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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Fri Jan 18, 2008 9:30 am Post subject:
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Thanks a million!
I guess it needs decoupling at the power input for the board (ferrite bead + 10uF + 100n) ?
Does Marc's board has decoupling caps for any of the chips?
Guys, remember that the Motorola version is not difficult to find and it's very cheap: MC1776
Here is a list of equivalents to the original K140UD12 (russian):
uA776
MC1776
LM776
LM4250 (NJR4250 seems to be an eq. too)
NTE888M
(The ICL8021 appears as equivalent too. It's different from th eothers but might worth further experiments)
Marc Bareille's page has good info too:
http://m.bareille.free.fr/modular1/vcf_polivoks/vcf_polivoks.htm
. Last edited by Fernando on Sat Jan 19, 2008 5:45 pm; edited 7 times in total |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
Audio files: 1
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Posted: Fri Jan 18, 2008 12:12 pm Post subject:
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thanks a lot for this...
David |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Jan 19, 2008 12:30 am Post subject:
FIrst graphic error found. |
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I forgot to label a resistor coming off U3 LM4250, it is supposed to be R15 1k resistor value. I have assembled one on protoboard, it took about 40min and not bad at all as far as wire jumpering. I used this protoboard:
http://futurlec.com/ProtoBoards.shtml
board: Prototyping Board - 777
I have found these to have some of the best board layouts, the rails were nicely thought out.
I still have to test it out. I only soldered it together today.
Once I am all done I am going to post the formula on what to buy and how i went about it so you can easyly build one. This is one of the easiest circuits so far that really kicks ass! considering the amount of components.
I say the hardest part of the project for a builder is figuring out how your going to supply the dual +/- voltages to power it up. I have that covered by the way. |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Jan 19, 2008 12:38 am Post subject:
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All the resistor values were intended for use with a LM4250 by the way. I live in california and those OG UA776 or MC1476's are no where to be found out here. If your going to use those you have to change R10, R11 to 110k.
This circuit is so easy to build i say build both versions! If you have that luxur y of finding those dam IC's of course. |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Sat Jan 19, 2008 12:54 am Post subject:
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Fernando wrote: | Guys, remember that the Motorola version is not difficult to find and it's very cheap: MC1776 |
Is it? I can't seem to find it anywhere. _________________ http://www.casia.org/modular/ |
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bubblechamber
Joined: Nov 04, 2006 Posts: 279 Location: NYC
Audio files: 1
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Posted: Sat Jan 19, 2008 12:56 am Post subject:
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I found a source for 2 of the 3 Russian components for this and they are cheap. the one missing is the Russian version of the 776(naturally)
KR140UD8B and KT315G
http://www.evita.lt/det-6599-mikroschema-kr140ud8b.html
I'd be willing to buy a bunch if anyone else is interested...
David |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Jan 19, 2008 1:02 am Post subject:
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Hey Etaoin,
I saw that you built a 16 step MFOS seq, did you have to modify it to get it to work correctly? I have the boards and haven't built it yet.
I hope all you had to do is build it stock.
You NL's have it made by the way. I love your country's laws and liberties. I'll trade you some CALI sunshine for some of your freedoms. LOL. |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Sat Jan 19, 2008 1:08 am Post subject:
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Haxter,
My MFOS Seq is unmodified, other than the mods I introduced myself. I'm using a second analog board and did away with the fine tune controls to create two 16 step tracks. I'm using it with a quantizer so no need for the fine tune pots. _________________ http://www.casia.org/modular/ |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Sat Jan 19, 2008 3:29 am Post subject:
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Etaoin wrote: | Fernando wrote: | Guys, remember that the Motorola version is not difficult to find and it's very cheap: MC1776 |
Is it? I can't seem to find it anywhere. |
I found it in one of my local shops in Barcelona so assumed it was easy to find... sorry. I just wanted to show five different chips that work so one can find one or another |
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austrohungaro
Joined: Dec 23, 2006 Posts: 42 Location: Barcelona (Spain)
Audio files: 1
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Posted: Sat Jan 19, 2008 4:00 am Post subject:
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Fernando wrote: | I found it in one of my local shops in Barcelona so assumed it was easy to find... |
Hola Fernando
I'd like to know which are the best local shops here in Barcelona.
