That's interesting Adam. I didn't know the JX-3P could do that! I don't see a modulation path from the analogue noise source to the DCOs though, so I guess the noise modulation you mention must be done digitally by the micro? -Richie, On 2026-01-18 21:52, Adam (synthDIY) wrote: > I wonder if it has something to do with the noise modulation option in > the JX3P, rather than just the use of noise as part of the patch mix? > > Noise modulation is available from the front panel but not from the > PG-200 > > A > >> On 19 Jan 2026, at 05:47, Richie Burnett >> <rburnett@richieburnett.co.uk> wrote: >> >> Thanks for the confirmation everyone. >> >> It just seemed like a strange thing to include what must have been an >> expensive BA662 OTA device at the time, instead of using yet another >> trim-pot to calibrate the noise level. >> >> Obviously the AGC approach would try to correct for long-term drift of >> the noise level and possible variation with temperature, but that >> can't account for that much amplitude variation, and the user can >> adjust the level of noise in the mix anyway! I would have thought the >> AGC circuit would need to measure the RMS of the noise in order to >> accurately control its perceived loudness anyway? >> >> It's interesting that it's used in other synths of the era like the >> Juno 6 & 60 and a variant in the Jupiter 6, but the Juno 106 design >> went back to using a trim-pot again (VR32). (See attached.) >> >> JX-8P and the Alpha Juno / MKS50 got the luxury of digital noise >> sources! >> >> -Richie, >> >> >> >> -----Original Message----- From: Florian Anwander via Synth-diy >> Sent: Sunday, January 18, 2026 6:15 PM >> To: synth-diy mailing list >> Subject: Re: [sdiy] JX-3P question >> >> >> >> Hello Richie >> >> Am 18.01.26 um 18:13 schrieb Richie Burnett: >> but on closer inspection it looks like the OTA is in some sort of >> local feedback loop, intended to keep the noise amplitude constant, >> maybe? >> >> I never investigated deeper on this circuit, but that is my impression >> too. Roland used that in the JX3P and in the Juno6/60. A similar >> circuit was used in the Jupiter6: >> >> >> >> >> >> >> I don't remember the JP8. >> >> Florian >> >> >> >> >> >> ________________________________________________________ >> This is the Synth-diy mailing list >> Submit email to: Synth-diy@synth-diy.org >> View archive at: https://synth-diy.org/pipermail/synth-diy/ >> Check your settings at: >> https://synth-diy.org/mailman/listinfo/synth-diy >> Selling or trading? Use marketplace@synth-diy.org >> >> -- >> This email has been checked for viruses by AVG antivirus software. >> www.avg.com<Juno106-Noise.PNG>________________________________________________________ >> This is the Synth-diy mailing list >> Submit email to: Synth-diy@synth-diy.org >> View archive at: https://synth-diy.org/pipermail/synth-diy/ >> Check your settings at: >> https://synth-diy.org/mailman/listinfo/synth-diy >> Selling or trading? Use marketplace@synth-diy.org
Message
Re: [sdiy] JX-3P question
2026-01-19 by rburnett@richieburnett.co.uk