Home made AC-AC power supply question

[Clubsprint]

I have a device requiring 9v AC 2.5 Amp.

So do I get a 240v-9v transformer from the electronics shop and put it in a
case, attach the correct leads and I'm done.

I suppose an inline fuse might be a safety precaution.

Is this all that's required or is there some sort of regualting curcuit that
I should add?

Tranformer I was thinking of using

http://www.rsaustralia.com/cgi-bin/bv/rswww/searchBrowseAction.do?N=0&Ntk=I18NRSStockNumber&Ntt=347-2802&Nty=1&D=347-2802&callingPage=/jsp/line/line.jsp&BV_SessionID=@@@@1961233655.1195777482@@@@&BV_EngineID=ccdcaddmigmekeecefeceeldgkidhgn.0&cacheID=auie&Nr=avl:au

 

[mc]

"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5777$hr6$1@news-01.bur.connect.com.au...

I have a device requiring 9v AC 2.5 Amp.

So do I get a 240v-9v transformer from the electronics shop and put it in
a case, attach the correct leads and I'm done.

I suppose an inline fuse might be a safety precaution.

Yes. The fuse should be in the live (not neutral) line. It should be a lot
less than 2.5 amps, of course, because it's on the high voltage side (before
you've traded volts for amps). Try 0.5 amp slow-blow.

Is this all that's required or is there some sort of regualting curcuit
that I should add?

Regulated AC is very uncommon. Your device probably does its own
regulating.

Tranformer I was thinking of using

http://www.rsaustralia.com/cgi-bin/bv/rswww/searchBrowseAction.do?N=0&Ntk=I18NRSStockNumber&Ntt=347-2802&Nty=1&D=347-2802&callingPage=/jsp/line/line.jsp&BV_SessionID=@@@@1961233655.1195777482@@@@&BV_EngineID=ccdcaddmigmekeecefeceeldgkidhgn.0&cacheID=auie&Nr=avl:au

Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0 amps
and will overheat in your application.

What kind of device are you powering and what was its original power source?

 

[Clubsprint]

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:Mjp1j.122$k27.110@bignews2.bellsouth.net...

Tranformer I was thinking of using

http://www.rsaustralia.com/cgi-bin/bv/rswww/searchBrowseAction.do?N=0&Ntk=I18NRSStockNumber&Ntt=347-2802&Nty=1&D=347-2802&callingPage=/jsp/line/line.jsp&BV_SessionID=@@@@1961233655.1195777482@@@@&BV_EngineID=ccdcaddmigmekeecefeceeldgkidhgn.0&cacheID=auie&Nr=avl:au

Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0
amps and will overheat in your application.

What kind of device are you powering and what was its original power
source?

The device I'm wanting to power is a Rocktron Chameleon Pre-amp. It says 9v
AC 2.5 Amp
on the back. But the manual says 2.0amp.
http://www.rocktron.com/site/support/manuals/chameleon.pdf.zip
Do you think I should look for something larger? Maybe 3A?
Thanks for the advice on the fuse.

 

[Clubsprint]

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:Mjp1j.122$k27.110@bignews2.bellsouth.net...

Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0
amps and will overheat in your application.

How about this one with the secondaries inn parallel?

http://www.altronics.com.au/index.asp?area=item&id=M5009

 

[mc]

"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5bb1$ln9$1@news-01.bur.connect.com.au...

What kind of device are you powering and what was its original power
source?

The device I'm wanting to power is a Rocktron Chameleon Pre-amp. It says
9v AC 2.5 Amp
on the back. But the manual says 2.0amp.
http://www.rocktron.com/site/support/manuals/chameleon.pdf.zip
Do you think I should look for something larger? Maybe 3A?

Let's see...

It's a preamplifier, so its power consumption is not going to vary much.

Can you supply it with power and see how much current it actually draws,
using an AC ammeter? I have no idea whether to believe the manual or the
panel markings.

