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Advice wanted (noobish questions)


Goblinz
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Hi, I'm new to this forum and there looks to be a lot of interesting stuff here. I saw the Midibox SID on Ucapps a while ago but have been waiting for V2 to be finished before I even start thinking about construction. I followed a link to Wilba's MB-6582 and my God it looks sexy, anyway, in short, I want one!

I'm trying to decide whether to follow the ucapps build guide and have seperate PCB's for each module or order a set of the all in one PCBs that Wilba has so kindly made available. I like the idea of being able to have seperate smaller boards to aid testing and fault finding, but like the compactness of Wilba's design (to be honest, I think I've fallen in love with his SID design). Can anybody give me any advise on this?

I was wondering if it's possible to add some midi controls to a Midibox SID. I would like a couple of sliders and encoders to control various things on fruity loops. Would this mean combining the SID with a midibox 64 or can I already use some of the pre-existing circuitry.

To be honest, I have never attempted a project this big, my electronics experience doesn't go much beyond GCSE electronics but I know how to use an iron and have done quite a few repairs and smaller projects. Any help/advise would be really appreciated.

    Thanks,

          Goblinz

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It's a bit of a trade-off... PCB modules are easier to troubleshoot, but sometimes the "trouble" is due to the wiring between the modules, or building the extra bits that don't come on a pre-made PCB. eg. to make a multi-SID MIDIbox SID, this usually involves making a custom PSU circuit to reuse an original C64 PSU transformer, and a PCB for one or more BankSticks (IIC EEPROM) to store patches.

When the "MB-6582" PCBs are ready, I'll make a construction guide and you can do things in stages, this avoids the need to troubleshoot when everything is already soldered and connected, and in most cases, swapping PIC and SID chips can diagnose if either of them are not working.

The "MB-6582" base PCB is probably not too big a project for someone who's soldered before, who understands electronics, knows how to use a multimeter to test for good soldering joints and no short circuits... but if you're interested in building other MIDIbox stuff too, get a Core and a DIN module and practice on that first, make a mini-MIDI controller with 8 knobs or something. You can always turn it into something else later.

I was wondering if it's possible to add some midi controls to a Midibox SID. I would like a couple of sliders and encoders to control various things on fruity loops. Would this mean combining the SID with a midibox 64 or can I already use some of the pre-existing circuitry.

The encoders on MIDIbox SID "step C" control surface are dedicated to controlling the synth. If you are wanting some extra encoders and sliders in the same case to work like MIDI controllers, then it wouldn't be too hard for an experienced PIC ASM coder to make those changes to the firmware... and it is easy to add another DIN module for adding more encoders.

So it's all up to you really... it's not too hard to solder the "MB-6582" base PCB, it's less work than making your own C64 PSU circuit and BankStick circuit on prototyping board, no chance of wiring errors between "modules" or in the C64 PSU circuit or BankStick circuit. I can't guarantee you won't have some problem that needs fixing, but I can guarantee it's not that much harder to work out what's wrong if you build and test things in stages. If you're still undecided, get a Core kit now and get some soldering practice in, get things like MIOS Studio working, connect an LCD display... all these bits can be reused in a second MIDIbox controller.

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Thanks for the advice. I thought the MB-6582 was a V2 (excuse my ignorance) Any ideas how long the V2 developement will take. I'm not being imaptient, just interested in how complete it is, I quite like the idea of possibly being one of the first few people to try out this new design as I can see that it's going to be around for a few years.

I think it's going to take me a long long time to get hold of all the SID chips. I already have a new style C64, but can't find any reasonably priced old machines in the local paper, ebay, etc. For some reason people have either thrown out their broken or aometimes, perfectly good machines and the rest have cottoned on to their resale value. I'm beginning to regret that stuff like this has become "retro" as it makes it harder for people to get hold of equipment who don't want it for the chic value. Personally my Atari STE is still sat where I set it up 2 years ago, the only difference is that I now have a collection of interesting hardware to go with it. Anyway, to the point, I've seen some chips for sale on the flea-market board, have you any ideas if there's many people dealing with this kind of thing in the UK?

