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How does one add a 12v trigger to an amplifier...?

B

bakin

Jan 1, 1970
0
I have a high power (2600 watts @ 4ohms min. mono bridge) amplifier
that I would very much like to be able to have turn on via the
existing 12v trigger in my av preamp. Any any suggestions as to the
specific component(s) and the cleanest, safest method of installing
them would be most appreciated! Thanks!
 
J

jasen

Jan 1, 1970
0
I have a high power (2600 watts @ 4ohms min. mono bridge) amplifier
that I would very much like to be able to have turn on via the
existing 12v trigger in my av preamp

what sort of power does the amp use? 12V at 300A ? three phase mains?
diesel?

what sort of on-off switch is already fitted?

easiest, prettiest, fix is probably adding a relay in the existing switch circuit.

Bye.
Jasen
 
B

bakin

Jan 1, 1970
0
Thanks for the response. It is a power amplifier used for audio
aplications. It draws ac line power at 120 volts plugged into a 20 amp
circut via a NEMA 5-20P plug. It powers on and off with a panel-mount
type, illuminated, rocker switch.
 
E

ehsjr

Jan 1, 1970
0
bakin said:
Thanks for the response. It is a power amplifier used for audio
aplications. It draws ac line power at 120 volts plugged into a 20 amp
circut via a NEMA 5-20P plug. It powers on and off with a panel-mount
type, illuminated, rocker switch.

Neat trick. You have a 2600 watt amplifier that
uses only 2400 watts maximum input.

You need to re-check the wattage figure for your
amp, and post the correct value.

Ed
 
R

Rich Grise

Jan 1, 1970
0
Neat trick. You have a 2600 watt amplifier that
uses only 2400 watts maximum input.

Those are audiophool watts, or "Peak Intermittent Modulated Power", i.e.
PIMP. ;-P

Cheers!
Rich
 
B

bakin

Jan 1, 1970
0
Rich said:
Those are audiophool watts, or "Peak Intermittent Modulated Power", i.e.
PIMP. ;-P

Cheers!
Rich

Yes, those are indeed "PIMP" watts. The wattage the manufacturer rates
the amplifier. I know that a device on a 20 amp circuit drawing a
maximum of 120 volts will not output more than 2400 watts. I realize
I'm a noobie and not as knowledgeable as other posters here in this
group-that's why I've posted here. In an attempt to improve my
knowledge and learn how to (hopefully) do specific things regarding
electronics. I try to be as accurate and detailed in my question
posting. It seems counter-productive and extranious to post "You need
to re-check the wattage figure for your amp, and post the correct
value." In stead of deducing that, since the amplifier is for audio
applications, the wattage I posted is manufacturers' rating or "PIMP"
(see above) wattage you could offer a solution to my original question
along with a suggestion for me to post the amplifier's true wattage so
one could more accurately discern what the proper hardware would be
for such a trigger imput device. Thanks to all who offer some useful
information regarding my question.
 
R

Rich Grise

Jan 1, 1970
0
Yes, those are indeed "PIMP" watts. The wattage the manufacturer rates
the amplifier. I know that a device on a 20 amp circuit drawing a
maximum of 120 volts will not output more than 2400 watts. I realize
I'm a noobie and not as knowledgeable as other posters here in this
group-that's why I've posted here. In an attempt to improve my
knowledge and learn how to (hopefully) do specific things regarding
electronics. I try to be as accurate and detailed in my question
posting. It seems counter-productive and extranious to post "You need
to re-check the wattage figure for your amp, and post the correct
value." In stead of deducing that, since the amplifier is for audio
applications, the wattage I posted is manufacturers' rating or "PIMP"
(see above) wattage you could offer a solution to my original question
along with a suggestion for me to post the amplifier's true wattage so
one could more accurately discern what the proper hardware would be
for such a trigger imput device. Thanks to all who offer some useful
information regarding my question.

Um, I hope you know that my use of the term "PIMP" was intended as a
joke.

They are, indeed, "marketing watts", but I made up that "peak intermittent..."
stuff:
http://en.wikipedia.org/wiki/Pimp

In the US, they drive big huge terribly terribly noisy cars, hence
the wattage figures.

Cheers!
Rich
 
E

ehsjr

Jan 1, 1970
0
bakin said:
Yes, those are indeed "PIMP" watts. The wattage the manufacturer rates
the amplifier. I know that a device on a 20 amp circuit drawing a
maximum of 120 volts will not output more than 2400 watts.

But *we* have no idea of what you know. And sometimes what
someone knows, or thinks he knows, is not quite correct:
A device does not draw volts. Nor will a properly manufactured
UL listed 120 volt device draw 20 amps from a 20 amp circuit,
unless it is defective or modified in violation of the National
Electrical Code. The code requires that no single device draw
more than 80% of the branch circuit rating. So the correct
maximum figure is 1920 watts, not 2400.

I realize
I'm a noobie and not as knowledgeable as other posters here in this
group-that's why I've posted here. In an attempt to improve my
knowledge and learn how to (hopefully) do specific things regarding
electronics.

Great. That is why I posted the information in the paragraph
above.
I try to be as accurate and detailed in my question
posting.
Great.

