hole", isn't it?.

    Sure it will be a hole, and bigger than the shaft too, but small enough so the knob skirt will cover it (see the MB6582 frontpanel; shafts poke through but holes are invisible with knobs on shafts).

    The acrylic will be glued to the alu from the bottom, and will have a recess for it to be flush with the frontpanel, like an LCD window.

    We can imagine a lot of nice things to do but the problem with metal panel is the price.

    Yes you are right; the cheapest option is probably to just have a second job and buy all your toys with the extra money. Building them yourself is a big part of the fun though, and fun is allowed to cost money IMHO :laugh:

  6. Small bump: I'm getting into modular stuff, partly because this allows me to finish stuff and expand on it later (opposed to the earlier mantra of "let's spend hours upon hours searchin for extra stuff I can add and never get this thing finished").

    I've come to the conclusion that I want to make all my Midibox (SID) CV output's bipolar, but this would make them incompatible with this VCA, which expects a CV range of 0-10V.

    I have recently aquired one of these VCA boards and want to make a companion board for this to make it compatible with a CV voltage of +/-5V. A simple solution would be to introduce a simple CV level shifter, that would add 5V to the +/-5V, making it 0-10V. I want to add a CV attenuator as well. The necessary components would involve 4 dual opamps (probably TL072) with 2 100n decoupling capacitors each, 2 small electrolytics for power integrity, a couple of resistors, 4 trimmers, and 4 potentiometers.

    Is there any public interest for such a companion board? If so, I'll make a design topic for it and offer a small bulk order for the final PCB in the end. If not I'll just dump the components on some veroboard and be done with it :tongue:

  7. Took some time off work to go to the post office this morning; all PSU's have been sent out :frantics:

    One comment on the female Molex connectors: these are not the exact type I had in mind, and need a small modification. These have a ridge that on certain male headers is used to secure the connector to the header. In the case of the Mean Well PSU the ridge interferes with the plastic of the header, and the ridge needs to be cut off. Just use a sharp cutter or a file and you'll be fine; the pins have enough friction to stay in place by themselves.

  8. When googling the subject of unipolar or bipolar control voltages there seem to be equally many modules (not VCO's per sé) that use unipolar 0-10V as there are modules that use bipolar +/-5V. Both standards give a range of 10V, so with my limited knowledge I guess there isn't much difference in operation other than a +5V offset.

    The level shifting I was talking about earlier I would either build as a separate utility module powered by +/-12V, or as an input expansion on the module that expects to see 0/10V on the CV input. Such a module is most probably powered by +/-12V or even +/-15V so power for a small level shifting circuit can be taken from there if you don't want to power the AOUT with +/-12V.

  9. I'm no expert with modular synths, so apologies in advance if this is nonsense!

    But, I thought the 1v/oct standard has a range of 0-10v. If the opamps are running off of +/-5v then doesn't that mean you can't get 0-10v from the AOUT?

    I already have 1 original AOUT and personally I was planning on doing 4 channels as nonbalanced i.e. 0-10v, for controlling the pitch of VC oscillators, and 4 channels balanced i.e. +/-5v for doing LFO / modulation type tasks.

    If the new board can't get above +5v, doesn't it mean the new AOUT board would be limited in this sense?

    It has already been discussed in this thread, but I'll give some quick answers based on my current knowledge;

    - The original AOUT standard gives a 0-10V response.

    - The original AOUT can be expanded (for example with a daughterboard) to give a +/-5V response.

    - The redesigned AOUT can give both 0/10V response and +/-5V response without the need of a daughterboard, the response is configured by replacing some resistors with bridges. Attention needs to be paid to certain resistor values (R_x and R_y) with each configuration. The configuration options will be documented as soon as a final design is accepted.

    - Both on the original AOUT and the redesigned AOUT the CV response can be configured per channel.

    - 1v/oct response depends on the used (target) module, and if it expects 0-10V or +/-5V. In both voltage flavors you have a 10V range.

    - It is still possible to use a level shifter to convert +/-5V to 0/10V and vice versa. A level shifter is a simple opamp design. I plan to build a set of shifters as a separate module, and will also build some as a preconfigured expansion on several modules that I have that currently expect 0/10V on the CV input.

  10. Regarding the resistors: I'm not in a hurry, so no problem :)

    If you on the other hand remember what part of the formula (to calculate the values) needs to be adjusted maybe I can work it out myself.

    Regarding the PSU: don't the opamps need the +/-12V for proper operation? Also, good chance that additional modules will be in the same housing as the AOUT that use +/-12V as this is one of the standard supply methods of synth modules. Well performing switching PSU's are nowadays available for as little as €25 (from Mouser and Reichelt for example) so I don't see the need to divert from the current form of power supply.

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