[sdiy] Waveform phases and hard sync, sawtooth vs. triangle?

[David G Dixon]

The Dixie and Rubicon have reversing sync -- we call it "Flip" -- and I
think it sounds fabulous.  I've always preferred it to resetting sync.
 

> -----Original Message-----
> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On 
> Behalf Of rsdio at audiobanshee.com
> Sent: Saturday, June 23, 2018 2:11 PM
> To: Synth DIY
> Subject: Re: [sdiy] Waveform phases and hard sync, sawtooth 
> vs. triangle?
> 
> 
> On Jun 22, 2018, at 4:34 PM, Tom Wiltshire 
> <tom at electricdruid.net> wrote:
> > On 22 Jun 2018, at 23:24, Mattias Rickardsson 
> <mr at analogue.org> wrote:
> >> The sync-behaviour in the CEM3340
> >> simply switches the load/unload "direction" of the VCO-core. So it 
> >> does
> >> not(!) do a reset, like the hard sync does in a saw core VCO.
> > 
> > .and that's why hardly anyone ever used the default 
> datasheet "sync" circuit. Instead, pretty much all the 
> commercial synth manufacturers went for the circuit that 
> mimics the typical ramp-core VCO reset sync, "Figure 5" which 
> appears on page 6 of the datasheet. Curtis clearly thought 
> that their version was more interesting and did something 
> new, but actually most people wanted the sync sound they 
> already knew and loved.
> 
> Considering the original goal - to reduce the discontinuity 
> at the point of sync - reversing the direction of the 
> triangle is the ultimate solution. It has no first order 
> discontinuity (although it does have a second order 
> discontinuity). It's a lot better than merely cutting the 
> discontinuity in half.
> 
> The fact that nobody (?) used the Curtis CEM3340 feature 
> commercially may give us our answer as to whether the goal is 
> a useful one. However, perhaps no engineer allowed the 
> reversing triangle sync out into the field long enough for 
> musicians to hear what it offered and make use of it where 
> appropriate.
> 
> I'd certainly like to hear what hard sync sounds like with a 
> triangle core VCO that reverses direction in response to sync pulses.
> 
> Brian Willoughby
> 
> 
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