Isolated, regulated, toroidal step down transformer AC power

[Mark]

It looks like a voltage doubling design to me. Everything that I have
described about the applications circuit is consistent with that conclusion.
A voltage doubling design CAN BE a variant of the simple half wave rectifier
design.

....You didn't know that!!?

It now appears that I have over estimated your claim to the 'right' to
decide. You see, I knew something that you didn't.

Bet then again, maybe you're just having an 'off day'?

No, it couldn't be that. That would ascribe to you the human characteristic
of fallibility. ...And you are infallible, right?

I didn't (and don't) claim any expertise in the area of electronics, but you
label ME arrogant and YOURSELF as infallible.

....and then you DON'T KNOW that a voltage doubling design CAN BE a variant
of the simple half wave rectifier!!? Fuck me, what am I dealing with here?

And another thing, Phil: I don't DECIDE what is 'necessary' for other people
to 'know'.

I DECIDE what I will or won't TELL them about my project. That is my RIGHT
as a human being. It is called exercising my 'free will'.

Some of what I DECIDE not to tell others, MAY or MAY NOT be 'necessary' for
their understanding, but I can't and don't decide what is or what isn't
'necessary' for their understanding. Only THEY can do that and no doubt they
do.

You see, this very distinction, or rather your total failure to grasp that
distinction, is at the hart of your belief that some people "get to decide
what others should accept or believe" whilst others "NEVER" do.

You see, you have assigned this power AS IF it EXISTED as a right, to be
held by some but not others, presumably on the basis of knowledge and
experience. Nobody holds that power, for it does not exist, IN TOTO. You can
not decide for others what those others "should accept or believe", period.
The power does NOT EXIST, at all, period.

The basic human tenant of "free will" excludes all possibility that it CAN
exist as a power. Why?

Because you can not FORCE anyone to BELIEVE anything. Quite clearly, you
believe that these 'deciders' as you called them, can do just that.

Indeed, you have said as much, about dozen times, in this very forum.

And another thing, you petty child. Toroidal core transformers are classed
and commonly refered to as 'Air Core' transformers. In this case, the 'Air'
refers to the hole in the middle (i.e in the 'Core') THAT YOU CAN SEE.

Iron cores (or Steel Core) transformers commonly have a hole in the middle
(of the Iron) as well, but you can't see it.

You can google all day Phil, but you still didn't know that a voltage
doubling rectifier is variant of the simple half wave rectifier.

Nar, nar, nan-nar-nar.

Child.

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:56va6nF2aur2bU1@mid.individual.net...

" Mark Ilsley = UTTER FUCKING LIAR "


BUT I DON'T want to eliminate the half wave rectifier!!! It is
pre-existing inside the application.


** Hey - you asinine CUNT.

YOU do not have the tiniest clue what a " half wave rectifier " is.

Cos you are a lying, fucking ass.



I don't want to alter the application, at all and I would prefer not even
to discuss it.

I would like to point out that my original question deliberately had
NOTHING to do with the application. The easiest way to eliminate the
unwanted discussion is to not provide information on the application.



** It don't matter a RAT'S FUCK what some vile, brain dead, autistic,
delusional CUNTHEAD might be psychotic enough to believe is not
necessary for other people to know.

When it is.



So, WE are stuck with AC as an input to the application. I wanted to
eliminate the AC/AC wall-wart transformer (which uses an Iron core
transformer) and replace if with a Toroidal core transformer.


** Got news for YOU - CUNT !!

Toroidal mains transformers have all got " IRON " cores too.

GOSS to be precise.



Do I need to justify this choice as well?


** Absofuckinglutely !!!!!!!!!!!!!!!

Cos toroidal mains transformers are * NOT LEGALLY APPROVED * as
SAFE for the same applications that plug packs ALL are.

Cos they have no better voltage regulation than plug packs of the same VA
rating - most are worse.

And because NO common AC supply transformer regulates against mains
variations.

Because they do not need to !!!!!!!!!!!!!!


THIS is absolutely bloody CLASSIC !!!

This ASININE, TOP POSTING, PITA DAMN FOOL

has just gotta be another ADD fucked audiophool MORON !!

What a bloody HOOOT !!!!!!!

Lets all keep the CRETIN on the fishing line as long as possible !!

What top entertainment !!





........ Phil

 

[Bob Parker]

On 29/03/2007 01:49 Mark wrote:

It looks like a voltage doubling design to me. Everything that I have
described about the applications circuit is consistent with that conclusion.
A voltage doubling design CAN BE a variant of the simple half wave rectifier
design.

...You didn't know that!!?

It now appears that I have over estimated your claim to the 'right' to
decide. You see, I knew something that you didn't.

Bet then again, maybe you're just having an 'off day'?

No, it couldn't be that. That would ascribe to you the human characteristic
of fallibility. ...And you are infallible, right?

I didn't (and don't) claim any expertise in the area of electronics, but you
label ME arrogant and YOURSELF as infallible.

...and then you DON'T KNOW that a voltage doubling design CAN BE a variant
of the simple half wave rectifier!!? Fuck me, what am I dealing with here?

And another thing, Phil: I don't DECIDE what is 'necessary' for other people
to 'know'.

I DECIDE what I will or won't TELL them about my project. That is my RIGHT
as a human being. It is called exercising my 'free will'.

Some of what I DECIDE not to tell others, MAY or MAY NOT be 'necessary' for
their understanding, but I can't and don't decide what is or what isn't
'necessary' for their understanding. Only THEY can do that and no doubt they
do.

