Synth-DIY Yahoo! Groups Archives

CGS48, how to be sure it's fine ?

2013-09-02 by jean0bender

Hi Everybody ! That's my first post here, as after building several modules, i think i've got some problems to fix on my cgs48. I've used a 2N3904 matched pair instead of the LM394. I think that my vco is working, but i can't really use the initial freq pot. It must be always in its center position if i want to hear the vco. Is it normal ? I only can tune the vco using the fine pot... In a post here, i've seen i could change the 1m resitor to a 2,2m one, and i did this change, but it just affect the fine tune pot, no the intial one. What should i check ? thanks for any help ! jean

Re: CGS48, how to be sure it's fine ?

2013-09-02 by cg_synth

If the span trimmer is not right, the VCO may be too sensitive to CV and to
the tuning pot.

Ken

Show quoted textHide quoted text

>Hi Everybody ! That's my first post here, as after building several

modules, i think i've got some problems to fix on my cgs48. I've
used a 2N3904 matched pair instead of the LM394. I think that my vco is
working, but i can't really use the initial freq pot. It must be always
in its center position if i want to hear the vco. Is it normal ? I only can
tune the vco using the fine pot... In a post here, i've seen i could
change the 1m resitor to a 2,2m one, and i did this change, but it just
affect the fine tune pot, no the intial one. What should i check ? thanks
for any help ! jean

>
>------------------------------------
>
>The CGS Modular Synth home page: http://www.cgs.synth.net/
>Yahoo! Groups Links
>
>
>
>

_______________________________________________________________________
Ken Stone sasami@... otherunicorn@...
Modular Synth PCBs for sale <http://www.cgs.synth.net/>

Re: CGS48, how to be sure it's fine ?

2013-09-02 by jean0bender

Well, thanks for your answer Ken... I think my problem is somewhere else, but can't see where.
If i use my sequencer on the vc fm, i can modulate the vco.
If i apply the same cv output to the cv in, my vco doesn"t respond. If i apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o input, nothing..

I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center position, but if i try to move them, they don't modulate a lot ( maybe from 11 to 1 oclock).

thanks for any help. I gonna check all the ics voltages and send it there, maybe it'll help !

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <sasami@...> wrote:

If the span trimmer is not right, the VCO may be too sensitive to CV and to

the tuning pot.

Ken

>Hi Everybody ! That's my first post here, as after building several

modules, i think i've got some problems to fix on my cgs48. I've

used a 2N3904 matched pair instead of the LM394. I think that my vco is

working, but i can't really use the initial freq pot. It must be always

in its center position if i want to hear the vco. Is it normal ? I only can

tune the vco using the fine pot... In a post here, i've seen i could

change the 1m resitor to a 2,2m one, and i did this change, but it just

affect the fine tune pot, no the intial one. What should i check ? thanks

for any help ! jean

>

>------------------------------------

>

>The CGS Modular Synth home page: http://www.cgs.synth.net/

>Yahoo! Groups Links

>

>

>

>

_______________________________________________________________________

Ken Stone sasami@... otherunicorn@...

Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

Re: CGS48, how to be sure it's fine ?

2013-09-02 by jean0bender

Well, here are my test. Seems to be a bit weird. I've multimetered my ics when my pots where center positionned

i can see that if i approach my fingers to the pots or some parts it's altering the sound...
I've rechecked all my links & solders...

IC1 / TLO72
1 : -1,55v
2 : 0
3 : 0
4 : -15
5 : 0
6 : 0
7 : 0
8 : 15

IC2 LM394/2N3904
1 : 0
2 : 0
3 : -0,5
4 : nc
5 : nc
6 : -0,5
7 : 0
8 : 0

IC3 : TLO72 near the unicorn

1 : 0
2 : 0
3 : 0
4 : -15
5 : 0
6 : 0
7 : 0
8 : 15

IC4 / CA3140

1 : -15
2 : 0
3 : 0
4 : -15
5 : -15
6 : 2
7 : 15
8 : 3,5

IC5 / LM3900

1 : 0,1v
2 : 0,4
3 : 0,5
4 : 0,15
5 : 0,15
6 : 0,55
7 : 0
8 : 0,53
9 : 2,2
10 : 2,2
11 : 0,5
12 : 0,37
13 : 0,37
14 : 15

IC6 / LM311

1 : -15v
2 : 2,2
3 : 4,96
4 : 15,3
5 : 15
6 : 15
7 : -15
8 : 15

IC7 / TLO72

1 : BTW +6 & +12
2 : 0
3 : 0
4 : -15
5 : BTW -2 & +2
6 : -0,3
7 : BTW -8 & +12
8 : 15

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <lofideadbeat@...> wrote:

Well, thanks for your answer Ken... I think my problem is somewhere else, but can't see where.

