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m00dawg

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Posts posted by m00dawg

  1. First thanks to dwestbury here on the forums for his work on the JST connectors and power discussions (here and here). It got my back to seeing if I can ressurect my MB6582 in the PT10 case. I've been working on a rackmount version for ... erhm...quite a long time we'll say, but if I can get my normal MB6582 going, that'll let me jam out much sooner and will help me decide if a 3U rackmount version is worth it. I've never been able to get the control surface working properly on mine due to the connectors. So the JSTs seem like an amazing solution!

    In any case, previously I made a real sketchy external PSU to provide +9 and +5V and keep all the heat out of the 6582. I thought about moving to Option E but instead, took Option E and updated my external PSU design. It uses a transformer (could be an external wall wart if you wanted) and then turns that into +5V and +9V that you would feed to the MB6582 directly (along with ground of course) via a cable. It's kinda like the C64 PSU in that regard, only there's no regulation going on inside the MB6582 itself and, thus, less heat. Since I had the room, I added protection diodes, an inductor/choke per the spec sheet and some extra smoothing caps. The one downside with an external PSU is wire length to the MB6582 itself. That could cause a bit of voltage drop but I never had any issues with my previous PSU with voltage stability so I think this should work ok.

    In my case I can use the same PSU for a rackmount version as well (where wire length also won't be as big of an issue).

    Here's the latest design. It uses 4 planes (GND, Unregulated DC, Regulated 9V and Regulated 5V). I'm not sure if that's the best solution (I have a version with just thick traces too) but seems sensible. The boards from Osh Park would cost about $21 (or $7 each) and the BOM from Mouser is about $30.52 if I didn't miss anything.

    Curious if anyone had any thoughts or suggestions?

    Screenshot from 2020-10-16 18-51-34.png

    Screenshot from 2020-10-16 18-50-40.png

    • Like 1
  2. I kinda went down a bit of a rabbit hole today while looking at these. I think I still favor an external option since that's how my MB6582 is currently setup. But I also like the idea of embracing the switchers so busted out an external board that would replacing my ugly and probably dangerous breadboard I was using previously. This would use a 12VAC transformer (might be able to get away with 9VAC perhaps - I can't remember what I used to use). And then, much like Option E, has the Recom switcher with a linear 7809.

    Since it's external to the MB6852 mainboard I've got some room to add protection diodes, a choke, and some caps per the spec sheets. I thought about adding fuses too but will settle for one on the AC side I think.

    I originally had a crazy 5, 9, +/- 12 design that was all linear. I still have the schematic for it but for now am not going to worry about adding any analog filters or anything. That might be better done as an MBCV project anyway where I could use the filter for other things, not just the SID.

     

    Screenshot from 2020-10-16 15-40-28.png

    Screenshot from 2020-10-16 15-35-34.png

  3. I think the only thing to consider is the switching frequency, although 550KHz seems pretty high. I would expect worse filtering performance if ordering from AliExpress but I mean who knows ;) That's part of the fun of using AE. 

     

    In my case, I'm trying to decide if I should keep with my external PSU option as I had before, going with the C64 PSU option or trying Option E as you noted above. I built an external linear PSU previously using a 7805 and 7809 and some power resistors to dissipate the heat before going into the 7805. It was a heater as you can imagine, and NOT UL listed :) But did the trick. I think I can improve that though. I like the idea of an external PSU because it keeps the heat out of the case gives me plenty of room for filtering (if using switchers) or a huge heat budget if I wanted to use linear regs.

    Switchers vs Linear was, at one point, pretty hotly debated on these forums but it sounds like in practice it's just not that big a deal anymore. The SID itself is noisy enough in ideal conditions so yeah I think the switcher at least on the 5V rail makes a lot of sense.

    • Like 1
  4. My goodness that looks fantastic and no having to hand solder or crimp any cables! Looks great!

    I was so excited I broke out my MB6852 which has been sitting on my closet all sad and alone for years. It will still take some work before it's ready to go beyond the connectors. I'm a bit worried the board may have some bad pads if I recall. However I think it's worth a shot.

    It looks like from the photos you use regular straight and right angle SIL connectors? I noticed the linked JSTs appear to include the straight connectors but I couldn't find right angled ones. Any suggestion on options there?

    • Like 1
  5. I haven't tried it but would love to see if this may work! The cabling issue for me was what prevented me from properly finishing my MB6582 to the point I just started to design a rackmount control surface for it. I'd still like to finish that (and these days with laser cutters maybe I can without breaking the bank). I love my sammichSID but working on patches has proven to be really difficult with the software and would be just soooo much better with a proper control surface.

    There was a modification that used right angle SIL headers that was interesting. Still very cramped but it worked, and allowed the panel to be separated from the base if needed.

    Good luck, please do share what you find!

  6. Another new track I've been working really hard on for the past few weeks. While it doesn't showcase the Midibox SID (sammichSID in my specific case), it definitely plays an important role! I used it for the sweet sqaurewave growl in the mid-section and for the in your face square arpeggiator fills. I should honestly bust out the sammichFM a bit more though I tend to use the Yamaha TX81z (which made an appearance as well).