  Thanks,

      G

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I would say go ahead and build everything and worry about the V2 stuff when they wrap it up.  There will be some changes made to the hardware but nothing that will stray that far from the current hardware.  SID chips can be found here, on ebay, or i'm sure at your local flea market

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Here's another daft question! I'm pricing up bits and pieces. I've never done anything with PICS before, but am wanting to have a play before I start my SID but to still be able to re-use the chips i'm buying in the SID-synth. From looking at an electronics supply website for a particular PIC (PIC18F4685). It's listed with loads of differnt aditional letters after the name (PIC18F4685-E/ML, PIC18F4685-ME/PL, etc). Which one do I actually need to order to ensure compatability with the SID project. Also, what package type would be best? I'm guessing that PDIP would fit the board designs which have been released. Also, would I be correct in assuming that the amount of "leads" is the amount of legs? They're generally either listed as 40 or 44, but one is 128.

Thanks,

          G

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Post a link to the website...

It's usually "-I/P" or "-E/P". First letter means temp. range, either is fine ("I" = Industrial, -40 to +85). Letters after the slash are package, "P"=PDIP, you don't want any of the others. It should be 40 pins (leads/legs).

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Please excuse the dodgy cut and paste job, the site used cookies to keeo the selection details so I couldn't just include a link. Would the second one in the list be a good start? These things seem to have quite a goof temp range, should I ever want to go to the arctic and make weird noises then i should be sorted :D

Thanks for your help with this.

        G

Part Number       Leads    Package Type          Temp Range      Packing

PIC18F4685-E/ML     44          QFN                    -40C to +125C      TUBE

PIC18F4685-E/P     40          PDIP                  -40C to +125C      TUBE

PIC18F4685-E/PT     44          TQFP                  -40C to +125C      TRAY

PIC18F4685-I/ML     44          QFN                    -40C to +85C      TUBE

PIC18F4685-I/P       40          PDIP                  -40C to +85C        TUBE

PIC18F4685-I/PREL  40          PDIP                    -40C to +85C      TUBE

PIC18F4685-I/PT     44          TQFP                  -40C to +85C      TRAY

PIC18F4685-I/PXXX  40          PDIP                    -40C to +85C      TUBE

PIC18F4685-ME/PL  128        LQFP                    10C to 50C        TRAY

PIC18F4685T-I/ML    44          QFN                    -40C to +85C      T/R

PIC18F4685T-I/PT    44          TQFP                  -40C to +85C      T/R

PIC18LF4685-I/ML    44          QFN                    -40C to +85C      TUBE

PIC18LF4685-I/P      40          PDIP                    -40C to +85C      TUBE

PIC18LF4685-I/PT    44          TQFP                  -40C to +85C      TRAY

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Please excuse the dodgy cut and paste job, the site used cookies to keeo the selection details so I couldn't just include a link. Would the second one in the list be a good start? These things seem to have quite a goof temp range, should I ever want to go to the arctic and make weird noises then i should be sorted :D

Part Number       Leads    Package Type          Temp Range      Packing

PIC18F4685-E/P     40          PDIP                  -40C to +125C      TUBE

PIC18F4685-I/P       40          PDIP                  -40C to +85C        TUBE

If they´re the same price and both are on stock, choose E/P, otherwise choose I/P. As you can see, in the arctic there´s no difference between them, only in full Sahara sun ;)  8)

Seppoman

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It is the microchip website. To be honest, I'm looking at getting a couple of different chips as samples. That way I can have a play and start looking at how to program PICs without risking frying something that I've bought in for a project. I know it's a little cheeky, but I will be buying chips from then in the future.

              G

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It is the microchip website. To be honest, I'm looking at getting a couple of different chips as samples. That way I can have a play and start looking at how to program PICs without risking frying something that I've bought in for a project. I know it's a little cheeky, but I will be buying chips from then in the future.

              G

I have no problem with sampling, I just answered Wilba's question which website it was. Sample as much as you need, if you develop things related to PICs, and other people also want to build these projects, they might buy more PICs, so the sampling for R&D is justified in my opinion.

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If you're sampling from Microchip, you can get 3x PIC18F4658-E/P and 3x PIC18F4658-I/P and also 3x 24LC512 (PDIP package)... you can also donate any unused PICs to others here.

I have sampled before, but I also bought their PIC burner so I don't feel guilty ;D and I suppose I've generated some demand for their chips by making a PCB that needs 12 of them!