If i use my sequencer on the vc fm, i can modulate the vco.

If i apply the same cv output to the cv in, my vco doesn"t respond. If i apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o input, nothing..

I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center position, but if i try to move them, they don't modulate a lot ( maybe from 11 to 1 oclock).

thanks for any help. I gonna check all the ics voltages and send it there, maybe it'll help !

--- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

If the span trimmer is not right, the VCO may be too sensitive to CV and to

the tuning pot.

Ken

>Hi Everybody ! That's my first post here, as after building several

modules, i think i've got some problems to fix on my cgs48. I've

used a 2N3904 matched pair instead of the LM394. I think that my vco is

working, but i can't really use the initial freq pot. It must be always

in its center position if i want to hear the vco. Is it normal ? I only can

tune the vco using the fine pot... In a post here, i've seen i could

change the 1m resitor to a 2,2m one, and i did this change, but it just

affect the fine tune pot, no the intial one. What should i check ? thanks

for any help ! jean

>

>------------------------------------

>

>The CGS Modular Synth home page: http://www.cgs.synth.net/

>Yahoo! Groups Links

>

>

>

>

_______________________________________________________________________

Ken Stone sasami@... otherunicorn@...

Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

Re: CGS48, how to be sure it's fine ?

2013-09-02 by Ove Ridé

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its
place)? When I built a similar VCO using discrete transistors instead of an
LM394, I forgot to place this resistor, and the oscillator didn't work.
This is the resistor that is supposed to sit over the LM394 for thermal
coupling, which is why I forgot it when using transistors.

Show quoted textHide quoted text

On 2 September 2013 16:15, <lofideadbeat@...> wrote:

> **
>
>
> Well, here are my test. Seems to be a bit weird. I've multimetered my ics
> when my pots where center positionned
>
> i can see that if i approach my fingers to the pots or some parts it's
> altering the sound...
> I've rechecked all my links & solders...
>
> IC1 / TLO72
> 1 : -1,55v
> 2 : 0
> 3 : 0
> 4 : -15
> 5 : 0
> 6 : 0
> 7 : 0
> 8 : 15
>
> IC2 LM394/2N3904
> 1 : 0
> 2 : 0
> 3 : -0,5
> 4 : nc
> 5 : nc
> 6 : -0,5
> 7 : 0
> 8 : 0
>
> IC3 : TLO72 near the unicorn
>
> 1 : 0
> 2 : 0
> 3 : 0
> 4 : -15
> 5 : 0
> 6 : 0
> 7 : 0
> 8 : 15
>
> IC4 / CA3140
>
> 1 : -15
> 2 : 0
> 3 : 0
> 4 : -15
> 5 : -15
> 6 : 2
> 7 : 15
> 8 : 3,5
>
> IC5 / LM3900
>
> 1 : 0,1v
> 2 : 0,4
> 3 : 0,5
> 4 : 0,15
> 5 : 0,15
> 6 : 0,55
> 7 : 0
> 8 : 0,53
> 9 : 2,2
> 10 : 2,2
> 11 : 0,5
> 12 : 0,37
> 13 : 0,37
> 14 : 15
>
> IC6 / LM311
>
> 1 : -15v
> 2 : 2,2
> 3 : 4,96
> 4 : 15,3
> 5 : 15
> 6 : 15
> 7 : -15
> 8 : 15
>
> IC7 / TLO72
>
> 1 : BTW +6 & +12
> 2 : 0
> 3 : 0
> 4 : -15
> 5 : BTW -2 & +2
> 6 : -0,3
> 7 : BTW -8 & +12
> 8 : 15
>
>
>
> --- In cgs_synth@yahoogroups.com, <lofideadbeat@...> wrote:
>
> Well, thanks for your answer Ken... I think my problem is somewhere else,
> but can't see where.
>
> If i use my sequencer on the vc fm, i can modulate the vco.
>
> If i apply the same cv output to the cv in, my vco doesn"t respond. If i
> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o
> input, nothing..
>
> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center
> position, but if i try to move them, they don't modulate a lot ( maybe from
> 11 to 1 oclock).
>
> thanks for any help. I gonna check all the ics voltages and send it there,
> maybe it'll help !
>
>
>
> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:
>
> If the span trimmer is not right, the VCO may be too sensitive to CV and to
>
> the tuning pot.
>
> Ken
>
> >Hi Everybody ! That's my first post here, as after building several
>
> modules, i think i've got some problems to fix on my cgs48. I've
>
> used a 2N3904 matched pair instead of the LM394. I think that my vco is
>
> working, but i can't really use the initial freq pot. It must be always
>
> in its center position if i want to hear the vco. Is it normal ? I only can
>
> tune the vco using the fine pot... In a post here, i've seen i could
>
> change the 1m resitor to a 2,2m one, and i did this change, but it just
>
> affect the fine tune pot, no the intial one. What should i check ? thanks
>
> for any help ! jean
>
> >
>
> >------------------------------------
>
> >
>
> >The CGS Modular Synth home page: http://www.cgs.synth.net/
>
> >Yahoo! Groups Links
>
> >
>
> >
>
> >
>
> >
>
> __________________________________________________________
>
> Ken Stone sasami@... otherunicorn@...
>
> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >
>
>
>

