Opinions on adding fuses to power amp

[Ecnerwal]

Anyone know the term for laying double traces of solder along copper traces
to increase current carrying , so I can research it ?

No, but it's a dumb idea. It's fairly easy to dump solder "accurately"
on a trace (if not covered by soldermask, hopefully that's obvious) -
just heat and feed solder, it will follow the trace, and you can build
it up quite a ways simply from surface tension. If you need more current
capacity on the trace, bend up a chunk of copper wire that actually
conducts well and solder that on. Solder is a lousy conductor, compared
to copper. The copper will hold more solder on there, but most of the
current will be carried by the copper.

 

[Eeyore]

I would imagine that the stray object originated inside the amp,
probably a panel screw or captive nut never secured in the first place.

I thought the OP said something did actually fall inside ?

How often you you pick up an item of gear and hear something loose
rolling around inside

Thankfully not too often. I do recall one time about 30 yrs ago when I withdrew a
Bulgin mains lead and the earth prong of the equipment connector came out with it
though ! They were just held in place with screws !

Graham

 

[Eeyore]

As I understand it, in modern pcb production, the majority of the solder
is 'silk screened' as a paste, onto the board as part of the process,
then once the majority of components have been positioned, the whole
assembly is passed between radiant heaters to melt the solder paste and
fuse the whole lot together.

With surface mount that's the typical way. It's called infra-red reflow.

Of course, I could be wrong.

It's a miracle that any electronic stuff works at all these days!

See my comment about lead-free (wrt your Behringer EP2500) in a.ap.l-s.

Graham

 

[Eeyore]

No, but it's a dumb idea. It's fairly easy to dump solder "accurately"
on a trace (if not covered by soldermask, hopefully that's obvious) -
just heat and feed solder, it will follow the trace, and you can build
it up quite a ways simply from surface tension. If you need more current
capacity on the trace, bend up a chunk of copper wire that actually
conducts well and solder that on. Solder is a lousy conductor, compared
to copper. The copper will hold more solder on there, but most of the
current will be carried by the copper.

I've seen something similar done intentionally and neatly inside a couple of
amplifiers.

The power trace has a number of tinned copper wire 'links' in parallel with it on
the 'top' of the pcb. Quite clever since it can be done with auto-insert
machinery.

Personally I prefer to use equipment cable to deliver power to where it's needed
rather than string it out along pcb traces.

Graham

 

[Ron(UK)]

I thought the OP said something did actually fall inside ?
Maybe


Thankfully not too often. I do recall one time about 30 yrs ago when I withdrew a
Bulgin mains lead and the earth prong of the equipment connector came out with it
though ! They were just held in place with screws !

They were held in by the same screw that held the cable iirc

I once found the entire tip and centre core of a jackplug neatly welded
twixt power transistor and heatsink. Presumably some clown snapped off
the plug, so pushed it right through with another.

The one thing most designers fail to allow for is the stupidity of the
end user.

Ron(UK)

 

[Phil Allison]

"Nutcase Fucking ****"

I'm just trying to engineer a more respectable equivalent of fuses for
trace
rupture.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Eventually one DC rail ruptured as a fuse.

** BULLSHIT !!!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

I've now decided to do some
calculation to determine what the rupture current for that trace was.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Then as the common return almost fused and is the same dimension but in
the
even worse case then carries twice the current , halving this trace
rupture
current to use as the fuse rupture current and reduce that for current
carying capacity , by half again ?

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

If all output trannies fused short circuit all round so loading both DC
rails the combined common return would have ruptured at whatever that
rupture current is for the trace that did burn up.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Anyone know the term for laying double traces of solder along copper
traces
to increase current carrying , so I can research it ?

** That term is : BOLLOCKS !!!!!!!!!!!

I'm intrigued how you lay quite accurate molten solder runs and parallel
over and with existing traces.

** YOU are intrigued with eating your own putrid faeces.

Anyway measurements:
Copper trace 3.5 x .02mm and as 2 half approximated elipses of solder then
area of 1 elipse of tin+lead which is Pi x a x b , a and b minor and major
axes of .15mm and .8mm.

** Where are the guys in white suits ???

Hope they have those tranquillisers jabs handy ...

