I called Crown today and got an answer on this...


The K1 (and presumably the K2 and other Crown switching amps) has a circuit
that shuts down the output stage when the input signal drops below 0.5mV
(!!!) for 56 seconds. (The timeout is configurable, though I didn't ask
how.)

This circuit can be disabled without voiding the warranty. *

1. Remove the bottom plate.

2. Turn the amp so you can see the input board.

3. Note the vertically mounted cap. Near it are two solder pads with a "Z1"
label.

4. Solder a jumper to the pads.

The power-down circuit is now disabled.

* That's what Crown says, but if you butcher the amp, you know they ain't
gonna fix it for free.


0.5mV is an awfully low signal level. With a amplifier voltage gain of 20,
that's an output of 10mV -- 25 microwatts into a 4 ohm load!


If a K1 amp is constantly shutting down while a signal is going through it,
there must be something wrong with the amp.

If a K1 amp is constantly shutting down while a signal is going through it,
there must be something wrong with the amp.

Or, given an entire rack of K1s & K2s toggling, the signal is extremely
subtle. I mix Kronos pretty damn quietly. The PA has to integrate with
their acoustic sound.

Scott Fraser

On Mon, 5 Jun 2006 16:50:35 -0700, "William Sommerwerck"
wrote:

0.5mV is an awfully low signal level. With a amplifier voltage gain of 20,
that's an output of 10mV -- 25 microwatts into a 4 ohm load!


If a K1 amp is constantly shutting down while a signal is going through it,
there must be something wrong with the amp.

OTOH, it's only about 50dB below 1 watt, or presumably below
some likely 0dB VU for monitoring. Seems marginal.

Thanks, as always,

Chris Hornbeck

Or, given an entire rack of K1s & K2s toggling, the signal
is extremely subtle.

That's weird. If Crown has given me the correct specs (the guy stopped to
look them up), how can the amps possibly be shutting down? You really ought
to call and ask.

Anyhow, you now know how to shut off the circuit -- it you're willing to
remove the amps from the rack and schlep them over to the workbench.

I mix Kronos pretty damn quietly. The PA has to integrate
with their acoustic sound.

But _so_ quietly the signal falls below 500 microvolts for a period of a
minute? No way!

"Chris Hornbeck IDIOT "


OTOH, it's only about 50dB below 1 watt, or presumably below
some likely 0dB VU for monitoring. Seems marginal.


** It is NOT marginal when you allow for the FACT the signal level must
remain 50 dB BELOW 1 watt CONTINUOUSLY for over a minute.

PLUS and more importantly, an audience in an auditorium CANNOT hear anything
from an amp where the output remains continuously 50 dB below 1 watt.

In practice, the normal ( and inaudible to an audience ) background noise
that is always there in a PA system prevents the "green circuit" operating.




........ Phil

On Tue, 6 Jun 2006 12:43:05 +1000, "Phil Allison"
wrote:

In practice, the normal ( and inaudible to an audience ) background noise
that is always there in a PA system prevents the "green circuit" operating.

Surprising then that it's included, since it's prevented from
operating. However I'd be more surprised if William were intending
doing sound reinforcement. Course, I could be wrong.

Chris Hornbeck

William Sommerwerck wrote:

I called Crown today and got an answer on this...

The K1 (and presumably the K2 and other Crown switching amps) has a circuit
that shuts down the output stage when the input signal drops below 0.5mV
(!!!) for 56 seconds. (The timeout is configurable, though I didn't ask
how.)

This circuit can be disabled without voiding the warranty. *

1. Remove the bottom plate.

2. Turn the amp so you can see the input board.

3. Note the vertically mounted cap. Near it are two solder pads with a "Z1"
label.

4. Solder a jumper to the pads.

The power-down circuit is now disabled.

* That's what Crown says, but if you butcher the amp, you know they ain't
gonna fix it for free.

0.5mV is an awfully low signal level. With a amplifier voltage gain of 20,
that's an output of 10mV -- 25 microwatts into a 4 ohm load!

It's not that low really. Only -66dB wrt 1 Volt input or -64dBu. You'll easily
hear the effect on reverb tails for example.

If a K1 amp is constantly shutting down while a signal is going through it,
there must be something wrong with the amp.

It must also not be working quite right if it's shutting down before the 56 !
seconds are up. I'm puzzled why they didn't just say one minute btw.

Graham

"Pooh Bear"


0.5mV is an awfully low signal level. With a amplifier voltage gain of
20,
that's an output of 10mV -- 25 microwatts into a 4 ohm load!