--
/Ove

Blog: <http://blog.gg8.se/>

"Here is Evergreen City. Evergreen is the color of green forever."

[Non-text portions of this message have been removed]

Re: CGS48, how to be sure it's fine ?

2013-09-02 by jean0bender

yep, i didn't forget it. The fact is i can see on my scope the saw out, the sine one, but i can't have square out. Tomorrow i'll desolder all the pots & out, and change my transistors & tempco... we'll see what happens !

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its

place)? When I built a similar VCO using discrete transistors instead of an

LM394, I forgot to place this resistor, and the oscillator didn't work.

This is the resistor that is supposed to sit over the LM394 for thermal

coupling, which is why I forgot it when using transistors.

On 2 September 2013 16:15, < lofideadbeat@... > wrote:

> **

>

>

> Well, here are my test. Seems to be a bit weird. I've multimetered my ics

> when my pots where center positionned

>

> i can see that if i approach my fingers to the pots or some parts it's

> altering the sound...

> I've rechecked all my links & solders...

>

> IC1 / TLO72

> 1 : -1,55v

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC2 LM394/2N3904

> 1 : 0

> 2 : 0

> 3 : -0,5

> 4 : nc

> 5 : nc

> 6 : -0,5

> 7 : 0

> 8 : 0

>

> IC3 : TLO72 near the unicorn

>

> 1 : 0

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC4 / CA3140

>

> 1 : -15

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : -15

> 6 : 2

> 7 : 15

> 8 : 3,5

>

> IC5 / LM3900

>

> 1 : 0,1v

> 2 : 0,4

> 3 : 0,5

> 4 : 0,15

> 5 : 0,15

> 6 : 0,55

> 7 : 0

> 8 : 0,53

> 9 : 2,2

> 10 : 2,2

> 11 : 0,5

> 12 : 0,37

> 13 : 0,37

> 14 : 15

>

> IC6 / LM311

>

> 1 : -15v

> 2 : 2,2

> 3 : 4,96

> 4 : 15,3

> 5 : 15

> 6 : 15

> 7 : -15

> 8 : 15

>

> IC7 / TLO72

>

> 1 : BTW +6 & +12

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : BTW -2 & +2

> 6 : -0,3

> 7 : BTW -8 & +12

> 8 : 15

>

>

>

> --- In cgs_synth@yahoogroups.com , <lofideadbeat@...> wrote:

>

> Well, thanks for your answer Ken... I think my problem is somewhere else,

> but can't see where.

>

> If i use my sequencer on the vc fm, i can modulate the vco.

>

> If i apply the same cv output to the cv in, my vco doesn"t respond. If i

> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o

> input, nothing..

>

> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center

> position, but if i try to move them, they don't modulate a lot ( maybe from

> 11 to 1 oclock).

>

> thanks for any help. I gonna check all the ics voltages and send it there,

> maybe it'll help !

>

>

>

> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

>

> If the span trimmer is not right, the VCO may be too sensitive to CV and to

>

> the tuning pot.

>

> Ken

>

> >Hi Everybody ! That's my first post here, as after building several

>

> modules, i think i've got some problems to fix on my cgs48. I've

>

> used a 2N3904 matched pair instead of the LM394. I think that my vco is

>

> working, but i can't really use the initial freq pot. It must be always

>

> in its center position if i want to hear the vco. Is it normal ? I only can

>

> tune the vco using the fine pot... In a post here, i've seen i could

>

> change the 1m resitor to a 2,2m one, and i did this change, but it just

>

> affect the fine tune pot, no the intial one. What should i check ? thanks

>

> for any help ! jean

>

> >

>

> >------------------------------------

>

> >

>

> >The CGS Modular Synth home page: http://www.cgs.synth.net/

>

> >Yahoo! Groups Links

>

> >

>

> >

>

> >

>

> >

>

> __________________________________________________________

>

> Ken Stone sasami@... otherunicorn@...

