[sdiy] Help with Jupiter 8 clone

[brianw]

Is it possible that the "Hi-Fi Special" diodes that Roland selected were merely chosen because they put less noise on the supply rails?

I agree with John that a modern power supply is better than bothering with recreating the old. You might want to try both switching and linear, but there's probably not any other details worth worrying about.

Brian


On Aug 1, 2022, at 11:24 AM, John Speth via Synth-diy <synth-diy at synth-diy.org> wrote:
> For reference, the JP8 schematic is here: http://www.synthfool.com/docs/Roland/Roland_Jupiter8/roland_jp8_service_manual.pdf
> 
> The Hi Fi Special diodes are probably what Roland and others might have called them in the 80s. From the schematic, the only function I can think that they could possibly perform is over-voltage shunting. Metal Oxide Varistors (MOVs) perform that same function in modern circuits. I think those diodes are the 80s version of MOVs. A modern day PS might serve you better than trying to clone an ancient design.
> 
> JJS
> 
> On 8/1/2022 10:57 AM, Luís Marka via Synth-diy 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!