From tables of fusing currents for copper, also tin and lead (NB in the
form
of circular wires ) for different diameters.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Copper fusing current of the trace = 12 amps
Lead+Tin elipse then 6 amps (not as much as I would have intuitively
thought)

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Total 18 amps so 18/4 = 4.5 amps conventional fuse rating.
Presumably the circular to sheet allowance would up this 4.5 amp figure ,
but by how much ?

** BULLSHIT !!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Diverse Devices, Southampton, England

** Straight from the local schizophrenia ward to YOU !!!!!!!!


Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy .............


- have we got ourselves a fucking LIVE ONE !!




......... Phil

 

[Phil Allison]

"Nutcase Fucking ****"

I'm just trying to engineer a more respectable equivalent of fuses for
trace
rupture.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Eventually one DC rail ruptured as a fuse.

** BULLSHIT !!!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

I've now decided to do some
calculation to determine what the rupture current for that trace was.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Then as the common return almost fused and is the same dimension but in
the
even worse case then carries twice the current , halving this trace
rupture
current to use as the fuse rupture current and reduce that for current
carying capacity , by half again ?

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

If all output trannies fused short circuit all round so loading both DC
rails the combined common return would have ruptured at whatever that
rupture current is for the trace that did burn up.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Anyone know the term for laying double traces of solder along copper
traces
to increase current carrying , so I can research it ?

** That term is : BOLLOCKS !!!!!!!!!!!

I'm intrigued how you lay quite accurate molten solder runs and parallel
over and with existing traces.

** YOU are intrigued with eating your own putrid faeces.

Anyway measurements:
Copper trace 3.5 x .02mm and as 2 half approximated elipses of solder then
area of 1 elipse of tin+lead which is Pi x a x b , a and b minor and major
axes of .15mm and .8mm.

** Where are the guys in white suits ???

Hope they have those tranquillisers jabs handy ...

From tables of fusing currents for copper, also tin and lead (NB in the
form
of circular wires ) for different diameters.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Copper fusing current of the trace = 12 amps
Lead+Tin elipse then 6 amps (not as much as I would have intuitively
thought)

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Total 18 amps so 18/4 = 4.5 amps conventional fuse rating.
Presumably the circular to sheet allowance would up this 4.5 amp figure ,
but by how much ?

** BULLSHIT !!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Diverse Devices, Southampton, England

** Straight from the local schizophrenia ward to YOU !!!!!!!!


Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy .............


- have we got ourselves a fucking LIVE ONE !!



......... Phil

 

[Phil Allison]

"Nutcase Fucking ****"

I'm just trying to engineer a more respectable equivalent of fuses for
trace
rupture.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Eventually one DC rail ruptured as a fuse.

** BULLSHIT !!!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

I've now decided to do some
calculation to determine what the rupture current for that trace was.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Then as the common return almost fused and is the same dimension but in
the
even worse case then carries twice the current , halving this trace
rupture
current to use as the fuse rupture current and reduce that for current
carying capacity , by half again ?

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

If all output trannies fused short circuit all round so loading both DC
rails the combined common return would have ruptured at whatever that
rupture current is for the trace that did burn up.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Anyone know the term for laying double traces of solder along copper
traces
to increase current carrying , so I can research it ?

** That term is : BOLLOCKS !!!!!!!!!!!

I'm intrigued how you lay quite accurate molten solder runs and parallel
over and with existing traces.

** YOU are intrigued with eating your own putrid faeces.

Anyway measurements:
Copper trace 3.5 x .02mm and as 2 half approximated elipses of solder then
area of 1 elipse of tin+lead which is Pi x a x b , a and b minor and major
axes of .15mm and .8mm.

** Where are the guys in white suits ???

Hope they have those tranquillisers jabs handy ...

From tables of fusing currents for copper, also tin and lead (NB in the
form
of circular wires ) for different diameters.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Copper fusing current of the trace = 12 amps
Lead+Tin elipse then 6 amps (not as much as I would have intuitively
thought)

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Total 18 amps so 18/4 = 4.5 amps conventional fuse rating.
Presumably the circular to sheet allowance would up this 4.5 amp figure ,
but by how much ?

** BULLSHIT !!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Diverse Devices, Southampton, England

** Straight from the local schizophrenia ward to YOU !!!!!!!!


Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy .............


- have we got ourselves a fucking LIVE ONE !!



......... Phil

 

[Phil Allison]

"Nutcase Fucking ****"

I'm just trying to engineer a more respectable equivalent of fuses for
trace
rupture.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Eventually one DC rail ruptured as a fuse.