>

> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

>

>

>

--

/Ove

Blog: < http://blog.gg8.se/ >

"Here is Evergreen City. Evergreenï»¿ is the color of green forever."

[Non-text portions of this message have been removed]

Re: CGS48, how to be sure it's fine ?

2013-09-02 by jean0bender

yep, i didn't forget it. The fact is i can see on my scope the saw out, the sine one, but i can't have square out. Tomorrow i'll desolder all the pots & out, and change my transistors & tempco... we'll see what happens !

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its

place)? When I built a similar VCO using discrete transistors instead of an

LM394, I forgot to place this resistor, and the oscillator didn't work.

This is the resistor that is supposed to sit over the LM394 for thermal

coupling, which is why I forgot it when using transistors.

On 2 September 2013 16:15, < lofideadbeat@... > wrote:

> **

>

>

> Well, here are my test. Seems to be a bit weird. I've multimetered my ics

> when my pots where center positionned

>

> i can see that if i approach my fingers to the pots or some parts it's

> altering the sound...

> I've rechecked all my links & solders...

>

> IC1 / TLO72

> 1 : -1,55v

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC2 LM394/2N3904

> 1 : 0

> 2 : 0

> 3 : -0,5

> 4 : nc

> 5 : nc

> 6 : -0,5

> 7 : 0

> 8 : 0

>

> IC3 : TLO72 near the unicorn

>

> 1 : 0

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC4 / CA3140

>

> 1 : -15

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : -15

> 6 : 2

> 7 : 15

> 8 : 3,5

>

> IC5 / LM3900

>

> 1 : 0,1v

> 2 : 0,4

> 3 : 0,5

> 4 : 0,15

> 5 : 0,15

> 6 : 0,55

> 7 : 0

> 8 : 0,53

> 9 : 2,2

> 10 : 2,2

> 11 : 0,5

> 12 : 0,37

> 13 : 0,37

> 14 : 15

>

> IC6 / LM311

>

> 1 : -15v

> 2 : 2,2

> 3 : 4,96

> 4 : 15,3

> 5 : 15

> 6 : 15

> 7 : -15

> 8 : 15

>

> IC7 / TLO72

>

> 1 : BTW +6 & +12

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : BTW -2 & +2

> 6 : -0,3

> 7 : BTW -8 & +12

> 8 : 15

>

>

>

> --- In cgs_synth@yahoogroups.com , <lofideadbeat@...> wrote:

>

> Well, thanks for your answer Ken... I think my problem is somewhere else,

> but can't see where.

>

> If i use my sequencer on the vc fm, i can modulate the vco.

>

> If i apply the same cv output to the cv in, my vco doesn"t respond. If i

> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o

> input, nothing..

>

> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center

> position, but if i try to move them, they don't modulate a lot ( maybe from

> 11 to 1 oclock).

>

> thanks for any help. I gonna check all the ics voltages and send it there,

> maybe it'll help !

>

>

>

> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

>

> If the span trimmer is not right, the VCO may be too sensitive to CV and to

>

> the tuning pot.

>

> Ken

>

> >Hi Everybody ! That's my first post here, as after building several

>

> modules, i think i've got some problems to fix on my cgs48. I've

>

> used a 2N3904 matched pair instead of the LM394. I think that my vco is

>

> working, but i can't really use the initial freq pot. It must be always

>

> in its center position if i want to hear the vco. Is it normal ? I only can

>

> tune the vco using the fine pot... In a post here, i've seen i could

>

> change the 1m resitor to a 2,2m one, and i did this change, but it just

>

> affect the fine tune pot, no the intial one. What should i check ? thanks

>

> for any help ! jean

>

> >

>

> >------------------------------------

>

> >

>

> >The CGS Modular Synth home page: http://www.cgs.synth.net/

>

> >Yahoo! Groups Links

>

> >

>

> >

>

> >

>

> >

>

> __________________________________________________________

>

> Ken Stone sasami@... otherunicorn@...

>

> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

>

>

>

--

/Ove

Blog: < http://blog.gg8.se/ >

"Here is Evergreen City. Evergreenï»¿ is the color of green forever."

[Non-text portions of this message have been removed]

Re: CGS48, how to be sure it's fine ?

2013-09-02 by cg_synth

Square out is a different issue altogether. No square out happens when the PWM voltage is outside the range covered by the sawtooth. The CV issue is a problem somewhere in your input mixer, where you seem to have excessive gain.

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

yep, i didn't forget it. The fact is i can see on my scope the saw out, the sine one, but i can't have square out. Tomorrow i'll desolder all the pots & out, and change my transistors & tempco... we'll see what happens !

