Wilba
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Posts posted by Wilba
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I've been thinking about a ribbon controller myself... the reverse side of Mini DV tape is a good resistor (but fairly high resistance, 100K per cm!)
One thing to be wary of with these ribbon controllers - if you are using them as a simple voltage divider, like a slide or rotary pot, the first major difference is that the "wiper" can be off the strip, the SECOND major difference is that the "wiper" is not just one point - you can touch at multiple places and "short" up to the entire strip. That is, you can touch at the start and end of the strip and effectively short your power rails. It is unlikely you will intentionally do this, but it might happen accidentally.
To fix difference #1, you can do it the simple way (I'm guessing here, unproven) - ground the wiper through a big resistor. That should stop the jitter, and when your finger is off, AIN input should be zero. If the resistor value is much, much greater than the strip resistance then its effect of reducing the resistance of the strip between the wiper contact and ground will be minimal. The more complex way is doing something fancy like this: http://www.paia.com/LabNotes/index.htm
To fix difference #2, if you don't mind sacrificing a little of the range, put some small resistors between each power rail and the strip ends, so that making a "short" across the entire strip still will go through these resistors instead of shorting the power rails. Or, do it the fancy way (see above link).
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It might be interesting to set something up that lets people compare the sound of their SID chips with others. The aim would be to combine a set of benchmarks (patch + MIDI sequence) that will drive the SID (i.e. filter sweeps, sync, ring mod, testing each oscillator, etc). It could even be interesting to listen to (like TK's demo MP3s). Then people could share an MP3 recording of a publicly available (and constant) benchmark for others to listen to.
Thus people who are building or have built a MBSID can:
- test their own SID is working and performing well (oscillators all work, filter works)
- compare a SID with other SIDs (their own or other MBSID users)
- hear the differences between SID revisions and filter cap choices.
- let builders make an informed choice of which SIDs they prefer and should try to obtain (6581 vs. 8580)
- let synth newbies (like me) learn from the gurus about filters, how the capacitors affect the sound, what makes a good sounding SID, how the 6581 and 8580 filters are different (why there are different preset patches for each), etc.
Obviously, some MBSID veteran needs to kickstart this process, and we can't ask TK to do everything, so the call is out for someone else to name the first benchmark. Keep it simple, one patch loaded into A1, record a short sequence on channel 1 to a MIDI file, include some parameter sweeps, or maybe something you know sounds different between the SIDs you have.
In case it is not obvious, I volunteer to setup and host the benchmarks, but I'm not the best person to name them.
Sidebar: The makers of HardSID would put SID chips in four "classes" using some some testing processes... http://www.hardsid.com/modules.php?name=Content&pa=showpage&pid=11 An ad-hoc benchmark system could perform the same function for the MBSID community.
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Don't waste your money.
Great prices, cheap postage: http://www.futurlec.com
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I tried a fresh BankStick, it formats all 128 patches, still switches to bank "H" when I plug it in, even though I only have one BankStick connected to address 0 (all address pins grounded). It appears as if I can't upload patches, or even get patches out of the BankStick with the MIDIbox Patch Manager app. I uploaded patches to the BankStick without a problem in an older version of MBSID, so I don't think it is circuit related (i.e. I've made the MIOS 1.7 hardware changes already, and I get the "pliiing" sound).
I now have realised that I have a 24LC512, not a 24LC256.
Is it the same as this issue?
http://www.midibox.org/forum/index.php?topic=5730.msg35248#msg35248
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After pulling out my Core + SID modules from over a year ago and reinstalling the latest MIOS and SID app, it boots nicely and shows the first screen. I recall it used to read "P 1 C 1 1---" and now reads "A 1 C 1 1---".
When I plug in my BankStick (which should contain patches from a LONG time ago) the "A" becomes an "H", and I get the "brrrring" sound. I don't think the old patches are there, as it stays on "Internal Patch" even if I change patch with MIOS Studio's keyboard. I also get the "brrrooop" sound when I unplug the BankStick.
I just wanted confirmation (since I can't find answers in the doco):
Does the "A" mean 1st BankStick, and when I plug in my BankStick, it goes to "H" because it thinks I've plugged in a BankStick in the 8th position??? (Even though all my address pins on the BankStick are grounded, i.e. A=0) Or does "H" mean something else?
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I hooked it up to a Core, looks fantastic! So much better than an LCD in negative mode. Great contrast - the black is truly BLACK.
Wiring note: Connect to Core as usual, but connect the contrast pot output (J15:V0) to the brightness control input (VBT, pin 3), thus letting you set VBT voltage in the range 2.5v-3.0v. Don't connect J15:B+ and J15:B- to anything - there is no backlight! Tweak the contrast pot until you see the display - if VBT is <2.5v you won't see anything!
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Just picked up a 20x2 character display - part # WP2002A (WP2002A-Y-JCS)
from Crest Technologies
AU$27.50, over the counter, from their warehouse in Nunawading, Vic.
