[sdiy] [AH] CEM3340 revG reissue --

Pete Hartman pete.hartman at gmail.com
Sat Jul 9 17:39:31 CEST 2016

You could test by clipping a 560K resistor across the 26.7K, which would
bring the parallel value down very close to 25.5K.


On Sat, Jul 9, 2016 at 10:22 AM, M V <mv_synths at hotmail.com> wrote:

> I had the same erroneous tuning issue on a couple voices with an otherwise
> perfectly working P-600 (when autotuning with the GliGli mod)--would doing
> this resistor swap resolve this? I'm not clear how changing the resistors
> for the old CEM 3340s (Rev?) would correlate with needing to do it on the
> new RevGs.
> Matt
> ------------------------------
> *From:* Eric Frampton <eric at ericframpton.com>
> *Sent:* Friday, July 8, 2016 8:04 PM
> *To:* Analogue Heaven; SDIY
> *Subject:* Re: [AH] CEM3340 revG reissue --
> I’ve had similar experience with my P-600 and GliGli: the Sequential 6.0.2
> firmware scaling and autotune routines work fine with the revG chips, and
> the GliGli scaling routine works fine, but the GliGli autotune routine
> fails miserably (the weirdness below middle C that I mentioned in earlier
> emails).
> Haven’t installed the 25.5K 1% resistors yet, though.
> e
> On Jul 8, 2016, at 4:48 PM, gm <montalbanogm at gmail.com> wrote:
> In case anybody was wondering about these...
> Received my order of new CEM3340s from Onchip.
> Installed some in my P5 and Pro-One (mixed in with original chips)--
> waveforms sound the same, response to PW & pitch mod is the same, tuning &
> scaling are the same.
> Installed them in my P600 (running firmware v6.0.8) and they tuned &
> scaled just fine.
> HOWEVER, installing the gligli firmware upgrade caused the oscillators to
> go wildly out of tune.
> Replaced the 26.7K trim resistors with 25.5K 1% (as per the service manual
> instructions on using revG chips), and running the gligli tune routine
> solved the problem.
> I realize that one point on a graph doesn't give the most accurate
> information; if anybody else is using these as replacements in vintage
> synths (Roland, SCI, etc) it would be helpful if you report your experience
> to the list.
> Thanks.
> ~GMM
> analogsynthservice.com
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