** BULLSHIT !!!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

I've now decided to do some
calculation to determine what the rupture current for that trace was.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Then as the common return almost fused and is the same dimension but in
the
even worse case then carries twice the current , halving this trace
rupture
current to use as the fuse rupture current and reduce that for current
carying capacity , by half again ?

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

If all output trannies fused short circuit all round so loading both DC
rails the combined common return would have ruptured at whatever that
rupture current is for the trace that did burn up.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Anyone know the term for laying double traces of solder along copper
traces
to increase current carrying , so I can research it ?

** That term is : BOLLOCKS !!!!!!!!!!!

I'm intrigued how you lay quite accurate molten solder runs and parallel
over and with existing traces.

** YOU are intrigued with eating your own putrid faeces.

Anyway measurements:
Copper trace 3.5 x .02mm and as 2 half approximated elipses of solder then
area of 1 elipse of tin+lead which is Pi x a x b , a and b minor and major
axes of .15mm and .8mm.

** Where are the guys in white suits ???

Hope they have those tranquillisers jabs handy ...

From tables of fusing currents for copper, also tin and lead (NB in the
form
of circular wires ) for different diameters.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Copper fusing current of the trace = 12 amps
Lead+Tin elipse then 6 amps (not as much as I would have intuitively
thought)

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Total 18 amps so 18/4 = 4.5 amps conventional fuse rating.
Presumably the circular to sheet allowance would up this 4.5 amp figure ,
but by how much ?

** BULLSHIT !!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Diverse Devices, Southampton, England

** Straight from the local schizophrenia ward to YOU !!!!!!!!


Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy .............


- have we got ourselves a fucking LIVE ONE !!



......... Phil

 

[Phil Allison]

"Nutcase Fucking ****"

I'm just trying to engineer a more respectable equivalent of fuses for
trace
rupture.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Eventually one DC rail ruptured as a fuse.

** BULLSHIT !!!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

I've now decided to do some
calculation to determine what the rupture current for that trace was.

** BULLSHIT !!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Then as the common return almost fused and is the same dimension but in
the
even worse case then carries twice the current , halving this trace
rupture
current to use as the fuse rupture current and reduce that for current
carying capacity , by half again ?

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

If all output trannies fused short circuit all round so loading both DC
rails the combined common return would have ruptured at whatever that
rupture current is for the trace that did burn up.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Anyone know the term for laying double traces of solder along copper
traces
to increase current carrying , so I can research it ?

** That term is : BOLLOCKS !!!!!!!!!!!

I'm intrigued how you lay quite accurate molten solder runs and parallel
over and with existing traces.

** YOU are intrigued with eating your own putrid faeces.

Anyway measurements:
Copper trace 3.5 x .02mm and as 2 half approximated elipses of solder then
area of 1 elipse of tin+lead which is Pi x a x b , a and b minor and major
axes of .15mm and .8mm.

** Where are the guys in white suits ???

Hope they have those tranquillisers jabs handy ...

From tables of fusing currents for copper, also tin and lead (NB in the
form
of circular wires ) for different diameters.

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Copper fusing current of the trace = 12 amps
Lead+Tin elipse then 6 amps (not as much as I would have intuitively
thought)

** BULLSHIT !!!!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Total 18 amps so 18/4 = 4.5 amps conventional fuse rating.
Presumably the circular to sheet allowance would up this 4.5 amp figure ,
but by how much ?

** BULLSHIT !!!!!!!!!!

You are a total fucking nut case ASSHOLE !!!!!!!

Diverse Devices, Southampton, England

** Straight from the local schizophrenia ward to YOU !!!!!!!!


Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy .............


- have we got ourselves a fucking LIVE ONE !!



......... Phil

 

[Phil Allison]

" Diverse Devices, Southampton, England"

http://home.graffiti.net/diverse:graffiti.net/


** Straight from the local schizophrenia ward to YOU !!!!!!

Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy ........

- have we got ourselves a fucking LIVE ONE !!





....... Phil

 

[Phil Allison]

" Diverse Devices, Southampton, England"

http://home.graffiti.net/diverse:graffiti.net/


** Straight from the local schizophrenia ward to YOU !!!!!!

Usenet is the GREATEST lunatic magnet in the known universe.

Boy oh boy ........

- have we got ourselves a fucking LIVE ONE !!





