Switching Regulator for Audio Amplifier

F

Fred

Jan 1, 1970
0
What's the state of the art in terms of Class D (or other PWM
architecture) audio amps in this power range?

Perhaps you could give up the idea of trying to clean up the supply for
a linear amp and really save yourself some power.

I think this problem is solved. I just have to verify that by buying
a $130 transformer and a couple mnore filter caps.

I actually have a chip set for a class D amplifier. Like the discrete
design it significantly more elaborate. Looking to the future
though...

Fred
 
I think this problem is solved. I just have to verify that by buying
a $130 transformer and a couple mnore filter caps.

Well, that would be weird.
for 130$ (89 Euro) you buy a 2 x 100W amp here with the 200VA
transformer in it,
in 19 inch rack, with XLR connectors, temp controlled fan, volume
controls, etc.
AND filter caps :)
Yes it is discrete. PA3000 www.conrad.nl
Yes and one transformer for both channels.

In these times, with markets crashing, I'd think trice about spending
dollars.
It does not make a lot of sense to build something if you can buy it
cheaper
with the same or better quality.
 
F

Fred

Jan 1, 1970
0
Well, that would be weird.
for 130$ (89 Euro) you buy a 2 x 100W amp here with the 200VA
transformer in it,
in 19 inch rack, with XLR connectors, temp controlled fan, volume
controls, etc.
AND filter caps :)
Yes it is discrete. PA3000www.conrad.nl
Yes and one transformer for both channels.

In these times, with markets crashing, I'd think trice about spending
dollars.
It does not make a lot of sense to build something if you can buy it
cheaper
with the same or better quality.

So, you want me to be a consumer rather than a producer?

Its actually a very scary thing that the bulk of our manufacturing has
all been outsourced to east asia, if you are economically aware.

I have learned so much about our global economic situation, with the
world bank want to rule in totalitarian fashion a single world
government, that it is depressing me to death.

Everywhere there are nay sayers. Don't do anything creative, Don't
do anything on your own initiave. Just do what you are told. Work
in service industry.

The service industry is basically all thats left in this county now.
I heard them talking ten years abo, about the economy of this country
moving toward becoming service industry oriented. Now I realize what
they meant.

What ever happens, in the end there will be the list of the thing I
created. Things I chose to do when I was able to, instead of
shivering with fear of the unknown. I'm truly beginning to think in
the end that will be my only solace.

Anyway, enough of that unpleasantness.

I have an amp to build, and its gonna rock!
 
E

Eeyore

Jan 1, 1970
0
Jan said:
Unless I've confused it, STM is about to obsolete its DMOS IC amps though.

Graham

Well, the future..
It is listed on the ST site,
http://www.st.com
and can be orderded, pressing 'Purchase' will show what is available around the world.
http://www.st.com/stonline/products/literature/ds/1057/tda7294.htm

A google search for 'end of life DMOS stm' fund no real links.
You have shares in national????[/QUOTE]

Either this is an updated version or STM changed their mind. Known funnier things happen. Philips
announed they were going the discontinue the P87C750, purchasing went into panic mode, yet they kept on
being delivered regardless.

Graham
 
E

Eeyore

Jan 1, 1970
0
Paul Hovnanian P.E. said:
What's the state of the art in terms of Class D (or other PWM
architecture) audio amps in this power range?

Depends who you ask. Philips have an interesting patent that seems to work
OK. They refer to it as UCD.
A Dutch company called Hypex makes modules using the technology.
http://www.hypex.nl/main.htm

IR have some app note circuits too that look pretty simple.

Graham
 
E

Eeyore

Jan 1, 1970
0
Well, that would be weird.
for 130$ (89 Euro) you buy a 2 x 100W amp here with the 200VA
transformer in it, in 19 inch rack, with XLR connectors, temp controlled fan,
volume
controls, etc. AND filter caps :)
Yes it is discrete. PA3000 www.conrad.nl
Yes and one transformer for both channels.

