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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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 Posted: Sat Nov 27, 2010 3:08 pm Post subject:
 my first vco and vca.. |
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Hi!! I have finished my first vco and vca if i connect the vco out to the vca in should i hear anything? I haven't trimm the vco yet...
tHanks.. |
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Sat Nov 27, 2010 3:34 pm Post subject:
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Hello Elektron026,
Actually you dont need a VCA for listen a VCO. The VCOs are outputing signal permanently.
VCA is a voltage controlled amplifier usually with gain+1, that means that in its maximum the output has the same amplitude than the input. So you can think the VCA as a voltage controlled attenuator.
So you can connect the VCO to the VCA(Simple VCA?) -to use it like attenuator- and with the gain and the input level at maximum, you should listen the vco, adjust then the levels for not overload the destination. |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Sat Nov 27, 2010 4:24 pm Post subject:
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So i don't need a cv keyboard to send voltage to the cv in to hear sinewave or sawtooth from the vco out .. right?
tHnX.. |
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Sat Nov 27, 2010 4:35 pm Post subject:
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yes right. you don't need.
Actually with the frequency control you are controlling the VCO with voltage.
See schematics you will see that coarse, fine, v/oct, fm... all them go to the same operational amplifier. Which is summing(and inverting) all these voltages. |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Sat Nov 27, 2010 5:23 pm Post subject:
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Thnx man!! Are you from Greece?Location: Αιγαίο Πέλαγος...
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Sun Nov 28, 2010 3:33 am Post subject:
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δεν είμαι από εδώ αλλά εδώ μένω. Στην Θεσσ/ εσύ;  |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Sun Nov 28, 2010 7:49 am Post subject:
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Egw eimai apo karpenhsi.. Alla menw a8hna..dystyxws..
elpizw kapoia stigmh na paw na mhnw Krhth!!!
exw mania me ta synth!!
3ekinisa na mazebw oti xreiazome geia na fteia3w to yusynth modular efteia3a 76 plaketes peripoy... exw agorasei ola ta olokliromena...kai transistor ..me ligh tyxh brhka 2sc1583 ta opoia poia einai kapws spaneia...
alla akoma moy leipoun antistaseis pyknwtes trimmers k pot...
e den eimai k kanenas plousios opote ta agorazw siga siga!!!
poy les .... eftia3a thn prwth gennhtria alla to provlima einai oti ta jacks poy pira den einai kala kai pernw kymatomorfes apo oles tis e3odous ektos apo to pulse....telika malon kati braxikiklosa k mallon xalase kati....
k isws akoma ena la8os moy einai oti sto ''trimmer 2'' ebala 20k anti geia 22 ews 25k...
to periergo einai oti stis tris protes e3odoys pernw pantou sawtooth ...fysika den exw palmografo akoma na to ri8misw...
se kana mina an brw lefta 8a parw...
mhpws ta ekapsa ola???
lol
yparxei tropos na ri8misw thn gennhtria me to pc geia palmografo?
Ena akoma provlhma einai oti sto vca to led anabe kanonika otan dexotan shma... twra an k e3akolou8w na akouw shma sthn e3odo to led den anabei isws telika na mhn geiononte kala ta kakhs poiothtas jacks....!!
tHnX!! |
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Sun Nov 28, 2010 10:11 am Post subject:
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| Elektron026 wrote: | Egw eimai apo karpenhsi.. Alla menw a8hna..dystyxws..
elpizw kapoia stigmh na paw na mhnw Krhth!!! exw mania me ta synth!! |
και έμενα θα μου άρεσε να πάω στην Κρήτη, παρόλα αυτα αν καμιά φορά έρθεις στην Θεσσαλονίκη μπορούμε να πιούμε καφέ και να τα πούμε για synth!
| Quote: | poy les .... eftia3a thn prwth gennhtria alla to provlima einai oti ta jacks poy pira den einai kala kai pernw kymatomorfes apo oles tis e3odous ektos apo to pulse....telika malon kati braxikiklosa k mallon xalase kati....
k isws akoma ena la8os moy einai oti sto ''trimmer 2'' ebala 20k anti geia 22 ews 25k...
to periergo einai oti stis tris protes e3odoys pernw pantou sawtooth ...fysika den exw palmografo akoma na to ri8misw...
se kana mina an brw lefta 8a parw...
mhpws ta ekapsa ola???
lol |
Αλλάζω στα αγγλικά γιατί ακόμα δε τα καταλαβαίνω όλα στα ελληνικά και με λατινικά γράμματα δε μπορώ να τα βρω στο λεξικό so, what means "gennhtria"?