It's not that low really. Only -66dB wrt 1 Volt input or -64dBu. You'll
easily
hear the effect on reverb tails for example.


** No you will NOT because it takes a WHOLE minute, remaining constantly
below that level, to activate.

Reverb tails do not last anywhere near 60 seconds.

Ditto for fading notes.




........ Phil

Chris Hornbeck wrote:

On Mon, 5 Jun 2006 16:50:35 -0700, "William Sommerwerck"
wrote:

0.5mV is an awfully low signal level. With a amplifier voltage gain of 20,
that's an output of 10mV -- 25 microwatts into a 4 ohm load!


If a K1 amp is constantly shutting down while a signal is going through it,
there must be something wrong with the amp.

OTOH, it's only about 50dB below 1 watt, or presumably below
some likely 0dB VU for monitoring. Seems marginal.

*ONLY* !!!!

You jest ?

Graham

Phil Allison wrote:

"Pooh Bear"


0.5mV is an awfully low signal level. With a amplifier voltage gain of
20,
that's an output of 10mV -- 25 microwatts into a 4 ohm load!

It's not that low really. Only -66dB wrt 1 Volt input or -64dBu. You'll
easily
hear the effect on reverb tails for example.

** No you will NOT because it takes a WHOLE minute, remaining constantly
below that level, to activate.

Reverb tails do not last anywhere near 60 seconds.

Ditto for fading notes.

I agreed. You snipped the bit about the time out obviously being wrong. Tim
Manas' post suggests the time constant's been changed at some time.

Graham

"Pooh Bear"

** No you will NOT because it takes a WHOLE minute, remaining
constantly
below that level, to activate.

Reverb tails do not last anywhere near 60 seconds.

Ditto for fading notes.

I agreed.


** Finally.


You snipped the bit about the time out obviously being wrong. Tim
Manas' post suggests the time constant's been changed at some time.



** I clearly recall a published review ( Connection Magazine ) of the K1,
when it first appeared ten years ago, that quoted a two minute delay.

What all the WHINERS have ignored is that if you simply TURN DOWN the front
panel level pot by so many dBs, the "green cct" threshold is REDUCED by the
same ratio.




........ Phil

Anyway, thanks for the post on the modification. Somehow that very
information was not forthcoming from other communications with Crown.

You're welcome. I tend to be lucky with such things.

Surprising then that it's included, since it's prevented from
operating. However I'd be more surprised if William were
intending doing sound reinforcement. Course, I could be wrong.

You're not wrong. This is for home use.

It's not that low really. Only -66dB wrt 1 Volt input or -64dBu. You'll easily
hear the effect on reverb tails for example.

Or stage ambience, or extremely low performance levels.

If a K1 amp is constantly shutting down while a signal is going through it,
there must be something wrong with the amp.

It must also not be working quite right if it's shutting down before the 56 !
seconds are up.

I'm not saying they have been shutting before the specified time. I'm
saying they are shutting down during an ongoing concert where dynamic
levels are extremely subtle. And it is audible to those audience
members seated closer to a stack than to the acoustic source.

I'm puzzled why they didn't just say one minute btw.

That may just be the result of the cap value they spec'ed while aiming
for 'about a minute'.

Scott Fraser

"Scott Fraser"


I'm not saying they have been shutting before the specified time. I'm
saying they are shutting down during an ongoing concert where dynamic
levels are extremely subtle.


** What utter gobbledegook.

This ASSHOLE is a LIAR.





.......... Phil

On Tue, 6 Jun 2006 13:58:55 +1000, "Phil Allison"
wrote:

YOU STUPID ASSHOLE !!!!

Etc.

Sorry folks. Our AI has been unusually combative since we
were outed by Ty Ford, whose group's competing AI, the
Communicative High Entropy Verbal Discussion Obfuscator,
has also been released into the newsgroup in very early
beta.

Members of Ty's think tank, especially Scott (code named
Nuclear American Guardian of Righteous Audio) and Mike (code
named Patriotic American Righting Rongs Of Terrorism),
are now outed in retaliation.

Many may think that testing these horrible weapons on
civilians is wrong, but I say Nah.

Good night, and Good luck,

Chris Hornbeck

K1 Sleep Circuit Disable:

There is a place by R15 to add a jumper to disable the sleep circuit and it
is labeled on the board. If you decided to do this the amplifier will run at
a idle current of around 200 Watts so it will be warm to the touch just
setting there.

?