In these times, with markets crashing, I'd think trice about spending
dollars.
It does not make a lot of sense to build something if you can buy it
cheaper with the same or better quality.

I rather doubt the sound quality of what is doubtless a cheap Chinese knock-off
of someone else's knock-off would compare with the Nat Semi chip which is
acknowledged to be pretty good.

However there is this which has had some decent reviews I gather.
http://www.thomann.de/gb/behringer_a500_studioendstufe.htm

The styling is vile to my eyes though.

Graham
 
J

Jan Panteltje

Jan 1, 1970
0
So, you want me to be a consumer rather than a producer?

Well, lemme put it this way, you can produce all you want,
but what if you cannot sell it?
That makes little economic sense.

There may be an educational aspect, then I would _still_ buy the Chinese amp,
as it has all parts and more for less money.
And play with those parts - now that is 'green'.

But there are many things that you can design that you cannot buy cheaper.
My last home project was a digital SWR power meter with LCD display.
Very cool :)

Its actually a very scary thing that the bulk of our manufacturing has
all been outsourced to east asia, if you are economically aware.

Does not scare me at all :)
It allows us to have many cool things, from DVD players to scooters,
for a low price, and the cheaper the more you can do with your money.

I have learned so much about our global economic situation, with the
world bank want to rule in totalitarian fashion a single world
government, that it is depressing me to death.
mm


Everywhere there are nay sayers. Don't do anything creative, Don't
do anything on your own initiave. Just do what you are told. Work
in service industry.

Well, do what you must do, do your thing.
Creativity comes in many ways, I did maintenance of complex systems for many
years, it can be as fulfilling as designing something.
Fulfilment is an inner experience.

Designing for a job can be extremely demanding.
'Service' can be extremely demanding.
Both can be fun too.
It is up to you.

Creativity includes not being stupid.
'do what you are told to to?' I dunno, what makes authority is you listening to it.

The service industry is basically all thats left in this county now.

Well, I dunno where you are, with that gmail address, but yes, service
industry always will be important.

See, if you want to design, you have to be better then the rest, cheaper too
perhaps, else it will never be a product that can be sold.
There is always the competition, so using a ridiculous big transformer
sort of makes your design void from that perspective.
 
E

Eeyore

Jan 1, 1970
0
Jan said:
On a sunny day (Mon, 15 Sep 2008 16:24:24 +0100) it happened Eeyore


Well, the future..
It is listed on the ST site,
http://www.st.com
and can be orderded, pressing 'Purchase' will show what is available around the world.
http://www.st.com/stonline/products/literature/ds/1057/tda7294.htm

A google search for 'end of life DMOS stm' fund no real links.
You have shares in national????

I would swear it said not recommended for new designs. I noticed because ages ago I recommended it to a
sub-contactor who was building us a powered stage monitor and I like to keep track of these things.

Actually they did a rail switching version of it (Class H) to keep the heat (and transformer size)
down. That was neat. See Fig 18 on the data sheet.

Graham
 
F

Fred

Jan 1, 1970
0
Well, that would be weird.
for 130$ (89 Euro) you buy a 2 x 100W amp here with the 200VA
transformer in it,
in 19 inch rack, with XLR connectors, temp controlled fan, volume
controls, etc.
AND filter caps :)
Yes it is discrete. PA3000www.conrad.nl
Yes and one transformer for both channels.

In these times, with markets crashing, I'd think trice about spending
dollars.
It does not make a lot of sense to build something if you can buy it
cheaper
with the same or better quality.

I looked at the PA3000 before. It omits mention of whether that is
watts music power or watts RMS.
I noticed the ST chip quotes figures large letter the specify music
power. The output of that chip is close to the NS chip when you look
at the RMS figures. The only improvement I see is that you can get
60-70 watts RMS out of it into 8 and 16 ohm as well as 4 ohm loads.

The price is good. The bet the manufactures buy lots of 10,000
transformers at a time etc. I've looked into temperature controlled
fans. It's easy to add on. My units will lack attenuators, but will
have a mute switch. That's all it needs to fulfill it purpose.