You see, this very distinction, or rather your total failure to grasp that
distinction, is at the hart of your belief that some people "get to decide
what others should accept or believe" whilst others "NEVER" do.

You see, you have assigned this power AS IF it EXISTED as a right, to be
held by some but not others, presumably on the basis of knowledge and
experience. Nobody holds that power, for it does not exist, IN TOTO. You can
not decide for others what those others "should accept or believe", period.
The power does NOT EXIST, at all, period.

The basic human tenant of "free will" excludes all possibility that it CAN
exist as a power. Why?

Because you can not FORCE anyone to BELIEVE anything. Quite clearly, you
believe that these 'deciders' as you called them, can do just that.

Indeed, you have said as much, about dozen times, in this very forum.

And another thing, you petty child. Toroidal core transformers are classed
and commonly refered to as 'Air Core' transformers. In this case, the 'Air'
refers to the hole in the middle (i.e in the 'Core') THAT YOU CAN SEE.

Iron cores (or Steel Core) transformers commonly have a hole in the middle
(of the Iron) as well, but you can't see it.

You can google all day Phil, but you still didn't know that a voltage
doubling rectifier is variant of the simple half wave rectifier.

Nar, nar, nan-nar-nar.

Child.

Like him or not, Phil knows his stuff. I'm not taking sides, but
you've just demonstrated how little you know about electronics and
electrical/magnetic theory and Phil's going to pounce on it.
And as I said before, if mains voltage changes are affecting your
secret audiophile preamp or whatever it is, it is *faulty* and needs to
be repaired not redesigned.


Bob

 

[Phil Allison]

" Mark Ilsley = AUTISTIC FUCKING IDIOT "


** Oh boy, I see this one - but I dooaaan believe it ........

And another thing, you petty child. Toroidal core transformers are classed
and commonly refered to as 'Air Core' transformers. In this case, the
'Air' refers to the hole in the middle (i.e in the 'Core') THAT YOU CAN
SEE.

** Well - bugger me.

I never woulda thought of that one in a thousand years.

And I'm still not thinking it.

Iron cores (or Steel Core) transformers commonly have a hole in the middle
(of the Iron) as well, but you can't see it.

** Gotta be real careful of those invisible holes in transformers.

Might stick your foot right in one..........

Like in some pile of smelly bovine excreta.

Dropped by Mark Ilsley, the congenital, donkey brained cunthead.


Heeee haawww, heeee haawwww





........ Phil

 

[Phil Allison]

"Bob Parker"

Like him or not, Phil knows his stuff. I'm not taking sides, but you've
just demonstrated how little you know about electronics and
electrical/magnetic theory and Phil's going to pounce on it.

** Meeeeeeoooooowwwwww ........




......... Phil

 

[Mark]

Well, I didn't think of searching for the '7815 datasheet', so fucking sue
me.

Quite fairly, I knew the extra voltage was required. It was never in doubt.
What was in doubt (and still is, in doubt) is HOW much over voltage my
particular IC can withstand and still continue to provide the required
voltage output at the peak current, under the load.

It's observed behaviour strongly indicates that it can not. (very strongly).

So maybe I have a faulty regulator. So maybe the faulty regulator was cased
by persistent voltage over loads in my domestic supply. Or, maybe the
particular 7815 /7915 pair that I have does not have the same spec.

Either way, the cheapest solution is sounding like I should exchange the
7815 /7915 pair, for a pair that DOES have that 30V spec. and in so doing,
eliminate the possible cause of the observed clipping during voltage
overloads.

Yes, whether you meant to or not, you are being rude to suggest that I
deserved this treatment BECAUSE my question was to simple.

Is that explanation the 'official fiction', or just the one you offer?

Also, I take umbrage (offence, to you) at your trite analogy. It isn't an
accurate portrayal of what happened or my actions or my motivations or my
attitude. I would welcome a point-by-point comparison of your analogy and my
behaviour.

An interesting aside is the cost of the Black Gates. I was and probably sill
can buy them at about the same price for comparable caps in the Rubycon
ZL/ZLH/ZA series sourced from Farnellinone (so ok, they are arse bandits as
well!)

Here is the link. http://www.kyoto-electro.com/nx.html

For example, a 6.3v, 47uF, NX Hi-Q (one of the very best caps BG makes) is
listed at $2.19. The same ZA sells for $1.50. For the extra dollar I'd have
the NX Hi-Q EVERY TIME. On the other hand, for the budget conscious amongst
you, the STD GB sells for $1.77.

Do the comparisons yourself, son, and you will find that the prices I PAY
for Black Gates are not laughable. You may find exceptions but in general,
they are comparable with the best Rubycon has to offer. If I find a price I
don't like, I go elsewhere.

Your PRESUMPTION that I must pay too much for my Black Gates is based on
what? An ASSUMPTION that I pay foolish prices. That is both insulting AND
ignorant (of how cheaply Black Gates can be purchased).

I also take umberage to your allegation that I am not "being straight-up
with [this group]".

You reckon that if i was being honest I would say "Actually, I built the
engine, it's running badly, does anyone want to buy some really good fuel
filters?" Here is why I wouldn't say such a thing:

a) I didn't build the application, I modified it.
b) It isn't running badly (under nominal conditions), it sounds superb.
c) I am not SELLING anything.

