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Hydrasynth - PSU?

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Re: Hydrasynth - PSU?

PostPosted: Sun Jun 28, 2020 3:25 pm
by James Perrett
Hugh Robjohns wrote:
James Perrett wrote:Not so cheap but these look very neat, have the required current rating, come from a good manufacture...

The datasheet says: Ripple and Noise <200mV p-p, which is quite a lot in comparison to a typical instrument audio signal level!

Yes, that's higher than the Recom ones linked to above (they're 120mV) but the input filtering on the keyboard should handle that. Especially as it is likely to be at a switching frequency that is outside the audio band. I've just had a look at a few others and ripple and noise at 1% of the voltage output seems to be a fairly standard spec.

Re: Hydrasynth - PSU?

PostPosted: Sun Jun 28, 2020 3:39 pm
by The Elf
So... Is this "Rats!" or "Hoorah!"? :lol:

Would one of those little 'slot in' power sockets work adequately for me?

I'm not saying *I* could do it, but it may make life easier for an engineer.

Re: Hydrasynth - PSU?

PostPosted: Sun Jun 28, 2020 4:48 pm
by James Perrett
I suspect that one of those slot in IEC sockets won't be able to supply enough current. It may well work most of the time but could let you down at the most inopportune moment.

The Traco supply that I linked to should be powerful enough and can be screwed to any handy surface - apparently even to flammable surfaces like wood. There are also other similar supplies with cable input and output which are often designed for applications like CCTV. I just linked to the Traco one because I've used their supplies extensively in the past and had no problems with them.

If I was doing the modification I'd want to study the power input circuitry on the Hydrasynth before committing to a definite solution - especially with respect to grounding and what to do with the earth pin on the IEC connector. Does your engineer have a favourite solution? It is possible that they've been down this road already.

Re: Hydrasynth - PSU?

PostPosted: Sun Jun 28, 2020 5:16 pm
by BJG145
James Perrett wrote:It may well work most of the time but could let you down at the most inopportune moment.

You mean when he rocks up for a gig at Maida Vale and some dude says, "Excuse me, sir, can I see your PAT certificate?"

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Re: Hydrasynth - PSU?

PostPosted: Sun Jun 28, 2020 6:22 pm
by Folderol
I'm inclined to agree with James to a great degree. For the self contained socket one, I'd want the 'normal' 12V current draw to be 330mA or less. (about 4W). That's a bit tight even for modern electronics, and would require the synth's internal power distribution to be a switching unit rather than just linear voltage regulators. Use on headphones rather than fed into an could wipe this out too.

Another advantage of the Traco supply that James suggested would be that as it has all the safety features required for a non-earthed setup you can use the two pin IEC type connector, which should keep a PAT tester happy that it is still Class 2 insulation, while allowing you to use standard IEC leads.

Ultimately of course, while you could mention these, it's down do what your tame techie is prepared to take responsibility for! :lol:

Re: Hydrasynth - PSU?

PostPosted: Sun Jun 28, 2020 6:43 pm
by The Elf
I'll show him this thread! :crazy:

That's a way off, so for now I'm just going to get to know the synth. It arrives tomorrow! :thumbup: