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nebula

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Posts posted by nebula

  1. Awesome OLED!!

    in Parts Questions

    Posted · Edited by nebula

    Not yet - and I will admit I have no experience hacking this type of stuff.  But ... I would pay to ship one to somebody who has experience with this sort of thing, and a reasonable prospect of getting it working with MIDIbox.

    (I may also check with suppliers to see if they have, or can get, documentation)

  2. Awesome OLED!!

    in Parts Questions

    Posted · Edited by nebula

    On 12/26/2018 at 2:49 PM, ilmenator said:

    Sure, unless the component breaks and you need a replacement. But I don't want to discourage you from going that route!

    The display is available through lots of suppliers now (Google "macbook touch bar replacement"), and Apple is still using them on MacBook Pros for the foreseeable future.  They're cheap enough to buy spares, and in 10 years if you need one and they've become obsolete, you should able to find a used MacBook Pro very cheaply to scavenge one from.

    And I think the shape is too potentially useful to ignore!

  3. Awesome OLED!!

    in Parts Questions

    Posted

    The thing stopping me from making a MIDIbox Logic Control has always been the lack of suitable commercially available displays.  Has anybody ever considered trying the MacBook Pro touch bar?  It's a 2170x60 colour graphical OLED, and it can be bought for around 30 dollars. Maybe it would be perfect for a scribble strip for 8 faders. I have no idea if data is available for this though....

    https://www.aliexpress.com/item/Original-NEW-A1706-Touch-Bar-for-Macbook-PRO-Retina-13-Inch-A1706-2016-Touchbar-Replacement/32821436004.html

     

    HTB1agWcSVXXXXXBapXXq6xXFXXXT.jpg

  4. Starting MB6582 build

    in MIDIbox SID

    Posted

    Hello Hybris, I made one of the first of these, using 8x 6582. A couple of thoughts I'd like to throw in:

    - I didn't use any LED standoffs.  Never had any trouble.  Just put the LEDs loosely in the PCB, then screw on the front panel ... carefully turn the assembly over and all the LEDs just kind of fall into the front panel holes. Get 'em snug and solder.  The leads are fairly rigid and should hold them in place.

    - The front panel top-right "L / R" LEDs will collide with top right screw hole in the PT-10 case, so you need to grind a bit of it the plastic away.

    - The weakest part of the design (IMHO) is the way the two boards connect together.  I used very short flex cables.  Others have used individual wires, ribbon cables, or pin headers and sockets so that you can take the two boards apart.  But there's very little clearance between the boards, so you will just kind of have to live with two boards that don't come apart.  (I would love to lay out a new panel board someday, with all the shift register ICs and resistor networks on it, which would connect to the main board using only about 5 wires.)


    - The rear dual-gang feedback pots really can enhance the sound.  Do not buy cheap pots for this.  Slight movements can change the sound a fair bit, so you want to be sure that the paired-up pots are equal in value and taper.  Buy brand-name for this application.  I put cheap pots on mine and I regret it because I try to turn them all the way down but the left and right SIDs sound a little different from one another.  I may replace mine with 3-position toggle switches (i.e. no feedback, 50% feedback, full feedback).  I wish this could be made programmable somehow, using CMOS switches or digital pots or something.

    - I have a fan and guard in my case.  I couldn't get the motor noise out of my audio, so I disconnected it.  That's the extent of my thermal management.  It has never overheated.

    - As mentioned above, don't use the C64 power supply.  I still use one.  It works OK, but my MB6582 has chewed through 3 separate Commodore bricks. That's right, I'm on my fourth.  Back in the 1980s and 1990s, my C64 probably also outlived 2 or 3 power supplies, so they were never particularly reliable. I understand the European and Australian power supplies are a bit more robust than the North American ones. YMMV

    - For the front panel, I did the JB Weld / standoff method as Wilba documented very well.  That stuff is amazing.  I haven't had a single standoff let go of the front panel, and there are no visible screws.  I cleaned, then roughed up the surfaces of the back of the panel AND the standoffs using a wire brush or sandpaper prior to applying the fillets of JB Weld.  Not sure if that helps make a stronger bond, but it certainly can't hurt.  Also you need lots of clamps, and lots of patience.