Reguarding the remainder of your comments, I feel compeled to correct you on
the following matters.

a) My bed ridden family member is not ill, he is handicapped and has been so
since birth. Not all handicaps are as a result of illness.

b) I do not feel compelled to accept the derision, no matter how common it
may have been in the past. I expect to be treated in exactly the same manner
that I treat others. I can't stop people from deriding me for on any
particular subject, but I don't have to ACCEPT it, period. You would
probably be amused to learn that it is actually possible to offer assistance
to others without assuming a condescending manner or belittling the
recipient. A skill you haven't acquired yet.

c) I choose to exercise my 'free-will' and I choose what I divulge to others
about me, my family, my interests AND my endeavours. If that personal policy
costs me some useful assistance then it is MY PREROGATIVE to assess the
opportunity cost and weigh it against the loss of the privacy of my
endeavours. That is my assesment to make and mine alone. You can not tell me
what I MUST tell people.

d) Regarding your objection to my posting style, it is frivolous. I can find
or fabricate just as many objections to bottom posting, or to Phils style of
endless analizing (sic).

I could just as easily object to your abhorrent spelling, not because I wish
to seize an opportunity to deride your intelligence but because it makes the
task of my own spell checker that much more tiresome.

I think that covers it for now

I look forward to our point-by-point comparison of your analogy with my
behaviour. I can't find many comparisons at all. Do you do this often? (that
is: make up stupid analogies that just don't work).

Oh, and maybe refrain from top-posting - it really does annoy people.

"Poxy" <pox@poxymail.com> wrote in message
news:ZfvOh.2902$M.565@news-server.bigpond.net.au...

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a7519$0$24869$c30e37c6@pit-reader.telstra.net...
Three things:

1) "7815" gives about 4 million hits on Goggle.

A Google on 7815 datasheet gets you the answer - very first result.
Secondly, it isn't really about the specific attributes of the 7815 - as
soon as you've had anything to do with power supplies, you get familiar
with
some very basic rules, one of which is that you need 2-3v extra at the
input
of a regulator for it to work - that applies to 7805s, 7812s etc.

2) I asked for the help a little over 48 hours ago, and since that time I
have had to suffer about 30 attacks, but NO HELP what-so-ever.

That's because you didn't provide sufficient information from the start,
and
I don't mean to be rude, but what you initially suggested was absurd - it
was. Really. It might have made sense to you given your background, but to
anyone with experience in almost any field of electronics, regulated power
supplies are such common and basic things that we pretty much all
understand
how they work, the issues that arise and how to deal with them.

What you said initially was the equivalent of saying: "How can I
synthesise
better fuel?" Then you say "I've purchased lots of really expensive fuel
filters, which are black by the way - that hasn't helped, so I clearly
need
to re-sythesise my existing fuel to make it more consistent".

Everyone laughs at you. Particulalry when we discover how much those fuel
filters cost.

Finally you say: "My engine is running badly, I think it's a fuel
problem".

And if you were really being straight-up with us, you'd also say
"Actually,
I built the engine, it's running badly, does anyone want to buy some
really
good fuel filters?"

3) I have a family and one particular dependant who is bed ridden.

What did you expect from me?

I'm honestly sorry to hear that one of your family is ill, and I'm also
sorry that you've had to endure such unpleasant language and abuse, but
it's
Usenet, a base level of mocking and general derision comes with the
protocol.

If you really want help, rather than seeking confirmation of your various
theories, just tell us what the actualy device is, who designed and built
it, what the voltage is at the input of the regulators is and what caps
you
have on each side of the regulator.

Oh, and maybe refrain from top-posting - it really does annoy people.






"Poxy" <pox@poxymail.com> wrote in message
news:mHtOh.2873$M.1140@news-server.bigpond.net.au...

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a43dc$0$24869$c30e37c6@pit-reader.telstra.net...
It certainly would be reassuring to know that I have more head room
than
I
remember.

Show me your spec please. I remember reading something less (much
less),
but
I haven't got it in front of me.

You haven't tried Googling 7815 datasheet?

I think you also need to revise basic power supply design, in
particular,
the manner in which regulators work, and the recommended filtering
configuration on the input and output of the regulator.

As others have pointed out, it may well be that your AC power supply
isn't
supplying adequate voltage to prevent one or both of the regulators
dropping
out under load.

I am sure that you can appreciate that since I am replacing a
wall-wart
power supply with a toroidal step down transformer, the cost of an
additional IC regulator is rather trivial when compared to the cost of
the
rest of the project.

No, I don't appreciate that perspective, because it isn't the most
obvious
answer to what you've explained. The fact that you believe a regulator
requires an input voltage within some percentage, either postive or
negative, of the output voltage underpins where your thinking has gone
wrong.

You're also convinced the issue is overvoltage, whereas looking at the
whole
system, it looks more like the AC transformer isn't putting out enough
voltage. It could well be that another plug pack with a higer output
voltage
and suitable current rating would solve the problem, or it could be
that
the
plugpack you have is a dud.

The application certainly occasionally behaves erratically (on/off
clipping
of output) and I know that this behaviour coincides with over voltage
supply
problems. I monitor the domestic supply using software which queries
and
records data from an UPS. So there is no doubt about the cause. 100%
correlation.

Possibly, but there's a much more obvious answer that does a better job
of
explaining your problem.

