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Difference between bridged and parallel amp?

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Anonymous
September 2, 2005 8:59:58 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

Looking at the datasheet for a National LM4780 audio amplifier IC I was
wondering: what's the difference between a parallel and a bridged amp? They
sort of seem to be doing the same thing.
Anonymous
September 2, 2005 8:59:59 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Fri, 2 Sep 2005 16:59:58 +0200, No One Really wrote:

> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp? They
> sort of seem to be doing the same thing.

No. Bridging doubles the output voltage, while parallel doubles the output
current. You need to choose your speaker impedance to suit either
condition.

d
Anonymous
September 2, 2005 8:59:59 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

No One Really wrote:

> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp? They
> sort of seem to be doing the same thing.

You got your answer but I'll add that I wouldn't recommend that parallel
configuration. It involves a pair of current sharing resistors that increase
the output impedance.

Graham
Related resources
Anonymous
September 2, 2005 8:59:59 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"No One Really" <noone@really.org> wrote in message
news:1125673453.32b95b4cc31f94002d7a5ff15be71d6e@teranews...
> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp?
> They
> sort of seem to be doing the same thing.
>
>
>
Take a close look to see how the speaker is hooked up in the bridge
configuration.
Tam
Anonymous
September 2, 2005 8:59:59 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Fri, 2 Sep 2005 16:59:58 +0200, "No One Really"
<noone@really.org> wrote:

>Looking at the datasheet for a National LM4780 audio amplifier IC I was
>wondering: what's the difference between a parallel and a bridged amp? They
>sort of seem to be doing the same thing.

---
What no one has commented on so far is that for a given load
impedance, using paralleled outputs will do nothing as far as
increasing the power into the load goes, while using bridged outputs
will result in _quadrupling_ the power into the load! That is, of
course, assuming the power supply can deliver the increased
(doubled) current.

--
John Fields
Professional Circuit Designer
Anonymous
September 2, 2005 8:59:59 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"No One Really" <noone@really.org> wrote in message
news:1125673453.32b95b4cc31f94002d7a5ff15be71d6e@teranews...
> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp?
> They
> sort of seem to be doing the same thing.

Use bridging when your amplifier is voltage limited, i.e. when it won't put
out enough voltage to drive your speaker to full power.

Don't use parallel amplifiers unless the feedback loop includes both
amplifiers, which it doesn't unless the amplifiers were specifically
designed for parallel operation.

Norm Strong
Anonymous
September 2, 2005 9:00:00 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"Don Pearce" <donald@pearce.uk.com> wrote in message
news:1pmnhaxm8z4sj.teozao66kryw$.dlg@40tude.net
> On Fri, 2 Sep 2005 16:59:58 +0200, No One Really wrote:
>
>> Looking at the datasheet for a National LM4780 audio
>> amplifier IC I was wondering: what's the difference
>> between a parallel and a bridged amp? They sort of seem
>> to be doing the same thing.
>
> No. Bridging doubles the output voltage, while parallel
> doubles the output current. You need to choose your
> speaker impedance to suit either condition.

The pedantic version would be ;-)

Bridging doubles the maximum available output voltage, which
may lead to a doubling of maximum output current. The latter
eventuality needs to be carefully considered because it is a
common pitfall of bridged operation.

Parallel operation doubles the output current that is
available for delivery to the load.

>You need to choose your speaker impedance to suit either
>condition.

Or, you need to choose your mode of operation to suit your
speaker load and needs for dynamic range.
Anonymous
September 2, 2005 9:15:39 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