Thanks for the advice on the fuse.

Glad to be of service!

 

[mc]

"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5bv3$m8t$1@news-01.bur.connect.com.au...

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:Mjp1j.122$k27.110@bignews2.bellsouth.net...


Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0
amps and will overheat in your application.

How about this one with the secondaries inn parallel?
http://www.altronics.com.au/index.asp?area=item&id=M5009

That's a fine transformer but more than you need. (One of the secondaries
by itself would be sufficient.)

When paralleling secondaries, be sure to use a voltmeter to check phasing.
For example, suppose A1 and A2 are the terminals of the first secondary, and
B1 and B2, of the second secondary. You propose to connect A1 to B1 and A2
to B2. To perform the test, go ahead and connect A1 to B1 but do not yet
connect B1 to B2. Instead, connect an AC voltmeter to B1 and B2. If you
see a very small voltage or none at all, go ahead and make the connection.
If you see double the secondary voltage, one of 'em is backward!

 

[Jamie]

mc wrote:

"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5bv3$m8t$1@news-01.bur.connect.com.au...

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:Mjp1j.122$k27.110@bignews2.bellsouth.net...

Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0
amps and will overheat in your application.


How about this one with the secondaries inn parallel?
http://www.altronics.com.au/index.asp?area=item&id=M5009


That's a fine transformer but more than you need. (One of the secondaries
by itself would be sufficient.)

When paralleling secondaries, be sure to use a voltmeter to check phasing.
For example, suppose A1 and A2 are the terminals of the first secondary, and
B1 and B2, of the second secondary. You propose to connect A1 to B1 and A2
to B2. To perform the test, go ahead and connect A1 to B1 but do not yet
connect B1 to B2. Instead, connect an AC voltmeter to B1 and B2. If you
see a very small voltage or none at all, go ahead and make the connection.
If you see double the secondary voltage, one of 'em is backward!


You're taking the fun out of it!

--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Clubsprint]

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:rVq1j.166$vt2.165@bignews8.bellsouth.net...

That's a fine transformer but more than you need. (One of the secondaries
by itself would be sufficient.)

When paralleling secondaries, be sure to use a voltmeter to check phasing.
For example, suppose A1 and A2 are the terminals of the first secondary,
and B1 and B2, of the second secondary. You propose to connect A1 to B1
and A2 to B2. To perform the test, go ahead and connect A1 to B1 but do
not yet connect B1 to B2. Instead, connect an AC voltmeter to B1 and B2.
If you see a very small voltage or none at all, go ahead and make the
connection. If you see double the secondary voltage, one of 'em is
backward!

I was wondering about this, however, shouldn't I measure the voltage between

A2 and B2 and if there is double the voltage that would mean that they are
wired in series?
There is a smaller toroidal transformer that supplies 9v at 3.3A with the
secondaries
in parallel.
http://www.altronics.com.au/index.asp?area=item&id=M4909A
I'm thinking rather than make an external power supply that I'd install
it in the unit if there is room.

 

[Phil Allison]

"Clubsprint"

I have a device requiring 9v AC 2.5 Amp.

** Buy an approved plug pack with that rating.

So do I get a 240v-9v transformer from the electronics shop and put it in
a case, attach the correct leads and I'm done.

** No - that is not safe.

I suppose an inline fuse might be a safety precaution.

** Fuses save equipment from fire - not people from electric shock.

The transformer you have cited is not safety approved for use as an external
PSU.

It is not short circuit proof and it does not have a thermal fuse.

Buy a 9 volt AC plug pack - it will cost far less anyhow.

Idiot.




....... Phil

 

[mc]

"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5kor$1q4$1@news-01.bur.connect.com.au...

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:rVq1j.166$vt2.165@bignews8.bellsouth.net...
That's a fine transformer but more than you need. (One of the
secondaries by itself would be sufficient.)

