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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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Posted: Wed Nov 09, 2016 2:58 am Post subject:
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13 dollars US on eBay. Took about 4 weeks to deliver from china. Mine is 15v+-
They have them in 12v+-
That one is running MIDI toCV, VCO, Divider Module, sequencer, mixer, LFO, 2 EGs, 2 VCAs, Noise generator, VCF. Not sure of the milliamp draw. But it does not heat up at all.
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Wed Nov 09, 2016 11:45 am Post subject:
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hey Grumble
i know you went mostly digital eheheh
as for switch power supply to avoid, what exactly are they? |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Wed Nov 09, 2016 11:56 am Post subject:
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hey Cfish
i am really glad you found this circuit to be useful !
i am yet to find time to set it up and give it a go.
According to Yves Usson it works flawlessly. A french friend of him , specifically a teacher, tested it before publishing so it should be alright!
its a type of circuit very hard to find on the net, i mean the old school way of generating CV GATE TRIGGER by the means of a fully analog circuitry and a resistor chain. so i was very happy to find it and share with you and other mates looking for the same basic keyboard controller.
as for the power supply ,i might consider buying a kit like yours. cheapo ! |
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Grumble
Joined: Nov 23, 2015 Posts: 1294 Location: Netherlands
Audio files: 30
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Posted: Thu Nov 10, 2016 1:35 am Post subject:
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alanwilder81 wrote: | hey Grumble
i know you went mostly digital eheheh
as for switch power supply to avoid, what exactly are they? |
Very basic: a switched power supply uses a technique where small portions of the mains voltage is used to charge a capacitor (your average iPhone and Android charger)
So you could imagine the noise this type of power supply creates...
A linear power supply uses a mains transformer and produce far less noise (mainly hum...)
Read more HERE |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Thu Nov 10, 2016 4:25 am Post subject:
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interesting matter Grumble.
so far i've focused only on studying EE basics, reading schematics ,building the various modules but never ever payed much attention to the power supply whole thing.
Sooner or later i'll have to get one |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Fri Nov 11, 2016 3:51 pm Post subject:
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hey Cfish,
i just posted a new message, but i cant find it, so i'll post it again
i finally managed to breadboard the CV GATE TRIGGER circuit we've been talking about.
It does work,although some tweaking may be needed.I'll now describe fast the procedure.
I used a CD4016 in place of the CD4066 the schematics calls for.I also used the TL084 instead of the TL074,That aside,no other modification took place.
Used 47 ohm resistor chain,one percent tollerance or better. for most of them i had a reading of 46.8 ohm or thereabouts. So,reasonably matched.
I got a CV output span from 1.1 V to 4.05 V, adjustable with the 10 K trimmer. The gate was around 11.6 V. Close to the values the schematics referres to.
I hope i got t right.How about yours? |
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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Sat Nov 12, 2016 1:23 pm Post subject:
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hey Cfish
congratulation on the keyboards and especially the the bottom one bare wood.I think it looks awesome! Are you a carpenter if i may ask?
I also plan to build myself a case like that.Or even a small cabinet,dont know yet. i am still struggling with the electronics.
My keyboard circuit, as i said, outputs both GATE and TRIGGER as well as CV to drive the VCO's. Trouble is, i dont have the CMOS 7555 to build my VCO to test the keyb circuit rigth away. Only have ne555's at hand , but they are totally worthless for that matter.
as far as your setup, how do VCO's responde to the CV output? you able to get proper frequencies and scales? Did it take you some trimming?
i now have my circuit sitting on the bench ready to be tested with a vco, i may be better ordering next week the missing component to realize it |
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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Sun Nov 13, 2016 6:25 am Post subject:
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hey cfish,
that sounds really fat and thick .just analog beauty. the sample and hold issue you refer to is about your self made circuit project, or the yusynth one you just built ?
to me,the Yves Usson SH works pretty well, at least my DMM reads a even voltage. as for the VCO you posted looks simple enough to give it a go for a quick and dirty test ! |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Sun Nov 13, 2016 7:07 am Post subject:
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thanks phobos for the support ! thats really sweet
we embarked on a hugely complex project i reckon ,we need some means of controlling the vco's ,just like a keyboard!!
i havent seen much on the net regarding pure analog keyboard circuits. So as soon as i found the schematics i posted i decided to share with you chaps, also to get all the help is needed to wrap my head around this mess.
it's stuff well over my head not having a formal EE education, but passion, perseverance, studying and swapping info on this forum can make up for it.
What are you phobos up to? ive seen many of your projects floating around ! let us know ! |
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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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Posted: Sun Nov 13, 2016 9:18 am Post subject:
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To alanwilder81. Yes that is my circuit I had been working on in the video. Not the yusynth circuit.
Not really my circuit. Started out with an old EFM circuit that I could never make work. However the initial opamp with the resistor chain in the feedback loop seemed to track CV really well. So I just kept trying to build on it.
I will note that the bass pedals in the video are passing the VCO through a passive low pass filter. And a PT2399 delay circuit. There is a thread about that project on here. Think it's titled easy analog synth project.
2n2646 UJTs are available on eBay in the US. Normally come from the U.K. Not sure why that is.