If the cost of certainty (solving the problem by putting in a bigger,
better
IC regulator) is about 10 bucks (and, apparently, putting up with a
few
arse-clowns because I was foolish enough to ask for help @
'aus.electronics') then I can go the extra distance, I guess.

Perhaps if you had stated from the start that your plugpack-powered
preamp
(I'm guessing) is exhibiting distortion and that you suspect a power
supply
issue, you might have gotten more rigorous and methodical advice. The
next
question would have been what are the regulators, what voltage is
appearing
at the input of each regulator, and are they getting hot.

That said, *nobody* deserves the kind of response and language that a
certain person has used in this thread.

Also, if you are asking for help and advice, it's polite to observe
accepted
etiquette - that inlcudes refraining from top-posting particularly if
asked
not to.





"Poxy" <pox@poxymail.com> wrote in message
news:MIqOh.2795$M.1126@news-server.bigpond.net.au...

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a28af$0$24860$c30e37c6@pit-reader.telstra.net...
The way I understand it, the regulation that already occurs
within
the
application can only operate within a tolerance of the regulating
IC's
nominal input voltage. The application is using 15 Volt DC
regulators
(output), after the bridge rectifier, and can only operate (+/-
x%)
of
15
volts DC input.

A common 7815 regulator will put out a stable 15v for input voltages
between
17.5v and 30v. That's plenty of headroom for any overvoltage
situation
on
the mains side.

 

[Mark]

That is the first thing that you've said in here that I actually agree with
Phil.

Bob is a Pussy.

But you still didn't know that a voltage doubling rectifier CAN BE a
variant of the simple half wave rectifier.

Nar, nar, nan-nar-nar!!!

Boy, this is fun isn't it.

"Phil Allison" <philallison@tpg.com.au> wrote in message
news:56vi6bF2ad3drU1@mid.individual.net...

"Bob Parker"


Like him or not, Phil knows his stuff. I'm not taking sides, but you've
just demonstrated how little you know about electronics and
electrical/magnetic theory and Phil's going to pounce on it.


** Meeeeeeoooooowwwwww ........




........ Phil

 

[Mark]

9 VAC, at a resonable cost.

"dmm" <dmmilne_REMOVE_@ozemail.com.au> wrote in message
news:dgpk03dblhp6f595blh3ru3fi157p07dq8@4ax.com...

On Mon, 26 Mar 2007 22:59:59 +1000, "Mark"
marknospampleaseilsley@dodo.com.au> wrote:

Can anybody point me to a good design of same.

240 VAC in, 9 VAC out.


Just about any audio amplifier and a sine wave generator will do the job.

What exactly is it that you want to achieve?

 

[Mark]

Well, he doesn't know his voltage doubling rectifier design. That point is
proven.

Philthy could get out of it by claiming that he has made a simple mistake
but I mean how likely is that event really? Huh???

Phil REALLY believes he is infallible and so would be incapable if making
such an admission.

That is why he is the 'decider' of "what others should accept or believe"
He has inferred as much, in this very forum, about a dozen times or so.


"Bob Parker" <bobp.deletethis@bluebottle.com> wrote in message
news:460a915d$0$7399$5a62ac22@per-qv1-newsreader-01.iinet.net.au...

On 29/03/2007 01:49 Mark wrote:
It looks like a voltage doubling design to me. Everything that I have
described about the applications circuit is consistent with that
conclusion. A voltage doubling design CAN BE a variant of the simple half
wave rectifier design.

...You didn't know that!!?

It now appears that I have over estimated your claim to the 'right' to
decide. You see, I knew something that you didn't.

Bet then again, maybe you're just having an 'off day'?

No, it couldn't be that. That would ascribe to you the human
characteristic of fallibility. ...And you are infallible, right?

I didn't (and don't) claim any expertise in the area of electronics, but
you label ME arrogant and YOURSELF as infallible.

...and then you DON'T KNOW that a voltage doubling design CAN BE a
variant of the simple half wave rectifier!!? Fuck me, what am I dealing
with here?

And another thing, Phil: I don't DECIDE what is 'necessary' for other
people to 'know'.

I DECIDE what I will or won't TELL them about my project. That is my
RIGHT as a human being. It is called exercising my 'free will'.

Some of what I DECIDE not to tell others, MAY or MAY NOT be 'necessary'
for their understanding, but I can't and don't decide what is or what
isn't 'necessary' for their understanding. Only THEY can do that and no
doubt they do.

You see, this very distinction, or rather your total failure to grasp
that distinction, is at the hart of your belief that some people "get to
decide what others should accept or believe" whilst others "NEVER" do.

You see, you have assigned this power AS IF it EXISTED as a right, to be
held by some but not others, presumably on the basis of knowledge and
experience. Nobody holds that power, for it does not exist, IN TOTO. You
can not decide for others what those others "should accept or believe",
period. The power does NOT EXIST, at all, period.

The basic human tenant of "free will" excludes all possibility that it
CAN exist as a power. Why?

Because you can not FORCE anyone to BELIEVE anything. Quite clearly, you
believe that these 'deciders' as you called them, can do just that.

Indeed, you have said as much, about dozen times, in this very forum.

And another thing, you petty child. Toroidal core transformers are
classed and commonly refered to as 'Air Core' transformers. In this case,
the 'Air' refers to the hole in the middle (i.e in the 'Core') THAT YOU
CAN SEE.

Iron cores (or Steel Core) transformers commonly have a hole in the
middle (of the Iron) as well, but you can't see it.

