TheAncientOne

That's the best way to use ebay - keep a google window open to check prices. A 5% discount on the new price is never worth the hassle of no guarantee or service. There is a lot of 'macho bidding' too - people who don't quit when they should, for entirely wrong reasons. I just put up my max and walk away from the computer. If you do a little 'completed item' research, you can get an idea of what is a reasonable top bid. Mike

There are bargains though: just before Christmas I picked up 7 C64's wiithout PSU's for £25, all working, and I got 4 later and 3 earlier units. I did have to desolder one SID.... I've figured out a trick to mount a temporary ZIF socket to my Mk1 MIDIbox SID board, so I can use it as a SID tester. A thought: if you are going rely on Your SID system for performance work, make sure you have some spares! Several user of Prphet 84's have reported blowing the chips, though I suspect that is due to faulty stage earthing. If I ever take mine live, I'm going to add some transformer outputs. Mike

Beaten to the punch here! The SN76489 is also used in the BBC Micro, so I might just do ROM for one of them and see if 2MHz 6502 is enough to drive it from MIDI. The BBC would make a reasonable control surface - it's got a 4channel 10 bit A-->D in the joystick port, a free VIA in the user port, and well as loads of other goodies. You can easily drive an LCD from the userport. If anyone in the UK/Europe needs a BBC, I've got a few to spare. Postage any further is horrendous. Mike

I think it wouldn't be too hard to build one into a metal tool case like this: http://www.maplin.co.uk/Module.aspx?ModuleNo=36796&criteria=tool%20box&doy=12m2 Or a briefcase, a bit like this: http://gallery.diy.synth.net/main.php?g2_itemId=873 or www.vintagesynth.com/misc/synthi.shtml With a bit of work you can make the lids removable Hinged units are not easy - I've built them in intrumentation work. You have to consider cable flex as well. Thre is also the ergonomics - how easy is it going to be to use, I do think a workstation style sequencer could be good, but a lot of thought on control layout would be needed. My own view would be to get running with a simple layout, and then re-case it when you were used to it, and the way it worked for you. As an example, on mine, I'm having the encoders on two staggered rows of four under each display, rather like MTE does here: http://www.midibox.org/forum/index.php?topic=8268.msg59062#msg59062 Because my fingers are a bit big for a linear layout, but despite having a lot of other ideas for panel design, I feel it's better to get it running and use it for while, before doing a design freeze on the layout, So my first panel will be home cut alloy, and 'Brother' labelled Best wishes Mike

A minor thought about distance sensors: I got some for robotics by breaking a few old polaroid cameras, bought at flea markets. Just look for the ones with the gold 'eye' to one side of the lens. I've been paying £1 to £3 for them. Not sure if the response time is good enough for you. HTH Mike (edited for ypting rerros)

Like this one by Marc Bareille? http://m.bareille.free.fr/index.html His site is a good source for filters and a few other things too. I'm not sure when he'll be releasing the mixer, but the good news is that he does PCB's. Best wishes Mike

Couldn't find it on ebay, but: http://www.thomann.de/gb/cordial_mir.htm Have it listed at 38 euro. Interesting idea. Mike

Thought this may be of use: http://www.sparkfun.com/commerce/product_info.php?products_id=8236 Mike

Sadly the pot boards are missing, and apparently people have been waiting over 12 months for the designer to supply them. I'm told there are "issues". Mike

http://www.musicsogood.com/duskfire/info1.htm Which is good for me too - I've found a remastered copy, because all I have is the Vinyl. Then I listened to some of the samples, and my screen went all blurry, as I was mentally dragged back to first hearing an album I've not played since I moved, which is means I've not heard it for over 4 years. Ardley was a genius, it still sounds fresh now. As soon as I saw the re-master I bought it! Music has an emotional hit that is hard to explain sometimes. It was a piece that got me into pattern loop work long ago, (well that and Terry Riley's stuff). I've not done any for over 20 years, and now I might know enough to make something worth keeping the recordings of! I do remember my earliest attempts at rhythm tracks as a kid in the 70's using spliced up tape loops. I'd get a sort of polyrhythm then usually submerged under a lot of tape noise! It was your idea started me thinking. Thank you very much for that. Algorithmic is better than FLT, I agree. I did have a thought along the lines of storing a precomputed seed in a table, and using that to generate the actual sequence, perhaps by PRBS. I need to get my PICing up to speed then I can make a more sensible contribution, rather than cheering from the sidelines. Presently I can usually follow code, but I think my writing is rather lame. There will be some kind of cyclic pattern eventually, though some could be a bit long - sudden horrible thought of someone trying to go all 'harmony of the spheres', (in the pythagorean sense, not another Ardley reference), and do 22/7! But I must take a look and see if there is any commonality with the 'comma of pythagoras' problem in tuning. Thanks again Mike