Which jacks have you chosen?
I have not built the yusynth VCO but looking at the schematics, trimmer 2 determine the V/oct accuracy. For stability you could use high quality trimmer there like "cermet". The exactly V/octave is in some point within those 25K advised. So maybe 20k will work for you. try it. If you found that you are close to the V/octave but the trimmer is at one extrme, you will should replace it for a 25K trimmer.
About the waveforms, the core of this nice oscillator is a saw. Pulse is derived from it with a comparator (look wiki) so its this because you have the pulse there.
Triangle is derived also from the saw, but with a rectifier. But you have to adjust the symmetry with a trim. Check also that the diodes d3 and d4 are correctly oriented.
Sine is derived from the triangle with two diodes that limite the peaks of the triangle. Nice. If the triangle is OK, the sine must be ok also. Check also if the diodes are correctly oriented.
And yes, you have palmografos or oscilloscope for PCs, obiously depending on the filters of your soundcard inputs you could analyze more or less low frequencies, but for the audio range you can use th PC perfectly.
I like and use the following freeplugins:
for oscilloscope: http://bram.smartelectronix.com/plugins.php?id=4
and for spectrometer: http://www.voxengo.com/product/span/
| Quote: | | Ena akoma provlhma einai oti sto vca to led anabe kanonika otan dexotan shma... twra an k e3akolou8w na akouw shma sthn e3odo to led den anabei isws telika na mhn geiononte kala ta kakhs poiothtas jacks....!! |
Led starts to shine in input signals over 8V peak to peak. Yusynth explains it here: http://electro-music.com/forum/post-287886.html&highlight=led+vca#287886 |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Sun Nov 28, 2010 11:02 am Post subject:
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I have chosen some old jacks from a store ... noname... can u sugest me to buy from internet some good quality jacks for modular? I will try to come someday to 8essalonikh!! Nice plugins ...for my mac!!!
An er8eis k esy A8hna kapoia stigmh 8a xarw na milisoyme geia synths apo konta!!
genitria=oscillator  |
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Sun Nov 28, 2010 11:26 am Post subject:
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| Elektron026 wrote: | I have chosen some old jacks from a store ... noname... can u sugest me to buy from internet some good quality jacks for modular? I will try to come someday to 8essalonikh!! Nice plugins ...for my mac!!!
An er8eis k esy A8hna kapoia stigmh 8a xarw na milisoyme geia synths apo konta!!
genitria=oscillator |
If I go Athina Ill tell you! I went twice and like that city.
Which jacks are you using 1/4 jacks or the little ones 1/8?
I use 1/8 the little ones.
For good quality in my opinion Lumberg is the best.
For male I recommend lumberg/kls-22
And for socket or female lumberg/1502-03 That is also switchable.
Edited links.
Last edited by Sound on Mon Nov 29, 2010 8:04 am; edited 1 time in total |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Mon Nov 29, 2010 3:48 am Post subject:
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The little ones!!I love them...
What cables do u use for the models.. and what cables for the little one jacks?And what's the standard spacing for the Yusynth pcb terminals i bought somefrom mouser but it was to big...?
How much models have u build?
Do you use other synths?
Den 3erw kala agklika...elpizw n me katalaveneis! |
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Sound
Joined: Jun 06, 2006
Posts: 842
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Tue Nov 30, 2010 3:19 am Post subject:
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Very nice Pictures on these threads!!
I have a problem with my vco ...i power on the circuit at the first 3-4 minutes i have only noise and after 6 minutes it starts to output sawtooth with pitch changing every some minutes then stops then starts again at the end it outputs sawtooth for 20-30 minutes stable then my circuit dies..
then i have to change the diodes and it works again but not stable like before......
maybe i have a wrong or defective component somewhere...
i have tempco the one from farnell..
and the silvered mica capacitor...
maybe somewhere i made a mistake with wrong resistor..
or is it possible i have a defective tempco? |
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Tue Nov 30, 2010 3:58 am Post subject:
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| Elektron026 wrote: | Very nice Pictures on these threads!!