When paralleling secondaries, be sure to use a voltmeter to check
phasing. For example, suppose A1 and A2 are the terminals of the first
secondary, and B1 and B2, of the second secondary. You propose to
connect A1 to B1 and A2 to B2. To perform the test, go ahead and connect
A1 to B1 but do not yet connect B1 to B2. Instead, connect an AC
voltmeter to B1 and B2. If you see a very small voltage or none at all,
go ahead and make the connection. If you see double the secondary
voltage, one of 'em is backward!

I was wondering about this, however, shouldn't I measure the voltage
between
A2 and B2 and if there is double the voltage that would mean that they are
wired in series?

YES! (Oops!) My mistake. Measure between the 2 that you are about to
connect, and if there is a large voltage, don't connect them.

There is a smaller toroidal transformer that supplies 9v at 3.3A with the
secondaries
in parallel.
http://www.altronics.com.au/index.asp?area=item&id=M4909A
I'm thinking rather than make an external power supply that I'd install
it in the unit if there is room.

That sounds like a suitable transformer. But I'd put it in a separate case
because this is a sensitive preamp and might pick up hum from the
transformer magnetically.

 

[mc]

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:5qn9onF113rtoU1@mid.individual.net...

"Clubsprint"

I have a device requiring 9v AC 2.5 Amp.

** Buy an approved plug pack with that rating.

Those are not especially easy to find, hence his question.

So do I get a 240v-9v transformer from the electronics shop and put it in
a case, attach the correct leads and I'm done.

** No - that is not safe.

I suppose an inline fuse might be a safety precaution.

** Fuses save equipment from fire - not people from electric shock.

The transformer you have cited is not safety approved for use as an
external PSU.

It is not short circuit proof and it does not have a thermal fuse.

Buy a 9 volt AC plug pack - it will cost far less anyhow.

Idiot.

By extension, are all people who build their own power supplies idiots?

You do point out an important advantage of "wall-wart" type transformers --
that, in general, they are designed so that when short-circuited, they
either do not overheat, or burn out without generating enough heat to start
a fire. However, with reasonable precautions (fuse, enclosure, etc.) I
don't think what this fellow is proposing to do is dangerous. He's only
going to use it with a specific preamplifier, not connect it to things at
random. And he's building one unit, not applying for safety certification.

 

[Phil Allison]

"mc" = masturbating cunthead

"Phil Allison"

"Clubsprint"

I have a device requiring 9v AC 2.5 Amp.

** Buy an approved plug pack with that rating.

Those are not especially easy to find, hence his question.

** Bollocks - they are quite easy to find.

So do I get a 240v-9v transformer from the electronics shop and put it
in a case, attach the correct leads and I'm done.

** No - that is not safe.

I suppose an inline fuse might be a safety precaution.

** Fuses save equipment from fire - not people from electric shock.

The transformer you have cited is not safety approved for use as an
external PSU.

It is not short circuit proof and it does not have a thermal fuse.

Buy a 9 volt AC plug pack - it will cost far less anyhow.

Idiot.

By extension, are all people who build their own power supplies idiots?

** If they build ones to replace compulsory safety approved plug packs that
came with equipment AND pay more in the process - yes, they are total
idiots.

You do point out an important advantage of "wall-wart" type
transformers -- that, in general, they are designed so that when
short-circuited, they either do not overheat, or burn out without
generating enough heat to start a fire.

** That is not what I pointed out - you fucking MORON.

The * advantage * of the approved plug pack is that it will not electrocute
you.

However, with reasonable precautions (fuse, enclosure, etc.) I don't think
what this fellow is proposing to do is dangerous.

** Errrr - just how the fuck would a pig ignorant ASS like you know ??

He's only going to use it with a specific preamplifier, not connect it to
things at random.

** What irrelevant CRAP !!

And he's building one unit, not applying for safety certification.

** You are clearly not one tiny bit sane.

240 volt AC power is LETHAL.

