guiseppi

There is a midi standard for tuning, but very few synths support it. (Perhaps a midibox synth could be adapted?) Most companies have stuck to their own methods of tuning using various methods of preset 12 tone variations, to complete keyrange reprogramming. A little info on the general here: http://www.midi.org/techspecs/midituning.php There are many software synthesisers that are very easy to do microtonal tunings for. The software called Scala is very complicated, but it is utterly massive in this arena so worth investigating: http://www.huygens-fokker.org/scala/ I started to code software (for PIC) to convert keystrokes into microtones for the Yamaha FB-01, but kind of left that in the dust due to the amount of work after realising I already had both hardware and software synths much more easily programmed and had even written software years ago for the Z1 to do so (doh!). Of course, you have to figure out that once your musical piece changes key, so the tuning shifts and it starts to become a bit more difficult to do it just-ice.... I just make sure my guitar is out of tune and randomly push and pull the bender these days ;)

FREEDOM!!! AND SHEEP!! *cough* Seems many places in England are still a bit stuffy about accepting Scottish minted notes. Or is that little misunderstanding all in the past? ;)

Is Scotland not a country? ;)

Oh. I didn't spot that ;) In that case, a few multiplexers rather than multiple PIC's would be more sensible, but it still means modifying or rewriting code. The analogue part of the circuit with the LM324's simply converts the pulses from the piezo's into a ~0-5v range for the PIC inputs, so could be used in any project as is for triggers. Kits can even be bought. It might be sensible to use fixed resistors at the piezo inputs or small cermet trimmers rather than so many pots. Calibration in software if needed..

The only project I know of that is close to that is the eDrum, which is an 8 channel velocity sensitive drum. With a little work, the analogue portion of the circuit could be expanded for many piezo's, the main parts are not too expensive. Obviously, this would also involve your own code, as well as using either a bunch of AD chips or 4x PIC with 13 AD inputs (e.g. 18F4420, I got these cheap from Rapid Electronics UK recently) and using one as a master device also. http://www.edrum.info/schematics.html

The exact AC voltages for EL on that part (and every EL backlight) are quite relaxed, with 200VAC being the recommended maximum. It's fiddly making an EL driver/inverter circuit. I've had good success using the driver packs from PC EL glow tape mod kits. Same thing. NOT the Cold Cathode kits (these spew out much higher voltages) PC Mod kits with either rope/string EL or Tape kits. I've bought this one recently: http://tinyurl.com/3wfwbs The circuit is potted/encapsulated and has holes for screws/bolts or a sticky pad to mount and two EL connectors... It works near silently with a 2x40 white EL BL I have for the MB-FM.. Can only hear a slight whine with ear right up to it, which is far better than my own circuit attempts so far.

According to this link: http://www.hardwarebook.info/Amiga_500/600/1200_Power_Supply There are 4 types for A500/600/1200. I only mentioned this in case someone has one lying around gathering dust or can get one. There are less of these floating around the second hand market than C64 PSU's. A C64 PSU would work well too, with less voltage (+/- 9v reg. or so from a voltage doubler) and I don't think that would make any noticeable difference.

So it's ok to cut up a C64 and use its power supply? :) Ah! Maybe I should clarify. Buy a PSU on its own on eBay or similar. Don't hack up your working Amiga, or C64, or WHY? if avoidable.

Simply to the point: Any old Amiga PSU. The Amiga PSU puts out 5v and -12v / +12v at totally over adequate ratings for the MBFM. It would be fine for even a highly expanded version. A bit chunky. You won't find the square DIN socket easily either unless removed from an Amiga. Just lop the end off and put on your own type of connectors. I just bought one in a lot with three joysticks, but really only wanted two of the joysticks. I will use the PSU in another project though if working.. A Kempston Competition Pro 5000 (my favourite joystick ever, for emulators) a Konix Speedking (another highly reputed stick) and another very obscure thing I can't find any info on at all. I will make a PS/2 or USB keyboard interface to convert these joysticks into keyboard keypress emus, for emus ;) http://www.ko-gathering.com/wiki/index.php?title=Joysticks Sidetracked ;) Just a thought as I'm sure an Amiga PSU is not hard to find and is much less hassle than other methods. External PSU will also allow more compact designs to a degree.