I have a problem with my vco ...i power on the circuit at the first 3-4 minutes i have only noise and after 6 minutes it starts to output sawtooth with pitch changing every some minutes then stops then starts again at the end it outputs sawtooth for 20-30 minutes stable then my circuit dies..
then i have to change the diodes and it works again but not stable like before......
maybe i have a wrong or defective component somewhere...
i have tempco the one from farnell..
and the silvered mica capacitor...
maybe somewhere i made a mistake with wrong resistor..
or is it possible i have a defective tempco? |
I would say that these things happen in first projects. This output intermittent could be any bad connection like a cold solder.
A cold solder is a solder that not was done correctly and is not making good contact. look for video tutorials of solder on Internet.
Listening the oscillator touch with your hands the cables and components to see if there is any part that when you touch it makes sound, noise or cut the sound.
A good practice after finish a module is observe it visually, including a maximizer glass. Observe if all components are soldered. If they are solder correctly, if there is not anything shorting two traces. It is good also clean the PCB with toothbrush and isopropanol.
With a multimeter look if all chips are receiving power supply in its supply pins.
Revise if all resistor values are correct and if diodes and transistors are correctly placed.
A question: This intermittent sound is present in all VCO outputs? |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Tue Nov 30, 2010 7:43 am Post subject:
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I never had sound at pulse out!!
I will double check everything again and i will tell you!
Is it possible that the problem is that i didn't clean very good the solder flux from the pcb? 
The crazy thing is that i had ... the vco running stable with a perfect sawtooth for almost two hours before it colapse..'without any noise' the first time i switched on the circuit...!!
Now if i try to switch on the circuit after 5-6 munites it is like it is trying to produce sound but then noise again... |
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Sound
Joined: Jun 06, 2006
Posts: 842
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| Posted: Tue Nov 30, 2010 8:03 am Post subject:
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Check it carefully and tell me. Always there is a solution. For example if you have not pulse output we will see in schematics the parts that compound the pulse output.
Lets go step by step.
So now make carefully the things explained in my previous post. |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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Sound
Joined: Jun 06, 2006
Posts: 842
Audio files: 1
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| Posted: Sat Dec 04, 2010 9:01 am Post subject:
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| Elektron026 wrote: | | Finnally got it to work!!I made a new one from scratch!!''used some of your tips,cleaned the board very well..'' Now everything works perfect!!I love it!! 2sc1583 version!THANKS FOR YOUR HELP!!!!!!! |
Glad to hear that! the oscillator looks great as well the test frontpanel!!!!
The resistors,
R8 is labeled 470K in schematics and with this trim associated sets , i think, the center of the frequency.
R36 and R51 sets the pulse span. If span is so width in the potentiometer extremes there is no sound output is just DC, this is because is limited. little value more span, big value less span. |
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Elektron026
Joined: Oct 30, 2010
Posts: 12
Location: Greece
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| Posted: Sat Dec 04, 2010 9:19 am Post subject:
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| So!What value is better to use? Span? Ti shmenei? |
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Sound
Joined: Jun 06, 2006
Posts: 842
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| Posted: Sat Dec 04, 2010 9:45 am Post subject:
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Span is the space within two points, so for example in the potentiometer of the frequency control, span will be the space from the lowest frequency to the highest frequency achieved.
Now observe the pulse output in the oscilloscope. And move the pulse width potentiometer. You will see that with the pot about the center, the wave is an square. If you turn to one side the pot you will see that negative phase of that square will increase while positive phase will decrease, and vice-versa if you turn the pot to the other side.
If you had a real oscilloscope and the span was enough width you would see that turning to one side this pot, one of the phases is going little and more little until disappears, becoming just DC, so no sound.
Think this potentiometer as the threshold of a comparator that compares the saw output with this threshold level. Setting the comparator to positive or negative state. If threshold is more up than saw amplitude, it will not switch its state.
So there are designers that prefer more widest span and designers that limit it to the audio range. I don't know what choose Yusynth. But you can mod to your taste also. |
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