I read in sci.electronics.design that Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote (in
<431874CB.29260F66@hotmail.com>) about 'Difference between bridged and
parallel amp?', on Fri, 2 Sep 2005:
>
>No One Really wrote:
>
>> Looking at the datasheet for a National LM4780 audio amplifier IC I was
>> wondering: what's the difference between a parallel and a bridged amp? They
>> sort of seem to be doing the same thing.
>
>You got your answer but I'll add that I wouldn't recommend that parallel
>configuration. It involves a pair of current sharing resistors that increase
>the output impedance.
>
One UK company sold/sells sound system amplifiers with two 60 W MOSFET
amp modules in parallel. It works, but it worried me a lot when I first
saw it. There are no current-sharing resistors and no cross-connections
of any sort. Not happy at full output at 20 kHz, though; smoke happens.
--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Anonymous
September 2, 2005 11:35:51 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"No One Really" <noone@really.org> wrote in message
news:1125673453.32b95b4cc31f94002d7a5ff15be71d6e@teranews...
> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp?
> They
> sort of seem to be doing the same thing.
>
>
>
As stated, output power is quadrupled because of the doubled voltage swing
and thus, doubled current in the output. However, one must pay attention to
the maximum current in the output devices. For example, an audio amplifier
IC may be rated to drive a 4 Ohm minimum load at rated supply voltage. When
bridged, it can no longer handle the 4 Ohm load. 8 Ohm would be the new
minimum. So, considering you are trying to get as much power from the amp by
using the lowest output impedance possible in any case, the maximum you can
gain by bridging is double the power.

John
Anonymous
September 3, 2005 5:12:41 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"No One Really"
>
> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp?
> They
> sort of seem to be doing the same thing.
>

** Only if you think that connecting two identical batteries in series or
parallel is the same thing.




........... Phil
Anonymous
September 3, 2005 6:27:16 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"No One Really" <noone@really.org> wrote in message
news:1125673453.32b95b4cc31f94002d7a5ff15be71d6e@teranews...
> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> wondering: what's the difference between a parallel and a bridged amp?
They
> sort of seem to be doing the same thing.

The main difference is the input connections. In the parallel amplifier
echematic, the inputs of the two channels ae the same, but in the bridged
amplifier schematic, the input of channel B is inverted wrt to the input of
channel A.

And so the outputs of the bridged amplifier are also inverted wrt to each
other; and by connecting the speaker across the outputs for both channels,
it will receive twice the voltage (one terminal at +V, one at -V, rather
than one terminal at +V and the other at 0V).

Tim
September 4, 2005 5:11:44 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Fri, 02 Sep 2005 17:15:39 +0100, John Woodgate wrote:

> I read in sci.electronics.design that Pooh Bear
> <rabbitsfriendsandrelations@hotmail.com> wrote (in
> <431874CB.29260F66@hotmail.com>) about 'Difference between bridged and
> parallel amp?', on Fri, 2 Sep 2005:
>>
>>No One Really wrote:
>>
>>> Looking at the datasheet for a National LM4780 audio amplifier IC I was
>>> wondering: what's the difference between a parallel and a bridged amp? They
>>> sort of seem to be doing the same thing.
>>
>>You got your answer but I'll add that I wouldn't recommend that parallel
>>configuration. It involves a pair of current sharing resistors that increase
>>the output impedance.
>>
> One UK company sold/sells sound system amplifiers with two 60 W MOSFET
> amp modules in parallel. It works, but it worried me a lot when I first
> saw it. There are no current-sharing resistors and no cross-connections
> of any sort. Not happy at full output at 20 kHz, though; smoke happens.

Isn't this the point where someone usually jumps in and says that MOSFET's
don't need current sharing resistors because resistance goes up with
temperature? This person might even cite an excellent and well known
electronics text.

And then someone else, possibly even one of the authors of that text jumps
in and says "No, when used in the linear region, virtually all power
MOSFET's DO need current sharing resistors?"

Just wondering.

--Mac
Anonymous
September 4, 2005 6:45:24 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

Mac wrote:

> On Fri, 02 Sep 2005 17:15:39 +0100, John Woodgate wrote:
>
> > I read in sci.electronics.design that Pooh Bear
> > <rabbitsfriendsandrelations@hotmail.com> wrote (in
> > <431874CB.29260F66@hotmail.com>) about 'Difference between bridged and
> > parallel amp?', on Fri, 2 Sep 2005:
> >>
> >>No One Really wrote:
> >>
> >>> Looking at the datasheet for a National LM4780 audio amplifier IC I was
> >>> wondering: what's the difference between a parallel and a bridged amp? They
> >>> sort of seem to be doing the same thing.
> >>
> >>You got your answer but I'll add that I wouldn't recommend that parallel
> >>configuration. It involves a pair of current sharing resistors that increase
> >>the output impedance.
> >>
> > One UK company sold/sells sound system amplifiers with two 60 W MOSFET
> > amp modules in parallel. It works, but it worried me a lot when I first
> > saw it. There are no current-sharing resistors and no cross-connections
> > of any sort. Not happy at full output at 20 kHz, though; smoke happens.
>
> Isn't this the point where someone usually jumps in and says that MOSFET's
> don't need current sharing resistors because resistance goes up with
> temperature? This person might even cite an excellent and well known
> electronics text.
>
> And then someone else, possibly even one of the authors of that text jumps
> in and says "No, when used in the linear region, virtually all power
> MOSFET's DO need current sharing resistors?"
>
> Just wondering.

