[sdiy] Help with Jupiter 8 clone

[Chromatest J. Pantsmaker]

My day job is as a Chief Engineer for some FM radio stations.  Our FM
transmitters use SMPSUs.  In fact, my 40KW fm transmitter has 32
switch-mode power supplies in it (there's a fair bit of redundancy).

If switch mode power supplies can push out FM radio signals at an effective
radiated power of 100,000 watts without spurious emissions, I think they
can be made pretty clean.

On Tue, Aug 2, 2022 at 10:25 AM <rburnett at richieburnett.co.uk> wrote:

> There are good and bad SMPSUs.  I've been responsible for EMC compliance
> of products at several places I've worked over the years, so have seen
> examples of some very good supplies, and also some real shockers.
> Sometimes literally! (>.<)
>
> I won't go into the details but certain supplies like flyback (wall-wart
> phone chargers) are notoriously noisy but you have to realise that they
> are made down to a target price, size and weight.  So they don't waste
> any money, space or weight on removing any more conducted and radiated
> emissions than they absolutely need to in order to achieve compliance
> whilst charging the battery in your cell phone!
>
> One of the last bastions of the analogue linear power supply used to be
> in RF communications receivers because the harmonic spectrum of a
> high-power switcher used to put all sorts of "birdies" across the
> spectrum of a sensitive broadband radio receiver.  But these days even
> high-end radio receivers have switched-mode power supplies inside them.
> It just means that they are well designed and people have learned how to
> manage things like common-mode noise and stop it getting into the RF
> front-end or the audio output.
>
> -Richie,
>
>
> On 2022-08-02 17:50, Mattias Rickardsson wrote:
> > Maybe it's possible to find some of those interference problems if you
> > combine an old or unrefined SMPS design with the old original
> > unshielded JP-8 PCB layout, but as a general "truth" it sounds quite
> > false. :-)
> >
> > /mr
> >
> > Den tis 2 aug. 2022 18:23Tom Wiltshire <tom at electricdruid.net> skrev:
> >
> >> +1 agree with Rob, evidence is definitely required for for such a
> >> bold claim.
> >>
> >> On 2 Aug 2022, at 16:51, rob hukin <rob at audiocircus.co.uk> wrote:
> >>
> >> *citation required
> >>
> >> rob.
> >>
> >> On 2 Aug 2022, at 16:46, Josh Nursing via Synth-diy
> >> <synth-diy at synth-diy.org> wrote:
> >>
> >> SMPS are the most polluting/noisy PSUs for audio purposes. Lots of
> >> high-frequency current spikes affect both downstream circuits and
> >> the mains they're connected to.
> >>
> >> And before you start telling me about filtering the output of them,
> >> that does absolutely nothing for the mains-side noise.
> >>
> >> Effects on audio are across the board - all audio frequencies
> >> suffer, and it's probably more noticeable in loss of bass
> >> frequencies.
> >>
> >> On Tue, Aug 2, 2022 at 11:41 AM Mike Bryant
> >> <mbryant at futurehorizons.com> wrote:
> >>
> >> How can audio suffer from putting a PSU in with 100 times better
> >> performance ?    No 50/100Hz at all and general noise almost zero.
> >> And it’s far less heat so everything else runs cooler and better.
> >> I think too many people see the noise from their phone charger or
> >> whatever and assume a proper SMPS is like that.
> >>
> >> From: Synth-diy [mailto:synth-diy-bounces at synth-diy.org] On Behalf
> >> Of Josh Nursing via Synth-diy
> >> Sent: 02 August 2022 16:35
> >> To: Synth DIY
> >> Subject: Re: [sdiy] Help with Jupiter 8 clone
> >>
> >> I really don't like the idea of replacing the linear PSU in those
> >> vintage synths with a SMPS one. Audio suffers.
> >>
> >> On Tue, Aug 2, 2022 at 7:45 AM Adam (synthDIY)
> >> <synthdiy at adambaby.com> wrote:
> >>
> >> Luís, I assume you’re aware of this
> >>
> >> https://synthronics.de/roland-jupiter-8-new-psu/
> >>
> >> and this guy, who has been ominously quiet of late
> >>
> >>
> >
> https://jup8restoration.wordpress.com/2019/10/22/new-power-supply-being-manufactured-for-a-jupiter-8/
> >>
> >>
> >> A
> >>
> >> On 2 Aug 2022, at 3:57 am, Luís Marka via Synth-diy
> >> <synth-diy at synth-diy.org> wrote:
> >>
> >> Hi guys,
> >>
> >> I am giving a serious thought about building a Jupiter 8 clone, and
> >> started to take a deeper look at the schematics (actually I already
> >> ordered some of the parts, so it looks like I will get it done
> >> eventually). In the PSU there are three GP-30G diodes tied at the
> >> -15, +15 and +5V outputs, listed as "Hi-Fi Special" both in the
> >> schematics and in the parts list. I never heard anything about a
> >> "hi-fi special" diode, any idea what that means??
> >>
> >> Cheers!
> >>
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
> >>
> >> _______________________________________________
> >> Synth-diy mailing list
> >> Synth-diy at synth-diy.org
> >> http://synth-diy.org/mailman/listinfo/synth-diy
> >> Selling or trading? Use marketplace at synth-diy.org
> >  _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
> > Rob Hukin
> > Audiocircus Ltd
> > 6 Blackstone St
> > Blackstone
> > Henfield
> > BN5 9TH
> > UK
> >
> > +44 7961 883 949
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> >
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> > _______________________________________________
> > Synth-diy mailing list
> > Synth-diy at synth-diy.org
> > http://synth-diy.org/mailman/listinfo/synth-diy
> > Selling or trading? Use marketplace at synth-diy.org
> _______________________________________________
> Synth-diy mailing list
> Synth-diy at synth-diy.org
> http://synth-diy.org/mailman/listinfo/synth-diy
> Selling or trading? Use marketplace at synth-diy.org
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://synth-diy.org/pipermail/synth-diy/attachments/20220802/1c186831/attachment.htm>