AndrewMartens
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Posts posted by AndrewMartens
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be very carful about your chioce of capacitors in audio circuits... especially in filter circuits, the chioce of the right ones or the wrong ones can make a huge difference.
Yeah, that's probably the issue. I'm using mylar caps everywhere in there, with the exception of the 68pF in the notch circuit, and the 10uF at the output. I'd use polystyrene, but I can't find those for purchase anywhere convenient. I'll probably just have to go with "inconvenient" and deal with the hassle of getting things shipped across the border from Mouser - at least they carry them at a reasonable price.
But in the meanwhile, I'll probably rebuild my Wasp filter over the holidays and double-check all the components values again.
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PS While I'm off topic, Sorry I'm quiet lately, arthritis/RSI is giving me hell...
Gahhh, good luck!
I'm getting some soreness in my wrists as well lately, though not as bad as the summer I worked for a dot-com in 2001 (OW OW OW OW OW).
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I should clarify there on my "single SID for $100" post - I only built the Control Surface A. Using the full CS will probably need a DIN and DOUT modules, a lot more LEDs, buttons and encoders. Still, that probably only adds another $50+.
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JH's Wasp Filter clone was on my "to do" project list for about 6 months. A few weeks ago, I finally breadboarded it. Alas, my first attempt met with no luck - I'm not sure if my CA3080s were shot, or if I just screwed up the circuit. The fact that it runs on +5VDC is fantastic, and I know that many people have built this circuit successfully. IIRC, the cutoff control worked okay, though the filter slope didn't sound steep enough, and all the resonance control did was decrease the volume instead of... well, increasing resonance. Right now the breadboard is just sitting there, waiting for me to go back and figure out WTF I did wrong with it.
Since then I tried a few other projects: Rat clone (success!), a +9VDC single-supply MS-20 filter clone that had an okay cutoff but just squealed noisily at resonance (scrapped that one), the "UBE Screamer" 4049/4069-based distortion (vey noisy, even at low gain,though it did distort nicely).
I'd be interested to see if anyone else here had success with the Wasp Filter. I followed JH's schematic exactly, even checking the Synth-DIY archives to determine typical values for the unlabelled components in the Cutoff section at the bottom right (I'll go and check what I put on my breadboard later). I think Cyndustries makes a dual-Wasp commercial version, and the sound samples were quite interesting. Hopefully I will have a chance to re-assemble this filter and determine what exactly I did wrong.
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I think my single MB SID ended up costing me ~ $100 CAD or so, not counting the additional tools that I bought when I was building it, or the surplus components (ie, needed 2, so I bought 10), etc. Rough breakdown:
core & SID PCB: $14 ($12 USD)
encoders/buttons: $3
jacks: $3
PIC: free sample
other components: $30? Tough call, this seems about right
LCD: $22 @ Digikey
enclosure: $25
So for that, I think it was totally worth it - the only real commercial option out there being the SIDstation, and that's priced at hundreds of dollars more. I should also point out that my enclosure was just a plastic sloped Hammond case with a hand-drilled aluminum panel - no fancy Schaeffer panels here!
Looking at making a MBFM in a 1U rackmount case, the cost/benefit analysis is somewhat more dismal:
core & OPL3 PCB: $13 ($11 USD)
encoders/buttons: $3
jacks: $6
powersupply: $8
PIC: free sample
donor soundcards: $10
other components: $60+ (I'm also building a filter into there)
LCD: $25 @ Digikey
enclosure: $50 (1U aluminum rack)
Total: $175 CAD, possibly more; again, including a hand-cut panel. I just saw a good condition TX-81Z go on the local Craigslist for $100, and that's a fairly common occurrence.
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Excellent work! I'm glad to see someone making progress on these concepts! Sadly my grand wavetable DCO plans never made it to the ASM stage due to lack of time. :'(
Using a separate module over IIC would work well, as one could conceivably just add some extra voices by adding more modules. Plus the MIDI/interface handling of the Core takes up a lot of the potential processing power.
Once you start applying modulation to the various parameters (ie via LFOs, ADSRs, etc.), not having the multiplier in a 16F88 would be a problem. However, even a 18F252 (or something with more flash, if you're going wavetable) would work just fine. PWM output is good, as would be an 8-bit (or better) R2R ladder - forget about DACs, they're too pricey! ;) I considered combining the two approaches, but I couldn't figure out how to apply an envelope to the PWM portion.