To answer your question, I've found that the audio specific lateral mosfets made by
Hitachi and also similar ones from Semelab and Exicon share current very well
without any ballast Rs..

Other mosfets types have very variable treshold voltages and can't be used reliably
in this way.

But that's only in the application where those devices are in a single amplifier.

Paralleling entire amplifiers is wholly unwise with current sharing Rs. Mainly
since they won't have exactly the same voltage gain, given normal component
tolerances. The feedback loop will win over everything.

Graham
Anonymous
September 5, 2005 3:10:59 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

I read in sci.electronics.design that Mac <foo@bar.net> wrote (in
<pan.2005.09.04.01.11.44.64653@bar.net>) about 'Difference between
bridged and parallel amp?', on Sun, 4 Sep 2005:

I wrote:

>> One UK company sold/sells sound system amplifiers with two 60 W MOSFET
>> amp modules in parallel. It works, but it worried me a lot when I first
>> saw it. There are no current-sharing resistors and no cross-connections
>> of any sort. Not happy at full output at 20 kHz, though; smoke happens.
>
>Isn't this the point where someone usually jumps in and says that
>MOSFET's don't need current sharing resistors because resistance goes
>up with temperature? This person might even cite an excellent and well
>known electronics text.
>
>And then someone else, possibly even one of the authors of that text
>jumps in and says "No, when used in the linear region, virtually all
>power MOSFET's DO need current sharing resistors?"
>
>Just wondering.

These are not paralleled devices but complete 60 W amplifier cards with
the outputs paralleled. The output source impedance of each is quite
low, due to negative feedback, but not audiophool low. Nevertheless,
each output must look like a near short-circuit to the other amplifier.
--
Regards, John Woodgate, OOO - Own Opinions Only.
If everything has been designed, a god designed evolution by natural selection.
http://www.jmwa.demon.co.uk Also see http://www.isce.org.uk
Anonymous
September 5, 2005 4:55:32 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Sun, 4 Sep 2005 23:10:59 +0100, John Woodgate
<jmw@jmwa.demon.contraspam.yuk> wrote:

>Nevertheless,
>each output must look like a near short-circuit to the other amplifier.

Then what about amps using multiple output devices in parallel ? They all
must look like near short-circuits to each other, don't them ?
Anonymous
September 5, 2005 4:55:33 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" wrote:

> On Sun, 4 Sep 2005 23:10:59 +0100, John Woodgate
> <jmw@jmwa.demon.contraspam.yuk> wrote:
>
> >Nevertheless,
> >each output must look like a near short-circuit to the other amplifier.
>
> Then what about amps using multiple output devices in parallel ? They all
> must look like near short-circuits to each other, don't them ?

John was pointing out correctly the difference between paralleling devices
inside and outside a closed feedback loop.

Graham
Anonymous
September 5, 2005 4:55:33 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in
message news:alumh15u1sm5batvq7ud7opkduiv3n5liq@4ax.com
> On Sun, 4 Sep 2005 23:10:59 +0100, John Woodgate
> <jmw@jmwa.demon.contraspam.yuk> wrote:
>
>> Nevertheless,
>> each output must look like a near short-circuit to the
>> other amplifier.
>
> Then what about amps using multiple output devices in
> parallel ?

Almost always done inside the same feedback loop.

Almost always done with current-balancing resistors.

>They all must look like near short-circuits to each other,
>don't them ?

