OT Amplifier problem

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H

Hirsty's

Guest
Forgive : son has chav chariot and his amp in the boot ( Renegade 720 ) has
gone into "protection mode ?? " red led only green unlit. He has 1000 watt
sub woofer attached with two smaller speakers.
Anybody tell me what protection mode is ?? please
My limit is 8 track stereo and a nice 69 427 Corvette (manual ) from them
real days.

I know, I know I swear at em as well but its making pops look a bit ignorant
!!

John H

--


" ..... it is the provenence of knowledge to speak, and it is the privelage
of wisdom to listen"


 
Hirsty's wrote:
> Forgive : son has chav chariot and his amp in the boot ( Renegade 720 ) has
> gone into "protection mode ?? " red led only green unlit. He has 1000 watt
> sub woofer attached with two smaller speakers.
> Anybody tell me what protection mode is ?? please

Odds on he' shorted the loudspeaker output terminals somewhere.
Protection mode might mean over temperature, or too much DC in the
signal, or a short.

Steve
 
In article <[email protected]>, steve
<[email protected]> writes
>Hirsty's wrote:
>> Forgive : son has chav chariot and his amp in the boot ( Renegade 720 ) has
>> gone into "protection mode ?? " red led only green unlit. He has 1000 watt
>> sub woofer attached with two smaller speakers.
>> Anybody tell me what protection mode is ?? please
>
>Odds on he' shorted the loudspeaker output terminals somewhere.
>Protection mode might mean over temperature, or too much DC in the
>signal, or a short.

Wot ee said.

Almost certainly a short across the output.

Best leave it like that - he'll thank you in late middle age when he can
still hear and all his mates are deaf*. I suggest a judiciously-placed
2BA brass bolt is probably favourite - good for about 100A at least!

Regards,

Simonm.

*actually I'm not kidding. Impulse noise, such as digitally recorded
uncompressed drum tracks, can cause a serious notch at 3kHz. That frequency is
one of the most important for speech sibilance (consonant recognition), and
that type of problem is replicated in classic industrial hearing damage.

There is empirical scientific evidence that the onset of deafness is caused by
enviromentally-induced damage over a lifetime, not an inherent feature of
growing old.

--
simonm|at|muircom|dot|demon|.|c|oh|dot|u|kay
SIMON MUIR, BRISTOL UK www.ukip.org
EUROPEANS AGAINST THE EU www.members.aol.com/eurofaq
GT250A'76 R80/RT'86 110CSW TD'88 www.kc3ltd.co.uk/profile/eurofollie/
 
On Thu, 03 Aug 2006 16:57:27 GMT, "Hirsty's" <[email protected]>
wrote:

>Forgive : son has chav chariot and his amp in the boot ( Renegade 720 ) has
>gone into "protection mode ?? " red led only green unlit. He has 1000 watt
>sub woofer attached with two smaller speakers.
>Anybody tell me what protection mode is ?? please
>My limit is 8 track stereo and a nice 69 427 Corvette (manual ) from them
>real days.
>
>I know, I know I swear at em as well but its making pops look a bit ignorant
>!!

I assume youve checked things like the fuse(s) on the side of the amp?

I used to have an old amp in the car, which liked to melt fuses and
when it had gone it still had a red light on the side.
 
>>> Forgive : son has chav chariot and his amp in the boot ( Renegade 720 )
>>> has
>>> gone into "protection mode ?? " red led only green unlit. He has 1000
>>> watt
>>> sub woofer attached with two smaller speakers.
>>> Anybody tell me what protection mode is ?? please

> Almost certainly a short across the output.
>
> Best leave it like that - he'll thank you in late middle age when he can
> still hear and all his mates are deaf

I agree a 1000 W sub woofer - I'll lend him a disc with the brown noise
frequency on it - that should be fun. I never understand why the young uns
of today want music that loud in a very small space - I wonder the sound
pressure level is ?? and how mangled their innards are !!!

Makes me laugh I used to do sound for concerts running much less than that
wattage on the main front of house PA rig !!!

Dave


 

"Hirsty's" <[email protected]> wrote in message
news:[email protected]...
> Forgive : son has chav chariot and his amp in the boot ( Renegade 720 )
> has
> gone into "protection mode ?? " red led only green unlit. He has 1000 watt
> sub woofer attached with two smaller speakers.
> Anybody tell me what protection mode is ?? please
> My limit is 8 track stereo and a nice 69 427 Corvette (manual ) from them
> real days.
>
> I know, I know I swear at em as well but its making pops look a bit
> ignorant
> !!
>
> John H
>
> --
>
>
> " ..... it is the provenence of knowledge to speak, and it is the
> privelage
> of wisdom to listen"
>
>

You'll find that (if the speaker is not shorted), one of the output power
transistors (FETS more likely) has shorted and the amp has sensed this and
shut down the final output stage.
In rare instances, one of the power supply switching FETS could be leaky or
shorted and the amp has shut down the power supply, however, most of them
cannot report this as a fault - it's simply "dead-in-the-water" if that
happens.