Doing a filter in software requires effort and knowledge of signal processing concepts. That was always my weakest point in university, and so I never really tackled that part. If you look at the code from Jarek's AVRsynth, he has some commented info about his DCF there.
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It's still optional at some dentists. When I needed a filling a few years back, they told me that my insurance only covered the cost of the cheap (toxic) ones, and if I wanted the better ones I would have to pay the difference. Well, I was still in school and all I could afford was the ones that I got for free. The dentist took pity on me and gave me a higher-quality filling at no charge... what a nice guy! :D
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I'll be breadboarding and setting them up for midibox control after some other projects are done.
Heh, heh, heh... I know how that goes!
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Hi TK, thought I would run this one by you (it's pretty easy, no big philosophical discussions here):
An associate of mine is looking for someone to build him something like the clockbox. I'm not sure yet if he's interested in the MIDIbox-based project yet, but it sounds like what he's looking for. Assuming that he would want me to build such a thing (I'm getting ahead of myself here), my pricing to him is cost of parts + shipping, that's it. Any payment above that is voluntary on his end, and I'm going to point out that you have a handy PayPal link at the top of the forums, in case he wants to bypass the middleman on this one :)
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Come on, you can MIDIbox one of those yourself! It's just a dual-oscillator wavetable synth, throw in a few CEMs, a digital delay/FX unit, a few filters, an arpeggiator, a sequencer... and you're done! Oh, well, a nice case, too.
Shouldn't cost more than a thousand dollars and a year of your life to build... ;)
At least, that's what I told myself when I was in the store looking at a DSI Evolver. ;D
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Very nice work on that panel! I drew a cardboard mock-up of my panel, but I ended up screwing the thing up so it looked like ass. Yours, on the other hand, looks very good for a hand-made panel. My only real concession to aesthetics was to paint my panel before grabbing the sharpie. I didn't even bother measuring the spacing for the holes evenly ;D
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The powersupply current does vary a great deal depending on the size of your implementation, as seppoman pointed out.
For a smaller (control surface A) design - like it appears you are planning to use - a 500mA supply will probably be fine. I have something similar (CS A with 16x2 backlit LCD, one SID), and it tends to draw about 210 mA at 13.8V from my supply. Again, this could vary a lot with your LCD.
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Ahh, Jorgen Bergfors and the Bergfotron. I remember seeing him post back on Synth-DIY a few years back (when I still had time to read the list). Fantastic work, I must say.
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Very well done! I bet you put on a crazy live show as you stretch those LDRs towards the lights... "There are four lights!"
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But the big issue is surface transfer. Touch the solder, then a tool, and the next time you handle that tool you get a little contact exposure.
Well, I certainly didn't think of that! Perhaps I shouldn't be soldering on my main computer desk in the middle of my "studio", then...
I was told the term "mad hatter" comes from the guys who hand formed lead shape inserts when shaping a hat in the old days.....apparently it was common for them to show signs of massive lead poisoning before anyone knew the dangers of lead.Heh, I had heard that back then they were using mercury for softening the fur pelts, or something like that...
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Whew, I used to know this one. It's been a while though, and I no longer have the 18Fxx2 datasheet memorized.
Just going off the top of my head here, isn't there a 4:1 PLL or something inside the PIC that turns that 10 MHz crystal into a 40 MHz signal internally? The instructions actually take 4 cycles each - but that's at 40 MHz - so on the outside it looks like you're getting 10 MIPS at 10 MHz. IIRC the 16F877 ran at the external oscillator frequency, so 20 MHz only gave you 5 MIPS.
That would explain why the calculation you used was only giving you 250k instead of 1M.
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My wife can at least appreciate that my synths are not junk, nor are the computers (she plays more computer games than I do!). Those boxes of old circuit boards in the closet *are* junk in her opinion, unfortunately. As a nice surprise to her, I pulled all the socketed ICs, removed any switches and useful components, and tossed the rest (to electronics recycling). That reduced three boxes down to half of a box, at least...
