I have on several occasions used such switches for speaker switching, in one case the old ready made ones and also some made by me. Always they seem to fail with dodgy contacts, some work if you squirt them others not.
I have on several occasions used such switches for speaker switching, in one >case the old ready made ones and also some made by me. Always they seem to >fail with dodgy contacts, some work if you squirt them others not. Is this >because the actual contacts clean themselves on mains voltages, but do not >on the lower voltage speaker lines?
Brian
On Thu, 1 Sep 2022 10:09:07 +0100, "Brian Gaff" <brian1gaff@gmail.com>
wrote:
I have on several occasions used such switches for speaker switching, in one
case the old ready made ones and also some made by me. Always they seem to >fail with dodgy contacts, some work if you squirt them others not. Is this >because the actual contacts clean themselves on mains voltages, but do not >on the lower voltage speaker lines?
Brian
Mains voltage has a way of fixing poor contact switches. You need
specific low voltage high current ones. They will have contacts that
wipe, not simply touch. The big old blade switches you used for
electrifying corpses for doctor Fran\enstein will do nicely.
Brian Gaff wrote:
====================
I have on several occasions used such switches for speaker switching, in
one
case the old ready made ones and also some made by me. Always they seem
to
fail with dodgy contacts, some work if you squirt them others not.
** Ones with plain brass contacts will fail, brass tarnishes and becomes non conducting at low voltages.
However nearly ALL mains rocker switches sold use plated contacts - silver or silver alloy - so there is no such issue.
Maybe you have trouble telling the difference ....
...... Phil
In article <6310afbf.19882218@news.eternal-september.org>,
Don Pearce <spam@spam.com> wrote:
On Thu, 1 Sep 2022 10:09:07 +0100, "Brian Gaff" <brian1gaff@gmail.com>
wrote:
I have on several occasions used such switches for speaker switching, in >> >one
case the old ready made ones and also some made by me. Always they seem >> >to
fail with dodgy contacts, some work if you squirt them others not. Is
this
because the actual contacts clean themselves on mains voltages, but do
not
on the lower voltage speaker lines?
Brian
Mains voltage has a way of fixing poor contact switches. You need
specific low voltage high current ones. They will have contacts that
wipe, not simply touch. The big old blade switches you used for
electrifying corpses for doctor Fran\enstein will do nicely.
On my old car, Lucas decided to use relays switched by the same high
current ones used on other versions and makes. Contacts are plain touch copper. When used to only switch a relay, go 'dirty' quite quickly and
need cleaning. On high current use, pretty well never. Did wonder about silver or whatever plating the contacts.
--
*He who dies with the most toys is, nonetheless, dead.
Dave Plowman dave@davenoise.co.uk London SW
To e-mail, change noise into sound.
Well, the rocker types big small or whatever have all given problems. Pity, >since they look nice in a panel!
In many cases those miniature toggles are far more reliable I find but it >kind of looks cheap.
Still, I guess nothing is quite so bad as jack plugs for grotty contacts!
Brian
You would think QED would not use rubbish
====================
I have on several occasions used such switches for speaker switching, in >> one
case the old ready made ones and also some made by me. Always they seem >> to
fail with dodgy contacts, some work if you squirt them others not.
** Ones with plain brass contacts will fail, brass tarnishes and becomes non conducting at low voltages.
However nearly ALL mains rocker switches sold use plated contacts - silver or silver alloy - so there is no such issue.
Maybe you have trouble telling the difference ....
The miniature toggle has the advantage that the contacts close with a
snap, which will break through corrosion to an extent.
Brian Gaff wrote:
==================
You would think QED would not use rubbish
** ????? Better think again.
Made in Taiwan by the cheapest contractor ......
Just one step removed from a total scam.
On Thu, 1 Sep 2022 18:09:49 +0100, "Brian Gaff" <brian1gaff@gmail.com>
wrote:
Well, the rocker types big small or whatever have all given problems. >>Pity,
since they look nice in a panel!
In many cases those miniature toggles are far more reliable I find but it >>kind of looks cheap.
Still, I guess nothing is quite so bad as jack plugs for grotty contacts!
Brian
The miniature toggle has the advantage that the contacts close with a
snap, which will break through corrosion to an extent.
d
Don Pearce wrote:
================
The miniature toggle has the advantage that the contacts close with a
snap, which will break through corrosion to an extent.
** Mini toggles do well at signal ( ie dry) switching, so are OK for speakers too.
All carry markings ( ie 250VAC, 5A) that suggest they are suitable for mains power but very few meet safety standards.
Creapage and clearance distances are not met and they do not "fail safe". Should always be used mounted on an *earthed* metal panel.
None will accept push on ( ie QC) connectors so factories hate them.
Not really mains switches at all.
.... Phil
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