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warland

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Posts posted by warland

  1. Just trawling thru some older posts and noticed the mention of the evolver.

    As many of you will know OnChip is the current name of the company once

    known as CEM.

    The chips used in the Evolver for analog signal processing are the PA397's.

    These are  a tweaked version of the CEM3396 as used in the Obi matrix

    6 and 1000. Also used in the Cheetah MS6. If you ask nicely and order

    about 25,000 of them, OnChip will make you some..=)

  2. As SLP has said but I will try to answer your questions directly. :)

    1. the amount of "expert knowledge" to actually build it is minimal. If you can read a schematic,

    understand how to interpret component types and values, can solder and have a general

    knowledge of electronic construction practices you should be fine. I would suggest you dig up

    some info on basic electronics (plenty is available off the web) and read up first.

    2. Read on www.uCApps.de. A couple of guys here sell PCB's and kits you can purchase.

    (At a really great price if I may add). You will need to source the SID chips yourself. Again look

    around the forums as some guys have a few for sale or hang out at Ebay and look to purchase

    a few old Commodore 64's.

    3. Time to build will vary on which version you decide to build, experience and how enthusiastic

    you are. Take your time as a beginner and don't rush things. Check your work after each step

    and DON"T put yourself under any time limits. It is better to work at a steady pace and check

    your work than to be chasing problems due to a rushed job.

    Look at the WIKI and these SID forums before jumping in and asking too many questions. You

    are not the first beginner and it's most likely the questions you wish to ask have been answered

    before.

    Above all, have fun and enjoy constructing a device that has no peer. There is something really

    good about having people say "man, that thing is great" and being able to reply with "I built

    it myself" ;D

  3. To keep costs down, some of the low cost plugpacks simply rectify the 12vac from

    the tranny with no filtering at all. I have seen some which dont even use a bridge

    recitifier (full wave rectification) and simply use a single diode (half wave rectification)

    which produces a large amount of noise (if you look at the DC from a half wave

    rectifier you will see that the DC is actually "switching" on and off 50/60 times a

    second.

    You may need to play around with the value of the filter cap to get rid of all the

    noise. Especially if it is only a halfwave recifier. Just make sure that the voltage

    rating is no less than 16v, preferably 25v.

    It is sometimes worthwhile to pay a bit extra for the fully regulated plugpacks.

  4. glad to be of help.

    As a matter of interest, the "ideal" filter capacitor value for placement after

    a bridge rectifier can be determined from a simple calculation, C=(I*T)/E

    where;

    C = capacitor value

    I = maximum current draw

    T = half cycle time (8.33ms @ 60hz or 10ms @ 50hz)

    E = the fall in voltage that will occur during one half cycle

    The capacitor selected must have a voltage rating of at least 20% more than the expected

    DC voltage output of the bridge rectifier. It is fine to go way over value (eg using a 100v

    rated cap on a 12 supply) but never less, unless of course you dont mind your filter

    cap going bang or shorting out!! The 20% allows for any fluctuation or spiking that may

    occur. Most countries supply AC with a reasonably tight tolerance to the rated value but

    in some circumstances this can vary considerably.

  5. Toroidal transformers are always the best choice over other transformer designs.

    In simple terms they are more efficient and due to the "closed" magnetic aspects

    of their construction are less prone to produce EMF type noise.

    As to fusing, remember a fuse or circuit breaker is intended to protect what comes

    after it in the circuit, NOT what comes before it. In this schematic a fuse of no more

    than the primary winding's rated current should be fitted. In this case I would fit a

    500mA fast blow in the "live" wire of the primary. This particular tranny appears to

    have a tapped primary for connection to 2 different supply voltages. (probably 110

    or 220-240). Never fit a fuse in the return or neutral side of the primary as if this

    blows and the device is still connected to the AC supply, a lethal voltage is still present

    on the tranny.

    The secondaries should be protected by a 1 Amp slow blow on each secondary. In this

    case one in connected between the white wire and the bridge rectifier and one connected

    between the green wire and it's bridge rectifier should be sufficient.

     

  6. My suggestion is to build the SID modules including ALL PSU components as shown in the original SID schematic.

    Build the optimised PSU as per the schematic without any modification at all.

    On each core module leave out IC3 (7805 voltage regulator)and fit a bridge wire between pins 1 and 3 of this regulators PCB pads (the 2 outer ones), leave out X1, leave out C6 (330nF), leave out C4 (10uF) and in place of C5 (2200uF) fit a 1000uF/16v electrolytic capacitor.

    A standard 78xxT series regulator is good for an output of 1 Amp. If fitted with a good heat sink this can rise to around 1.4 - 1.5 amps. If possible I would fit one of the 2 A rated 7805's if using in a system with multiple cores and sid's

    Hope this is clear and helps.