I'll bet pounds-to-pennys the music was as distorted as all hell just prior
to it going "nighty-night".

There's a limit to the amount of current that amplifiers can supply - and
when the sound starts distorting (clipping), that's a very good sign that
very soon after you will have a melted output stage - usually the resultant
DC to the speaker(s) also burns out or warps the voice coil as well if it's
not already done so just before the amp died.

-Craig.


 
CraigB wrote:
> "Hirsty's" <[email protected]> wrote in message
> news:[email protected]...
>> Forgive : son has chav chariot and his amp in the boot ( Renegade
>> 720 ) has
>> gone into "protection mode ?? " red led only green unlit. He has
>> 1000 watt sub woofer attached with two smaller speakers.
>> Anybody tell me what protection mode is ?? please
>> My limit is 8 track stereo and a nice 69 427 Corvette (manual ) from
>> them real days.
>>
>> I know, I know I swear at em as well but its making pops look a bit
>> ignorant
>> !!
>>
>> John H
>>
>> --
>>
>>
>> " ..... it is the provenence of knowledge to speak, and it is the
>> privelage
>> of wisdom to listen"
>>
>>
>
> You'll find that (if the speaker is not shorted), one of the output
> power transistors (FETS more likely) has shorted and the amp has
> sensed this and shut down the final output stage.
> In rare instances, one of the power supply switching FETS could be
> leaky or shorted and the amp has shut down the power supply, however,
> most of them cannot report this as a fault - it's simply
> "dead-in-the-water" if that happens.
>
> I'll bet pounds-to-pennys the music was as distorted as all hell just
> prior to it going "nighty-night".

How would one tell?

>
> There's a limit to the amount of current that amplifiers can supply -
> and when the sound starts distorting (clipping), that's a very good
> sign that very soon after you will have a melted output stage -
> usually the resultant DC to the speaker(s) also burns out or warps
> the voice coil as well if it's not already done so just before the
> amp died.
> -Craig.



--
If Your specification is vague or imprecise, you'll likely get what you
asked for not what you wanted!

He who says it cannot be done would be wise not to interrupt her doing
it.


 
On Friday, in article <[email protected]>
[email protected]sm "GbH" wrote:

> CraigB wrote:
> > "Hirsty's" <[email protected]> wrote in message
> > news:[email protected]...
> >> Forgive : son has chav chariot and his amp in the boot ( Renegade
> >> 720 ) has
> >> gone into "protection mode ?? " red led only green unlit. He has
> >> 1000 watt sub woofer attached with two smaller speakers.
> >> Anybody tell me what protection mode is ?? please
> >> My limit is 8 track stereo and a nice 69 427 Corvette (manual ) from
> >> them real days.
> >>
> >> I know, I know I swear at em as well but its making pops look a bit
> >> ignorant
> >> !!
> >>
> >> John H
> >>
> >> --
> >>
> >>
> >> " ..... it is the provenence of knowledge to speak, and it is the
> >> privelage
> >> of wisdom to listen"
> >>
> >>
> >
> > You'll find that (if the speaker is not shorted), one of the output
> > power transistors (FETS more likely) has shorted and the amp has
> > sensed this and shut down the final output stage.
> > In rare instances, one of the power supply switching FETS could be
> > leaky or shorted and the amp has shut down the power supply, however,
> > most of them cannot report this as a fault - it's simply
> > "dead-in-the-water" if that happens.
> >
> > I'll bet pounds-to-pennys the music was as distorted as all hell just
> > prior to it going "nighty-night".
>
> How would one tell?

Too late now, but perhaps it will be necessary to test the repaired
system with a few suitable recordings.

First suggestion--The Queen of the Night from "Die Fliedermaus", just to
de-wax the test apparatus. OK, it's not much good for the subwoofer
test.

--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."
 
David G. Bell wrote:

> First suggestion--The Queen of the Night from "Die Fliedermaus", just to
> de-wax the test apparatus. OK, it's not much good for the subwoofer
> test.

Digital cannons from the 1812 overture bugger the DC protection on my
amplifier.

Steve

 

Steve Taylor wrote:
> David G. Bell wrote:
>
> > First suggestion--The Queen of the Night from "Die Fliedermaus", just to
> > de-wax the test apparatus. OK, it's not much good for the subwoofer
> > test.
>
> Digital cannons from the 1812 overture bugger the DC protection on my
> amplifier.
>
> Steve

And that recording actually tore the base speaker cones suspension on
my demonstration Bang & Olufsen speakers in the shop I worked at. Damn
customer never showed me the warning on the cover untill after!