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Yeh, I just feel a little cheeky though ;D I could see it be a problem if lots of people were sampling and not buying. If they send out free samples to lots of people and don't get an order off the back of it then surely that gives them an indication that there isn't much demand for the chips and could result in them being withdrawn. Maybe I'm being a little OTT here.

        G

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Yeh, I just feel a little cheeky though ;D I could see it be a problem if lots of people were sampling and not buying. If they send out free samples to lots of people and don't get an order off the back of it then surely that gives them an indication that there isn't much demand for the chips and could result in them being withdrawn. Maybe I'm being a little OTT here.

        G

I dont think that is an issue.  Microchip is has over a billion in sales and saw an increase of 12% over last year and the synth DIY portion of their business accounts for nothing so if everyone on this list sampled as many chips as they could, they would not even bat an eye.

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  • 4 weeks later...

I have my chips! Will probably have some spare ones left over which I will either play with or offer on the forum :D

I'd just like to clarify a few things before I start buying the other bits so that I don't end up wasting a lot of money.

My understanding is that the old style machine's had inferior 6581 SID chips in them and the newer ones had  6582 chips. Some synth base soundcards came with 8580 chips built in, but these are hard to find. Wilba's uber-sexy MB-6582 synth requires either the 8580 or 6582 chips. Is this correct? I'm having problems soursing UK SIDS at a reasonable price, commodore 64s seem to be going for about EUR40 over here including P&P and although I accept that I may need to pay this I'd rather get something cheaper.

Also, can anyone let me know if wilba's design will run the SID v1.xx firmware or will it have to be the beta SID v2.xx firmware. I'm thinking of building a single SID synth on a breadboard without the control surface simply as a way to get to grips with this whole concept and as a way to learn about pic chips (which i'm finding a bit daunting).  I should think that by the time I finish messing around with the breadboard v1 synth that the v2 design will have been finished for a while so should give a nice step up.

          G

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Hi,

About the different SID versions:

The 6581 was used in the oder "breadbox" C64s, the 8580 in the newer ones. The 6582 was never used in production. There are different rumours why this chip was designed. Some people say it was meant for the C65 (successor to the C64, never sold, only prototypes exist). So the 6582 is the successor of the 8580 (audible differences are said to be subtle) and is quite hard to find.

About "inferior 6581" - that´s a matter of taste. Technically, the 6581 is inferior, much more background noise, the filter is weak regarding cutoff range. Personally, I prefer it over the 8580 anyway, because it has more dirt, the filter is gritty and growling unpredictably. My reason for loving the SID is that it can sound so LoFi and 80s. The 8580 is just cleaner and in some way fatter. For clean and classical fat sounds, I´ve got an Alesis Micron, so I really wanted some opposite to it :) But I know I´m one of the few 6581 defenders here, most people prefer the 8580/6582.

To learn more about Wilba´s PCB, just read here: http://www.midibox.org/forum/index.php?topic=9238.0 From what I understand, Wilba is modifying the PCB for complete V2 compliance and has added selectable SID voltage per pair, so that you can use all SID types.

Building a single MBSID on breadboard is a good experience (see my attempt on it: http://www.midibox.org/forum/index.php?topic=4873.0). You´ll learn a lot about how everything works and will be prepared to build a big version that suits your needs afterwards.

Seppoman

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a little annotation:

6581 can not double or triple filtering. That means that the 8580 can used for AND-Command between channels.

The missing function is a bug by developing 6581 chip.

The correct solution is included in 8580.

Another thing: Have someone ever tried to play Triangle + Saw or Pulse + Triangle, Pulse + Saw or all together ($31, $51, $61, $71) on C64 I with 6581 chip in it.

It's sound very quiet, low and nasal.... that was corrected in 8580.

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Hi Rio,

don´t know exactly what you mean with triple filtering and AND-Command, but my 6581 can combine different filter modes. Also, it does play all mixed waveforms correctly. I´ve noticed TK´s 6581 demo, so some 6581 do have problems there - mine doesn´t.

Seppoman

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The 6582 was never used in production. There are different rumours why this chip was designed. Some people say it was meant for the C65 (successor to the C64, never sold, only prototypes exist).

It was used in the SID Symphony carts, but I tend to believe the C65 rumours, I doubt they made a run of them just for that one cart ;)

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