  7. ???

    I think my view on what has been happening on ebay is quite obvious.

    As to your second statement I don't see what you are getting at !

    I have been kicking around (though I admit not a lot of posting) since

    2003. Previously with the nick cem3340. I have had contact with TK

    at times since his first midibox (16F84 based) way long ago. I have

    quietly been developing various MIOS devices over that period all of

    which now work happily in my studio. I am currently developing an

    8 channel Drum synth (fully programmable, with program storage)

    and a true analog synth voice card which will again be fully programmable,

    have program storage etc. This when mated with MIOS will be expandable

    so as to allow 6 note poly. (Using a similar method as the SID synth..ie.

    1 core per voice)

    I have been tempted many times to post up all the details, code, schematics

    etc over the years. At this point I simply wont do it for the fact of people

    like bluelantern and those who condone his/her activities.

    So no more from me on this ebay stuff. Sorry to hijack the thread with my

    waffle.

  8. Simple, lock this thread :-X I understand your point of view and maybe it is floggin

    a dead horse, but sometimes the horse is just sleeping. It's not my IP being sold

    so I suppose it's cool. It's not for me to decide if the work of the community is of

    no value and like most "democracies" freedom of speech is not truly free.

    Every now and then god dies and someone is elected to walk in his footsteps, so

    now is the time to probably lay down and admit defeat.

    ???

  9. I don't like kicking someone for there idea of taste and design concept but this guy

    is just unbelievable. Ok, what he does is wrong with regards to using unnameised

    IP, but it goes beyond that. He is making big bucks from other peoples lack of knowledge.

    Really, I find it distasteful that he passes of his 3rd world quality workmanship

    as something of value. My 12yr old daughter builds better gear than this stuff!!

    No amount of "coloured acrylic" bling or hotmelt glue can disguise the fact that

    this chap bangs these boxes together in a few hours with his only regard being

    to make as much money from the nieve as possible >:(

    From his recent sales ;

    11 units sold, highest price $510.00us, lowest price $115.06us, average price $314.00us

    net income $3457.06

    Sales history...Aug 1...Sept 4....Oct 6.

    Now if you assume he will sell 11 every 3 mths, using his current figures he will

    make an income of around $13828us a year from this scam. :o with not one cent

    going to the person (people) who made his little business possible.

    And why the sudden USA sales only policy...has he been the "victim" of a purchase

    scam himself?......I hope so ;D

  10. There are 2 reasons I can think of ;

    1) It may be that only the full versions (ie not demo or function limited) of the mentioned software

    will allow full checking of the Houston emulation

    2) Not wanting to be associated with any dodgy (ie cracked) versions of the steinberg apps  :o

  11. I'm an electronics tech by trade and see problems like this at times.

    Double check that ALL solder joints are good, hidden dry or bad joints

    can cause issues.

    Check for any shorts between PCB tracks. I have seen tiny "whiskers"

    of solder that once a PCB is warm caused shorting before. You need

    to use a magnifying glass to check.

    Have you tried using another 18F4685?

    Is there "noise" on the powersupply output?

    If all the "hardware" side of things look ok, have you tried re-downloading

    the SID file from the website and re-loaded that version. You may have

    a corrupted application file.

    All that said, does the reboot occur if no SID chips are fitted to the PCB but

    with the PIC running the SID app?

  12. Even under GPL licensing it is probable the guy is in breach of the licensing terms.

    His ad on ebay should clearly state that the device is covered by the GPL conditions

    and his device being sold should also be supplied with a copy of such license and

    all required documentation.

    See: http://www.gnu.org/licenses/gpl-violation.html

    I'm no legal eagle but a good read through the GPL conditions have surfaced a number

    of areas it could be argued a breach has occured.

  13. I have a bit of a question regarding reading a key matrix. To add fuel to the current fire

    I'm wondering if it's possible to scan a matrix but sensing a variable voltage at each

    crosspoint. In older keyboards, velocity was sensed by timing the crossover from a normally

    closed contact to a normally open contact on each key. Thus the quicker the change over

    the higher the velocity.

    Recent keyboards use a dynamic rubber button arrangement. On closure, the voltage output

    depends on the resistance at the time of closure. It works on the principle the harder the

    key is pressed the lower the contact resistance and therefore the higher the voltage at the time

    of reading. As an aside to this principle, it also allows aftertouch to be applied as well.

    On each scan, new key voltages are read and a midi note and velocity value sent. If a key scanned

    is already "flagged" as being on, the current voltage is read and sent as an aftertouch value.

    I hope my rough description is enough for someone to answer whether it is viable to use this approach with MIOS. I have a number of keyboard assemblies that use dynamic rubber contacts

    I could use if this could be achieved.  :)

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