    - Next time I have mine open (soon, because I've got a flaky encoder or two), I plan to wire the 8 audio outputs so they also appear on the DB25 jack.  Eventually I'll be able to use a single cable to connect my external box with 8 VCFs, 8 VCAs, AOUT and active summing and proper volume control (which the MB-6582 lacks).  In the meantime I'll be able to use a snake like this: https://www.proaudiola.com/product-p/8-m2932-db-ts-2-p.htm ... Think about that panel mount DB25 connector, and what it can do for you.  You can even use it for power if you like.

    This is an awesome synth.  I hope you have lots of fun with your build, as I did.

    • Like 1

  6. Simple PIC Project? Read a pot, output a value.

    in Design Concepts

    Posted

    The Juno-106 sure has had its share of problems.  The voice chips started to fail way back in the 1980s.  By the last 1990s / early 2000s, another component started to fail:

     

    It is the HPF slider.  On the front panel, all of the sliders are 50 K pots, except for the HPF slider, which is a 4-position slide switch.  They have all either oxidized or deteriorated internally, and so they're all failing!

     

    Technology Transplant has effectively recreated the slide pots, but no switch is available.

     

    Here is my idea:

    The pot form factor is VERY similar to the switch.  In fact, it would be pretty easy for an experienced technician to modify the board by snipping the traces from the 4-position switch - then, you could solder a slide pot into its place.  Of course, since we cut all the traces, it won't be connected to anything.  Now, we'll take some wire and solder the top and bottom pins of the pot to 0V and +5V, just like the rest of the pots.  Then we'll create a little circuit that reads the value of the pot, and outputs the value by setting any of 3 pins high.

    Position 1 would be from 0% to 24%  of 5V.  For this position, no pins would be high.

    Position 2 would be from 25% to 49% of 5V.  For this position, the circuit would set output pin 1 high.

    Position 3 would be from 50% to 74% of 5V.  For this position, the circuit would set output pin 2 high.

    Position 4 would be from 75% to 100% of 5V.  For this position, the circuit would set output pin 3 high.

     

    The output pins would be connected to a CMOS CD4016 bilateral switch, from which 3 switches would be connected to the Juno's panel board.  The only caveat (and it is a small one) would be that the slider wouldn't have that nice "click" into each of the 4 positions.

     

    I thought of 3 different ways this could be done:

    1. With discrete voltage divider circuitry for each output.
      Unfortunately this would take a lot of work to get the component values perfect, and you wouldn't want the possibility of gaps between the values (like at 49%, maybe you'd see no output, or maybe you'd see pin 1+2 high at the same time. Bad.
    2. LED bar graph driver like LM3916.
      Set the IC to "dot" mode.  With the correct reference voltage, you could probably set this IC to output in 4 discrete, evenly-spaced steps from 0-5V.  These outputs would be suitable to drive a CD4016 quad bilateral switch.  I don't know, I've never tried one.
    3. PIC microcontroller. 
      I just don't have the experience to program one of these from scratch.  Even though I don't need the power of MIOS, it would probably be easier for me to use a MIOS-programmed PIC, because I could then modify an existing MIDIbox app to achieve this function in a quick-and-dirty fashion.  The PIC should be able to draw power from the Juno's regulated 5V, and it wouldn't need MIDI i/o, so I could probably just build it on a small piece of perfboard instead of a Core PCB.

     

    What do you think?  If you wanted to make a simple circuit to replace a 4-position switch with a slide pot, which method would you use?  Or would you use something else (Arduino?  Other?)   If you like the MIDIbox PIC idea, what software would you receommend I start with?

    LM3916-datasheet.pdf

  9. SEQ4 Case Bulk Order 2012?

    in Bulk Orders

    Posted

    Just to throw in my situation:

    I have a SEQ v4 board and a CORE32. My SEQ board is mostly built, but I don’t have a panel or an enclosure.

    I’m in for almost any case bulk order. I don’t really care whether it’s 17†or 19â€. In either case I would like a sloped enclosure, not just a flat rack.

    Even though I have a STM 32 core, I recognize that the future is LPC, so I don’t mind if the case doesn’t fit my STM 32. I will gladly build an LPC Core and find another use for my STM.

    My original order on the failed heidenrich bulk was for a natural aluminum case, which I had planned to compliment a natural anodized aluminum panel. But since I’m in North America, it seems the Heidenrich case is not going to be a viable option for me, so I would consider almost any aesthetic just to finish this project! Still, I have decided that I’m not going to order a panel (easy to get) until I have a case in my hands (hard to get). Once I have the case it will be easy to decide the panel colour scheme.

