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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Thu Jan 03, 2008 6:40 pm Post subject:
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In case anyone is interested in listening to a Chord EGG from PAiA or learing more, see and hear the attached items:
Bill
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EGG_Track 1_ex1.mp3 |
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RF
Joined: Mar 23, 2007 Posts: 1502 Location: Northern Minnesota, USA
Audio files: 28
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Posted: Fri Jan 04, 2008 12:21 am Post subject:
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I like that
I've never heard of this - What parts are involved? I see LSI mentioned - that does not sound promising to recreate it. Is there a schematic around?
bruce |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Fri Jan 04, 2008 6:26 am Post subject:
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this PDF goes into details about the "Top Octave Generator" and mentions that the Chord EGG uses it something along the lines of a Mostek
MK50240.
Don Lancaster’s Hardware Hacker
http://www.tinaja.com/glib/hackar3.pdf
And here's a pic of the PCB:
_________________ Sneak-Thief - raw electrofunk Last edited by sneakthief on Fri Jan 04, 2008 6:27 am; edited 1 time in total |
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TheAncientOne
Joined: Dec 26, 2006 Posts: 144 Location: United Kingdom
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Posted: Fri Jan 04, 2008 6:26 am Post subject:
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RF wrote: | I like that
I've never heard of this - What parts are involved? I see LSI mentioned - that does not sound promising to recreate it. Is there a schematic around?
bruce |
Anders amazing site has it:
http://rubidium.dyndns.org/cag/pdf/egg.pdf
The problem part is the obsolete MK50240 top octave synthesizer chip. This is a frightening price as NOS.
I'm looking aroung for an updated PIC design. Jim Patchell did one, but it's about 4 octaves down, due to processor speed. I've heard of an AVR version but can't find it. Best suggestion I've heard so far is a small CPLD or FPGA, though that means a lot of design work. _________________ Mike |
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bugfight
Joined: Aug 02, 2007 Posts: 188 Location: Arlington, TX USA
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Posted: Fri Jan 04, 2008 9:09 am Post subject:
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Blue Hell wrote: |
Yes I remember that, it was marketed here under the Braun brand, but in the US as something else. Didn't have it myself, and it was a bit limited indeed, but I've always liked the concept; not building a circuit but drawing up schematics really. |
i bet that's the one, i don't remember what it was called...
forgot to mention the schematic thing. the blocks had the symbol on top so at the end you had the circuit and the schematic in one, which was not a bad idea. some of the "components" were nothing but wire connecting the terminals. you had to have a lot of blocks to do anything interesting (which i didn't of course)... |
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bugfight
Joined: Aug 02, 2007 Posts: 188 Location: Arlington, TX USA
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Posted: Fri Jan 04, 2008 9:16 am Post subject:
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[quote="State Machine"] Quote: | hehe i also remember making an arc lamp ..."top up a pot" ...
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LOL.
i never pissed in mine, i think that would have killed me for sure. it was totally homebrew too, with the "electrodes" being just bare wire, which did indeed corrode badly...
i had a friend, though, who pissed on an electric fence once...
once! |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
Audio files: 24
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Posted: Fri Jan 04, 2008 11:58 am Post subject:
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Quote: | I'm looking around for an updated PIC design. Jim Patchell did one, but it's about 4 octaves down, due to processor speed. I've heard of an AVR version but can't find it. Best suggestion I've heard so far is a small CPLD or FPGA, though that means a lot of design work. |
Would this website help? They seem a bit expensive but a good alternative.
http://www.organservice.com/crm/topdividers.htm
If forum members, or myself, wanted to roll their own "TOS" IC, that would be a fun learning experience. The topology of the design is quite simple actually as it is a series of redundant dividers with different feedback coefficients to provide the correct output frequency. Using an MCU's wide timers would work nicely or using a CPLD with redundant dividers would work equally well.