"William Sommerwerck" wrote in
message
Or, given an entire rack of K1s & K2s toggling, the
signal is extremely subtle.

That's weird. If Crown has given me the correct specs
(the guy stopped to look them up), how can the amps
possibly be shutting down? You really ought to call and
ask.

Anyhow, you now know how to shut off the circuit -- it
you're willing to remove the amps from the rack and
schlep them over to the workbench.

I mix Kronos pretty damn quietly. The PA has to integrate
with their acoustic sound.

But _so_ quietly the signal falls below 500 microvolts
for a period of a minute? No way!

I wouldn't count on it. If the room is live and the speakers are efficient,
and the SPLs are modest, the actual drive levels can be amazingly low.

But _so_ quietly the signal falls below 500 microvolts
for a period of a minute? No way!

I wouldn't count on it. If the room is live and the speakers are efficient,
and the SPLs are modest, the actual drive levels can be amazingly low.

Yup on all counts. 'Tis truly true.

Scott Fraser

I wouldn't count on it. If the room is live and the speakers are
efficient,
and the SPLs are modest, the actual drive levels can be amazingly low.

If I purchase these amps, you can bet I'll be running some measurements.

K1 Sleep Circuit Disable:

There is a place by R15 to add a jumper to disable the sleep circuit
and it is labeled on the board. If you decide to do this the amplifier
will run at a idle current [sic] of around 200 Watts so it will be warm
to the touch just setting there.

I'm curious as to where you obtained this "fact".

Even a conventional class AB power amp doesn't draw 200W at idle. And an amp
dissipating that much is a little more than just "warm to the touch".

Crown states that the K1 and K2 draw 1/10 the current of conventional,
non-switching amps. (This must mean at idle, as switching amps, though
considerably more efficient than linear amps, aree not _that_ efficient.) So
you're saying that a conventional class AB amp of similar power rating would
pull 2KW?

For what it's worth, a Krell KSA-250, which is class A (not AB) up to about
50 watts, pulls a bit over 6 amps from the wall outlet. You do the math.

By the way, it's watts, not Watts. Units named after people are capitalized
only when abbreviated.

"Scott Fraser" wrote in
message
oups.com

But _so_ quietly the signal falls below 500 microvolts
for a period of a minute? No way!

I wouldn't count on it. If the room is live and the
speakers are efficient, and the SPLs are modest, the
actual drive levels can be amazingly low.

Yup on all counts. 'Tis truly true.

I can estimate some numbers. I've monitored the voltage on the voice coils
of the 2 horns in the main cluster at church. They peak at well under 2
volts. Based on analysis of the board tapes I make of the services, actual
dynamic range of the signal is 75 dB or more. This excludes the times when
the main fader is below normal and the dynamic range of the signal applied
to the amp is far higher. 75 dB below 2 volts is about 400 microvolts.

Note that the claimed 75 dB dynamic range involves switching all (sometimes
upwards of 20) of the mics off but 1. So this is not the dynamic range of
the music, which is about 15 dB less.

I can estimate some numbers. I've monitored the voltage on the voice coils
of the 2 horns in the main cluster at church. They peak at well under 2
volts. Based on analysis of the board tapes I make of the services, actual
dynamic range of the signal is 75 dB or more. This excludes the times when
the main fader is below normal and the dynamic range of the signal applied
to the amp is far higher. 75 dB below 2 volts is about 400 microvolts.

Note that the claimed 75 dB dynamic range involves switching all
(sometimes
upwards of 20) of the mics off but 1. So this is not the dynamic range of
the music, which is about 15 dB less.

A few years back I stuck a Nakamichi T-100 on the amp outputs, feeding a
pair of large planar speakers (not Maggies). Even with the volume at a
pleasantly high level, there was no more than a few volts across the
speakers. I was rather surprised at how little voltage was need to get "a
loud sound" from speakers that are nowhere nearly as efficient as horns.

"Phil Allison" wrote in news:4eqin3F1ef17dU1
@individual.net:

Crown states that the K1 and K2 draw 1/10 the current of
conventional,
non-switching amps.

** ****ING WRONG AGAIN !!!!!!!!!!!!!!!!!!!!

Will someone go ****ing SHOOT this ASININE BLOODY LIAR

Phil, is there some way you can disagree emphatically without resorting
the the foul language and insults?

I defend your right to disagree, but I really wish you'd tone down the
language.