What the fuckwit OP proposed is beyond stupid and ILLEGAL.

I hope it kills him.

I'm afraid it will kill someone else.




....... Phil

 

[mc]

240 volt AC power is LETHAL.

I know, I know. But only when it comes in contact with your body.

What the ... OP proposed is beyond stupid and ILLEGAL.

Do you have laws in Australia against building electronic equipment?
Strange.

 

[Phil Allison]

"mc" = masturbating lying cunt

"Phil Allison"

"Clubsprint"

I have a device requiring 9v AC 2.5 Amp.

** Buy an approved plug pack with that rating.

Those are not especially easy to find, hence his question.

** Bollocks - they are quite easy to find.

So do I get a 240v-9v transformer from the electronics shop and put it
in a case, attach the correct leads and I'm done.

** No - that is not safe.

I suppose an inline fuse might be a safety precaution.

** Fuses save equipment from fire - not people from electric shock.

The transformer you have cited is not safety approved for use as an
external PSU.

It is not short circuit proof and it does not have a thermal fuse.

Buy a 9 volt AC plug pack - it will cost far less anyhow.

Idiot.

By extension, are all people who build their own power supplies idiots?

** If they build unsafe ones to replace compulsory safety approved plug
packs
that came with equipment AND pay more in the process - yes, they are
total
idiots.

Just like you - cunthead.

You do point out an important advantage of "wall-wart" type
transformers -- that, in general, they are designed so that when
short-circuited, they either do not overheat, or burn out without
generating enough heat to start a fire.

** That is not what I pointed out - you fuckwit MORON.

The * advantage * of the approved plug pack is that it will not electrocute
people.

However, with reasonable precautions (fuse, enclosure, etc.) I don't think
what this fellow is proposing to do is dangerous.

** Errrr - just how the fuck would a pig ignorant fucking ASS

like YOU know ??????????

He's only going to use it with a specific preamplifier, not connect it to
things at random.

** What irrelevant CRAAAA P !!

And he's building one unit, not applying for safety certification.

** You are clearly not one tiny bit sane.

240 volt AC power is LETHAL !

What the fuckwit OP proposed is beyond stupid and ILLEGAL.

I hope it kills him.

I'm afraid it will kill someone else instead.

Hopefully you.




....... Phil

 

[Michael A. Terrell]

Jamie wrote:

mc wrote:

"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5bv3$m8t$1@news-01.bur.connect.com.au...

"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:Mjp1j.122$k27.110@bignews2.bellsouth.net...

Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0
amps and will overheat in your application.


How about this one with the secondaries inn parallel?
http://www.altronics.com.au/index.asp?area=item&id=M5009


That's a fine transformer but more than you need. (One of the secondaries
by itself would be sufficient.)

When paralleling secondaries, be sure to use a voltmeter to check phasing.
For example, suppose A1 and A2 are the terminals of the first secondary, and
B1 and B2, of the second secondary. You propose to connect A1 to B1 and A2
to B2. To perform the test, go ahead and connect A1 to B1 but do not yet
connect B1 to B2. Instead, connect an AC voltmeter to B1 and B2. If you
see a very small voltage or none at all, go ahead and make the connection.
If you see double the secondary voltage, one of 'em is backward!


You're taking the fun out of it!

And you are being an ass. Safety first. You keep wanting to hurt or
kill people.


--
Service to my country? Been there, Done that, and I've got my DD214 to
prove it.
Member of DAV #85.

Michael A. Terrell
Central Florida

 

[Jamie]

Michael A. Terrell wrote:

Jamie wrote:

mc wrote:


"Clubsprint" <spamspamspamspam@nospam.com> wrote in message
news:fi5bv3$m8t$1@news-01.bur.connect.com.au...


"mc" <look@www.ai.uga.edu.for.address> wrote in message
news:Mjp1j.122$k27.110@bignews2.bellsouth.net...