Usually it is desirable to output a square wave with 50% duty cycle on each of the note outputs. When designing the hardware counter method, the divider is usually decoding a specific count then resets a counter giving you 1 pulse per "N" counts. The output of such a decoder would thus not be a 50% duty cycle but some really narrow pulse equal to the period of the master clock if synchronously loadable/resettable counters are used . To get around this, using an example of the /426 output of the chip illustration, I would create a divide by 213 using the above method then then feed this to a toggle flip-flop to divide this by 2, thus a 50% duty square wave with a division of 426 would be created. I hope I did not go too far with this
Anyway, I will dig up my EGG and take a peek at the TOS chip and post some pictures of it as well ......
Bill
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
Audio files: 24
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Posted: Fri Jan 04, 2008 12:00 pm Post subject:
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Quote: | never pissed in mine, i think that would have killed me for sure. it was totally homebrew too, with the "electrodes" being just bare wire, which did indeed corrode badly...
i had a friend, though, who pissed on an electric fence once... |
Oh dude this is so funny man !!!!!!! Thanks for the humor ! Too bad you did not have pictures of this experiment of yours
Bill |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Fri Jan 04, 2008 12:11 pm Post subject:
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i'm not sure if that ks-87 will work as a drop-in replacement - compare that to the frequencies that the MK50240 uses:
in the EGG schematic, it's using the following divisions:
239
253
319
358
379
426
478
However, I think the MO83 would:
_________________ Sneak-Thief - raw electrofunk |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Fri Jan 04, 2008 12:26 pm Post subject:
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Quote: | i'm not sure if that ks-87 will work as a drop-in replacement - compare that to the frequencies that the MK50240 uses: |
Oh yes. Thanks. I was siting a design example for rolling your own but YES, I appreciate this clarification very much !!!!!! Good detective work there I hope I did not mislead anyone
Bill |
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sneakthief
Joined: Jul 24, 2006 Posts: 569 Location: Berlin
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Posted: Fri Jan 04, 2008 12:46 pm Post subject:
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btw, i found a possible source for the MK50240 for $24 US. i'll let you guys know if it goes through
ps. sorry to hijack this thread! _________________ Sneak-Thief - raw electrofunk |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Fri Jan 04, 2008 1:23 pm Post subject:
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Quote: | btw, i found a possible source for the MK50240 for $24 US. i'll let you guys know if it goes through
ps. sorry to hijack this thread! |
I took a peek at my EGG and it has an AMI S50240 installed and it's frequency table matches the Mostek device.
Your not hijacking, your adding value to the thread
But lets see more DIY stuff you guys did when you were youngsters !
Bill |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Fri Jan 04, 2008 10:47 pm Post subject:
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Here is my Chord EGG as it stands today and a closeup of the TOS chip from AMI used in it.
Bill
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
Audio files: 224
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Posted: Sat Jan 05, 2008 3:41 pm Post subject:
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Crystal sets (several), pentode audio preamp, #27 triode RF oscillator capable of transmitting, super-regenerative receiver (tube), game of "Nim" (also called Black Match) using relays, guitar driven UJT relaxation oscillator circuit for making weird synth sounds, transistor amplifiers. I'm sure there's more, but that was a very long time ago... |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Sat Jan 05, 2008 4:42 pm Post subject:
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Quote: | UJT relaxation oscillator circuit for making weird synth sounds |
OH yes, I had designed a UJT relaxation oscillator years ago but not to make any sound but as part of a PWM circuit in a DC motor controller to drive a radar antenna at various speeds I have not used UJT's since. Thats was many years ago also. Brought back memories from my old radar lab .......
I take it you have a radio operators license ?? The ARRL handbook was a goldmine of information. I currently just have a "TECH" class license because of my amateur rocketry efforts. I was more interested in ATV and DATA transmission (telemetry) rather than the VOX stuff on 2/6 meter ......
Bill |
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JovianPyx
Joined: Nov 20, 2007 Posts: 1988 Location: West Red Spot, Jupiter
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Posted: Sat Jan 05, 2008 5:52 pm Post subject:
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State Machine wrote: | Quote: | UJT relaxation oscillator circuit for making weird synth sounds |
I take it you have a radio operators license ?? The ARRL handbook was a goldmine of information. I currently just have a "TECH" class license because of my amateur rocketry efforts. I was more interested in ATV and DATA transmission (telemetry) rather than the VOX stuff on 2/6 meter ......