You can google all day Phil, but you still didn't know that a voltage
doubling rectifier is variant of the simple half wave rectifier.

Nar, nar, nan-nar-nar.

Child.

Like him or not, Phil knows his stuff. I'm not taking sides, but you've
just demonstrated how little you know about electronics and
electrical/magnetic theory and Phil's going to pounce on it.
And as I said before, if mains voltage changes are affecting your
secret audiophile preamp or whatever it is, it is *faulty* and needs to be
repaired not redesigned.


Bob

 

[Bob Parker]

On 29/03/2007 04:13 Mark wrote:

That is the first thing that you've said in here that I actually agree with
Phil.

Bob is a Pussy.

But you still didn't know that a voltage doubling rectifier CAN BE a
variant of the simple half wave rectifier.

Nar, nar, nan-nar-nar!!!

Boy, this is fun isn't it.

You really don't get it, do you Mark? It's all over your head like a
tent. I felt a bit sorry fot you and tried to steer you in the right
direction, but you won't listen.


Bob (the one Phil's comment was aimed at - you think)

 

[Mark]

There is probably about a million ...no, no, a billion things I don't "get",
but I've learnt not to worry about contingencies and just deal with matters
as they happen.

I would need a microscope to find your compassion, mate. That is one of the
defining characteristics of the 'Phil-o-phile'.

He has the hart of a Pussy.




"Bob Parker" <bobp.deletethis@bluebottle.com> wrote in message
news:460abdec$0$7405$5a62ac22@per-qv1-newsreader-01.iinet.net.au...

On 29/03/2007 04:13 Mark wrote:
That is the first thing that you've said in here that I actually agree
with Phil.

Bob is a Pussy.

But you still didn't know that a voltage doubling rectifier CAN BE a
variant of the simple half wave rectifier.

Nar, nar, nan-nar-nar!!!

Boy, this is fun isn't it.


You really don't get it, do you Mark? It's all over your head like a
tent. I felt a bit sorry fot you and tried to steer you in the right
direction, but you won't listen.


Bob (the one Phil's comment was aimed at - you think)

 

[Trevor Wilson]

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a3c82$0$24870$c30e37c6@pit-reader.telstra.net...

I realise that my breath is wholly wasted on this Philistine, but:

A regulated circuit can benefit from the pre-regulation of the incoming
AC.

**ANY pre-regulation should always be done at DC. AC regulation is
expensive, insane and unnecessary. With modern regulators, pre-regulation is
not likely to be required.

Specifically, where the incoming AC strays outside the operating range of
the regulating IC's output voltage, the benefits may include, for example,
not having any blue smoke emanating from the unit.

**Again. Proper selection of transformer will eliminate any problems.

Regulating IC's aren't expensive, so it seems a common sense precaution
to make, particularly where other work, (the replacement of the existing
wall-wart with a toroidal step down transformer) is envisaged. Which is
EXACTLY what I originally indicated.

**No, it is not what you originally indicated.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

 

[Trevor Wilson]

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a3c82$0$24870$c30e37c6@pit-reader.telstra.net...

I realise that my breath is wholly wasted on this Philistine, but:

A regulated circuit can benefit from the pre-regulation of the incoming
AC.

Specifically, where the incoming AC strays outside the operating range of
the regulating IC's output voltage, the benefits may include, for example,
not having any blue smoke emanating from the unit.

Regulating IC's aren't expensive, so it seems a common sense precaution
to make, particularly where other work, (the replacement of the existing
wall-wart with a toroidal step down transformer) is envisaged. Which is
EXACTLY what I originally indicated.

**BTW: Depending on your application (which you foolishly have declined to
tell us) a toroidal transformer may well be the WORST choice imaginable.
Toroidal transformers are certainly trendy and have a low radiated flux, but
they lose out to EI transformers in most other areas, including regulation
and line noise rejection. For the best line noise rejection, an 'R' core
transformer is best.

But you won't tell us what you are trying to do, so we really can't help
you.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

 

[Poxy]

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460aae4a$0$24872$c30e37c6@pit-reader.telstra.net...

Well, I didn't think of searching for the '7815 datasheet', so fucking sue
me.

That shows that you are not experienced in working with electronics -
anybody who regularly does searches for component numbers would
automatically add "datasheet". Furthermore, anyone with electronics
experience would understand the operating characteristics of a common linear
regulator without needing to refer to a datasheet - it's really common,
basic stuff.

Either way, the cheapest solution is sounding like I should exchange the
7815 /7915 pair, for a pair that DOES have that 30V spec. and in so doing,
eliminate the possible cause of the observed clipping during voltage
overloads.

The first thing to do is measure voltages at key points - at the output of
the AC plugpack at the input of the regulators, at the output of the
regualtors etc. Boring I know, but that is how you start the diagnosis a
power supply problem. That you don't appear to realise that really basic
fact demonstrates a lack of knowledge and experience with simple power
supplies and suggests that you're not equipped to diagnose nor fix the
problem.

Also, I take umbrage (offence, to you) at your trite analogy. It isn't an
accurate portrayal of what happened or my actions or my motivations or my
attitude. I would welcome a point-by-point comparison of your analogy and
my
behaviour.

My analogy, horribly misspelt as it probably was, was reasonable, if not as
amusing as I would have liked. You clearly don't get how challenging it is
to design and implement what you wanted - it's *really* complex stuff. By
comparison, getting a standard dual-rail, linear regulator power supply to
behave is trivial.