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its

place)? When I built a similar VCO using discrete transistors instead of an

LM394, I forgot to place this resistor, and the oscillator didn't work.

This is the resistor that is supposed to sit over the LM394 for thermal

coupling, which is why I forgot it when using transistors.

On 2 September 2013 16:15, < lofideadbeat@... > wrote:

> **

>

>

> Well, here are my test. Seems to be a bit weird. I've multimetered my ics

> when my pots where center positionned

>

> i can see that if i approach my fingers to the pots or some parts it's

> altering the sound...

> I've rechecked all my links & solders...

>

> IC1 / TLO72

> 1 : -1,55v

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC2 LM394/2N3904

> 1 : 0

> 2 : 0

> 3 : -0,5

> 4 : nc

> 5 : nc

> 6 : -0,5

> 7 : 0

> 8 : 0

>

> IC3 : TLO72 near the unicorn

>

> 1 : 0

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC4 / CA3140

>

> 1 : -15

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : -15

> 6 : 2

> 7 : 15

> 8 : 3,5

>

> IC5 / LM3900

>

> 1 : 0,1v

> 2 : 0,4

> 3 : 0,5

> 4 : 0,15

> 5 : 0,15

> 6 : 0,55

> 7 : 0

> 8 : 0,53

> 9 : 2,2

> 10 : 2,2

> 11 : 0,5

> 12 : 0,37

> 13 : 0,37

> 14 : 15

>

> IC6 / LM311

>

> 1 : -15v

> 2 : 2,2

> 3 : 4,96

> 4 : 15,3

> 5 : 15

> 6 : 15

> 7 : -15

> 8 : 15

>

> IC7 / TLO72

>

> 1 : BTW +6 & +12

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : BTW -2 & +2

> 6 : -0,3

> 7 : BTW -8 & +12

> 8 : 15

>

>

>

> --- In cgs_synth@yahoogroups.com , <lofideadbeat@...> wrote:

>

> Well, thanks for your answer Ken... I think my problem is somewhere else,

> but can't see where.

>

> If i use my sequencer on the vc fm, i can modulate the vco.

>

> If i apply the same cv output to the cv in, my vco doesn"t respond. If i

> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o

> input, nothing..

>

> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center

> position, but if i try to move them, they don't modulate a lot ( maybe from

> 11 to 1 oclock).

>

> thanks for any help. I gonna check all the ics voltages and send it there,

> maybe it'll help !

>

>

>

> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

>

> If the span trimmer is not right, the VCO may be too sensitive to CV and to

>

> the tuning pot.

>

> Ken

>

> >Hi Everybody ! That's my first post here, as after building several

>

> modules, i think i've got some problems to fix on my cgs48. I've

>

> used a 2N3904 matched pair instead of the LM394. I think that my vco is

>

> working, but i can't really use the initial freq pot. It must be always

>

> in its center position if i want to hear the vco. Is it normal ? I only can

>

> tune the vco using the fine pot... In a post here, i've seen i could

>

> change the 1m resitor to a 2,2m one, and i did this change, but it just

>

> affect the fine tune pot, no the intial one. What should i check ? thanks

>

> for any help ! jean

>

> >

>

> >------------------------------------

>

> >

>

> >The CGS Modular Synth home page: http://www.cgs.synth.net/

>

> >Yahoo! Groups Links

>

> >

>

> >

>

> >

>

> >

>

> __________________________________________________________

>

> Ken Stone sasami@... otherunicorn@...

>

> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

>

>

>

--

/Ove

Blog: < http://blog.gg8.se/ >

"Here is Evergreen City. EvergreenÃ¯Â»Â¿ is the color of green forever."

[Non-text portions of this message have been removed]

Re: CGS48, how to be sure it's fine ?

2013-09-03 by jean0bender

Ok Ken, thanks for the answer.
Is it normal if the sine output is not so loud as the other outputs ? I'm powering the vco via +/-15v. Maybe i should change some resistors to fix that ? I've seen the schematic uses +/-12v. If not, what should i check ? Changing the two 100K resistors near the 1v/o inputs ?

thanks !

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Square out is a different issue altogether. No square out happens when the PWM voltage is outside the range covered by the sawtooth. The CV issue is a problem somewhere in your input mixer, where you seem to have excessive gain.

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

yep, i didn't forget it. The fact is i can see on my scope the saw out, the sine one, but i can't have square out. Tomorrow i'll desolder all the pots & out, and change my transistors & tempco... we'll see what happens !

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its

place)? When I built a similar VCO using discrete transistors instead of an

LM394, I forgot to place this resistor, and the oscillator didn't work.

This is the resistor that is supposed to sit over the LM394 for thermal

coupling, which is why I forgot it when using transistors.

