[sdiy] two VCOs on 1 PCB - problems

[neil harper]

thanks tim,
i have decoupling caps next to every IC. no ic's are shared between the
two vco's and each vco has separate power supply lines. however, the
grounding isn't separate.. should i do separate ground planes for each
vco on the pcb?



On Thu, 2012-12-27 at 14:13 -0800, Tim Parkhurst wrote:
> On any design like that, you should separate the supply lines (and
> ground) to each VCO, and join them only at one common point. You might
> also want to consider a low value resistor to isolate the supply lines
> going to each VCO. Dave D also has a good suggestion about trying
> additional decoupling caps - make sure you have one for each supply
> line to each IC.
> 
> Tim (that syncing feeling) Servo
> ---
> "Sire, the church of God is an anvil that has worn out many hammers."
> - H.L. Hastings
> 
>  
>  
> On Thu, Dec 27, 2012 at 1:04 PM, neil harper <metadata at gmx.com> wrote:
>         hi everyone,
>         seasons greetings from canada
>         
>         as my christmas project, i built two Thomas Henry VCO-1's on a
>         single
>         protoboard. so far everything seems like it's working and
>         sounds great,
>         but I am noticing a few "quirks".
>         
>         - as the tuning of each oscillator gets very close, they seem
>         to lock
>         together.
>         
>         - when the oscillators are tuned close, i believe i'm hearing
>         one of the
>         oscillators reset (sounds like an occasional 'tick' maybe once
>         every
>         second - goes away when i detune the other oscillator).
>         
>         i only have experience doing circuit boards for small digital
>         stuff, so
>         i know this is a bit over my head as a first synth project. :)
>         i'd like
>         to make this on a proper PCB for myself, so does anybody have
>         any tricks
>         i can do on the PCB layout to eliminate these problems?
>         
>         
>         
>         --
>         //neil harper
>         

-- 
//neil harper