    A case that supports the LPC should IMHO include an opening for its ethernet jack. Also, an elegant SD card solution should exist for this! I was sad that the LPC Core was introduced without a component footprint for an SD Card slot, leaving MIDIboxers to figure out (i.e. hack) a solution for an external card slot for every build. But … it is what it is, so the case (or a relevant rear-panel design) should include the means for a sourcable SD card socket.

    This is all just my opinion, and I appreciate the efforts of everybody who is designing stuff. I would have created an enclosure myself but I have found myself going through an ugly separation/divorce, so realistically I don’t expect to get into the seruous DIY designing again until maybe mid-2013.

  12. AOUT redesign

    in Design Concepts

    Posted

    It's nice to see some initiative taken with the original AOUT design. Years ago I bought a board manufactured to the original design (but with plated though holes - nice), and I managed to destroy it by getting overzealous with my mods. I also didn't like that there were some omissions on the original layout. So I would probably purchase one if you get some made, since I already have the SMT shunt and a couple 525's.

    Thanks for adding the 4 pin SIP header. I am concerned it is too close to the neighbouring IC though, as an IDC connector might collide with the DIP socket. I suggest you move it closer to the Molex connector, since a builder would probably only populate the board with one style of power connector.

    This isn't a really big deal to me, but I would like to take a moment to mention a preference of mine. Others may not care or agree: I'm not a big fan of the way lots of boards (including your proposed layout) has eight 2-pin headers when there are really only 8 unique pins. If it was my design I would either use a 9-pin (or 10 if that is unavailable), or more likely an 8x2 header with the 8 unique pins together, and the other side just ground. The reason is that it makes for a neater end project - the panel-mounted jacks could be wired to a single ribbon cable and connector, instead of having 8 dangling connectors. It also is a little less expensive to buy one big connector instead of 8 little ones.

  14. Encoder accuracy (bourns) MB-6582?

    in MIDIbox SID

    Posted · Edited by nebula

    You're right! I just looked at the MB-SID setup files and I couldn't find a debounce setting. But when I developed my MB-808 sequencer I remember looking at that ... from the Midibox 808 setup file we have this:

    ;

    ; debounce counter (see the function description of MIOS_SRIO_DebounceSet)

    ; Use 0 for high-quality buttons, use higher values for low-quality buttons

    #define DEFAULT_SRIO_DEBOUNCE_CTR 32

    ... Since this is a MIOS function, I was wondering if you could (or should) add it to the MB-6582 setup.asm , but then I did some searching and found this:

    As of MIOS 1.9c there is no encoder debounce parameter.

    Sorry 'bout that!

  16. Re'an knobs - new manufacturer?

    in Parts Questions

    Posted

    Everybody was saddened when the news surfaced that Re'an knobs are no longer available.

    Today I went to www.reanknobs.com and ... the web site is the same but there is a different manufacturer on the top left. Does anybody have any knowledge of this? Perhaps all those sexy soft-touch knobs are coming back?

  19. Encoder accuracy (bourns) MB-6582?

    in MIDIbox SID

    Posted

    I'm sure somebody more experienced with encoder problems will have something to say, but I'm thinking of two possible problems:

    1. There is a "debounce" parameter in the app config for the encoders. Did you experiment with that?

    2. For some reason there is electrical noise interfering with your ground, or with your DIN chain. Your solder joints around the 595s, the encoders, the ribbon flexes are all good? ICs firmly in their sockets? Are you using a fan? What are you using for a power supply? Are any of the buttons acting weird (like double-triggering) as well?

    I hope you sort it out, but perhaps more importantly, congratulations on your build!

  24. SSM2164 - where did you get your VCA IC?

    in Parts Questions

    Posted

    A couple years ago you could get SSM2164 from Digi-Key. They're no longer available now, but since recently some people here built Seppo's SSM2164 quad VCA PCB (and I'm about to build one too), I'm wondering if anybody can recommend a source.

    I found ebay item # 280893036724 from "sharpseller2000" looks like a pretty good deal ... but I thought I'd check here first. I'd also be willing to buy one privately within the community if anybody wants to let one go.

    Thanks

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