On 2 September 2013 16:15, < lofideadbeat@... > wrote:

> **

>

>

> Well, here are my test. Seems to be a bit weird. I've multimetered my ics

> when my pots where center positionned

>

> i can see that if i approach my fingers to the pots or some parts it's

> altering the sound...

> I've rechecked all my links & solders...

>

> IC1 / TLO72

> 1 : -1,55v

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC2 LM394/2N3904

> 1 : 0

> 2 : 0

> 3 : -0,5

> 4 : nc

> 5 : nc

> 6 : -0,5

> 7 : 0

> 8 : 0

>

> IC3 : TLO72 near the unicorn

>

> 1 : 0

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC4 / CA3140

>

> 1 : -15

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : -15

> 6 : 2

> 7 : 15

> 8 : 3,5

>

> IC5 / LM3900

>

> 1 : 0,1v

> 2 : 0,4

> 3 : 0,5

> 4 : 0,15

> 5 : 0,15

> 6 : 0,55

> 7 : 0

> 8 : 0,53

> 9 : 2,2

> 10 : 2,2

> 11 : 0,5

> 12 : 0,37

> 13 : 0,37

> 14 : 15

>

> IC6 / LM311

>

> 1 : -15v

> 2 : 2,2

> 3 : 4,96

> 4 : 15,3

> 5 : 15

> 6 : 15

> 7 : -15

> 8 : 15

>

> IC7 / TLO72

>

> 1 : BTW +6 & +12

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : BTW -2 & +2

> 6 : -0,3

> 7 : BTW -8 & +12

> 8 : 15

>

>

>

> --- In cgs_synth@yahoogroups.com , <lofideadbeat@...> wrote:

>

> Well, thanks for your answer Ken... I think my problem is somewhere else,

> but can't see where.

>

> If i use my sequencer on the vc fm, i can modulate the vco.

>

> If i apply the same cv output to the cv in, my vco doesn"t respond. If i

> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o

> input, nothing..

>

> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center

> position, but if i try to move them, they don't modulate a lot ( maybe from

> 11 to 1 oclock).

>

> thanks for any help. I gonna check all the ics voltages and send it there,

> maybe it'll help !

>

>

>

> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

>

> If the span trimmer is not right, the VCO may be too sensitive to CV and to

>

> the tuning pot.

>

> Ken

>

> >Hi Everybody ! That's my first post here, as after building several

>

> modules, i think i've got some problems to fix on my cgs48. I've

>

> used a 2N3904 matched pair instead of the LM394. I think that my vco is

>

> working, but i can't really use the initial freq pot. It must be always

>

> in its center position if i want to hear the vco. Is it normal ? I only can

>

> tune the vco using the fine pot... In a post here, i've seen i could

>

> change the 1m resitor to a 2,2m one, and i did this change, but it just

>

> affect the fine tune pot, no the intial one. What should i check ? thanks

>

> for any help ! jean

>

> >

>

> >------------------------------------

>

> >

>

> >The CGS Modular Synth home page: http://www.cgs.synth.net/

>

> >Yahoo! Groups Links

>

> >

>

> >

>

> >

>

> >

>

> __________________________________________________________

>

> Ken Stone sasami@... otherunicorn@...

>

> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

>

>

>

--

/Ove

Blog: < http://blog.gg8.se/ >

"Here is Evergreen City. EvergreenÃÂ¯ÃÂ»ÃÂ¿ is the color of green forever."

[Non-text portions of this message have been removed]

Re: CGS48, how to be sure it's fine ?

2013-09-03 by cg_synth

Sine is always going to sound quieter. It doesn't have all the harmonics. Reducing the 330k connected to pin 12 of the 3900 may help increase the volume. It may also cause distortion.

+/-15 is correct. It's an old diagram.

Ken

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Ok Ken, thanks for the answer.

Is it normal if the sine output is not so loud as the other outputs ? I'm powering the vco via +/-15v. Maybe i should change some resistors to fix that ? I've seen the schematic uses +/-12v. If not, what should i check ? Changing the two 100K resistors near the 1v/o inputs ?

thanks !

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Square out is a different issue altogether. No square out happens when the PWM voltage is outside the range covered by the sawtooth. The CV issue is a problem somewhere in your input mixer, where you seem to have excessive gain.

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

yep, i didn't forget it. The fact is i can see on my scope the saw out, the sine one, but i can't have square out. Tomorrow i'll desolder all the pots & out, and change my transistors & tempco... we'll see what happens !

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its

place)? When I built a similar VCO using discrete transistors instead of an

LM394, I forgot to place this resistor, and the oscillator didn't work.

