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 Forum index » DIY Hardware and Software » YuSynth
Vco
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Karlisss



Joined: Apr 20, 2015
Posts: 13
Location: Latvia (EU)

PostPosted: Mon Apr 20, 2015 4:15 am    Post subject: Vco Reply with quote  Mark this post and the followings unread

Can i build and use nonmached transistors for vco to get just any sound out of it, without plans to play vco with keyboard?
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bubzy



Joined: Oct 27, 2010
Posts: 572
Location: United Kingdom
Audio files: 63

PostPosted: Mon Apr 20, 2015 4:35 am    Post subject: Reply with quote  Mark this post and the followings unread

yup, the matching of transistors is to ensure that pitch tracking is correct. so you can absolutely use unmatched, its just that you might get odd results if you plan to use it in the future for something more pitch critical

oh and welcome

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Karlisss



Joined: Apr 20, 2015
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Location: Latvia (EU)

PostPosted: Mon Apr 20, 2015 5:37 am    Post subject: Reply with quote  Mark this post and the followings unread

Thank you!
Iam now in etching stage, so i wil use
Transcendental matching metode with brain energy Very Happy

Btw Hallo
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marfoski



Joined: Jan 26, 2011
Posts: 27
Location: Italy

PostPosted: Tue Apr 21, 2015 4:42 am    Post subject: Reply with quote  Mark this post and the followings unread

Actually it's not that difficult to match transistors.

This thread, for instance, contains several useful methods :

http://electro-music.com/forum/post-276867.html
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Karlisss



Joined: Apr 20, 2015
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PostPosted: Wed Apr 22, 2015 12:38 am    Post subject: Reply with quote  Mark this post and the followings unread

thanks a lot!!
funny, i found LM394 just here in my city!!!
http://www.ericasynths.lv/en/shop/4859-npn_matched_transistors_in_dip8_case.html
only must put in different place, cos pin layout is different.
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Karlisss



Joined: Apr 20, 2015
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Location: Latvia (EU)

PostPosted: Sat May 23, 2015 1:22 pm    Post subject: Reply with quote  Mark this post and the followings unread

so, i almost finished pcb's component part except some, harder to find parts.
but

1.
there is one ALIEN part, i never met before

220pf 1% silver mica

witch option i should choose, there are alot:

http://lv.farnell.com/webapp/wcs/stores/servlet/Search?st=220pf+1%25+styroflex+silver&catalogId=15001&categoryId=700000005411&langId=371&storeId=10166

2.
do all 7xL12 voltage regulators have similar pins?
i go for +/-12v and i have
L78L12 A GE 95D
and
TSC 79L12 2D1
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gdavis



Joined: Feb 27, 2013
Posts: 188
Location: San Diego

PostPosted: Tue Jun 02, 2015 8:46 pm    Post subject: Reply with quote  Mark this post and the followings unread

Karlisss wrote:
so, i almost finished pcb's component part except some, harder to find parts.
but

1.
there is one ALIEN part, i never met before

220pf 1% silver mica

witch option i should choose, there are alot:

http://lv.farnell.com/webapp/wcs/stores/servlet/Search?st=220pf+1%25+styroflex+silver&catalogId=15001&categoryId=700000005411&langId=371&storeId=10166


On that page, in the filters section check 220pf for capacitance and 1% for tolerance and you will get one result. That is the one you want.

Karlisss wrote:

2.
do all 7xL12 voltage regulators have similar pins?
i go for +/-12v and i have
L78L12 A GE 95D
and
TSC 79L12 2D1


As long as they are TO-92 packages I believe they will be the same. You can always check the pinout in the data sheet to make sure.

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AlanP



Joined: Mar 11, 2014
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PostPosted: Tue Jun 02, 2015 10:06 pm    Post subject: Reply with quote  Mark this post and the followings unread

78XX and 79XX have DIFFERING pinouts.

78XX is Out-Ground-Input, and 79XX is Output-Input-Ground. The low current versions are mirrored, and so different again.

Check your datasheets.
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gdavis



Joined: Feb 27, 2013
Posts: 188
Location: San Diego

PostPosted: Wed Jun 03, 2015 11:03 am    Post subject: Reply with quote  Mark this post and the followings unread

AlanP wrote:
78XX and 79XX have DIFFERING pinouts.

78XX is Out-Ground-Input, and 79XX is Output-Input-Ground. The low current versions are mirrored, and so different again.

Check your datasheets.


Of course, but I don't think he's asking about 78LXX vs 79LXX, rather one 78LXX vs another 78LXX and one 79LXX vs another 79LXX. He's just looking for the right + and - regulators for the VCO.

Any TO-92 78L12 for +12V and 79L12 for -12V should be correct.

But yes, in general it's good to know that the pinouts are different between the different types.

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Karlisss



Joined: Apr 20, 2015
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Location: Latvia (EU)

PostPosted: Thu Jun 11, 2015 12:51 am    Post subject: Reply with quote  Mark this post and the followings unread

all components are placed, waiting for Tayda Pots and LM394 !!
Smile
edit: ups, i placed silver mica 220pf 5% instead of 1%... should it work?
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Karlisss



Joined: Apr 20, 2015
Posts: 13
Location: Latvia (EU)

PostPosted: Tue Aug 18, 2015 9:39 am    Post subject: Reply with quote  Mark this post and the followings unread

Welll.... After great hopes something went terribly wrong.
1.
I rechecked wires and gnds and should be ok. If i connect my onehand with lfo output jack and other hand with pcb, then there is modulation. Where i should star to search failure? What is idea behind such behavior?
2.
I put round lm394 with pin positions as in drawing. Only difference : there is one more diode on each side in russian lm394, but it shouldt affect vco functionality.

So here is video

https://m.youtube.com/watch?v=Tmg6zQqkibg

And here is drawing rus394 vs as it should be (in my understanding)


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Karlisss



Joined: Apr 20, 2015
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Location: Latvia (EU)

PostPosted: Tue Aug 18, 2015 11:56 am    Post subject: Reply with quote  Mark this post and the followings unread

Can someone tell or finish drawing, to help me understand
Which shematic part is must have to be soldered on pcb, to have one working saw vave without any cv ins and line fm etc... Just pure sawwave with freq pot.
I have another pcb, so i want to go from simplest side, and then i can add all extras one by one.


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gdavis



Joined: Feb 27, 2013
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Location: San Diego

PostPosted: Tue Aug 18, 2015 8:30 pm    Post subject: Reply with quote  Mark this post and the followings unread

Post hi-res pics of both sides of your board. Sometimes people can spot mistakes. Most likely culprits are bad solder joints, shorts, open traces or misplaced components.

The part you're touching in your video is very sensitive, I don't think you can read anything into that.

The problem with leaving out some components is that some of the "unneeded" opamps share an IC with needed opamps. Leaving the inputs of those unused opamps unconnected can cause problems with the opamps that are in use. If you were redoing the circuit you could leave parts out but I wouldn't just leave parts off of this board without modifying it.

Have you gone through the calibration procedure? Do you have a scope? Normal debugging procedure after checking the obvious is to go step by step through the circuit measuring each point to narrow down the trouble spot.

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