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jaytee

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Posts posted by jaytee

  1. I had originally planned on a standard barrel jack for power. I ended up going with the 7-pin DIN for a few reasons.

    Probably the main reason is that the header pads for a panel-mounted power jack are close enough to the edge of the board that they kind of interfere with placing a panelmount jack at the same location. You might be able to get around this by placing the jack higher up on the rear panel or elsewhere on the panel altogether, by using angled headers instead of straight, or by simply wiring the jack directly to the board (though this list option will make servicing in the future more difficult).

    The above hurdle could have probably been surmounted, but lo and behold, a 7-pin DIN connector randomly fell into my lap. I had been asking around for a source on the OG power switch, and a kind forum member hacked off a piece of original C64 PCB for me that contained both the DIN jack and the switch. Obviously this won’t be the case for y’all, but having the part in hand made the decision a bit tougher.

    Other, minor reasons I went with the DIN jack: no need to redesign that part of the panel (I had custom panels made but I didn’t want to change any more than I had to), and no possibility of using the wrong voltage/polarity power adapter ever.

    Attaching the new jack to a power adapter was really easy; don’t let that be the only reason you shy away from the DIN connector.

    That all said, if the part hadn’t magically appeared for me like that, I’d have probably figured out how to use a barrel jack. I’m afraid I can’t advise on how to adapt the DIN sized hole to a barrel jack though, that’s a tough one. I had planned on custom panels from the beginning.

    • Like 1
  2. Ask all the questions you like! Not like this forum is super busy anyway.

    I’m away from my synths at the moment, but I have a Mix Out jack wired up. IIRC, I used 10k resistors (pretty standard for passive mixing), but I’d have to double check that. I use the mix jack almost exclusively and I haven’t noticed any issues with output level.

  3. Short answer: trust the MIDIbox build docs. It’s supposed to be a 22nF cap.

    Long answer: it’s fine to experiment with different values and types of caps. You should be socketing this cap anyway so that you can easily install 6581 chips at some point in the future, but that also makes it easy to experiment with different caps and see what sounds best to your ears. There are also a couple values in the MB SID firmware that let you calibrate the filter response. IIRC, you can adjust the response range as well as choosing either linear or log response (the latter depends more on which SID chip you have, but go ahead and try both to get an idea of the difference).

    Back to short answer: just stick with the recommended 22nF caps. The SID filter is never gonna be stunning or full of character, and the 22nF caps are known to work well.

  4. For cheaper parts with cheap shipping to US, I like Tayda (very cheap, regularly has 15% sales announced on Facebook, easy to order common parts like resistors and caps, but sometimes low quality, no-name parts), and I’ve been digging Arrow lately too (free shipping, often has lower prices on same parts as Mouser, only downside is hilariously wasteful packaging).

    • Like 1
  5. If I still had a spare set of the panels I made with the trippy graphic behind the mod matrix, I would send you one for free if you promised to install rainbow blinky lights in it. ;)

    On a more serious note, what Hawkeye said is right on the money. If you’re talking about the kind of LED that has just two leads and color-changes automatically, it can probably be done (no idea what kind of current those things draw though). It would be a masterpiece of rainbow barf and I heartily approve.

    If you want to actually control the color changing, or you want to use LEDs with more than two leads, you’re not going to be able to do it with the current MB-6582 PCBs. Would require a redesign of both the circuit board as well as a fair few code changes, I would expect. Way more work than I’d be willing to do, but again, I encourage any and all rainbow barf-themed projects, so I say go for it! ;)

    • Like 2
  6. Ah, you’re absolutely right, I missed that it was just a single core module and SID module. They mentioned multiple PSU options and my mind immediately went to the option a, option b, option c, etc from the Mb-6582 documentation. 7805 will work fine then, lol. The MB-6582 is a current hog but a single SID is pretty manageable.

    The switching regulator isn’t any more complex though—it’s a drop in replacement—but it’s *way* more expensive and not at all necessary for a small SID synth.

    Pay me no mind, I’ll back out ;)

  7. I have noticed a few recent questions about how to power the MB-6582, so I figured I'd give this thread a little bump to make it easier to find.

    Additionally, I went ahead and added this tutorial to the wiki like I promised I would over a year ago. It's live now, and I went ahead and edited the main page to add "PSU Option E" to the list of power options. Hopefully this makes things easier on novice builders.