This is the resistor that is supposed to sit over the LM394 for thermal

coupling, which is why I forgot it when using transistors.

On 2 September 2013 16:15, < lofideadbeat@... > wrote:

> **

>

>

> Well, here are my test. Seems to be a bit weird. I've multimetered my ics

> when my pots where center positionned

>

> i can see that if i approach my fingers to the pots or some parts it's

> altering the sound...

> I've rechecked all my links & solders...

>

> IC1 / TLO72

> 1 : -1,55v

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC2 LM394/2N3904

> 1 : 0

> 2 : 0

> 3 : -0,5

> 4 : nc

> 5 : nc

> 6 : -0,5

> 7 : 0

> 8 : 0

>

> IC3 : TLO72 near the unicorn

>

> 1 : 0

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC4 / CA3140

>

> 1 : -15

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : -15

> 6 : 2

> 7 : 15

> 8 : 3,5

>

> IC5 / LM3900

>

> 1 : 0,1v

> 2 : 0,4

> 3 : 0,5

> 4 : 0,15

> 5 : 0,15

> 6 : 0,55

> 7 : 0

> 8 : 0,53

> 9 : 2,2

> 10 : 2,2

> 11 : 0,5

> 12 : 0,37

> 13 : 0,37

> 14 : 15

>

> IC6 / LM311

>

> 1 : -15v

> 2 : 2,2

> 3 : 4,96

> 4 : 15,3

> 5 : 15

> 6 : 15

> 7 : -15

> 8 : 15

>

> IC7 / TLO72

>

> 1 : BTW +6 & +12

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : BTW -2 & +2

> 6 : -0,3

> 7 : BTW -8 & +12

> 8 : 15

>

>

>

> --- In cgs_synth@yahoogroups.com , <lofideadbeat@...> wrote:

>

> Well, thanks for your answer Ken... I think my problem is somewhere else,

> but can't see where.

>

> If i use my sequencer on the vc fm, i can modulate the vco.

>

> If i apply the same cv output to the cv in, my vco doesn"t respond. If i

> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o

> input, nothing..

>

> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center

> position, but if i try to move them, they don't modulate a lot ( maybe from

> 11 to 1 oclock).

>

> thanks for any help. I gonna check all the ics voltages and send it there,

> maybe it'll help !

>

>

>

> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

>

> If the span trimmer is not right, the VCO may be too sensitive to CV and to

>

> the tuning pot.

>

> Ken

>

> >Hi Everybody ! That's my first post here, as after building several

>

> modules, i think i've got some problems to fix on my cgs48. I've

>

> used a 2N3904 matched pair instead of the LM394. I think that my vco is

>

> working, but i can't really use the initial freq pot. It must be always

>

> in its center position if i want to hear the vco. Is it normal ? I only can

>

> tune the vco using the fine pot... In a post here, i've seen i could

>

> change the 1m resitor to a 2,2m one, and i did this change, but it just

>

> affect the fine tune pot, no the intial one. What should i check ? thanks

>

> for any help ! jean

>

> >

>

> >------------------------------------

>

> >

>

> >The CGS Modular Synth home page: http://www.cgs.synth.net/

>

> >Yahoo! Groups Links

>

> >

>

> >

>

> >

>

> >

>

> __________________________________________________________

>

> Ken Stone sasami@... otherunicorn@...

>

> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

>

>

>

--

/Ove

Blog: < http://blog.gg8.se/ >

"Here is Evergreen City. EvergreenÃÂ¯ÃÂ»ÃÂ¿ is the color of green forever."

[Non-text portions of this message have been removed]

Re: CGS48, how to be sure it's fine ?

2013-09-03 by jean0bender

Ok, i've got it working. I had troubles with my transistor pair & the span trimmer... Well, i just need now to tune it.
thanks for the help..

Show quoted textHide quoted text

--- In cgs_synth@yahoogroups.com, <cgs_synth@yahoogroups.com> wrote:

Sine is always going to sound quieter. It doesn't have all the harmonics. Reducing the 330k connected to pin 12 of the 3900 may help increase the volume. It may also cause distortion.

+/-15 is correct. It's an old diagram.

Ken

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Ok Ken, thanks for the answer.

Is it normal if the sine output is not so loud as the other outputs ? I'm powering the vco via +/-15v. Maybe i should change some resistors to fix that ? I've seen the schematic uses +/-12v. If not, what should i check ? Changing the two 100K resistors near the 1v/o inputs ?

thanks !

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Square out is a different issue altogether. No square out happens when the PWM voltage is outside the range covered by the sawtooth. The CV issue is a problem somewhere in your input mixer, where you seem to have excessive gain.

