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Waves in and out of phase
http://www.paia.com/talk/viewtopic.php?f=8&t=621
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Author:  Billb3 [ Tue Nov 18, 2014 1:19 pm ]
Post subject:  Waves in and out of phase

how is it that the @ fatman oscillators dont go out of phase?

it seems to me that changing the frequency of osc 1 and then returning it to be the same as osc 2 should result in out of phase 50% of the time.

am I missing something? (obviously)

Author:  toneman [ Wed Nov 19, 2014 12:49 am ]
Post subject:  Re: Waves in and out of phase

billb3,

IF U are referring to "soft syncing" of the 2 555 vcos...

This is Scott Lee's fix for that:
http://www.cykong.com/Synths/PAiA%20930 ... E%20DIODES

Author:  Billb3 [ Wed Nov 19, 2014 3:09 pm ]
Post subject:  Re: Waves in and out of phase

by "out of phase" I mean that when one oscillators wave is at its peak the others is in a valley. the result is no sound output as the waves cancel each other out.

this is randomly happening with my sub oscilators. I can cause it by changing the pitch of vco1 slightly and then returning it to locked in tune. its kinda cool to watch on an oscilloscope. especially the -2 suboctave which has more ways to vary in phase.

Author:  toneman [ Wed Nov 19, 2014 5:21 pm ]
Post subject:  Re: Waves in and out of phase

Billb3 wrote:
by "out of phase" I mean that when one oscillators wave is at its peak the others is in a valley. the result is no sound output as the waves cancel each other out.

this is randomly happening with my sub oscilators...


for the first part...
don't see how this is possible with 2 555's that aren't *exactly* sync'd together. even then, the 2 vcos would have to be *exactly* 180deg out.
syncing them would make them *zero* degrees to each other.
U still would have to have exact amplitudes also.. (?)

Ahhhh....
for the 2nd part, that word "randomly" might mean an intermittant connection. from your links, looks like U have a LOT of connections and long runs.

that's all I got......

Author:  PAiA-Scott [ Wed Dec 03, 2014 10:56 am ]
Post subject:  Re: Waves in and out of phase

Re the diode mod Tone linked, the VCO APL (anti-phase-lock) details posted here are more complete:

viewtopic.php?f=15&t=238

With square waves from the divider circuit for sub-octave circuit and instances where the two vcos phase-lock, it would be a more constant cancellation than with the ramp waves. With the VCO APL changes, it will be less likely the waves are exactly 180deg out-of-phase resulting in minimized output from the one/two mix.

Author:  Billb3 [ Wed Dec 03, 2014 12:41 pm ]
Post subject:  Re: Waves in and out of phase

I need to break out my 4 channel scope and make a video of it.

its actually kinda cool to watch it phase in and out. my sub octave is running off the reset pulses (i think) so if the flip flop misses a pulse the it will change its phase state. the -1 sub is either in or out, the -2 sub has 2 other states of partially out.

also, if I change the tuning one vco and then bringing it back in there is a 50% chance the -1 sub will be either in phase or out of phase (I watched it on the scope)
I am wondering if I designed the sub oct poorly, I used a 4013, I will see if I can make a schematic for what I did.

billb

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