Looks identical to Crystalfontz CFAP2002A-Y-ECS
http://www.crystalfontz.com/products/CFAP2002M/index.html
and has practially identical datasheet to this one:
http://www.spezial.de/doc/winsta/wp2002ayjcs.pdf
Aussies will find them cheaper than Crystalfontz - possibly only AU$11 postage.
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I would buy SID chips if I could... but...
In case anyone has a spare SID chip, or is willing to salvage one from C64s you can get your hands on (that I can't), I can trade for rotary encoders and 3mm blue LEDs (opaque blue plastic) and which are hard to come by for some (I had to buy in bulk). I will pay for all shipping.
So if you need a lot of rotary encoders and blue LEDs for the price of a C64 on eBay, let me know.
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So if my second core module is using the to-com it should be like this?
0000000000000102 ?
The master and all slaves must share the same baud rate, so the "to-COM" interface bit must be the same for the master and all the slaves, or the slaves won't receive the MIDI from the master.
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The output ratings are the same as mine, and the same as the specifications (see below). Double-check the voltages with a multimeter, just in case. There seems to be great variation in C64 power supplies, which makes sense since they're usually country-specific.
My one is a black box with ventilation slots, huge transformer and a 7805 regulator with a massive (and I mean massive) heatsink. The schematics show that the older ones used a transistor to regulate voltage (apparently the transistor and 300k resistor can be replaced with a 7805).
http://www.funet.fi/pub/cbm/schematics/computers/c64/c64extps.gif
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Don't go crazy trying to make single row header connectors with a pair of pliers. Buy yourself a cheap crimping tool and follow this simple guide:
The Art of Crimping
http://www.seetron.com/apps/app_connectors.html
Those fiddly little pins will fit nicely into the plastic housing and you'll save time too.
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First of all, there are no stupid questions - only answers !
Correction: There are no stupid questions, only stupid people.
(In no way am I suggesting anyone here is stupid)
Wilba
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A pull-up resistor holds an input pin high if the pin isn't connected to anything (ie. connected to an open switch is the same thing). If the pin is brought low by a switch to ground or a low output pin, then current flows from the positive rail through the pull-up resistor to ground/low output pin.
Thus 10K is used because it's low current (0.5 mA @ 5V).
The cheapest, ceramic 1/4 watt 5% tolerance ones are fine. And if you pay more than US$0.01 each for them, you're getting ripped off. Best to order in bulk from Futurlec and get the chips for US$0.35 too.
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Piku: Keep the SID station. The community needs someone with a SID station and a MIDIbox SID, so they can help convert SID station patches to MIDIbox SID.
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Perhaps you are right... Futurlec are probably the best ones to petition. In case people didn't know, they ship stuff straight out of Bangkok, so they are in a prime position to import ALPS parts from the factory, and they seem to specialize in upmarket hobbyists like us (they stock PIC18F452 chips, serial EEPROMs, etc.) PLUS their shipping is cheap.
I am on good terms with the Futurlec sales manager (having emailed him in the past a few times) so if there aren't any objections, I can write him an email regarding this idea.
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This guy is selling 8580R5 SID chips on eBay -->
(It looked like DriftZ bought the last one he sold!)
He's in Germany (Hannover), I'm in Australia, and I need help with the transaction. I emailed him and he can send me two (maybe more) chips for 7 Euro each. But he does not accept Paypal and it costs too much to pay him with bank drafts in foreign currency.
Is anyone willing to help me out with this (preferably a German speaker living in Europe)? They can get their own chips in the same order (I will pay for postage). I will even send them some tinted blue 3mm LEDs to return the favour.
Gruss,
Wilba
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Switches Plus (www.switchesplus.com.au) stock encoders... I was after the ALPS 16mm non-detented "audio-feeling" ones (model EC16B24304) but they said ALPS suggest the newer, smaller ones.
From Switches Plus, I picked up ALPS tactile switches with long shafts, (model SKHHDH) I think the same that TK used on his SID... 10-99 = AU$0.44, 100+ = AU$0.34 (plus GST)
I didn't get an encoder quote but I reckon the price will be relatively good. I could probably arrange a bulk order if there are enough interested in getting a decent number for a good price, ie. I'm not going to bother them for anything less than a 100+ order, because they may have to import them.
Post here with the number of encoders you need... don't forget to add a couple more spares. Once the numbers hit 80 or so, I'll arrange a deal, people can pay me via Paypal.
This offer is not exclusive to Aussies - if you're willing to pay the postage to your country, come on board.
** UPDATE **
Specs are here:
http://wilba.lowerdimension.com/EC12E122_0511.pdf
The deal is for the EC12E244, vertical type, no switch (that's my choice only because it seems the best one to get, it might not be available).