The more I think about it, Bob's advice is correct - you should get someone
with a solid background in electronics to fix your preamp for you.

Your PRESUMPTION that I must pay too much for my Black Gates is based on
what? An ASSUMPTION that I pay foolish prices. That is both insulting AND
ignorant (of how cheaply Black Gates can be purchased).

Hey, if they give the sparkling audio performance you like, fair enough. I
probably haven't paid enough attention to the musicality of the caps I buy.

I also take umberage to your allegation that I am not "being straight-up
with [this group]".

You reckon that if i was being honest I would say "Actually, I built the
engine, it's running badly, does anyone want to buy some really good fuel
filters?" Here is why I wouldn't say such a thing:

a) I didn't build the application, I modified it.

You never said that. It does explain a lot. In my analogy, it would be like
revealing that you'd modified your engine while at the same time giving the
strong impression you don't really know how engines work.

b) It isn't running badly (under nominal conditions), it sounds superb.
c) I am not SELLING anything.

That was a joke. Sorry. I was kind of thinking that if your "thing" didn't
end up working, you could recover some cash-money by Ebaying them fancy
caps.

I look forward to our point-by-point comparison of your analogy with my
behaviour. I can't find many comparisons at all. Do you do this often?
(that
is: make up stupid analogies that just don't work).

Look, I've got nothing to add. I thought my insightful analogy would help
you understand why people responded to you with derision. Obviously you
still don't get it, and that seems to be because you don't have the
knowledge and experience in electronics to diagnose and solve the fault -
everything you say reinforces that fact.

Get someone who knows what they are doing to look at your device. If it's a
power supply problem they'll diagnose and fix it very quickly.

And you might be able to pay them in capacitors

 

[Trevor Wilson]

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a6eb1$0$24861$c30e37c6@pit-reader.telstra.net...

BUT I DON'T want to eliminate the half wave rectifier!!! It is
pre-existing inside the application.

I don't want to alter the application, at all and I would prefer not even
to discuss it.

I would like to point out that my original question deliberately had
NOTHING to do with the application. The easiest way to eliminate the
unwanted discussion is to not provide information on the application.

So, WE are stuck with AC as an input to the application. I wanted to
eliminate the AC/AC wall-wart transformer (which uses an Iron core
transformer) and replace if with a Toroidal core transformer.

Do I need to justify this choice as well?

**YOU don't have to justify anything. YOU should be aware that, for low
level audio applications, a toroidal transformer will be your worst choice.
See what happens when you tell us what you are doing? You get sensible
answers. Dump the toroidal and look for a decent 'R' core transformer.
Additionally, I suggest you dump the 78XX & 79XX regulators and redesign
with LM317/LM337 regulators. Much more significant than bothering with those
silly Blackgate caps.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

 

[Chris Jones]

Mark wrote:

The way I understand it, the regulation that already occurs within the
application can only operate within a tolerance of the regulating IC's
nominal input voltage. The application is using 15 Volt DC regulators
(output), after the bridge rectifier, and can only operate (+/- x%) of 15
volts DC input.
No. At the input of a typical 15V regulator you need 17V or 18V as a

minimum, and the maximum will typically be either around 30V-35V, or less
if large load currents are being drawn such that the heat sink of the
regulator gets so hot that the power dissipation of the regulator needs to
be reduced by lowering the input voltage below 30V.

The rectification of (nominally) 9 VAC I understood to result in 18 VDC
No, not if the "(nominally) 9 VAC" is actually anywhere near 9VAC, the peak

value of the waveform is sqrt(2) (about 1.4 times) the RMS value, and 9VAC
is conventionally used to refer to 9VRMS, unless otherwise stated.

(ignoring any small voltage drop across the diodes).
It is not small enough to ignore.

So even when the
input voltage is nominal,
the input voltage to the regulating IC's is only within 20% of their
nominal output.
It needs to be well ABOVE the nominal output OR IT WILL NOT WORK.

Now what happens if the domestic supply voltage is not nominal?
If you are using the regulators properly, then they will regulate. On a bad

day, the output voltage might change by a millivolt or so, and nobody will
notice. On a good day it will change even less and you will have great
difficulty even measuring the change.

If the domestic supply comes in at 264 VAC (+10%), the existing linear
regulator now supplies 9.9 VAC to the application,
No, not if it is a regulator. Maybe you mean "transformer".

the bridge rectifier
doubles that to 19.8 VAC. The input voltage to the regulating IC's is now
only within 40% of their nominal output!
Should work just fine with 19.8V into a 15V regulator.

I monitor the domestic supply and regularly see voltages coming into our
house outside the range of +/- 10%.
Ok, that's why you already have a regulator. If you are using it properly

then you should not be having any problems.

One solution, of course, would be to redesign the power supply within the
application's case, including upgrading the regulating IC's input voltage
tolerance to at least 40% of its output, if such an IC can be found!
All common regulators will accept inputs 40% above the output voltage. It

is when the input voltage is NOT at least a couple of volts greater than
the output voltage that you will have trouble.

However space within the applications case would not allow for a toroidal
transformer, which I consider to be the optimum solution for a number of
reasons that I don't need to explain here (or maybe they will insist that
I do that as well?!!), and I have already invested considerable effort
(and a small amount of money) in upgrading the capacitors within the
existing application's power supply and really don't want to loose out on
the already considerable improvements I have made therein.
I am not sure that you would make any improvement by changing the

capacitors. It is possible that you have introduced problems due to the
modifications. If you would explain what you have done then people would
probably help you, but you indicated that you did not want to do that.

