[sdiy] BBD clock bleed

Ben Bradley ben.pi.bradley at gmail.com
Tue Oct 23 16:56:26 CEST 2018


R38 through R42 should be 1 percent, that should help for matching and
canceling the clock, but probably most resistors already are 1 percent
thesedays.

You might try replacing R38 and R40 with a pot as I described earlier,
and see if the clock can be nulled out any better.

On Tue, Oct 23, 2018 at 9:37 AM Quincas Moreira <quincas at gmail.com> wrote:
>
> I’ve thought of using na integrator to derive a triangle from the clock pulse, then an OTA to distort it into a sine, then invert it and sum it to the BBD output thus cancelling most of the bleed but now we’re talking a full on daughterboard, lol
>
> Sent from my iPad
>
> > On Oct 23, 2018, at 8:12 AM, Tom Bugs <admin at bugbrand.co.uk> wrote:
> >
> > There appears to be minimal input and output filtering also.
> >
> >
> >> On 23/10/2018 14:07, Vladimir Pantelic wrote:
> >> no output balance trimmer between out1 and out2 on this one
> >>
> >>> On 23.10.2018 14:46, Quincas Moreira wrote:
> >>> Sorry Folks, please follow this link
> >>> https://drive.google.com/open?id=1O5kKkaJZqom61W8WQKQCfm3gLF83goz0
> >>>
> >>> Sent from my iPhone
> >>>
> >>> On Oct 23, 2018, at 06:13, Tom Wiltshire <tom at electricdruid.net
> >>> <mailto:tom at electricdruid.net>> wrote:
> >>>
> >>>> The list strips attachments. Can you post a link?
> >>>>
> >>>>
> >>>>> On 23 Oct 2018, at 08:30, Quincas Moreira <quincas at gmail.com
> >>>>> <mailto:quincas at gmail.com>> wrote:
> >>>>>
> >>>>> thanks folks. It’s a new
> >>>>> module, not yet released V3205 based. Strange that you don’t see the
> >>>>> pdf attachment, I’ll try again in the morning
> >>>>>
> >>>>> Sent from my iPhone
> >>>>>
> >>>>> On Oct 22, 2018, at 23:59, Pete Hartman <pete.hartman at gmail.com
> >>>>> <mailto:pete.hartman at gmail.com>> wrote:
> >>>>>
> >>>>>> As others have said a lot depends on which BBD we're talking about.
> >>>>>>
> >>>>>> Most of my BBD experience is with Blacet's Time Machine.  It uses
> >>>>>> the MN3005 which has balanced outputs, which can be trimmed to
> >>>>>> minimize the clock bleed, and it also uses clock dependent filtering
> >>>>>> and compansion to help reduce the noise further.  I have also played
> >>>>>> some with the Doepfer A-188-2 which uses a tapped BBD, and that does
> >>>>>> *not* have balanced outputs, so the bleed is harder to tame.
> >>>>>>
> >>>>>> I looked at the Erica site as well, and honestly, I can't tell which
> >>>>>> one you're asking about either.  Let us know/attach the schem, and
> >>>>>> I'm sure someone will have suggestions :)
> >>>>>>
> >>>>>> Pete
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> On Mon, Oct 22, 2018 at 8:55 PM Quincas Moreira <quincas at gmail.com
> >>>>>> <mailto:quincas at gmail.com>> wrote:
> >>>>>> Hey friends! I'm working in a review of the new Erica Synths BBD
> >>>>>> module, and I'm getting massive bleed of the clock frequency (though
> >>>>>> it looks sinusoidal rather than square)
> >>>>>> Any tips on minimizing this bleed? Anytime the clock steps into
> >>>>>> audible range it's super loud
> >>>>>>
> >>>>>> Schematics included...
> >>>>>>
> >>>>>> Thanks!!
> >>>>>>
> >>>>>>
> >>>>>>
> >>>>>> --
> >>>>>> Quincas Moreira
> >>>>>> Synth Diy Guy
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