I do have several extras if someone needs a couple. PM me
PhoBoS. I would love to see what you come up with on the volt per octave keyboard project. I have learned so much from your threads. Thank you so much for being here. |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Sun Nov 13, 2016 10:09 am Post subject:
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alanwilder81 wrote: | not having a formal EE education, but passion, perseverance, studying and swapping info on this forum can make up for it. | It is pretty much the same for me although I do have somewhat of an EE education. But I never finished it and honestly hardly learned anything
from it. Before I had internet access I learned mostly from studying schematics published in Elektuur (elektor magazine) and when I finally got
online a whole new world opened and it became a lot easier to find information. Of course this forum has been a huge help and inspiration.
As usual I am currently working on a couple of projects but my Scraprack has the highest priority as it will save me some space and makes it
possible to connect more stuff together.
Quote: | PhoBoS. I would love to see what you come up with on the volt per octave keyboard project. I have learned so much from your threads. Thank you so much for being here. | aw you are too kind I am learning things from you as well and you're as much a part of the EM community as I am!
If I would make a volt-per-octave keyboard it would probably not be very different than what I see here. Unless you go digital there aren't many
options and you will quickly end up with a resistor string and a temperature stable buffer/converter. A comparator for a trigger/gate output is of
course very useful and you can expand with a S&H and glide.
hmm, I just realized a S&H might or at least could be used here for stability, I guess I have to read back a bit. _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Sun Nov 13, 2016 10:17 am Post subject:
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to phobos,
yes, the net opened up a whole new world to anyone.Before that, you could only rely on magazines,manuals and stuff lke that.
Nowadays even a complete noob like myself can have access to goldmines like this forum and therefore be able to build himself the hell out of synth modules .And the willing member are always there to lend a hand or share some knowledge.Priceless !! |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Sun Nov 13, 2016 10:21 am Post subject:
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phobos,
anyway stay tuned. Cfish and I have been working on the above project, so, i hope some nice resoults will come soon |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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Posted: Tue Nov 15, 2016 3:30 pm Post subject:
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Hi Alamwilder81
LM358 is a single supply opamp ( power to ground not -v) I don't see a reason TL07xx won't work at a glance. As long as you tie -v to -v not ground
+ inputs on TL07xx still tie to ground. Ground being half reference voltage in +-12v which I think you are using |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Tue Nov 15, 2016 3:39 pm Post subject:
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thanks Cfish,
i'll give a solid TL074 a try. They are my workhorse and are cheap.By the way, what's your faved op amp? |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Tue Nov 15, 2016 4:23 pm Post subject:
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LM358 works just as well with a dual supply. I am actually not sure what the main difference is but I think it has some sort of internal
biasing. It's output can also swing closer to the power rails (especially the negative/GND one). Also, the TL072 has J-FET inputs and
therefor a much higher input impedance. So for example a S&H would work better with a TL072 than an LM358.
I personally have a soft spot for the uA741, because the first couple of opamp circuits I build used that one. But I rarely use it nowadays. _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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Posted: Tue Nov 15, 2016 4:31 pm Post subject:
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I also have a ua741 soft spot, for the same reasons. I tend to use 741 and Tl071 the most. My Thomas Henrey VCO1, I built with 071s on a 5x7 perfboard, so I had plenty of room to get in with the meater and scope and really figure it out.
One of the best moves I ever made.
Second VCO1 I built with 074. Fits in 1/4th the space on perf |
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Tue Nov 15, 2016 5:10 pm Post subject:
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lol
I cant wait to get the LM13700 and 7555 to start building the crap out of the Thomas Henry VCO's .Those projects are wonderfully laid out, easy to understand and so clear, schematic wise. And sound remarkably good.
Those VCO's will be the crowning achievement of my DIY project they are in store.
As for the opamps, i am a green horn,so my only experience is limited to the all-round TL071 and TL074.Thomas Henry himself used them in galore.
To my ears they sound thik and fat |
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Cfish
Joined: Feb 24, 2016 Posts: 477 Location: Indiana
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alanwilder81
Joined: Sep 03, 2016 Posts: 310 Location: italy
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Posted: Tue Nov 15, 2016 6:01 pm Post subject:
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yes Chris,
i remember you mentioning a project you couldnt get to work both GATE and TRIGGER of,hence giving up on it.is that really the case of a suspect counterfeit chinese chip lot?
Well, the only reason i haven't yet bought those CA 3080 or LM13700 off ebay is because of fear of scams .They are ridicolously cheap compared to the US or EU market but i definitely didnt feel like running the risk. I'm about to shell out the cash and get the bloody LM13700 off an italian seller,for around 1.50 dollars each. Not bad i guess |
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PHOBoS
Joined: Jan 14, 2010 Posts: 5591 Location: Moon Base
Audio files: 705
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Posted: Tue Nov 15, 2016 6:07 pm Post subject:
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ow that's easy, it's an ehm wait, what ?!
The 0.1uF capacitor does indeed make some sense in triggering the S&H everytime a key is pressed, I don't know why an OTA is being
used there though especially in the way it is connected. And I would say the GATE out is actually a TRIGGER out. But the opamp you circled
in green ?, I can't make sense of it. Almost looks like a connection is missing but it is probably just a connection in my brain. Would be nice if
someone could explain it (the circuit, not my brain).
(1,50 is not a bad price for an LM13700 and it is a nice chip) _________________ "My perf, it's full of holes!"
http://phobos.000space.com/
SoundCloud BandCamp MixCloud Stickney Synthyards Captain Collider Twitch YouTube |
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