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

yep, i didn't forget it. The fact is i can see on my scope the saw out, the sine one, but i can't have square out. Tomorrow i'll desolder all the pots & out, and change my transistors & tempco... we'll see what happens !

--- In cgs_synth@yahoogroups.com , < cgs_synth@yahoogroups.com > wrote:

Have you fitted the 1k tempco resistor (or a regular 1k resistor in its

place)? When I built a similar VCO using discrete transistors instead of an

LM394, I forgot to place this resistor, and the oscillator didn't work.

This is the resistor that is supposed to sit over the LM394 for thermal

coupling, which is why I forgot it when using transistors.

On 2 September 2013 16:15, < lofideadbeat@... > wrote:

> **

>

>

> Well, here are my test. Seems to be a bit weird. I've multimetered my ics

> when my pots where center positionned

>

> i can see that if i approach my fingers to the pots or some parts it's

> altering the sound...

> I've rechecked all my links & solders...

>

> IC1 / TLO72

> 1 : -1,55v

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC2 LM394/2N3904

> 1 : 0

> 2 : 0

> 3 : -0,5

> 4 : nc

> 5 : nc

> 6 : -0,5

> 7 : 0

> 8 : 0

>

> IC3 : TLO72 near the unicorn

>

> 1 : 0

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : 0

> 6 : 0

> 7 : 0

> 8 : 15

>

> IC4 / CA3140

>

> 1 : -15

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : -15

> 6 : 2

> 7 : 15

> 8 : 3,5

>

> IC5 / LM3900

>

> 1 : 0,1v

> 2 : 0,4

> 3 : 0,5

> 4 : 0,15

> 5 : 0,15

> 6 : 0,55

> 7 : 0

> 8 : 0,53

> 9 : 2,2

> 10 : 2,2

> 11 : 0,5

> 12 : 0,37

> 13 : 0,37

> 14 : 15

>

> IC6 / LM311

>

> 1 : -15v

> 2 : 2,2

> 3 : 4,96

> 4 : 15,3

> 5 : 15

> 6 : 15

> 7 : -15

> 8 : 15

>

> IC7 / TLO72

>

> 1 : BTW +6 & +12

> 2 : 0

> 3 : 0

> 4 : -15

> 5 : BTW -2 & +2

> 6 : -0,3

> 7 : BTW -8 & +12

> 8 : 15

>

>

>

> --- In cgs_synth@yahoogroups.com , <lofideadbeat@...> wrote:

>

> Well, thanks for your answer Ken... I think my problem is somewhere else,

> but can't see where.

>

> If i use my sequencer on the vc fm, i can modulate the vco.

>

> If i apply the same cv output to the cv in, my vco doesn"t respond. If i

> apply the cv output to the 1v/o in, nothing. If i apply 1v to the 1v/o

> input, nothing..

>

> I've got 0v on ic1 pin 7, when i've got my tune and freq pot in center

> position, but if i try to move them, they don't modulate a lot ( maybe from

> 11 to 1 oclock).

>

> thanks for any help. I gonna check all the ics voltages and send it there,

> maybe it'll help !

>

>

>

> --- In cgs_synth@yahoogroups.com , <sasami@...> wrote:

>

> If the span trimmer is not right, the VCO may be too sensitive to CV and to

>

> the tuning pot.

>

> Ken

>

> >Hi Everybody ! That's my first post here, as after building several

>

> modules, i think i've got some problems to fix on my cgs48. I've

>

> used a 2N3904 matched pair instead of the LM394. I think that my vco is

>

> working, but i can't really use the initial freq pot. It must be always

>

> in its center position if i want to hear the vco. Is it normal ? I only can

>

> tune the vco using the fine pot... In a post here, i've seen i could

>

> change the 1m resitor to a 2,2m one, and i did this change, but it just

>

> affect the fine tune pot, no the intial one. What should i check ? thanks

>

> for any help ! jean

>

> >

>

> >------------------------------------

>

> >

>

> >The CGS Modular Synth home page: http://www.cgs.synth.net/

>

> >Yahoo! Groups Links

>

> >

>

> >

>

> >

>

> >

>

> __________________________________________________________

>

> Ken Stone sasami@... otherunicorn@...

>

> Modular Synth PCBs for sale < http://www.cgs.synth.net/ >

>

>

>

--

/Ove

Blog: < http://blog.gg8.se/ >

"Here is Evergreen City. EvergreenÃÂÃÂ¯ÃÂÃÂ»ÃÂÃÂ¿ is the color of green forever."

[Non-text portions of this message have been removed]

Cgs synth

CGS48, how to be sure it's fine ?

CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

Re: CGS48, how to be sure it's fine ?

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