One reason why amps in parallel look more like short
circuits to each other are the individual feedback loops.
Anonymous
September 5, 2005 12:34:27 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 05 Sep 2005 00:55:32 +0200, François Yves Le Gal
<flegal@aingeal.com> wrote:

>On Sun, 4 Sep 2005 23:10:59 +0100, John Woodgate
><jmw@jmwa.demon.contraspam.yuk> wrote:
>
>>Nevertheless,
>>each output must look like a near short-circuit to the other amplifier.
>
>Then what about amps using multiple output devices in parallel ? They all
>must look like near short-circuits to each other, don't them ?

---
No, they must look like infinite impedances to each other. That is,
they should sink and source current into only the load an never into
or out of one another.

--
John Fields
Professional Circuit Designer
Anonymous
September 5, 2005 3:00:02 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 05 Sep 2005 00:11:32 +0100, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:

>John was pointing out correctly the difference between paralleling devices
>inside and outside a closed feedback loop.

I know. But you can parallel two amp modules, use proper current balancing
resistors and derive proper feedback (if needed).
Anonymous
September 5, 2005 3:02:25 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Sun, 4 Sep 2005 21:13:26 -0400, "Arny Krueger" <arnyk@hotpop.com> wrote:

>One reason why amps in parallel look more like short
>circuits to each other are the individual feedback loops.

Correct. But it's quite easy to properly parallel two amps.
Anonymous
September 5, 2005 4:46:38 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" wrote:

> On Mon, 05 Sep 2005 00:11:32 +0100, Pooh Bear
> <rabbitsfriendsandrelations@hotmail.com> wrote:
>
> >John was pointing out correctly the difference between paralleling devices
> >inside and outside a closed feedback loop.
>
> I know. But you can parallel two amp modules, use proper current balancing
> resistors and derive proper feedback (if needed).

That's true but the result is inferior to a single amp designed for the
purpose.

Graham
Anonymous
September 5, 2005 6:20:09 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 05 Sep 2005 12:46:38 +0100, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:

>That's true but the result is inferior to a single amp designed for the
>purpose.

Probably. But who cares nowadays with very high quality 1 Kw/4 Ohm class D
amp modules - with built-in SMPS, of course! - costing less than USD 200 in
OEM quantities ?
Anonymous
September 5, 2005 6:20:10 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" wrote:

> On Mon, 05 Sep 2005 12:46:38 +0100, Pooh Bear
> <rabbitsfriendsandrelations@hotmail.com> wrote:
>
> >That's true but the result is inferior to a single amp designed for the
> >purpose.
>
> Probably. But who cares nowadays with very high quality 1 Kw/4 Ohm class D
> amp modules - with built-in SMPS, of course! - costing less than USD 200 in
> OEM quantities ?

I guess that depends on the THD figures and so on that you don't mind.


Graham
Anonymous
September 5, 2005 6:49:02 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 05 Sep 2005 13:29:00 +0100, Pooh Bear
<rabbitsfriendsandrelations@hotmail.com> wrote:

>I guess that depends on the THD figures and so on that you don't mind.

These modules are state of the art. A number of "audiophile" companies are
using them in stock form, other have slightly customized versions
manufactured for them.
Anonymous
September 6, 2005 12:45:35 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal"
Some pommy dickhead
>
>>John was pointing out correctly the difference between paralleling devices
>>inside and outside a closed feedback loop.
>
> I know. But you can parallel two amp modules, use proper current balancing
> resistors and derive proper feedback (if needed).
>


** There is at least one proper, engineering type way to do it.

The two or more power stages are made to have unity gain - ie 100% NFB.

Then, a single voltage amp drivis them all.






........... Phil
Anonymous
September 6, 2005 2:26:51 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal"

> Probably. But who cares nowadays with very high quality 1 Kw/4 Ohm class D
> amp modules - with built-in SMPS, of course! - costing less than USD 200
> in
> OEM quantities ?
>


** Care to reveal the merchant ?

Tres interessant.




............ Phil
Anonymous
September 6, 2005 2:26:52 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 5 Sep 2005 22:26:51 +1000, "Phil Allison" <philallison@tpg.com.au>
wrote:

>Care to reveal the merchant ?