Whoa... None of those is rated to deliver 2.5 amps. The biggest is 2.0
amps and will overheat in your application.


How about this one with the secondaries inn parallel?
http://www.altronics.com.au/index.asp?area=item&id=M5009


That's a fine transformer but more than you need. (One of the secondaries
by itself would be sufficient.)

When paralleling secondaries, be sure to use a voltmeter to check phasing.
For example, suppose A1 and A2 are the terminals of the first secondary, and
B1 and B2, of the second secondary. You propose to connect A1 to B1 and A2
to B2. To perform the test, go ahead and connect A1 to B1 but do not yet
connect B1 to B2. Instead, connect an AC voltmeter to B1 and B2. If you
see a very small voltage or none at all, go ahead and make the connection.
If you see double the secondary voltage, one of 'em is backward!



You're taking the fun out of it!



And you are being an ass. Safety first. You keep wanting to hurt or
kill people.


Excuse me?

At what point have I ever threaten to hurt some one?

Those kind of remarks can lead you into something you wish
you never stepped into.

Making accusations of a serious nature is really not the
route you want to go.


--
"I'm never wrong, once i thought i was, but was mistaken"
Real Programmers Do things like this.
http://webpages.charter.net/jamie_5

 

[Hammy]

On Fri, 23 Nov 2007 19:43:27 +1100, "Phil Allison"
<philallison@tpg.com.au> wrote:

The transformer you have cited is not safety approved for use as an
external PSU.

It is not short circuit proof and it does not have a thermal fuse.

Buy a 9 volt AC plug pack - it will cost far less anyhow.

Idiot.

You dumb piece of shit do you believe everything you read. I have a
box of wallwarts behind me and the majority of them are just a fuse
and a transformer. Any asshole can get a UL or other agency approval
sticker and stick it on there product. Read a paper once in a while.
There's more to life then trolling and molesting Kangaroos.

And nothing is 100% short cct proof.

The 350W SMPS on my PC has UL ,CSA Approval but yet it lacks a proper
EMI filter, and looks like it was soldered by a twelve year old. The
silkscreen is there for the CM choke as well as Y-caps but they
aren't. Do you think this is "short cct. proof"? The supply is an
ANTEC these are the geniuses in SMPS design scary.

I hope it kills him.

If you're that paranoid, use redundant protection, Fuse, polyfuse
active current limiting, multiple MOV's. Size your transformer for
what you design your current limit for.

I'm afraid it will kill someone else.

Hey Phil I just built some short cct proof PSU's. I'll ship some to
you free.

 

[Phil Allison]

"Hammy the Fuckhead "
"Phil Allison"

The transformer you have cited is not safety approved for use as an
external PSU.

It is not short circuit proof and it does not have a thermal fuse.

Buy a 9 volt AC plug pack - it will cost far less anyhow.

Idiot.

You dumb piece of shit do you believe everything you read.

** LOL - not even a single word from you is to be believed by anyone.

I have a
box of wallwarts behind me and the majority of them are just a fuse
and a transformer.

** That little transformer is kinda special, though.

If not, it CANNOT be sold in Europe or Australia inside a plug pack - as
every new plug pack design must be submitted for stringent safety test and
formal agency approval before going on sale.

Each one sold top the public gets a code number which MUST be printed on
the unit so the approval can be tracked to the equipment maker/importer and
the agency that supplied the certificication.

The OP is in Australia, in case you missed that important detail.

Any asshole can get a UL or other agency approval
sticker and stick it on there product. Read a paper once in a while.
There's more to life then trolling and molesting Kangaroos.

** You are nothing but a know nothing, lying septic tank asshole.

One of the countless many.

And nothing is 100% short cct proof.

The 350W SMPS on my PC ....

** Which is NOT a plug pack transformer.

I hope it kills him.

I'm afraid it will kill someone else.

Hey Phil I just built some short cct proof PSU's. I'll ship some to
you free.