Quite frankly, I am astounded and reviled that such a simple request has
generated such a vile reaction from this group. I can only assume that it
is because they, like me, were unable to Goggle a suitable design. So as
to maintain their allusion of expertise and so they hide their inability
to self-design a suitable solution, with insults!

I wonder what would happen if I took a simular request for such a simple
thing to another newsgroup, say 'us.electronics', and pointed out to them
that 'aus.electronics' does not have a single contributor who can satisfy
the request. I wonder what they would say. "Too difficult", do you think?

The problem seems to be that you started out by asserting as facts a few
things that happen not to be correct, and then insulted anyone who tried to
point out your errors. If you had started out with more humility and less
conviction that you already knew everything on the subject of power
supplies, then you would have received more helpful replies.

I suggest you learn what is inside a voltage regulator and how it works
(from application notes on the National Semiconductor and On Semiconductor
websites if you don't have any suitable books), learn what a half-wave
rectifier and a full-wave bridge rectifier is, learn the relationship
between the peak and RMS voltages of a sine wave, and next time when you're
not sure about something, remember that you won't be attacked for not
knowing something but you will be mocked and insulted viciously if you
pretend to know things that you don't know and persist in asserting with
confidence things that are incorrect rather than listening to correct
(albeit not particularly polite) advice.

Chris

 

[budgie]

On Wed, 28 Mar 2007 23:02:47 +1000, Bob Parker <bobp.deletethis@bluebottle.com>
wrote:

Black Gate Electrolytic Capacitors
----------------------------------

There are very few audio parts that promise a guaranteed improvement
when replacing practically any other part, but this is what the BLACK
GATE™ capacitors actually do. Exchanging any electrolytic capacitor
anywhere in the circuit of a CD-player, amplifier or in the crossover of
a speaker will greatly improve sound quality. BLACK GATE™ are recognised
worldwide as the best electrolytics capacitors money can buy.

aaahhhh - the electrolytic equivalent of monster OFC cables ;-)

 

[Trevor Wilson]

"budgie" <me@privacy.net> wrote in message
news:4c3m03ltbrbe507oe9thma13l5057tdfl4@4ax.com...

On Wed, 28 Mar 2007 23:02:47 +1000, Bob Parker
bobp.deletethis@bluebottle.com
wrote:


Black Gate Electrolytic Capacitors
----------------------------------

There are very few audio parts that promise a guaranteed improvement
when replacing practically any other part, but this is what the BLACK
GATET capacitors actually do. Exchanging any electrolytic capacitor
anywhere in the circuit of a CD-player, amplifier or in the crossover of
a speaker will greatly improve sound quality. BLACK GATET are recognised
worldwide as the best electrolytics capacitors money can buy.

aaahhhh - the electrolytic equivalent of monster OFC cables ;-)

**Not really. Monster Cables are designed to possess attractive cosmetics,
with no real regard for any tangible performance criteria. Blackgate caps,
OTOH, DO have some measurably significant parameters. HOWEVER, none of those
parameters is significant for power supply filtering. IOW: There are better
caps available, at lower cost for filtering. Mind you: After purchasing some
of those Dick Smith 'Joe Master' branded monstrosities once (and ONLY once)
I can readily understand why some purchasers would spend the Bucks for a cap
which is quite well made and performs respectably enough (Blackgate).


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

 

[swanny]

Mark wrote:

The way I understand it, the regulation that already occurs within the
application can only operate within a tolerance of the regulating IC's
nominal input voltage. The application is using 15 Volt DC regulators
(output), after the bridge rectifier, and can only operate (+/- x%) of 15
volts DC input.

The rectification of (nominally) 9 VAC I understood to result in 18 VDC
(ignoring any small voltage drop across the diodes). So even when the input
voltage is nominal,
the input voltage to the regulating IC's is only within 20% of their nominal
output.

Now what happens if the domestic supply voltage is not nominal?

If the domestic supply comes in at 264 VAC (+10%), the existing linear
regulator now supplies 9.9 VAC to the application, the bridge rectifier
doubles that to 19.8 VAC. The input voltage to the regulating IC's is now
only within 40% of their nominal output!

I monitor the domestic supply and regularly see voltages coming into our
house outside the range of +/- 10%.

One solution, of course, would be to redesign the power supply within the
application's case, including upgrading the regulating IC's input voltage
tolerance to at least 40% of its output, if such an IC can be found!

However space within the applications case would not allow for a toroidal
transformer, which I consider to be the optimum solution for a number of
reasons that I don't need to explain here (or maybe they will insist that I
do that as well?!!), and I have already invested considerable effort (and a
small amount of money) in upgrading the capacitors within the existing
application's power supply and really don't want to loose out on the already
considerable improvements I have made therein.

Quite frankly, I am astounded and reviled that such a simple request has
generated such a vile reaction from this group. I can only assume that it is
because they, like me, were unable to Goggle a suitable design. So as to
maintain their allusion of expertise and so they hide their inability to
self-design a suitable solution, with insults!

I wonder what would happen if I took a simular request for such a simple
thing to another newsgroup, say 'us.electronics', and pointed out to them
that 'aus.electronics' does not have a single contributor who can satisfy
the request. I wonder what they would say. "Too difficult", do you think?