Not only for chips. I need to buy cable right now.
Gracias
GenĂs |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Jan 19, 2008 10:24 am Post subject:
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Fernando you should buy all the stock off that shop and sell them on ebay or to us.
I'm gonna try to test my protoboard this weekend, probably sunday. |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Sat Jan 19, 2008 11:00 am Post subject:
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haxster wrote: | Fernando you should buy all the stock off that shop and sell them on ebay or to us. |
I hope I will never be forced by missfortune to do that (Jane Austen atmo adequate here)
BTW, Mouser has the NTE888 iirc and the 4250 is pretty easy to find too (DigiKey for instance)
. Last edited by Fernando on Sat Jan 19, 2008 11:34 am; edited 3 times in total |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Sat Jan 19, 2008 11:04 am Post subject:
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[quote="FernandoBTW, Mouser has the NTE888 iirc and the 4250 is pretty easy to find too[/quote]
Yes, but Mouser charges $70 shipping to Europe, so that makes it almost the same as unavailable. _________________ http://www.casia.org/modular/ |
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Sat Jan 19, 2008 11:14 am Post subject:
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I think Conrad has it. Reichelt has it too.
First try in your nearest local shop and I'm shure you'll find one of the 5 alternatives, this chip was very common, almost as the 741. |
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ickystay
Joined: Nov 15, 2006 Posts: 142 Location: Oregon
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Fernando
Joined: Dec 30, 2006 Posts: 286 Location: Barcelona & Emporda, Spain
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Posted: Sat Jan 19, 2008 5:30 pm Post subject:
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That should be another equivalent |
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etaoin
Joined: Jun 30, 2005 Posts: 761 Location: Utrecht, NL
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Posted: Wed Jan 23, 2008 11:41 pm Post subject:
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haxster: why are you using a dual opmap (LF442) for U2? You seem to have kept the pinout of a single opamp there, which can't be right... _________________ http://www.casia.org/modular/ |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Dec 06, 2008 11:42 pm Post subject:
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THE POTS ARE NOT CRITICAL, they can be 100k or 50k. The 100k trimmer will calibrate the cutoff range anyway. On this layout the FM input is not on this one. This is a simple version of the polivoks to get you at least making sound. |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Dec 06, 2008 11:49 pm Post subject:
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The Transistor is 2N3904, there is a Typo. For beginners---> on the Audio In and CV inputs use 50K or 100k Pots and wire them like this: (1)ground, (2)CV or AUDIO IN(the one your working on), (3) to the jack you like-1/4" phono or 3.5mm etc. |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sat Dec 06, 2008 11:51 pm Post subject:
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The Switch is a little Hack I found, if you build one you will hear a cool hack!
FOr the switches it reads like this: SWITCH#1 - (PIN)1, SWITCH#1 - (PIN)2.........SWITCH#2 - (PIN)1, SWITCH#2 -(PIN)2. |
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Funky40
Joined: Sep 24, 2005 Posts: 875 Location: Swiss
Audio files: 1
G2 patch files: 5
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Posted: Sun Dec 07, 2008 5:33 pm Post subject:
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what are you doing exactly with the switch ?
What result you get soundwise ?
thanks for posting ! |
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haxster
Joined: Feb 01, 2006 Posts: 246 Location: MONTEREY PARK, CA 91754
G2 patch files: 2
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Posted: Sun Dec 07, 2008 7:40 pm Post subject:
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You get different Rez notches, it is a Rez Notch Hack. |
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handsfelloff
Joined: Sep 01, 2008 Posts: 24 Location: uk
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Posted: Mon Jan 19, 2009 1:48 pm Post subject:
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Hey Haxter,
Thanks for all of this great info! There is very little else where that I have found.
i would love to build this circuit. However, I am a novice... but I am optemisitc and this circuit does not look too crazy to built. Ideally I would like to etch a pcb as well. the works
How did you solve the power supply -12 +12 issue I would like to run it off a standard 12v wall psu. It would be massivley helpful in the pursuit of understanding this build if any sucessful polyvox diyer's could impart a break down of the build.
As a novice its sometimes hard to fill in the gaps!
Any advise further info/tips would be really appreciated
cheers and thanks for the info so far! |
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