HybrisBehemoth

Starting MB6582 build

19 posts in this topic

I basically got in to DIY-synths a couple of months ago because I wanted to be able to build a MB6582. After building a Shruthi XT and a sammichFM kit I'm starting to feel ready for the challenge. So I bought the PCBs from Modular addict and read through all the documentation I could find here. Just getting ready to order the parts from Mouser and have a few questions before doing so.

 

- 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?

- 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?

- 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.? 

- 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?

- 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?

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

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

- 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.

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

 

Thanks for any input.

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Hi there,

the MB6582 is great, you will love it!

A few answers, just the ones i could directly answer :)

* personal opinion: regarding a mixed SID setup: i'd recommend to go for all 8580/6582, the filters are just better, the noisefloor of the 6581 is higher and imho the "flexibility" to divide it up is not worth the "cost" of not being able to play four near-identical sid stereo voices in poly mode.

* power supply: recommended to change it, because the 5V vreg can (and will, i have a defective C64 original PSU here :)) go haywire over time and will burn your SIDs and maybe the PICs... 11.06 V AC is not necessarily cricital if it was not measured under load. The PSU might be ok, but for long time use, it is highly recommended to replace it. There are recipies around this forum how to do it, look for a solution from orange_hand to go for an energy efficient one :)

* OLEDs work, see Izze's thread:

* A case fan is  imho not really required if you use 8580/6582. I had my MBSID in use since 2010 without it, not a single SID failed so far. Just use thermic glue and normal IC headspreaders for classic DIP ICs. Fans are known to add noise to the audio outs and physical "airflow" noise in your studio.

* 1.5mm acrylic will not be stable enough, got to go for an aluminum frontplate, it is expensive, but it will last!

---

Sorry for incomplete answers, you should be able to find answers to most of the other questions here on the forums.

Many greets, Peter

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agree with fans noise. lower with filtering caps but still hearable - no need for fan

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Quote

 

- 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.

Quote

- 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/

Quote

- 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.

Quote

- 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.

Quote

- 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.

Quote

- 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.

Quote

- 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.

Quote

- 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.

Quote

- 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!

Edited by jaytee
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5 minutes ago, jaytee said:

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,

interesting - please upload some pictutes

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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

Edited by jaytee

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Figured this might be a good thread to start on, I have also just purchased PCB's from Modular addict (the MB6582 Base and control surface), a case and panels from The Beast and a C64 replacement power supply from Amazon as although I intend to use 8580's for the initial build I woould like to keep things open to the possibility of using 6581's in the future.

I am guessing the next step from reading the above is to grab a scrap c64 board to cull the power din and the rocker switch ?

Additionally I did find this place selling heatsinks for SID size chips https://www.retroleum.co.uk/c64-repairs-and-mods

Edited by Freakbag23

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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.

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Thanks everyone for the informative feedback!

 

Decided to go with power option E and 8580s only. Really cool solution with the PCB-panels! When I saw it I had already ordered case and panels from http://thebeast.co.uk/ though.

I have (finally) gone through the BOM and created my Mouser shopping list (can be copy/pasted here https://no.mouser.com/tools/part-list-import.aspx):

 

512-1N4148T50A|100
688-SKHHDT|50
604-WP424HDT|115
652-PEC16-4220FN0024|15
313-1250F-100K|4
161-MJ355W-EX|1

 

575-11044640|5
575-1104762841001000|10

502-PC722A|1
502-57PC5F|2
550-20301|4

710-860040478015|1
710-860241375002|10
647-ULD1E101MED1TD|1
647-ULD1H010MDD1TD|10

75-2C20X7R334K050B|1
581-SR215C104K|38
75-1C20C0G330J050B|8
505-FKP2.022/63/2.5T|16
581-SR211A102JAATR1|16
594-K471J15C0GF5UH5|8

858-36FR10KLF|5

264-10K-RC|10

610-BC337|1
512-BC547BTA|16

859-6N138|1
579-24LC512-E/P|8
595-SN74HC165N|5
595-SN74HC595N|11
579-PIC18F4685-I/P|4

774-ATS10A-E|4

511-L7809CV|1
532-577202B00|1
532-574502B03700G|1
919-R-78B5.0-1.5|1

 

660-MF1/4DCT52R5601F|100

660-MF1/4DCT52R1201F|100
660-MF1/4DCT52R1001F|100
660-MF1/4DCT52R1002F|100

660-MF1/4D52R1000F|100
660-MF1/4DCT52R2200F|100

 

Doest this look OK? Any suggested changes? Correct ICs, transistors? I went for longer lifespan electrolytic caps. Any opinions on those? Better options for the SID filter caps ( 505-FKP2.022/63/2.5T )?  