    Incidentally, I also cleaned the main MB-6582 wiki page up a little, removing some severely outdated links and adding links to the Modular Addict MIDIbox store. No more link to Wilba's 6582 megasale that hasn't been happening for over 10 years!

  8. Just now, Phatline said:

    interesting - please upload some pictutes

    Just edited my post with a link to some pictures I took while I was trying to sell the excess.

    Ill snap a couple more right now though. Those pictures were taken to emphasize the flaws, as I was trying to be fully transparent about selling them, and don’t include any photos of the finished synth. IMHO, it came out looking pretty good.

    edit: forum software hates my pictures (too big?) but here’s a link to some quick photos of the finished synth: https://imgur.com/gallery/a7Zsgz2

  9.  

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    - Does anybody sell pre-burnt PICs for the MB6582? I assume I need 4 pre burnt ones if I want to use all the slots?

    Now that SmashTV has closed up shop, I’m not sure about this one. You might make a post in the classifieds forum here, or maybe someone will see your post here and offer you some. Can’t hurt either to email Modular Addict about whether they’d consider carrying them; they were extremely responsive when I suggested they carry the MB6582-specific knobs.

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    - I have an original C64 power supply. It turns on. But when I tested the voltages referencing https://www.c64-wiki.com/wiki/Power_Supply_Connector I get 5,29 V DC between pin 2 and 5. But between pin 6 and 7 I get 11,06 V AC. I assume this means that the supply is starting to fail and that I need to look for a new one. Any suggestions when it comes to buying a newly produced C64 supply for this project?

    My suggestion: don’t use a C64 power supply. The originals will flake out on you, the replacements are pricey, and overall, it’s completely unnecessary and impractical. I wrote a detailed guide on how to modify the MB-6582 to run on a single-supply, based on altitude’s original work on the subject.

    edit: Here is the relevant tutorial. Really can’t recommend this enough. http://midibox.org/forums/topic/20376-one-mb-6582-one-power-supply-a-tutorial/

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    - I'm probably going for PSU option B. Currently I only have one 8580 SID and I might stay with just 8580s, but I want the flexibility if I do get 6581s... if there isn't any drawbacks compared to PSU option A that is... heat etc.? 

    The tutorial mentioned above on how to use a single-supply also explains your options for a mixed SID environment. It’s a pretty trivial change if I remember correctly. I think 6581s run a bit hotter than 8580/6582s, but not significantly so, and installing the power option without actually installing 6581s has no downside except for the added cost of another Vreg.

    That said, I agree with the poster above who suggested sticking with an 8580/6582-exclusive setup. I know some people are in love with the 6581 sound, but the 8580 is (IMHO) the superior choice for use in a dedicated musical instrument. Lower noise, better filter/resonance, full use of combined waveforms... As well, I gotta agree that it’s nice to have four full stereo voices that all sound alike. Anyway, that’s just my totally subjective opinion on the matter; no matter what you choose, it’s not hard to implement the power supply.

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    - I assume the Modular addict PCBs are the same as "revision 2 PCBs" from SmashTV, and that there are no errors to correct as in the first PCBs?

    As far as I know, yes. Their boards are identical in design to the most recent Mb-6582 boards from Smash.

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    - Are there any better display options out there now that will work with the PCBs and the PT-10? OLEDs? Would that require switching out other components?

    I don’t know much about swapping out the LCD, but I know folks have done it. Run a search of the forum and you’ll find threads about it. IMHO, not really worth it. My LCD was affordable and looks pretty great; there’s no practical reason to “upgrade” and there’s very little cosmetic reason even.

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    - Any recommendations for a fan? A very quiet one would be great.

    I’ll find a link to the one I used. I really like it. It’s audible “in the room” so to speak, though quite quiet still, but more importantly, I cannot hear it in the MB-6582’s output.

    edit: the fan I used can be found here: https://www.amazon.com/dp/B00NEMGCIA/ref=cm_sw_r_cp_api_aTqOBbTFRP1N8

    That said, it’s probably not necessary.

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    - I'm not at all sure what heat sinks to get from Mouser. Suggestions?

    Heat sinks...for the SID chips? I didn’t bother; I don’t think most folks bother. If you’re installing a fan, I definitely don’t think it’s necessary. If you’re using 8580s, probably not necessary. If you forgo the fan *and* install 6581s...I would still rank it as “probably not necessary though not a bad idea.” Sorry though, I’m not sure which heat sinks would work either.

