Now as I've said here before, I have a sub here, which for no apparent
reason will go off with a bang, apparently because the psu relay is dropped
out by a sudden fault condition.
This is compounded by the fact that my sighted friend can have it running
on a bench with a dummy load for ever with no apparent problems.
Thus I have ruled out the speaker itself, no sign of a short when moving
the cone.
I am thinking that it could be the relay itself which controls the two
halves of a supply, if one contact did suffer just a bit from a high
resistance while on, it might trigger the protection as the transistor on
the other side would be conducting too much. It is after all mostly dc
coupled.
So long preamble, Does anyone produce a module that could output something
to, say a USB port that can measure plus and minus voltages. I guess a bit
like a digital version of a storage scope. The idea being that it should if,
say it records than last two minutes of activity, and is stopped by the
switch off, to see if indeed the supply lines vary, and which way the
voltage leaps, giving us the side to watch.
Brian

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I use a Scarlett 2i2 to output and gather audio for analysis, etc. The 3rd
gen example is pretty good. Calibrate against a DVM.

If you run a 'probe sinewave' though the unit being tested it would
presumably show when/how the signal dies when the unit stops.

Jim

In article <t8p9j0$jjh$1@dont-email.me>, Brian Gaff <brian1gaff@gmail.com>
wrote:
> So long preamble, Does anyone produce a module that could output
> something to, say a USB port that can measure plus and minus voltages. I
> guess a bit like a digital version of a storage scope. The idea being
> that it should if, say it records than last two minutes of activity, and
> is stopped by the switch off, to see if indeed the supply lines vary,
> and which way the voltage leaps, giving us the side to watch. Brian

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Please use the address on the audiomisc page if you wish to email me.
Electronics https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
Audio Misc http://www.audiomisc.co.uk/index.html

Actually all you hear is a very loud bang from the speaker normally.
Sometimes it will rustle a bit then go bang which is what made me suspect
the relay. We tried making the protection less fast and it trashed two
output transistors. Bah humbug. Common types though, but not really meant to
be used as fuses!
It can be days before it starts to misbehave again, hence my thought of
just having what is in fact a virtual chart recorder monitoring both
supplies against the centre earth.
Brian

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"Jim Lesurf" <noise@audiomisc.co.uk> wrote in message
news:59fb7f4c2bnoise@audiomisc.co.uk...
>I use a Scarlett 2i2 to output and gather audio for analysis, etc. The 3rd
> gen example is pretty good. Calibrate against a DVM.
>
> If you run a 'probe sinewave' though the unit being tested it would
> presumably show when/how the signal dies when the unit stops.
>
> Jim
>
> In article <t8p9j0$jjh$1@dont-email.me>, Brian Gaff <brian1gaff@gmail.com>
> wrote:
>> So long preamble, Does anyone produce a module that could output
>> something to, say a USB port that can measure plus and minus voltages. I
>> guess a bit like a digital version of a storage scope. The idea being
>> that it should if, say it records than last two minutes of activity, and
>> is stopped by the switch off, to see if indeed the supply lines vary,
>> and which way the voltage leaps, giving us the side to watch. Brian
>
> --
> Please use the address on the audiomisc page if you wish to email me.
> Electronics
> https://www.st-andrews.ac.uk/~www_pa/Scots_Guide/intro/electron.htm
> biog http://jcgl.orpheusweb.co.uk/history/ups_and_downs.html
> Audio Misc http://www.audiomisc.co.uk/index.html
>