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Yeah... I vote for per-geographical-area forums... so us Aussies/New Zealanders can share tips and arrange bulk orders. Maybe TK can add a sticky thread to each one in which users can post their location... people could get a feel for who is around you and watching that forum.
But TK has a point: collective orders can span countries too, as does a PIC burning service. Maybe another forum dedicated to these two topics? Another concept which I'd like to raise: some people just cannot find some parts locally or even get them shipped to their country... ie. I can't get stuff from Reichelt. (My personal can't-get item is large vectorboard!) Are some people willing to get parts delivered to them and re-ship to others? Perhaps that can be combined with their own order so that the favour is repayed by paying the shipping costs of their own order. Or maybe repayed with a share of a bulk order. It seems to me that this whole community is willing to share ideas and give their time helping others in their endeavours - so this is just an extension of that... helping those who can't get what they need. So maybe a forum just for that would be really helpful: collective orders, reshipping favours, PIC burning, etc.
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:) Lucky you... we could have been bidding against each other! Everyone else, be nice and don't outbid Hermes!
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Another Aussie here... how many are there? It would be nice to gather a mailing list or even a forum so we could arrange bulk orders together. While I can easily obtain the common stuff quite cheap locally (eg. 100 resistors for $1.70 from Rockby) and order in PICs and other chips from Futurlec, it's a real pain trying to source things like rotary encoders and long shaft ALPS tactile switches. I still cannot find LARGE vectorboard/veroboard like what DriftZ and TK use :'(
BTW: TK it looks awesome... yet another toy I need to make *sigh* ;)
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Futurlec has them cheap: US$1.50 each, US$3 postage for <US$30 orders. They also have all the other chips you'll need for MIDIbox modules (CORE/DIN/DOUT/BankStick), cheapest I've ever found anywhere else.
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I would love to buy these just so I had four matched SIDs... but I already have 2x SID 6581 R3 and 1x 6581 R2 and don't really need four more...
SO I pass on this information in the hope that some MIDIbox SID gets these babies rather than some HardSID user ;)
If anyone bids and wins, let us know how they sound...
HURRY!!! Auction ends in 24 hours!!!!
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I initially designed my quad-SID PCBs with this idea (4x combined CORE/SID PCB) but then realised it would ultimately be easier and more flexible to just make smaller/optimised SID and CORE module PCBs.
(ALSO, I didn't know how to route the power and audio tracks to minimise noise, and wanted to support new features when they come... that's why I and others also gave up on the "single-PCB Quad-SID" plan.)
Being able to swap SID boards in your setup and even swapping ports/pins used for CORE->SID comms... these are great benefits when you need to debug why it doesn't work! It's also easier to do application uploads when you can just stuff the optocoupler into a slave CORE and connect the MIDI In cable to it.
My opinion is that the modular design is best. Don't view it as "so many PCBs"... in surface area it's not that much different... but your plan involves three PCB designs instead of just using/reusing two PCB designs. That's usually cheaper to make too, if you get someone to make them for you (check out www.futurlec.com) - ie. you save on the per-design overhead more than the very minor reduction in PCB area.
Re-use is the best thing on earth, isn't it?Re-use TK's brilliant modular design!
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I used a 0.05 inch grid in a drawing package to design the front panel, making sure that component pins were aligned to a 0.1 inch grid.
DO NOT assume your laser printed artwork is accurate, especially along the length of the paper (ie. the axis that goes around the roller). I observed such a large error that I've had to rethink how to make an accurate drill guide (and print my artwork). The printer is fairly accurate along the width of the paper. What I'm doing now to compensate is printing my wide SID frontpanel across three A4 sheets, along the most accurate axis, then joining them up. The error across the page length over the 5 inch height of the panel isn't that bad.
So get a good steel ruler, print out a 1" grid and MEASURE!
SID benchmark
in MIDIbox SID
Posted
kokoon: thanks for your input.
There are so many combinations of pitch, waveform and filter that it might be tedious and not really that useful.
I was thinking of two kinds of benchmark, one kind is just a pure test of the oscillators/filters working, the other kind a demo of a given patch. Maybe the pure tests consist of a single patch and all you do is play a note , although you could repeat the test with different notes (one per octave or something).
Waveform Test #1
- a wavetable that plays the each waveform combination in sequence on oscillator 1, then repeats again on osc 2 and osc 3.
Waveform Test #2
- a pulse waveform on oscillator 1 only, modulated by a slow LFO.
Filter Test #1
- a wavetable that switches between each of the filter options and resonance 0/127. Cutoff modulated by a slow LFO.
These are pretty basic, and what I do manually to test my SIDs.
What I was hoping for was some SID guru to come up with a more musical demo kind of thing - i.e. a patch and a sequence they think shows off the SID (with cool filter use) that a newbie can listen to and compare to the same patch/sequence played on their own SID. Sort of like the demo samples that TK put on the MIDIbox SID page.