The manufacturer... Scandinavian-based. Ice something.
:-)
Anonymous
September 6, 2005 2:26:53 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in
message news:j8foh19bv8etl3guis12ec0gbv6bh3go4j@4ax.com

> On Mon, 5 Sep 2005 22:26:51 +1000, "Phil Allison"
> <philallison@tpg.com.au> wrote:
>
>> Care to reveal the merchant ?
>
> The manufacturer... Scandinavian-based. Ice something.
> :-)

Not exactly a KW for $1.98 but still impressive:

http://www.hypex.nl/

http://www.adireaudio.com/Home/UcDAmps.htm
Anonymous
September 6, 2005 2:26:53 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 05 Sep 2005 14:44:08 +0200, François Yves Le Gal
<flegal@aingeal.com> wrote:

>On Mon, 5 Sep 2005 22:26:51 +1000, "Phil Allison" <philallison@tpg.com.au>
>wrote:
>
>>Care to reveal the merchant ?
>
>The manufacturer... Scandinavian-based. Ice something.

Aah, are you referring to the B&O ICE modules? Proving very popular
now that they've proved their chops in the Lab 5 speakers.
--

Stewart Pinkerton | Music is Art - Audio is Engineering
Anonymous
September 6, 2005 2:26:54 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 5 Sep 2005 09:07:04 -0400, "Arny Krueger" <arnyk@hotpop.com> wrote:

>Not exactly a KW for $1.98 but still impressive:
>
>http://www.hypex.nl/

The Hypex UCD modules are excellent, but don't include the (SM)PS.

Have a look at say, http://www.icepower.bang-olufsen.com/sw2049.asp
Anonymous
September 6, 2005 2:26:55 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in
message news:p vhoh192g5fmaqdoe3jm34579ugd2ki79l@4ax.com
> On Mon, 5 Sep 2005 09:07:04 -0400, "Arny Krueger"
> <arnyk@hotpop.com> wrote:
>
>> Not exactly a KW for $1.98 but still impressive:
>>
>> http://www.hypex.nl/

> The Hypex UCD modules are excellent, but don't include
> the (SM)PS.

> Have a look at say,
> http://www.icepower.bang-olufsen.com/sw2049.asp

The issue of price was raised:

http://www.audiokabel.dk/da-amps.htm

3900 Kroener exchanges out at about $650. About 6 DKK per
USD
Anonymous
September 6, 2005 2:26:56 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 5 Sep 2005 09:55:07 -0400, "Arny Krueger" <arnyk@hotpop.com> wrote:

>The issue of price was raised:
>
>http://www.audiokabel.dk/da-amps.htm
>
>3900 Kroener exchanges out at about $650. About 6 DKK per
>USD

That's the retail price for a *complete* amp, including case, connectors,
packaging et al.

The OEM module - here a 500 w/4 ohm version - costs much less, say less than
USD 150 FOB in OEM quantities.

Now a little bit of fun.

Let's have a look at the web site of a manufacturer using ASP modules:

Say, Red Dragon Audio.

http://www.reddragonaudio.com/main.htm

Their SA 1000 is sold direct for USD 1,799 (plus tax and shipping)

http://www.reddragonaudio.com/sa1000.htm

It uses two 1000ASP modules housed in a very nice aluminum box fitted with
sturdy sockets, jacks, binding posts and feet,, which looks identical to the
Entry 130 manufactured in China and sold in North America by Digital
Analogue DIY for USD 130 (Qty one, end user price).

http://www.digitalanaloguediy.com/entry130.html

Hmmm. Some modules - minimum order is half a pallet, 80 modules, so you have
to front something like 30 G's, some nice boxes, a couple of feet of
internal wiring, a mains cable, a sturdy UPS-proof box and a laser-printed
user manual

Presto, a new "manufacturer" is born...

(All this in order to show that the wide availability of OEM modules will
have the same effect on the audio market than it had on PC's: we'll see more
and more state of the art products at affordable prices. We'll also see
manufacturers trying to differentiate their offerings with tweaked or
custome solutions).
Anonymous
September 6, 2005 2:26:57 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in
message news:f5moh15hjnpgk15kkvopfbg5oi3cj85aiv@4ax.com
> On Mon, 5 Sep 2005 09:55:07 -0400, "Arny Krueger"
> <arnyk@hotpop.com> wrote:
>
>> The issue of price was raised:
>>
>> http://www.audiokabel.dk/da-amps.htm
>>
>> 3900 Kroener exchanges out at about $650. About 6 DKK per
>> USD
>
> That's the retail price for a *complete* amp, including
> case, connectors, packaging et al.