 

I'm leaving the fan out. Got these heat sinks for SIDs and PICs. Might be too tall... How much space is there between the PCBs?: 

https://www.ebay.com/itm/8pcs-14x30x8-mm-DIY-fans-cooling-Heatsink-Aluminum-Profile-Cooler-With-Tape/123021408514?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

https://www.ebay.com/itm/12pcs-10x35x10mm-Extruded-Heatsink-With-Thermal-Tape-Aluminium-Profile-For-DIP/112681555348?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2060353.m2749.l2649

Also ordered this dirt cheap display. Measurements look good. Any opinions as to whether it will work with the PIC? If not; suggested display from Mouser/EU-supplier?:

https://www.aliexpress.com/item/1pcs-LCD-2004-20x4-Character-LCD-Display-Module-HD44780-Controller-Green-screen-backlight-forarduino/32691168548.html?spm=a2g0s.9042311.0.0.400f4c4dSOqlAZ

Also ordered a PicKit3.5 as I should be able to use that to program the PICs, right?

https://www.aliexpress.com/item/new-1set-PICKIT3-5-PIC-KIT3-5-PICKIT-3-5-Programmer-Offline-Programming-Simulation-PIC-Microcontroller/32847321104.html?spm=a2g0s.9042311.0.0.400f4c4dSOqlAZ

https://www.aliexpress.com/item/PIC-ICD2-PICKit-2-PICKIT-3-Programming-Adapter-PICKIT2-PICKIT3-Universal-Programmer-Seat/32730403341.html?spm=a2g0s.9042311.0.0.400f4c4dSOqlAZ

Wasn't quite sure how much current the 7809 would have to handle if I got 8 8580s sometime. Thus I wasn't sure how big a heat sink is needed. So I got two options and plan to mount the biggest one I can fit into the space between the PCBs. 

Edited by HybrisBehemoth

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Thanks jaytee! :) You still have a beer on my tab, say a word, whenever you are near Munich! :cheers:

Many greets, Peter

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I'm just starting this too, so thanks for all the advice on this thread (including where to get the rocker switch!)

That Control surface guide is brilliant Hawkeye, makes me much more confident I can do this!



 

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this is a totally silly question..... but just in case anyone has an opinion........ am I mad to use colour change LEDs for this project?

I figure the answer might be that it make more sense for the indicator buttons, but it would be really silly to do it for the matrix.... but maybe it's just a stupid idea all round.

 

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@the_duckchild

Thanks, and which kind of color change LEDs are you thinking of, would you have a product link?


The MB6582 only supports single color LEDs everywhere, but you can use different colors of LEDs in different sections of the frontpanel, although many people prefer to stay with a single color.

If the "color changers" only require two pins and then internally do the color changing, then they could work, if they are standard 3mm LEDs, although your build would probably be blinking madness :)

Many greets,
Peter

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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! ;)

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6 hours ago, Hawkeye said:

your build would probably be blinking madness :)

44 minutes ago, jaytee said:

I would send you one for free if you promised to install rainbow blinky lights in it. ;)

:cheers:

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17 hours ago, jaytee said:

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.

I

Yes, rainbow blinky barf is what I am after really, Mario Kart Rainbow Road in synth form. 
The two pin rainbow colour change ones was what I meant - I was slightly concerned that the forward voltage might change as it changes colour and make things a bit illegible.... I guess I could just test that though thinking about it now. 
I suspect I may eventually regret  the decision due to it NEVER STOPPING, but on the other hand, it's going to look ridiculous and insane and I think that might well be worth it.

:)

Thanks for the encouragement in this folly, I was expecting a lot of "oh I wouldn't do that" 

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