Why do you need to regulate the input voltage to the regulator?
It is the function of the regulator to accept an unregulated input and provide a
stable, regulated output.

 

[Mark]

The subject of the OP was "Isolated, regulated, toroidal step down
transformer AC power supply design."

So I actually didn't indicate what 'it' was that was being replaced. Good on
you for making that observation.

Brevity and relevance play a part in the formulation of my subjects for
obvious reasons. Limited character space being one of them.

I did indicate what I wanted to replace 'it' with, in the subject matter of
the OP.

So OK, why don't you help me select the 'self regulating' transformer that
will eliminate all my over voltage problems. 240 VAC in (nominal), 9 VAC
out. Fused at about 2 amps at the input. (it isn't critical.)

Tell me what else you need to know and I'll decide what I tell you, or not.

Regarding your speculation that "with modern regulators, pre-regulation is
not likely to be required.":

"Not Likely" is a very soft qualification in the face of the observed
behaviour of the applications performance during times of over supply. A
100% correlation suggests that it is VERY LIKELY. Statistically significant,
in other words.

What isn't clear is why my Regs (assuming it is my Regs) misbehave. I have
already conceded that the most cost effective action for me to take would be
to replace the 7815/7915 pair with a new pair that DOES have the 30V spec.
and see what happens.

But I may have to replace all other Regs in the applications power supply,
for the same reason, before I get to the bottom of it. I don't have the
necessary test equipment or the expertise to pre-determine which Regs are at
fault.

Apparently AC regulation is a difficult task. TXU certainly do it VERY
BADLY.


"Trevor Wilson" <trevor@SPAMBLOCKrageaudio.com.au> wrote in message
news:460acee8$0$16283$88260bb3@free.teranews.com...

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460a3c82$0$24870$c30e37c6@pit-reader.telstra.net...
I realise that my breath is wholly wasted on this Philistine, but:

A regulated circuit can benefit from the pre-regulation of the incoming
AC.

**ANY pre-regulation should always be done at DC. AC regulation is
expensive, insane and unnecessary. With modern regulators, pre-regulation
is not likely to be required.


Specifically, where the incoming AC strays outside the operating range of
the regulating IC's output voltage, the benefits may include, for
example, not having any blue smoke emanating from the unit.

**Again. Proper selection of transformer will eliminate any problems.


Regulating IC's aren't expensive, so it seems a common sense precaution
to make, particularly where other work, (the replacement of the existing
wall-wart with a toroidal step down transformer) is envisaged. Which is
EXACTLY what I originally indicated.

**No, it is not what you originally indicated.


--
Trevor Wilson
www.rageaudio.com.au



--
Posted via a free Usenet account from http://www.teranews.com

 

[Trevor Wilson]

"Mark" <marknospampleaseilsley@dodo.com.au> wrote in message
news:460b371c$0$24862$c30e37c6@pit-reader.telstra.net...

The subject of the OP was "Isolated, regulated, toroidal step down
transformer AC power supply design."

So I actually didn't indicate what 'it' was that was being replaced. Good
on you for making that observation.

Brevity and relevance play a part in the formulation of my subjects for
obvious reasons. Limited character space being one of them.

I did indicate what I wanted to replace 'it' with, in the subject matter
of the OP.

So OK, why don't you help me select the 'self regulating' transformer that
will eliminate all my over voltage problems. 240 VAC in (nominal), 9 VAC
out. Fused at about 2 amps at the input. (it isn't critical.)

**Obtain a signal generator, capable of delivering a stable 50Hz sine wave.
Operate it into a small (say) 50 Watt power amp. Drive the power amp into a
suitable power transformer. That'll work.

Tell me what else you need to know and I'll decide what I tell you, or
not.

Regarding your speculation that "with modern regulators, pre-regulation is
not likely to be required.":

"Not Likely" is a very soft qualification in the face of the observed
behaviour of the applications performance during times of over supply. A
100% correlation suggests that it is VERY LIKELY. Statistically
significant, in other words.

**Bullshit. The only time pre-regulation will be required, is for
under-Voltage events. That is easy enough to deal with.

What isn't clear is why my Regs (assuming it is my Regs) misbehave.

**How (precisely) do they "misbehave"?

I have

already conceded that the most cost effective action for me to take would
be to replace the 7815/7915 pair with a new pair that DOES have the 30V
spec. and see what happens.

**HUH? ALL 78XX/79XX regulators are specc'd virtually identically. Except
for a couple of low power variants, all have a 35 Volt maximum Vin limit.
Allhave a 2-2.5 Volt 'drop-out' Voltage. IOW: You should have AT LEAST 18
Volts DC at the regulator input terminal. There is a gotcha here too. You
need to measure the ripple too, as any ripple which has peaks falling below
the 2 - 2.5 Volt limit will impress that ripple on the output. IOW: Measure
the ripple to the input of the regulators.

But I may have to replace all other Regs in the applications power supply,
for the same reason, before I get to the bottom of it. I don't have the
necessary test equipment or the expertise to pre-determine which Regs are
at fault.

**Then you are screwed. You need to perform measurements to determine where
the problem is. I'll betcha it ain't the regulators. Regulators are VERY
reliable. And they all perform pretty much the same, if the have the same
designation.

Apparently AC regulation is a difficult task.

**And a stupid idea.

TXU certainly do it VERY

BADLY.

**TXU?

We're all bored with your top-posting now.


--
Trevor Wilson
www.rageaudio.com.au



--
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