"Carey Carlan"

I defend your right to disagree,


** But you *simultaneously* defend blatant and dangerous nut cases criminal
charlatans.

Make YOU guilty of being an "accessory" to the same harm being done by
them.

Have you NO COMPREHENSION OF REALTY WHATEVER ?????????



I sincerely hope YOU choke.







........ Phil

"Phil Allison" wrote in
:


"Carey Carlan"

I defend your right to disagree,

** But you *simultaneously* defend blatant and dangerous nut cases
criminal charlatans.

Makes YOU guilty of being an "accessory" to the same harm being
done by them.

Have you NO COMPREHENSION OF REALTY WHATEVER ?????????

I sincerely hope YOU choke.

Over the top verbal violence impacts your credibility as well, Phil.

When your arguments are correct and valid this name-calling and foul
language undermines your position, because it sounds like a desperate
attempt using personal attacks to salvage an untenable position.

"Carey Carlan"

( snip this tormenter's asinine tripe )


** All you are doing, Mr Carlan, is posting ABUSE.

Exactly the same as countless criminal, usenet trolls !!!


The deal you are offering me is this:


YOU want ME to debate YOUR wrong opinions of ME with YOU !!!

With *YOU* acting as a self appointed JUDGE as to what is correct !!!


Only a **complete* FOOL would buy into such a corrupt deal.

So I am not.

Go **** off.






........ Phil

It came from Crown via email.

"William Sommerwerck" wrote in message
. ..
K1 Sleep Circuit Disable:

There is a place by R15 to add a jumper to disable the sleep circuit
and it is labeled on the board. If you decide to do this the amplifier
will run at a idle current [sic] of around 200 Watts so it will be warm
to the touch just setting there.

I'm curious as to where you obtained this "fact".

Even a conventional class AB power amp doesn't draw 200W at idle. And an
amp
dissipating that much is a little more than just "warm to the touch".

Crown states that the K1 and K2 draw 1/10 the current of conventional,
non-switching amps. (This must mean at idle, as switching amps, though
considerably more efficient than linear amps, aree not _that_ efficient.)
So
you're saying that a conventional class AB amp of similar power rating
would
pull 2KW?

For what it's worth, a Krell KSA-250, which is class A (not AB) up to
about
50 watts, pulls a bit over 6 amps from the wall outlet. You do the math.

By the way, it's watts, not Watts. Units named after people are
capitalized
only when abbreviated.

Crown states that the K1 and K2 draw 1/10 the current of conventional,
non-switching amps.


** ****ING WRONG AGAIN !!!!!!!!!!!!!!!!!!!!


Will someone go ****ing SHOOT this ASININE BLOODY LIAR

I'll show you the literature, if you care to see it.

"William Sommer****** ****WIT !!!!!! "


Crown states that the K1 and K2 draw 1/10 the current of conventional,
non-switching amps.


** ****ING WRONG AGAIN !!!!!!!!!!!!!!!!!!!!


Will someone go ****ing SHOOT this ASININE BLOODY LIAR






......... Phil

William Sommerwerck wrote:

Crown states that the K1 and K2 draw 1/10 the current of conventional,
non-switching amps.

** ****ING WRONG AGAIN !!!!!!!!!!!!!!!!!!!!

Will someone go ****ing SHOOT this ASININE BLOODY LIAR

I'll show you the literature, if you care to see it.

I'm sorry but that is just so plain wrong it begs belief that Crown even printed
it.

Graham

I'll show you the literature, if you care to see it.

I'm sorry but that is just so plain wrong it begs belief
that Crown even printed it.

Actually, it's entirely possible for a switching amp to draw 1/10 the power
of a linear amp -- under idle conditions.

I went back and re-read the literature. Crown actually said "1/10 the heat".
Which is not the same thing.

"William Sommer****** ****wit "


I went back and re-read the literature. Crown actually said "1/10 the
heat".
Which is not the same thing.



** The ASD ****ed FOOL had to be kicked real hard to make it look at its
own poop.






........ Phil

The ASD ****ed FOOL had to be kicked real hard to make it
look at its own poop.

Actually, I look at it every morning without being coerced.

ASD?

"Tim Padrick"

If you decide to do this the amplifier
will run at a idle current [sic] of around 200 Watts so it will be warm
to the touch just setting there.

It came from Crown via email.


** Might just as well have come from Mars.


According to Crown's published data, idle power draw is less 90 watts.

http://www.crownaudio.com/pdf/amps/k1_2calc.pdf

With speech peaking at FULL POWER on both channels, a K1 draws only 172
watts !!!





........ Phil