    This song is part of a hopefully upcoming EP I hope to finish in the summer. We'll see!

    • Like 1
  7. Check this out, specifically:

    • Five “BankStick” slots, so you can store 4 banks of 128 patches, plus 128 “Ensembles” (engine and patch configurations)
    So what you're seeing is correct - A through D are normal banks and G is the ensemble bank (and yep each chip equates to one bank). I can confirm this is how it's working on my sammichSID as well.
    • Like 2
  8. Ooooh nice! Well that's helpful! That's a definitive possibility then. I worked on the LED Matrix yesterday. My previous iteration used SMDs, which definitely save space, but since I use a second board for the ICs, I had enough room to try thru-hole components since they're easier to work with. I wanna say it's about $75 for both the boards from OskPark. PCBWay and, erhm, the other one, are less expensive of course.

    The front panel is still about $275 from FPE. It's always been about the same price. I think I am going to convert the screw holes to blind threaded holes though.

    I'm actually between jobs due to Mr. Virus so for now I'm just trying to plan and gauge how much work is left and work on how best to approach the DIN/DOUT stuff Last time I landed on using 2x5 headers (just like CORE's J8/J9) but I really only need 6 pins (+5V, GND, Clock, Latch, DIN, DOUT).

  9. Nice to hear from you Hawkeye! Really love that tune! I also feel your pain about the flying rules. I sold my quadcopter gear and got into film photography fairly big. Kept doing music, though more-so in a band with a different sound. Been getting back into as of late. Nice to see you are too!

    Glorious tune!

  10. I found my old Eagle layouts for my rackmount SID I was wanting to make. I've been using the sammichSID quite a bit lately to the point I'm wanting a bigger control surface (never had a whole lot of luck with CTRLR) and just to cross this off my list :P Hadn't touched this since 2011 heh. Anyways this is where I left it:

    http://wiki.midibox.org/doku.php?id=mb-sidr8tr:start#led_matrix

    The question I had was, is FrontPanel Express and Eagle still the way to go? Been trying KiCAD since it could allow me to have a single board control surface (without getting nailed by licensing limits Eagle has) but the downside is that's a lot of cost to sink into it if I mess it up. So I think going with my separate board solution probably makes sense. I noticed OSHPark now does laser cutting of metal which made me wonder about using that over FPE (though FPE has always produced stunning panels).

    For those wondering why not just build an MB-6582 - I like Rackmount and the cables connecting the lower and upper boards have been my undoing. That plus a rackmount gives me tons of space to add, say, filters, a nice PSU, a fan for the SIDs, etc. The baseboard will still be using the MB-6582.

  11. To add on a bit, it was/is originally built by a guy (TK) but the designs and code are available (with commercial restrictions) which allows for things like the standard module-based setup, the MB6582 and the sammichSID (the latter not being currently available alas) among others. The MB6852 is, more or less, a bunch of MidiBox modules put onto a single mainboard. The code is mostly the same as if you did the same thing with module boards with the only big customizations being for the control surface.

    These devices are all just different implementations of the designs. So they're all effectively MidiBox SIDs just with different modules built-in. There have been some fairly customized versions of the MidiBox SID (and FM) that have popped up here from folks that added their own customizations as sort of one-offs. Things like combining MBCV with external filters in a single enclosure, that sort of thing. There's a TON you can do with the platform.

  12. The one warning I have with the MB6582 is to get the proper ribbon cables between the control surface and the mainboard. I believe some folks may have used right angled headers for one of the boards but there isn't really enough room to use headers for both since the boards connect at the front of the enclosure (where there is the last amount of space). This ended up being my downfall. I got everything else put together wonderfully, except those darn headers. Hence why I want to make a rackmount version...one day.

    • Like 1
  13. I use my sammichSID regularly albeit alongside a number of other synths (modern and vintage). I still have some of my board layouts for a rackmount 3U MB6582 based synth as well but it's been a bit cost prohibitive to go that route.

    So yes it's still viable and useful! The main issue is finding a working SID (or two for stereo) or the various SID-like options (e.g. SwinSID). If you have that sorted the MidiBox SID platform is quite good as a modern and fairly unique synthesizer - explains why I use it in nearly every song I write.

     

  14. Ah man so close, but I still want a Rackmount solution fairly badly. My GM5 is sitting on a rack shelf in the back with some nylon screws and standoffs. It works fine but makes things awkward and a bit vulnerable (it's not in an enclosure). But otherwise that's an impressive option if it lives up to the hype (and if it's using the new Ploytech chips I'm guessing it is).

  15. geez, latencies are already pretty damn good on the GM5 relative to many other interfaces. That's also good to hear! I'm at the point where, build or buy, I need a MIDI interface that has multiple ports, handles sync well, is low latency, and reliable. GM5 almost gets me there but sometimes it just likes to completely junk out while I'm in Ableton Live (it's entirely possible it's something I'm doing since I'm the one that populated the board :P). Rackmount would be a nice plus.

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