Just had another thought, which connects with the scales thread. If a Pelog scale could be added, then with this you've got the basis for an electronic gamelan orchestra. The late Neil Ardley would have loved this for "A Kaleidoscope of Rainbows". Mike

Beautiful peace of work stryd_one! I dimly remember a similar problem coming up in the design of some kind of digital oscillator, to do with the output bit rate and the number of instruction cycles available for each sub process. It was a long time ago, and I swore I'd never look at another one of those old TI DSP chips again. The notes are quietly mouldering away on a backup somewhere, but I can remember that the solution involved factoring for the mutually prime factors, and then a lookup table. The problem was in a similar domain to yours, no floating point allowed, and speed being very much of ther essence, both processor and project! With the processors we've got here, there might be enough space for precomputed FLT's for all possible instances. How far up the count scales do you need to go? you'd be able to pull out the regular ones and then just FLT the mutual primes, I think. I could just be barking madly up ther wrong tree here though. Best wishes Mike

You've found a SCSI flash card reader? I'd be very interested to find out about that as a boot source for a NAS unit I'm building. Happy crimping. MIke

OK, I guesss the main problem stems from the board being flat on the bottom of the case. There is a bodge I once used, it's not nice, but it does work.... Buy two RS 334-549, or similar. These are wire-wrap pin header strips. Cut to 25 way. Spend some time bending the long wire-wrap pins to line up with the PCB holes. Fit both into a spare 50 way IDC cable socket (for alignment purposes). Fit to the board. Solder the unit in place as close to the board as it will go, without unduly stressing the board. (optional) I then put a fillet of hot-melt glue under the unit to give more support remove the alignment plug Make up a ribbon cable string for the connectors Plug, and hopefully go. Personally I think I'd do a loop cable with IDC 50 Pin SCSI plgs and sockets, and slip the ribbon into the case by bending the lid a little if need be - I hate modifying original boards, I just like my mods to be reversible and easy to transfer. Comes of experience on the road with custom gear, so probably not applicable to your setup. If you;re taking custom gear on the road, build it to MIL spec: hmm, perhaps the Area 51 option isn't that bad after all, Mike

So, the easy one is: RS 235-6355 IDC 50 Pin SCSI plug short 50 way ribbon, enough to go where you want, then crimp on a RS 121-0371 Cable mounting plug. Job done - not too neat, but functional Sorry I haven't got suitable pix to upload, you'll have to plug the numbers into www.rswww.com to see what I mean best I can come up with that's not a pain to solder Mike

First off: Centronics is 36 pin, do you actually mean a 50 pin 'harmonica' connector? (1) The easiest way would be to keep the 50 Pin board mounted socket, buy a 50Pin IDC plug, crimp a short length of ribbon into that, and then crimp a cable mounting 50 pin header on the other end, this is bulky but would work. Otherwise it's adapter time: (2). Small PCB with drop pins, (nasty layout job), (3) Get a cable mount 50 pin IDC header crimp a short bit of ribbon on, and solder the other ends, (nasty soldering job). I'd probably go for (3) if I really need the connector and the space, or (1) if speed was important. Having had to look for something similar once, if you want the actual connector it's time for (Cue Music): http://www.heatherlynn.net/Songs82/Mission_Impossible_Theme.mid and don that black balaclave....... (Quick edit to add - the problem has to do with a lack of 2mm pitch ribbon cable to go in aforementioned plug......) Mike

I've had a thought, though it may be too much work for a minority usage, but might it be possible to dedicate an extra PIC to being the control surface processor, so that it would be possible to remote the surface from the sound generator system? I know from industrial work that CAN is a very robust interface, and I have this vision of 4 (or More) SID's in a rack module, with all their I/O out of the way, and a neat 9 Pin D connecting to a control surface. Dumb idea probably . . . . . :-\ Mike

It might be worth mentioning that you can get 20K resistors in 1%, (you are using close tolerance I hope), which means a bit less soldering - use them instead of the 2x10K in series in the R-2R ladders. I have a veroboard layout too, but I need to refine it a bit, If I can afford a copy of Lochmaster I'll give a layout drawing a go. What did you draw yours with? Nice work! Mike