Also, Digikey appears to stock both 2N2222s and the 2N2222A - they're both $1.18 CAD, though (for a transistor? ouch!), P/N 497-3106-5-ND for the 2N2222. STMicro version.
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Happy birthday dear TK, happy birthday to you!
Best birthday wishes for you, and many thanks again for the awesome MIDIbox projects that you keep releasing to the community!
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I used to do my soldering on the kitchen stove with the hood fan on. That worked okay, but required hauling all my parts, equipment, etc. downstairs, and was very inconvenient. Other times I used the bathroom counter, but the fan was too far away to do much good.
Lately I've just been soldering up on my desk (where I have an anti-static mat as well) with the window open (for some fresh air), and have been careful where and when I breathe. Just before I apply the iron to the solder, I typically hold my breath and breathe out slowly. When I need to breathe, I finish exhaling - which blows all the solder smoke away from me - and then turn my head to the side and inhale. No problems to report here.
That said, I haven't soldered for 10 hours a day (!!), usually just a few hours at a go in the evening.
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a collation of information about quite obscure soundchips, mostly yamaha & closely related to the ym2612
Very amusing, since I'm working on my MB FM right now: in the entry just below the YMF262, I found the YM2164. Apparently this chip is used in the Korg 707, and I just happened to pick one of those up a few months ago. For a 49-key MIDI controller with velocity and aftertouch, and an old FM synth built-in, $70 wasn't a bad price. The odd thing about the 707 is that Korg has the patches setup in the virtual analog style: oscillator waveforms, envelopes, modulators, etc... even though it sounds very VERY digital.
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Give them a warm welcome ... cause we all started once in this forum with a silly question ... don't forget that!
Oh, come on doc! I've never asked a silly question on this forum ever! Sure, I've made silly suggestions, and had silly ideas, but silly questions? Hah! ;)
I can understand how it is difficult for new users to get going on a given MIDIbox project. The only reason I have my head (mostly) wrapped around a lot of the MIDIbox designs is because I've been lurking on-and-off around these parts for several years now - and even then I only got around to finishing my SID a few weeks ago!
Some of the information can be a bit tricky to locate, unless you're thorough and find the right PDF. That said, the build info on ucapps is quite thorough, and searching the forum can fill in the gaps. But still, it's a matter of knowing where to search (ucapps? the wiki? the forum?), and also how to search. It's like soldering, or reading schematics - gathering and parsing information is just another skill to pick up. Everyone will get there in time, and learn things. As long as new users aren't demanding or rude, I see no reason to not respond to them warmly.
If you're getting fed up of the same old questions, just take a bit of a break - go and work on your next MIDIbox or make some music! ;D
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I've had 2 cheap rotary tools in the past, never a dremel - the one thing that always annoys me about the cheapy ones is that they're so easy to stall the motors, even the mains-powered ones. is the dremel the same?
Those cheapies can be annoying - I have one myself. Just cutting out the hole for the LCD in thin aluminum was an exercise in patience...
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Maybe it's just for microcontrollers... Either way, I'll try again hmmmm
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Microchip currently only accepts online sample orders from registered business or university email addresses. We currently do not accept orders from generic ISP accounts. Please do one of the following:
1. Register with a valid business or university email address and place your sample order
:( Anyway... Maxim will send me samples... of what they have... :-/ lol
Ahhh, it was the *email* address. Sorry, I didn't pick up on that for some reason. Well, you could always register a domain name and get hosting for it, but that might negate the "getting free samples" part. Still, if I were to think of it that way, I'm sure that the samples I got this year would have already paid for my domain and hosting costs...
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At some point it just makes sense to buy a simple
MIDI cable like the UNO..
Even if it is "less fun"
That's what I was thinking. For a 1-in, 1-out interface, you should be able to buy something relatively cheap. Even looking at multi-port MIDI interfaces, I think if the 4x4 MIDIbox USB idea was up and running, then it *might* be price-competetive with some commercial devices. Still, I got a brand-new MOTU MicroLite (5x5) interface for only $153 CDN (regular price).
a Analog heavy bands music, 20yrs of it... Seriously want to steal their Wave ;)
in Songs & Sounds
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They might not be opposed to DIY... they do have a P3 sequencer in there, after all (though it may be one of the non-DIY versions).