Alan C

 
"David G. Bell" wrote:

|| First suggestion--The Queen of the Night from "Die Fliedermaus",
|| just to de-wax the test apparatus.

Die Zauberflöte, isn't it?

|| OK, it's not much good for the
|| subwoofer test.

But it'll push the rest of the kit to its limits.

http://www.dutchdivas.net/frames2/cristina_english.html and click on
"Cristina" at the bottom of the page. Frightening. Brings a prickle to my
eyes every time.

--
Rich
==============================

I don't approve of signatures, so I don't have one.


 
In article <[email protected]>, Steve Taylor
<[email protected]> writes
>David G. Bell wrote:
>
>> First suggestion--The Queen of the Night from "Die Fliedermaus", just
>>to de-wax the test apparatus. OK, it's not much good for the
>>subwoofer test.
>
>Digital cannons from the 1812 overture bugger the DC protection on my
>amplifier.

There's a wonderful (and I believe, true) story about the famous Telarc
'digital cannon' record of the 1980s so beloved of the late Angus
McKenzie et al. The story was that your hi-fi was only acceptable if
aforementioned cannon (digitally recorded and played into the direct-cut
recording, IIRC) could track the noisy bit properly.

In frustration, someone applied a travelling microscope to their copy of
the disc, only to discover that the groove wall angle was almost on a
radius at the leading edge of the cannon envelope - in other words, it
had been cut-able by a *driven* cutter head, but was totally
un-trackable by a stylus deriving its output from movement against the
groove wall.

Good game, while it lasted. I think the 'vinyl is best' adherents now
advocate 'burning-in' gold-flashed power cables...

Regards,

Simonm.

--
simonm|at|muircom|dot|demon|.|c|oh|dot|u|kay
SIMON MUIR, BRISTOL UK www.ukip.org
EUROPEANS AGAINST THE EU www.members.aol.com/eurofaq
GT250A'76 R80/RT'86 110CSW TD'88 www.kc3ltd.co.uk/profile/eurofollie/
 
On or around 4 Aug 2006 10:29:04 -0700, [email protected] enlightened us
thusly:

>
>Steve Taylor wrote:
>> David G. Bell wrote:
>>
>> > First suggestion--The Queen of the Night from "Die Fliedermaus", just to
>> > de-wax the test apparatus. OK, it's not much good for the subwoofer
>> > test.
>>
>> Digital cannons from the 1812 overture bugger the DC protection on my
>> amplifier.
>>
>> Steve
>
>And that recording actually tore the base speaker cones suspension on
>my demonstration Bang & Olufsen speakers in the shop I worked at. Damn
>customer never showed me the warning on the cover untill after!

digital cannons? bah. proper 1812 is done with real genuine analogue
cannons and gunpowder. Usually possible to detect this as it's almost
impossible to get the timing perfect. Mind, I'd expect B&O speakers to cope
with pretty much anything.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Any man's death diminishes me, because I am involved in Mankind; and
therefore never send to know for whom the bell tolls, it tolls for thee"
John Donne (1571? - 1631) Devotions, XVII
 
Austin Shackles wrote:

> digital cannons? bah. proper 1812 is done with real genuine analogue
> cannons and gunpowder.

Digitally RECORDED cannons Austin, to get the sharpest possible rising
edge on the shockwaves...

Steve
 
On Saturday, in article
<[email protected]>
[email protected] "Austin Shackles" wrote:

> On or around 4 Aug 2006 10:29:04 -0700, [email protected] enlightened us
> thusly:
>
> >
> >Steve Taylor wrote:
> >> David G. Bell wrote:
> >>
> >> > First suggestion--The Queen of the Night from "Die Fliedermaus", just to
> >> > de-wax the test apparatus. OK, it's not much good for the subwoofer
> >> > test.
> >>
> >> Digital cannons from the 1812 overture bugger the DC protection on my
> >> amplifier.
> >>
> >> Steve
> >
> >And that recording actually tore the base speaker cones suspension on
> >my demonstration Bang & Olufsen speakers in the shop I worked at. Damn
> >customer never showed me the warning on the cover untill after!
>
> digital cannons? bah. proper 1812 is done with real genuine analogue
> cannons and gunpowder. Usually possible to detect this as it's almost
> impossible to get the timing perfect. Mind, I'd expect B&O speakers to cope
> with pretty much anything.

If you have the full version of "Master and Commander" on DVD, one of
the extras shows them recording the sound of cannon fire. And some guns
do ring. They also set up a wooden strcture, and put a 12-pound shot
through it.