** You have not got even the * tiniest clue * what this is all about -
fuckhead.

SMPS are not even part of the topic - you MORON !!!

FYI:

A inherently short circuit proof transformer is one that by design will NOT
overheat and damage its insulation even if the secondary is shorted
indefinitely - obviously only fairly small ones can do this.

Others normally rely on a thermal fuse ( means opens at a set temperature)
embedded in the primary winding to disable the transformer in case of a
sustained overload or fault developing in the any of the windings. They also
have special insulation and construction that prevents a dangerous situation
arising for the user under all the usual failure and accidental overload
conditions.

Yet others again use fire-proof insulation & special construction to prevent
any possibility of the primary winding contacting the iron core & frame or
the secondary winding even IF the unit burns out due to overload etc.

The vast majority of general purpose transformers offered for sale by
component dealers have only basic insulation & no special safety oriented
design features.

They are only safe to use inside equipment that has no metal case AND no
connectors going to external devices OR else all secondary side circuits
are directly linked to the AC supply safety ground.




....... Phil

 

[Hammy]

On Sat, 24 Nov 2007 11:14:46 +1100, "Phil Allison"
<philallison@tpg.com.au> wrote:

** That little transformer is kinda special, though.

I bet your mommy tells you your special. Do you have your special
helmet on?.I dont think you could handle more brain damage.

If not, it CANNOT be sold in Europe or Australia inside a plug pack - as
every new plug pack design must be submitted for stringent safety test and
formal agency approval before going on sale.

Who regulates this Phil the respective goverments. That will probaly
slide right over your helmeted head too.

Each one sold top the public gets a code number which MUST be printed on
the unit so the approval can be tracked to the equipment maker/importer and
the agency that supplied the certificication.

Must be a long waiting list for wal warts,considering they are all
undergoing stringent safety tests. You actually belive that every
single PSU is tested.WOW your guilible.

You miss my point fuckwit! A small quantity is submitted for testing
,not everyone. If you believe that every single PSU is tested you are
the idiot! They rely on the integrity of the company, usually chinese
and they couldnt give a fuck about your regs.Toy recalls ring a bell
asshole.

Like I said if you watched the news once in a while,you'd know that
what is submitted for approval is'nt what always winds up on the
shelf.

The OP is in Australia, in case you missed that important detail.

I couldnt give a shit. He does have my sympathy though because you
also live in Australia.

** You are nothing but a know nothing, lying septic tank asshole.

One of the countless many.

Your the top of the heap in that department assjam .

And nothing is 100% short cct proof.

The 350W SMPS on my PC ....


** Which is NOT a plug pack transformer.
To stupid to get my point again asshole!Snipped away the relevent bit

..

I hope it kills him.

I'm afraid it will kill someone else.

Hey Phil I just built some short cct proof PSU's. I'll ship some to
you free.

The offer still stands!

** You have not got even the * tiniest clue * what this is all about -
fuckhead.

Right back at you .
Stick to battery operated 555 timer ctt.s ass before you hurt yourself

SMPS are not even part of the topic - you MORON !!!

FYI:

A inherently short circuit proof transformer is one that by design will NOT
overheat and damage its insulation even if the secondary is shorted
indefinitely - obviously only fairly small ones can do this.

Who you quoteing here Phil. Are you incapble of independent thought.

Others normally rely on a thermal fuse ( means opens at a set temperature)

Was the expalanation of what a polyfuse is for your benifit,or did you
not notice it when you C/P someone elses work.

Insert Phils rambling here----

Yes all nice and good but how many that actually make it on the shelf

actually conform to these standards. Like I said dont believe
everything you read.

Happy googling dipshit.

 

[Phil Allison]

"Hammy the Septic Tank Cunt "


( snip the maniac's absurd, paranoid crap)



** Killfile this spamming CRIMINAL pile of sub human garbage.

NOW !!!!

Before any more of it's putrid droppings pollute your mind.





........ Phil