Beautiful work. I've seen pro kit that doesn't look half as good. Mike

The following link might be of use: http://billpentz.com/woodworking/PVC.html I once made a glycerine tank for friends, we used domestic immersion heaters, without their thermostats, solid stae relays and a commercial temperature controller (recycled, old), and a cut down old domestic water tank, (rectangular metal one). An oil drum cut vertically in half might be good. You need a tray to support the plastic, which should have long hadles for lifting the plastci out of the very hot liquid. Smaller bits can be put in the oven at home. With a bit of work you can blow, or vac form domes. Just be careful, hot plastic can give nasty burns. Mike

Hi Roger The problem isn't the opto system - there are plenty of those in old VCR's, tape drives, printers and the like, but the slotted wheel that acts as rotation detector. add to that the interesting little problem of aligning them in phase quadrature to detect direction, and an old mouse seems a bargain. In the UK, I get get new, but older types, at computer fairs for £2.30, if I go to the electronic scrapper I know locally he's glad for me to take some of this stuff away. Even some sites new ones are very cheap. e.g. http://www.scan.co.uk/Products/ProductInfo.asp?WebProductID=406749 The magnetic idea is good, I think some aircraft systems use it, as well as some professional joysticks. The thing I want is an up/down wheel, or pseudo slider, to get away from fixed end point pots. I'll try and get some pix of some of the stuff I like. More ideas the merrier though. Mike

Just spent a while digging in the junkbox for redundant mice. Conclusions so far: The older serial ones are more use - the more modern ones have too much of the mechanics integrated into the case, on the older ones it's board mounted. A couple of cheap modern wheel mice had a wheel assembly that could be removed from the PCB, by some judicious de-soldering. I then had a wheel with a single LED at one side, and a dual photo device at the other. I need a bit more time to dig into the device, but it's probably a pair of phototransistors, with maybe some threshold circuitry attached. Anyway, it should be easy enough to clean up the output, sort out some drivers and feed it into a DIN just like a switched encoder. The number of teeth parameter will need to be edited, thats all. I wonder if I could use this on my MIDIbox monitor instead of the up and down buttons? I found a nice blue negative 4 line display, and a blue tinted transparent Hammond box to put it in, (very iMac, only a bit spoiled by my veroboard). A wheel would be a very intuitive way of scrolling through the display, and would go with the look of the box. (Hmm since it's my first formal bit of MIDboxing, perhaps I should get the photographer over). The other mouse internals had two pairs of phototransister & led at opposite sides of the wheel. I can cut the PCB to leave them both assembled, and the circuitry for the phototrnasistors looks simple enough to copy or cut off and splice back on. The return of Frankenmouse..... "It's alive I tell you! alive!", (just practising). I found a meccano wheel with a rubber tyre which could run easily on the original spindles, and that would gear it up a lot. I think the search is on for something COTS, (Commercial Off The Shelf), for the wheel itself, unless we stick to filleting new cheap wheel mice, and stick to small devices Well, I've made a start. Mike

Now you've done it! My mouse saw that and is now hiding under the monitor. Seriously, that could be a good way to get the difficult bits. Make the faders in pairs then the mouse chips can be used. Same technique might work for wheels too. The thought of a wheel unit with a rubber tyre, just running on part of the original mouse mech seems neat. The old, expensive, and now virtually useless serial port mice have just got themselves a new job..... I wonder if there is something in the Lego portfolio that might do for the wheel itself? Nice idea! Mike

I think you're right. Motors have limited uses, I only like them for mixdowns, and the track would look neat too, as well as being a more intuitive too. I think optic sensing might be the way to go: longer lasting and quite compact, and those little slotted pickups are really cheap. I'll have to get thinking seriously again. Mike

The Penny and Giles ones use a wire loop, which wraps around a small 'drum' on the motor shaft. can be spring tensioned and thus somewhat self adjusting. I don't know how ALPS do it, their motors seem to be end mounted. I did think of a motor fader based around an ordinary pot at one end, and a motor at the other joined by toothed belt. A bit like the famous 'Coffee Proof' ones I saw years ago. The trouble was, that without some very fancy machining work, they were over twice as wide as an ordinary fader. I used four as masters in an experimental (pre MIDI!) lighting desk. When they got worn, I replaced them with large edge wheels and and an LED display. We were only using 16 steps for the full range anyway. Mike