SergeModular

Shouldn't be a problem. I'll try to get to it by the end of the weekend.

James R. Coplin
***************
If anyone asks of my whereabouts,
simply tell them i've gone out the window
for a spot of tea and am not
expected back any time soon.
***************

> -----Original Message-----
> From: metafoetus2002 [mailto:jan-hinnerk.helms@...]
> Sent: Wednesday, January 19, 2005 1:51 PM
> To: SergeModular@yahoogroups.com
> Subject: [SergeModular] Re: Serge Sync
>
>
>
> Hi James,
>
> thanks much for this explanation! Do you think it is possible to post a
> short sound file of
> just an [NTO] square wave being hard-sync'd and being slowly tuned from
> unison upwards
> (relative to the sync source oscillator), so that we hear the humps as
> well as the sync
> sound? Hope this is possible, as it would really be instructional before
> attempting to
> modify.
>
> Best regards,
> thanks in advance,
> Jan-Hinnerk
>
> --- In SergeModular@yahoogroups.com, "James R. Coplin" <moog@q...> wrote:
> > I can try a little. At first, removing the resistor completely made the
> osc
> > much more receptive to resets, super hard sync with no effort. Any kind
> of
> > an edge would be enough to reset the osc. However, *anything* would also
> go
> > directly into the core via the reset circuit: DC, noise, the evil eye,
> etc.
> > It was fairly easy to get "odd" behavior besides the desired reset. It
> was
> > just too sensitive, any positive short voltage would reset the core,
> often
> > when you didn't want it to.
> >
> > This is why Ken recommended putting at least a small value resistor to
> > provide protection for signals leeching in that were not intended to
> reset
> > and provide sync. This worked better at removing the oddness in having
> the
> > wire and provided a degree of input protection for the core.
> >
> > Going on the "if a little is good, more is better approach", I started
> > increasing the value of the resistor to see what the largest resistor
> (ie,
> > closer to the osc. design spec) that would work and provide hard sync
> > behavior would be. 3k seems to be about the largest value that still
> lets
> > the core get reset by strong edges while providing an adequate buffer
> > against the external world. It is enough to block nearly all the DC,
> misc
> > noise, etc. that could impact the stability of the osc. So far so

good...

> >
> > However, a lot of this is personal preference. The 3k resistor is not
> super
> > hard sync. It is kind of a medium-hard sync. You could use a lower value
> if
> > you want the reset touchier. All of this being said, it is not perfect.
> > There are noticeable humps when the two osc are close together. The sync
> > circuit was not designed for hard sync, so you are getting part of the
> > behavior (enough to satisfy me at least) but not perfect behavior. I
> find
> > that you need to offset the freq of the slave osc to stop the humps and
> keep
> > the modulations from ending near the next freq crossover. Within these
> > ranges, it works lovely.
> >
> > Again though, this works fine for me (I've converted all of mine and
> don't
> > have any problems) but it is not a STS sanctioned, blessed, or
> recommended
> > mod. It does change the circuit (although slightly) and has not gone
> through
> > the rigorous bench testing that a STS sanctioned change would have to go
> > through.
> >
> > Bottom line, if you really want hard sync (and I did) this is probably
> the
> > only option you have as a STS change in the osc to accommodate hard sync
> is
> > unlikely. Later!
> >
> > James R. Coplin
> > ***************
> > If anyone asks of my whereabouts,
> > simply tell them i've gone out the window
> > for a spot of tea and am not
> > expected back any time soon.
> > ***************
> >
> > > -----Original Message-----
> > > From: metafoetus2002 [mailto:jan-hinnerk.helms@t...]
> > > Sent: Tuesday, January 18, 2005 7:38 PM
> > > To: SergeModular@yahoogroups.com
> > > Subject: [SergeModular] Serge Sync
> > >
> > >
> > >
> > > Hi,
> > >
> > > last December we saw some posts regarding modification of the Serge
> [PCO]s
> > > and [NTO]s
> > > from Soft Sync to Hard Sync.
> > >
> > > James R. Coplin suggested to replace the 22k Ohm resistor on the Sync
> > > input with a blank
> > > wire.
> > > Then Ken Stone suggested to replace the 22k Ohm with a 220 Ohm for
> circuit
> > > protection.
> > > One month later James suggested to replace the 22k Ohm with a 3k Ohm
> for
> > > "best sound
> > > and minimal (note I didn't say none) core effects".
> > >
> > > I am very thankful and excited about this possibility to get hard sync
> on
> > > my Serge. Now I
> > > wonder if someone of the more electronically knowledgeable guys on
> this
> > > list could be so
> > > kind and explain
> > > - the possible core effects
> > > - what's the trade-off between circuit safety and hard sync sound
> > > - why the difference between soft and hard sync is just changing a
> > > resistor
> > >
> > > Thanks much in advance,
> > > best regards,
> > > Jan-Hinnerk
> > >
> > >
> > >
> > >
> > >
> > >
> > > Keep on Patchin'!
> > >
> > > Yahoo! Groups Links
> > >
> > >
> > >
> > >
> > >
> > >
> > >
>
>
>
>
>
>
> Keep on Patchin'!
>
> Yahoo! Groups Links
>
>
>
>
>
>
>