....... Phil

 

[N Cook]

No, but it's a dumb idea. It's fairly easy to dump solder "accurately"
on a trace (if not covered by soldermask, hopefully that's obvious) -
just heat and feed solder, it will follow the trace, and you can build
it up quite a ways simply from surface tension. If you need more current
capacity on the trace, bend up a chunk of copper wire that actually
conducts well and solder that on. Solder is a lousy conductor, compared
to copper. The copper will hold more solder on there, but most of the
current will be carried by the copper.

I get the impression board layout designers just use what has worked before
as far as track dimensions etc and don't actually consider in great detail
catastrophic failure modes. Yes this kit does support the CE mark.
I've not been able to find design data/tables for such traces.
I may dig out a low voltage 60 amp transformer fed via a variac and
sacrifice some otherwise unaffected tracks on this board to determine what
sort of amperage to cause excessive heating and then another bit of track to
find the rupture current. Having to avoid localised failure at my test
join-points with a lot of distributed solder.

 

[Eeyore]

They were held in by the same screw that held the cable iirc

There was another one - oh actually I think that terminal section did actually have a
male thread on it.

I once found the entire tip and centre core of a jackplug neatly welded
twixt power transistor and heatsink. Presumably some clown snapped off
the plug, so pushed it right through with another

LOL !

The one thing most designers fail to allow for is the stupidity of the
end user.

'Tis often true.

Graham

 

[Eeyore]

I get the impression board layout designers just use what has worked before
as far as track dimensions etc

There are published guidelines for temp rise vs current, copper thickness and
track width. You'll find a chart of same in IEC60065 (electrical safety) in
fact.

The board layout guy will only use the data supplied by the design engineer.
They're not psychic. Some 'design engineers' have a clue however.

and don't actually consider in great detail
catastrophic failure modes.

Good designers will design for that.

Yes this kit does support the CE mark.

So what's the damn make and model FFS ! Why are you refusing to tell us one of
the most important pieces of information ?

Graham

 

[Ron(UK)]

I get the impression board layout designers just use what has worked before
as far as track dimensions etc and don't actually consider in great detail
catastrophic failure modes.

On a well designed circuit board, you can often see which traces are
involved with each part of the circuit. Broad traces carry the heavy
current, spidery ones are the signal path. I remember a time when some
quality gear actually had the signal path screened onto the component
side of the board, together with typical voltages etc. That was when
they actually wanted us to repair the stuff.

I dont think any designer worries too much about 'catastrophic failure'!



.. Yes this kit does support the CE mark.

You still havent shared with us the make and model


Ron(UK)

 

[Ron(UK)]

Eeyore wrote:
I do recall one time about 30 yrs ago when I withdrew a

There was another one - oh actually I think that terminal section did actually have a
male thread on it.

Aye that`s right, and when they came loose, Johnny guitar would try to
tighten it by sticking a screwdriver (table knife) in the slot in the
pin and twist, neatly snapping half the pin off!

Ron(UK)

 

[Straw Man]

Q. How many Phil Allisons does it take to **** a dog?

A. One

 

[Arfa Daily]

I get the impression board layout designers just use what has worked
before
as far as track dimensions etc and don't actually consider in great detail
catastrophic failure modes. Yes this kit does support the CE mark.
I've not been able to find design data/tables for such traces.
I may dig out a low voltage 60 amp transformer fed via a variac and
sacrifice some otherwise unaffected tracks on this board to determine what
sort of amperage to cause excessive heating and then another bit of track
to
find the rupture current. Having to avoid localised failure at my test
join-points with a lot of distributed solder.

Just interested ... Do you actually make a living out of repairing this
stuff ? If I spent as much time as you seem to, worrying about esoteric
things like how much current a track will take before it vapourises, I would
long since have ceased to earn enough money to get by on. These days, I find
that it has to be 'wheel it in, fix it, wheel it out , invoice it, next
please'. If the bit called 'fix it' takes longer than an hour, and the value
of the kit is less than 150 quid, that bit changes to 'bin it' ...

Arfa

 

[joseph2k]

Fix the amp, put the fuses of your choice in and put it through its paces.
You'll probably want to run some music through it at high volume
preferably some Hip Hop <barf>. See which fuses blow and which don't.

There are uses for sine, square, multiple sine, and complex waveforms in
testing. I suggest using each for what it will make esily visible in the
performance.