By the way
Power is 9V ac. Gets rectified, so becomes 11.5V. Passes through 100 ohm, and then feeds the opamp...
That opamp will never produce 12V...
power mod C7 C8
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Please be positive and constructive with your questions and comments.
- antto
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Re: power mod C7 C8
well, yeah.. my 12V is around 11.87 iirc
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Re: power mod C7 C8
Measured the ps too?antto wrote:well, yeah.. my 12V is around 11.87 iirc
- antto
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Re: power mod C7 C8
haven't but that's the reading for example at the VCO section where it is connected to 12V so..
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Re: power mod C7 C8
Yeah. I guess the ps is never the same.antto wrote:haven't but that's the reading for example at the VCO section where it is connected to 12V so..
- antto
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Re: power mod C7 C8
component tollerance does make a difference, together with component tollerance of the adaptor (and it's type)
i'm not good with electronics, that's just my impression
i'm not good with electronics, that's just my impression
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Re: power mod C7 C8
Yeah that's what i meant, tolerance of the apaptor, plus the fluctuations of the voltage from the wall. Here its 230V but most of the time it's 235V. Etc...antto wrote:component tollerance does make a difference, together with component tollerance of the adaptor (and it's type)
i'm not good with electronics, that's just my impression
Time to build...
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Re: power mod C7 C8
Building the ps i ran into a problem, i put it in a separate post. Rectifier mod...r
- aminoacid
- Posts: 352
- Joined: Tue Jun 20, 2006 5:27 am
Re: power mod C7 C8
has anybody measured VCC of the op amp (12V) of the 303? or how much it variates on different 303´s / adapters?
- aminoacid
- Posts: 352
- Joined: Tue Jun 20, 2006 5:27 am
Re: power mod C7 C8
i was thinking that VCC (depending on the VAC of adaptor) would change the 12V line but thats not how it works if im right...
the 12V line is determined by r178, r179, 5.333V and voltage offset of the op amp.
if i calculated this correct 12V can swing depending on r178 and r179 between 12.53V and 11.23V (regardsless of input voltage offset).
so r178 and r179 would determine the voltage of the 12V line.
ac adapter will determine the current of the 12V line.
i might have to socket r178 and r179 now
the 12V line is determined by r178, r179, 5.333V and voltage offset of the op amp.
if i calculated this correct 12V can swing depending on r178 and r179 between 12.53V and 11.23V (regardsless of input voltage offset).
so r178 and r179 would determine the voltage of the 12V line.
ac adapter will determine the current of the 12V line.
i might have to socket r178 and r179 now
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- Posts: 110
- Joined: Sun May 13, 2012 8:35 pm
Re: power mod C7 C8
Just one, 178 or 179. Replace it by a trimpot to adjust the 12v.aminoacid wrote:i was thinking that VCC (depending on the VAC of adaptor) would change the 12V line but thats not how it works if im right...
the 12V line is determined by r178, r179, 5.333V and voltage offset of the op amp.
if i calculated this correct 12V can swing depending on r178 and r179 between 12.53V and 11.23V (regardsless of input voltage offset).
so r178 and r179 would determine the voltage of the 12V line.
ac adapter will determine the current of the 12V line.
i might have to socket r178 and r179 now
- aminoacid
- Posts: 352
- Joined: Tue Jun 20, 2006 5:27 am
Re: power mod C7 C8
well how is your psu mod going?
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Re: power mod C7 C8
I build the PS, and got the right voltages.aminoacid wrote:well how is your psu mod going?
But to properly test it, I need to build the VCO and the VCF...
next days I'm busy, so... it will take a while
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- Joined: Sun May 13, 2012 8:35 pm
Re: power mod C7 C8
actually its best to replace r178 with a (precision) 4,7k trimpot. I'm gonna do that, so I'll be able to get 12V, although i dont think i really think it will matter...evostars wrote: Just one, 178 or 179. Replace it by a trimpot to adjust the 12v.
- aminoacid
- Posts: 352
- Joined: Tue Jun 20, 2006 5:27 am
Re: power mod C7 C8
just did it with a multiturn 5k pot.
i dont know whats happening more than cutofff is increasing...
but i liked having the voltage a bit higher how ever.
also i tried two different ac adaptors and seemd to prefer one of them...
i feel a bit like a bull shiter
i dont know whats happening more than cutofff is increasing...
but i liked having the voltage a bit higher how ever.
also i tried two different ac adaptors and seemd to prefer one of them...
i feel a bit like a bull shiter
Please be positive and constructive with your questions and comments.