OK. Just the cut-down Core to knock up on strip board now. And the case.. And the keyboard... And.... ;)

Hi. Crystal again ::) I bought a 14.31818 crystal from Rapid Electronics a while ago (they no longer have them) but the range is on this page: http://www.rapidonline.com/Electronic-Components/Frequency-Control/Oscillators/Crystal-oscillator-modules/72920 I'm a bit confused about the 3.3v/5v versions of these oscillators, as if you check the datasheets for either, they all say 5v parts. A picture of the crystal in circuit: Looking at the code on the part, it seems to suggest it might be suitable for both 3.3v/5v? Might this affect the operation, before I plug it in and get into trouble? Cheers.

> FB-01. Use STEEM Atari ST emulator with YSEditor or SoundQuest Midiquest. http://www.home.zonnet.nl/m.tarenskeen/yseditor.htm > "i have to rub my audio equipment with leather care!" Yes. I do. And I'm not too ashamed ;)

To move from the bipolar power supply itself to the transformer (I made a bipolar from a 7812 and 7912 pretty much lifted from the PDF datasheets, but with more input capacitance).... When I made valve amps in the past, the transformers always put most projects out of range. I've hand wound 3 High Voltage and Heater toroid valve mains transformers which have run without hitch for years. This means removing all the secondary windings then adding your own. For these kind of voltages, you're talking about hundreds, if not closer to a thousand+ coils ;) It's worth it! They make great PSUs. I've actually wound a toroid especially for the MBFM already, here's a poor picture: I modified the 5.8v~ winding up to 9+v~ for the 5v, but the other winding is fine. Should be enough for the low current draw. Already tested the +/- 12v circuit. Oh. You may notice I have no centre taps on the secondaries? No problem. There is a voltage doubler in the +/- 12v circuit, so 12.8v~ is fine and actually produces roughly +/- 18v DC. I haven't managed to rewind a laminated transformer yet without problems, so I don't recommend doing this with the ordinary laminated transformers, just toroids. To do this, you need to make a long shuttle, about 8-12" long, narrow enough to fit through the centre of the toroid. Like the shuttles in weaving. I used thin mdf and pine. Wind on an overestimate of the wire to this first and wind away. Coated copper wire of course. If you choose a toroid with a suitable winding on it already, you'll need less additional windings ::) Generally, I've found toroids with higher voltage secondaries need less windings per volt. (easier on you) To measure the windings per volt, wind on 10 turns and measure the AC volts. This also tells you the rough primary windings.. Make sure your wire is rated above the approximate current draw of the circuit it is to power and double that to be safe. Within reason. It may sound like a real PITA, but it only takes about an hour or two to do once you've done one and they work a treat.

I have a few circuits for EL: One scavenged from a toy EL rope/string thing. PC Mod kits with either rope/string EL or Tape kits (cheaper than buying an inverter generally) Like these: http://tinyurl.com/3wfwbs I've just received the red tape, but it is closer to bright pink! Hmmm :) I can confirm that the EL power supply is almost completely silent with two different normal backlights, with a variable voltage of, say, between 4-12v, a good range of brightness can be had. It is encapsulated, or potted in a plastic shell about 45mm x 26mm with a self adhesive foam pad in place. Not super cheap as in near free, but it does have 2 EL connectors, so you could power 2 backlights (MB seq) or use the mod tape as well for some flashy light strips on or inside your project. I shall buy more of these in the future for EL BL, I've tried a few other ones that were noisy. I also made a circuit with a very small VA transformer, about 240v->12v, reversed and wired up to a 555 timer circuit with adjustable PWM triggering a power transistor to drive it. The one I made, even though I stuck to the recommended freq. etc. is loud. I toned down the noise to bearable levels by reducing voltage, but this also reduces brightness.. This noise is not transferred into the synth sound at all. It's just a bit annoying, but not as loud as the noise the Yamaha A3000 makes, which is louder than the PC tower.. I'm not whining now (aiiiee) :)

Some of the other kit lying about close by might be more interesting... [img width=600]http://www.sphinx.f2s.com/SID/10.JPG But the WAF (wife acceptance factor) is zero and dropping fast.. [img width=600]http://www.sphinx.f2s.com/SID/11.JPG Hurr, hurr ;D