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    - The front panel seems to be the most expensive part! Looks like I can get one for 85 £ (I'm in EU). Any other options out there? Did anybody try 1,5 mm laser cut acrylic? Not sure if it would be sturdy enough.

    Yeah, the panels are definitely the single most expensive part. There are a few options though.

    The acrylic could work. Not sure how well JB-Weld adheres to it. Importantly, none of the controls are panel mounted, so the panel itself won’t be under much stress. I’ve seen some MB-6582s encased completely in acrylic; not sure if I’ve seen any using the PAC-Tec case with acrylic panels though.

    Julian, a fellow MIDIboxer, makes high-quality panels. That might be the £85 option you saw—thebeast.co.uk or something? Pricey, but by all accounts worth it.

    Front Panel Express is also pricey, but also high quality. Could be a good option if you want something very fancy and customized.

    What I found to be the most cost-effective option, and what I used on my own personal MB-6582, is having PCBs printed on aluminum, with the soldermask as the main panel color and the silkscreen for my labels (you can even go crazy and use a copper layer for additional decoration). AllPCB in particular can print PCBs on aluminum, though even the normal PCB material makes a decent panel. The initial order is about as expensive as going with Julian or FPE, but the minim order is 5 panels, so if you don’t mind waiting, you can make most of your money back by selling the extra panels here on the forums. This option is nice because you can fully customize your panel at almost no extra cost. One caveat: these are still PCBs, from a PCB maker, so they are manufactured and shipped as if they would never be seen by an end user. Expect blemishes, scuffs, and small imperfections. I am 100% happy with how my panels turned out, and I can’t see the imperfections unless I get up close and inspect, but if you’re the type who demands total perfection, maybe not the option for you.

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    - What PCB-mount on-off switch (from Mouser) would work with the panels and PT-10?        

    Hoo boy. Those fucking power switches... I went through hell to track one down. The switch—along with the 7-pin DIN power port that is no longer necessary if you’re not using a C64 PSU—make a strong argument for customizing your rear panel.

    What I ended up doing was salvaging a switch and DIN connector from a busted C64. I might not have gone this route, but a forum member offered them to me, and I figured “what the hell?” They fit the PCB foot prints (cuts down on wiring) and they fit the existing panel designs (though it’s not a big deal to alter those designs). So if you have a busted C64 handy and don’t mind butchering it, it *is* a pretty handy option.

    If you don’t have access to those original parts, I would go with panel-mounted parts instead. The switch does have a modern equivalent, but I had trouble actually tracking down someone who actually had them for sale. BE CAREFUL. There is an easy-to-find part that *looks* like an identical match, but actually is not; the pins have a slightly different spacing or oft height or something. Instead, just get a standard toggle switch and modify the rear panel design to accommodate it.

    Same goes for the power jack. I don’t think 7-pin DIN ports are impossible to find, but they aren’t exactly common, and if you’re using a single-supply PSU, all you need is a standard power jack. I used the 7-pin DIN because I had it handy, but it required me to buy a male DIN plug and modify my power cord. A standard panel-mounted barrel jack is probably the better option.

    If you do a PCB panel, modifying the panel designs before having them manufactured is not as scary as it might sound. I had zero experience with PCB design software or panel design before I started, and I just learned along the way. I didn’t end up modifying the power switch/jack parts of the panel, but I did alter a few other things about my panels and it went quite smoothly. I added some graphics, text and mounting screwholes to the front panel, and on the rear I added a 1/4” “Mix Out” jack with label, right above the power switch.

    edit: here is a thread with some information about the correct switches, as well as a few other notes on the BOM that might come in handy: http://midibox.org/forums/topic/20281-mb-6582-bom-questions/#comment-176598

    edit: and here is the thread where I was selling my PCB panels. I’m all sold out now, but it has lots of pictures to give you an idea what these types of panels look like in the end. http://midibox.org/forums/topic/20402-fs-cheap-mb-6582-panels/#comment-177811

     

    Congrats on the impending MB-6582!

    • Like 2
  10. Sorry if I missed this, but how much SMT soldering is there?  I prefer thru-hole, not so much because of the soldering but because I can actually see the components...

    This looks amazing, but it’s definitely the “deluxe.” Not sure I need a sequencer with $120 worth of displays in it. ;)

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