--
David G. Bell -- SF Fan, Filker, and Punslinger.

"I am Number Two," said Penfold. "You are Number Six."
 
steve wrote:

|| Austin Shackles wrote:
||
||| digital cannons? bah. proper 1812 is done with real genuine
||| analogue cannons and gunpowder.
||
|| Digitally RECORDED cannons Austin, to get the sharpest possible
|| rising edge on the shockwaves...
||
|| Steve

I think he meant genuine cannons on stage and fired at the appropriate
moment. You can always tell on a recording - if the cannons fire on the
beat, there is NO WAY they are in "real time" with the music, as it were. I
can just imagine the guy with the match and the big responsibility - well,
we've timed the fuse to burn an average of 4.5 seconds, so that's six
crotchets and a dotted quaver, so when the trumpet hits the sharp A flat,
count to four-and-a-half and BURN, baby! Kadoof.

"Genuine" recordings I have heard seem to get the cannon within half a beat
of where it should be, which I think is pretty good, and they must have
burned a lot of powder to get it even that close.

--
Rich
==============================

I don't approve of signatures, so I don't have one.


 
On or around Sat, 05 Aug 2006 12:16:59 +0100, steve
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>
>> digital cannons? bah. proper 1812 is done with real genuine analogue
>> cannons and gunpowder.
>
>Digitally RECORDED cannons Austin, to get the sharpest possible rising
>edge on the shockwaves...

which just proves the point about digital recording... sound is analogue in
nature. You can record sound digitally and use the digital record to
re-create an analogue sound which, if you throw enough money at it, is
extremely close to the original and to be honest, if I listen to a GOOD
digital recording played on decent equipment I can't tell the difference.

however, the process of A-D and D-A can't, in the ultimate analysis, exactly
reproduce an analogue signal. If it's done well you can produce a new
signal which is indistinguishable to the average or even to the trained ear
- however, it's not always done well (and of course, neither is analogue
recording) and especially in the case of music to which compression has been
applied, you can easily spoil the sound.

The compression thing is amply demonstrated in a way that's appreciable to
almost everyone by looking at heavily-compressed jpeg images, or mpeg
movies. The picture is still recognisable, but the detail is lost or
rendered fuzzy. Jpeg is an impressive system, in fact, and does better than
many other compression systems in preserving detail while also making small
file sizes, and I presume that mpeg does similar tricks to audio - jpeg
seems to work by making large-ish areas of nearly-the-same colour actually
the same, while preserving detail by having small areas where there are
high-contrast colour changes. By this method you can get a recognisable
picture in very small file space, but it's not a GOOD picture, and even
quite high resolution uncompressed digital images struggle to approach the
quality of high-definition film.

--
Austin Shackles. www.ddol-las.net my opinions are just that
Travel The Galaxy! Meet Fascinating Life Forms...
------------------------------------------------\
>> http://www.schlockmercenary.com/ << \ ...and Kill them.
a webcartoon by Howard Tayler; I like it, maybe you will too!
 
Austin Shackles wrote:
>
> however, the process of A-D and D-A can't, in the ultimate analysis, exactly
> reproduce an analogue signal.

In the ulitmate analysis nothing can, and no analogue recording method
can offer the dynamic range or SNR of a digital recording.

Steve
 
On or around Sat, 05 Aug 2006 16:48:50 +0100, steve
<[email protected]> enlightened us thusly:

>Austin Shackles wrote:
>>
>> however, the process of A-D and D-A can't, in the ultimate analysis, exactly
>> reproduce an analogue signal.
>
>In the ulitmate analysis nothing can, and no analogue recording method
>can offer the dynamic range or SNR of a digital recording.

I'd put it the other way around... in theory, you could get an analogue
recording to exactly replicate the pressure waves that we interpret as
sound. OK, in practice, you can't. However, digital recording can't manage
it even in theory.

again, in practical terms, it might be that digital recording can produce
better results on a limited budget. But there are flaws - there's been much
talk of streaming audio and bitrate - the beeb reduced the bitrate on R3
'cos they wanted some of the bandwidth for something else. Proms listeners
were unamused. This is I assume the equivalent of too much compression
affecting sound quality.
--
Austin Shackles. www.ddol-las.net my opinions are just that
"Carpe diem, quam minimum credula postero" (sieze today, and put
as little trust as you can in tomorrow) Horace (65 - 8 BC) Odes, I.xi.8
 
Austin Shackles wrote:
> However, digital recording can't manage
> it even in theory.

Yes it could, if the signal resolution was below that of the theoretical
SNR. In an analogue system, that SNR sets the miniumum possible - you
can't recover the signal from below the noise floor, unless its encoded.

Steve
 
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