Isolated, regulated, toroidal step down transformer AC power supply design.

[Poxy]

Ummm, can someone enlighten me as to what a Backgate capacitor
is...? I did the obligatory Google searching but didn't find anything
very informative.

My guess? They're "acoustically transparent" and cost a bomb.

 

[Mark]

*Black Gate. I don't know how I can live with myself.

 

[dmm]

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?

 

[Bob Parker]

My guess? They're "acoustically transparent" and cost a bomb.

Correct (see my other post with the info). Just the thing for
transparently filtering 100Hz ripple.

Bob

 

[Poxy]

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.

 

[Bob Parker]

*Black Gate. I don't know how I can live with myself.

How could I not have realized that's what you meant?
For everyone's edification, from
http://www.hificollective.co.uk/components/black_gate_caps.html ....


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.

 

[Phil Allison]

"Poxy"

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

** Oh yes they do - plus a whole lot more besides.

The likes of " Mark Ilsley " are among the most vile creatures infesting
the face of the earth.

A bullet to the forehead would be far too kind a fate for an individual who
has continually tortured so many innocents for so many years.

No surprise that a prick like you is in sympathy with this oxygen thief.

Cos YOU are another one of the same fucking pukes.





........ Phil

 

[Mark]

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?

 

[Mark]

Three things:

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

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.

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

What did you expect from me?

 

[Bob Parker]

Three things:

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

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.

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

What did you expect from me?

I haven't been paying close attention to this thread, but no item of
audio (or any other mains-powered) equipment which is working properly
is going to be affected by tiny mains voltage variations. If that's
happening, then it's faulty and it should be looked at and repaired by
someone who understands electronics.
All this talk about toroidal transformers, voltage regulators and
acoustically transparent capacitors seems irrelevant, or did I miss
something by not reading everything?
BTW: 'wall wart' is another Americanism creeping into the Australian
vernacular. I suppose one day we'll have 117V 60Hz mains and beoome the
51st or 52nd or whatever it is state of the USA.

 

[Poxy]

"Poxy"




** Oh yes they do - plus a whole lot more besides.

The likes of " Mark Ilsley " are among the most vile creatures infesting
the face of the earth.

Oh be nice and go to bed Phil.

 

[Poxy]

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 clealry 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.

 

[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!!? **** 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.

 

[Bob Parker]

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!!? **** 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.

 

[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.

 

[Mark]

9 VAC, at a resonable cost.

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.