What is it they say about ignoring the things beyond your control,
doing the things within your control, and having the ability to tell
the difference...

Fred
 
J

Jan Panteltje

Jan 1, 1970
0
I rather doubt the sound quality of what is doubtless a cheap Chinese knock-off
of someone else's knock-off would compare with the Nat Semi chip which is
acknowledged to be pretty good.

Cannot compare to the National chip, but I do have both the ST amp and the Chinese
(that actually is a German design as classical as they come).
Lemme put it this way:
'If I had to evacuate because of floods, and was allowed to carry only one,
then I would take the Chinese amp'.
However there is this which has had some decent reviews I gather.
http://www.thomann.de/gb/behringer_a500_studioendstufe.htm

Yea, but looks ugly :)
 
J

Jan Panteltje

Jan 1, 1970
0
I looked at the PA3000 before. It omits mention of whether that is
watts music power or watts RMS.

It is 2 x 100 W RMS in 4 Ohm, 2 x 60 W RMS in 8 Ohm,
and 2 x 180 music power, whatever that may be.
 
B

Bob Eld

Jan 1, 1970
0
Fred said:
I think you mean +/-42V. And that is exactly what my PS was supplying
at no-load. It was under heavy load that two of the devices failed.
Nation said the only way to destroy the chips was wtih excessive
supply voltage combined with low load resistance.

Fred

Sounds like second breakdown to me. The solution: beg, borrow, steal, make,
purchase, design or whatever, a better amplifier. If these chips can't
handle their ratted current at even less than the rated voltage, they are no
damn good, period.

One caution, if the current voltage and power ratings are compromised in the
specs., what other specifications are in question? Likely much of the spec.
sheet is full of lies and half truths. Nothing can be trusted without
verification.
 
E

Eeyore

Jan 1, 1970
0
Jan said:
Fred wrote


Does not scare me at all :)
It allows us to have many cool things, from DVD players to scooters,
for a low price, and the cheaper the more you can do with your money.

So where are all the jobs now ?

Graham
 
P

Phil Allison

Jan 1, 1970
0
"Bob Too Elderly to Post Here"
Sounds like second breakdown to me.


** Bet a dope like you has no idea what that even is.

Hint - it is not normally an issue with resistive loads.

Plus the LM3886 has very effective internal SOA protection (called SPIKE )
as well as thermal shut down if the chip reaches 165C.

Bet you have never even seen one on them.

It is one of the most popular audio power amp ICs ever made and found in
countless professional audio products.



..... Phil
 
E

Eeyore

Jan 1, 1970
0
Fred said:
The service industry is basically all thats left in this county now.
I heard them talking ten years abo, about the economy of this country
moving toward becoming service industry oriented. Now I realize what
they meant.

Where are you Fred ?

In the UK Margaret Thatcher really kicked this off. We are now 70% dependent on
the service sector and wait 'til that starts getting outsourced too.

Manufacturing industry is but 16-17% of GDP and much of the rest is low-wage
agriculture.

And this country was once called 'the workshop of the world'. We built everything
and anything. Now we can't even make cruise liners for the (American owned) P&O
Line and Cunard. Instead they come from Germany, France and Italy.

Graham
 
E

Eeyore

Jan 1, 1970
0
Jan said:
On a sunny day (Mon, 15 Sep 2008 23:31:24 +0100) it happened Eeyore


Yea, but looks ugly :)

We certainly agree on that then !

Graham
 
E

Eeyore

Jan 1, 1970
0
Bob said:
"Fred" wrote

Sounds like second breakdown to me. The solution: beg, borrow, steal, make,
purchase, design or whatever, a better amplifier. If these chips can't
handle their ratted current at even less than the rated voltage, they are no
damn good, period.

One caution, if the current voltage and power ratings are compromised in the
specs., what other specifications are in question? Likely much of the spec.
sheet is full of lies and half truths. Nothing can be trusted without
verification.

He could adapt fig 18 of the datasheet for the STM TDA7294 perhaps and apply it
to the National chip.

Graham
 
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