Agreed.

> The OEM module - here a 500 w/4 ohm version - costs much
> less, say less than USD 150 FOB in OEM quantities.

Let's hope so, or the guys at
http://www.audiokabel.dk/da-amps.htm are running a
money-losing operation.

> Now for a little bit of fun.

> Let's have a look at the web site of a manufacturer using
> ASP modules:

> Say, Red Dragon Audio.

> http://www.reddragonaudio.com/main.htm

> Their SA 1000 is sold direct for USD 1,799 (plus tax and
> shipping)

> http://www.reddragonaudio.com/sa1000.htm


Pricey for a 600 wpc/8 ohm amp.

> It uses two 1000ASP modules housed in a very nice
> aluminum box fitted with sturdy sockets, jacks, binding
> posts and feet,, which looks identical to the Entry 130
> manufactured in China and sold in North America by
> Digital Analogue DIY for USD 130 (Qty one, end user
> price).
>
> http://www.digitalanaloguediy.com/entry130.html

Isn't that the same gif on both web sites?

> Hmmm. Some modules - minimum order is half a pallet, 80
> modules, so you have to front something like 30 G's, some
> nice boxes, a couple of feet of internal wiring, a mains
> cable, a sturdy UPS-proof box and a laser-printed user
> manual

> Presto, a new "manufacturer" is born...

i.e., red dragon audio! ;-)

> (All this in order to show that the wide availability of
> OEM modules will have the same effect on the audio market
> than it had on PC's: we'll see more and more state of the
> art products at affordable prices. We'll also see
> manufacturers trying to differentiate their offerings
> with tweaked or custom solutions).

Could be.
Anonymous
September 6, 2005 6:34:35 AM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 5 Sep 2005 13:59:55 -0400, "Arny Krueger" <arnyk@hotpop.com> wrote:

>Isn't that the same gif on both web sites?

It awfully looks like the same .gif.

I can't be affirmative as I've not run an ABX double blid triple Dutch
test...
:-)
Anonymous
September 6, 2005 2:06:08 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"François Yves Le Gal" <flegal@aingeal.com> wrote in
message news:o soph19fbq7ns2qr75abn8q10ndl40fcr7@4ax.com
> On Mon, 5 Sep 2005 13:59:55 -0400, "Arny Krueger"
> <arnyk@hotpop.com> wrote:
>
>> Isn't that the same gif on both web sites?
>
> It awfully looks like the same .gif.
>
> I can't be affirmative as I've not run an ABX double blid
> triple Dutch test...
> :-)

I think it was clever how they avoided the need for a new
gif by keeping the front panel clean. I do like at least a
power indicator on the front panel, though. ;-)
Anonymous
September 7, 2005 10:03:05 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

On Mon, 05 Sep 2005 13:59:55 -0400, Arny Krueger wrote:

> "François Yves Le Gal" <flegal@aingeal.com> wrote in
>> http://www.reddragonaudio.com/main.htm
>
>> http://www.digitalanaloguediy.com/entry130.html
>
> Isn't that the same gif on both web sites?

No, they're the same, but they're jpg's. ;-)

$ ls en*
entry130_front.jpg-1 entry130_front.jpg-2
richgrise@thunderbird:~
$ diff entry130_front.jpg-1 entry130_front.jpg-2
richgrise@thunderbird:~
$

Cheers!
Rich
Anonymous
September 14, 2005 4:28:50 PM

Archived from groups: rec.audio.tech,sci.electronics.design (More info?)

"John Woodgate" <jmw@jmwa.demon.contraspam.yuk> wrote in message
news:p dEAQvjrqHGDFwyF@jmwa.demon.co.uk...

> One UK company sold/sells sound system amplifiers with two 60 W MOSFET amp
> modules in parallel. It works, but it worried me a lot when I first saw
> it. There are no current-sharing resistors and no cross-connections of any
> sort. Not happy at full output at 20 kHz, though; smoke happens.

Amplifiers run on smoke. When the smoke comes out they stop running. Very
simple!
!