Bill |
Sadly, I do not have a license. I was close to a Novice lic. back then, I had the code speed at the required 5+ wpm send and 7+ wpm receive. I knew the theory too, just never took the test. Got busted by the radio cops once for sending out a 60 Hz halfwave buzz on 1000 KHz. I had it on a horizontal longwire antenna that was 30 feet off the ground (normally used for crystal sets). I wanted to see how far it went as I rode my bike with a transistor radio. When I came home, there they were. They told me I didn't belong on that wavelength and that I should get a license... [sigh]. But I digress and go off thread a bit. |
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cappy2112
Joined: Dec 24, 2004 Posts: 2465 Location: San Jose, California
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G2 patch files: 1
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cappy2112
Joined: Dec 24, 2004 Posts: 2465 Location: San Jose, California
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Posted: Sat Jan 05, 2008 6:26 pm Post subject:
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v-un-v wrote: | (Rockets were so much FUN!!). Rockets meant that you spent more time in the sunshine rather than the dark. However when I got into photography, 95% of the time was spent in the darkroom anyway! |
Oh yes. Who could forget the rocket kits from Estes and what is the name of that other company?? There were two companies that I remember that sold model rocket kits when I was a kid.
I never saw my first rocket after the initial launch. The wind took it far far away. _________________ Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home. |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Sat Jan 05, 2008 7:13 pm Post subject:
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Quote: | I still have a Radio Shack Electronics dictionary from 1974-75, and many of the Engineers Notebooks from Forrest Mims. |
Oh the Mims books, yes !!! I loved them and built many of those circuits Those old catalogs from PAiA trigger some memory cells as well.
Quote: | Oh yes. Who could forget the rocket kits from Estes and what is the name of that other company?? There were two companies that I remember that sold model rocket kits when I was a kid. |
The other company was "Century Engineering" they made fantastic model rocket kits. There was also "Flight Systems Inc." and "Enerjet". I believe they made solid propellant motors also. "Cox" also made black powder motors and kits also.
Thanks for your posts !
Bill |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Sat Jan 05, 2008 7:18 pm Post subject:
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Quote: | Got busted by the radio cops once for sending out a 60 Hz halfwave buzz on 1000 KHz. |
Oh but what a cool experiment. How else to learn but to take empirical data. I probably would have been just as curious as you were about how far that signal would travel. Nice .....
Bill |
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cappy2112
Joined: Dec 24, 2004 Posts: 2465 Location: San Jose, California
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Posted: Sat Jan 05, 2008 7:40 pm Post subject:
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State Machine wrote: |
Oh the Mims books, yes !!! I loved them and built many of those circuits Those old catalogs from PAiA trigger some memory cells as well.
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Well that Chord egg sounds pretty neat, for a paia kit. Most of the things they made didn't sound so good.
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Thanks for your posts !
Bill |
Good thread. Thanks for starting it (while I can still remember this stuff)! )
Were any of you into stamp collecting? ;-0 _________________ Free Tibet. Release the Panchen Lama from prison. Let the Dalai Lama return to his home. |
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blue hell
Site Admin
Joined: Apr 03, 2004 Posts: 24079 Location: The Netherlands, Enschede
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Posted: Sat Jan 05, 2008 7:46 pm Post subject:
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cappy2112 wrote: | Were any of you into stamp collecting? ;-0 |
Yup, but the electrons moved in boring patterns _________________ Jan
also .. could someone please turn down the thermostat a bit.
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Sat Jan 05, 2008 8:58 pm Post subject:
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Quote: | Yup, but the electrons moved in boring patterns |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
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Posted: Sat Jan 05, 2008 9:02 pm Post subject:
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Quote: | Good thread. Thanks for starting it |
We can thank "Liquidpaper" for that What a great handle that is !
Bill |
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State Machine
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Joined: Apr 17, 2006 Posts: 2809 Location: New York
Audio files: 24
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Posted: Sat Jan 05, 2008 9:11 pm Post subject:
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Quote: | Were any of you into stamp collecting? ;-0 |
My Profile :
Occupation: Electrical Engineer
Interests: Electronic Music / Electronics/Electronic Design/Electronic Instrument DIY / Electronic Music & Computer History/Amateur Rocketry/Stamp Collecting |
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