[sdiy] Monitoring my Dotcom system's supply voltages

[nicolas]

I think it depends a bit on whether your synth is a locked down, stay in the studio thing, or a living collection of modules that regularly gets added to, gigged with, etc.  A good power supply might be fine in the studio, but still might have issues sitting on stage next to a lighting controller.  Or it might be fine with modules x and y, but when you add module z to the rig it might cause problems.  Especially if module z is a fresh-off-the-bench DIY design that hasn't had all the kinks ironed out yet.

Nicolas

----- Original Message -----
From: Giorgio <dancemachine at gmail.com>
To: nicolas <nicolas3141 at yahoo.com.au>
Cc: Synth DIY <synth-diy at dropmix.xs4all.nl>
Sent: Friday, 14 September 2012 3:30 PM
Subject: Re: [sdiy] Monitoring my Dotcom system's supply voltages

this thread begs the question: why? 
I'd say get a good power supply and trust it.  no?



On Sep 13, 2012, at 8:10 PM, nicolas <nicolas3141 at yahoo.com.au> wrote:

> Simple comparators will show you overall sag, but a bigger problem in a synth is noise, spikes, hum, transient glitches, etc.  So some way of detecting any small AC component on those lines would be very useful, which could be low freq hum or audio crosstalk or hi freq digital crosstalk or broad spectrum noise or RF interference.  And also a way of capturing very brief excursions (+ve and -ve) and latching an LED for a few seconds so that you can see it, in case you are getting transient spikes or dropouts.  Something that could do all that reliably and simply would be useful thing to have :)
>  
> Nicolas
> 
> ________________________________
> From: Stewart Pye <stewpye at optusnet.com.au>
> To: Synth DIY <synth-diy at dropmix.xs4all.nl> 
> Sent: Thursday, 13 September 2012 8:17 AM
> Subject: Re: [sdiy] Monitoring my Dotcom system's supply voltages
> 
> If you use a pic you'd still have to divide down the input voltages. I'd probably just use a single voltage reference and a quad comparator. You'd have to put a voltage divider on all the inputs you are measuring, but the voltage reference can be used for all inputs if the voltage divider for the negative voltage is an inverting amplifier. That's only 6 or 7 resistors (plus the LED current limit resistors) 1 voltage ref, 1 op amp 1 quad comparator. You may even be able to get away with using a quad op amp for the comparators + op amp.
> 
> Alternatively use two voltage references, or invert the positive one with an op amp.
> 
> Regards,
> Stewart.
> 
> 
> 
> On 9/13/2012 1:35 AM, Jean-Pierre Desrochers wrote:
>> Good point André,
>> 
>> I've been browsing around lots of analog solutions
>> so far ending with voltage refernces + voltage comparators
>> + a bunch of passive components..
>> I'm starting to think of a digital solution (!!)
>> Just a simple Microchip PIC with analog inputs
>> could do all the voltage checks, hysteresis and
>> leds driving for my 3 voltages, and that in one chip.
>> The -15v will even be monitorable with some tweekings..
>> I already have a +5v to supply it without
>> disturbing my +/-15v lines with digital spikes..
>> Hmmm, the only problem with micros is futur repairs (in the next xx years)..
>> Much easier to replace analog parts than programmed PIC's.
>> I'm still doing some searchs..
>> JP
>> 
>> 
>>  On Wed 12/09/12 11:55 , Andre Majorel aym-htnys at teaser.fr sent:
>>> On 2012-09-12 09:13 -0400, Jean-Pierre Desrochers wrote:
>>> 
>>>> Here what I found by chance:
>>>> http://www.reuk.co.uk/TL431-Battery-Voltage-Monitor.htm
>>> This thread on sci.electronics.components may be of interest :
>>> 
>>> http://groups.google.com/forum/?fromgroups#!topic/sci.electroni
>>> cs.components/uDYcuMy4RYQ
>>> What I got out of it is that using a TL431 with less than 3 µF
>>> between anode and cathode is asking for trouble.
>>> 
>>> -- André Majorel http://www.teaser.fr/~amajorel/_______________________________________________
>>> Synth-diy mailing list
>>> S
>>> ynth-diy at dropmix.xs4all.nlhttp://dropmix.xs4all.nl/mailman/listinfo/synth-diy
>>> 
>>> 
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