It seems counter-productive and extranious to post "You need
to re-check the wattage figure for your amp, and post the correct
value."

Ok. That is your opinion. Perhaps some day you
will wish to answer someone's request where you
want accurate information to do so. You will then
understand that it is neither counter-productive
nor extraneous to tell the person seeking the
solution to re-check and provide accurate value(s).
In stead of deducing that, since the amplifier is for audio
applications, the wattage I posted is manufacturers' rating or "PIMP"

I could just as easily deduce that you made a typo or
mis-read the wattage rating. This (next sentence) is
not an attack on you, just an observation. You were
careless in your post: you did not take sufficient care
when you posted to provide us with either the manufacturer
name or the model of your power amp, nor did you take
sufficient care to post the manufacturer name or model
number of your av amp. With that evidence of careless
posting, it is certainly not unreasonable to think there
may have been a typo or a mis-read or some other error
in your posting of the 2600 watt figure.
(see above) wattage you could offer a solution to my original question

That is accurate, I could offer a guesswork solution.

along with a suggestion for me to post the amplifier's true wattage so

Which is precisely what I did.
one could more accurately discern what the proper hardware would be
for such a trigger imput device.

Post the brand/model numbers of the units you have,
plus any details in the instruction manuals that refer
to using the av to turn on another unit. You mentioned
the av 12 volt trigger - specs on what current it
can provide are needed. If there are web sites with
information on your equipment, post the url(s).

Ed
 
B

bakin

Jan 1, 1970
0
O.K. Point made and taken on the importance of posting accurate
information. I apologize for my uppityness. I did read the watt
ratings off the amp speaker outputs but, I now realize, that doesn't
mean the info is technically accurate. Anyway the power amplifier that
I wish to power on via the 12v trigger is a Mackie FR2600 high current
power amplifier. The preamp that has the 12v trigger is a Krell KAV
preamp. I'll double check the exact model number and find the specs on
what current the 12v trigger can provide and post that information.
Again, apologieson my lackof specificness.
 
E

ehsjr

Jan 1, 1970
0
bakin said:
O.K. Point made and taken on the importance of posting accurate
information. I apologize for my uppityness. I did read the watt
ratings off the amp speaker outputs but, I now realize, that doesn't
mean the info is technically accurate. Anyway the power amplifier that
I wish to power on via the 12v trigger is a Mackie FR2600 high current
power amplifier. The preamp that has the 12v trigger is a Krell KAV
preamp. I'll double check the exact model number and find the specs on
what current the 12v trigger can provide and post that information.
Again, apologieson my lackof specificness.

No problem. Armed with the preamp name, I was able
to find some (but not enough :-( ) information.

I couldn't find info on the FR 2600, but did find
the FR 2500. Assuming they are similar, the FR 2600
does not have a built in provision for remote turn on.
Please correct my assumption if it's wrong.

Based on the scanty information, 2 possibilities
suggest themselves, and another is speculative.

1) You may be able to directly operate a relay
via the 12 volt trigger signal. That depends on
how much current the 12V trigger can provide, and
whether it is a pulse or a constant 12 volts. I
could not find that in the owner's or developer's
manual. The circuit would be as diagrammed below:

+-----|<----+
------- | |
| +|---+---[Rly]---+
|12V DC | |
|Trigger| |
| -|---------------+
-------

2) If the current available from the 12V trigger
is low (ie less than the 75 mA that the relay coil
needs) or if it is unknown, you can use this circuit,
provided the 12V signal from the Krell is constant
and not a pulse:

+-----|<----+
-------- | |
| +|---+---[Rly]---+
| 12V DC | /c
| Power | +---[1K]---| PN2222
| Supply | | \e
| -|---------------+
------- | |
| |
Trigger + ---+ |
Trigger - ---------------+

The power supply above should be a 12V DC wall wart
rated 200 mA or more. The wall wart can plug in to
the same receptacle as the Krell. The Mackie needs
to be on a dedicated circuit.



For either circuit you need a heavy duty relay:
Mouser part # 677-PCF-112D2M
The relay needs 75 mA at 12 volts to operate,
and its contacts are rated to switch 20 amps
inductive or 25 amps resistive. The contact
wiring is shown below:

|> |
| | -------
AC Mains Hot --Fuse--o o----| | | |---+
| o | |
------- |
| |
AC Mains Ground ------------------+ |
|
AC Mains Neutral -------------------------+

You will need a heavy duty line cord. Install
add a 25 amp fuse from the black (hot) wire to the
relay contact. The fuse, relay and receptacle
are all mounted in a heavy duty plastic project
box.


The last idea is speculative: there may be
a manufactured product that will accept the
12V trigger from the Krell to turn on a
power distribution box (for lack of a better
term) that will provide power to your Mackie.
You could contact Krell to ask:
Krell Industries, Inc.
45 Connair Road
Orange, CT 06477-3650 USA
TEL 203-799-9954
E-MAIL [email protected]


If you can get the details on the 12V signal,
you can choose the approach that fits. If the
trigger is a pulse instead of a constant signal,
it gets more complex.

Ed
 
bakin said:
Yes, those are indeed "PIMP" watts. The wattage the manufacturer rates
the amplifier. I know that a device on a 20 amp circuit drawing a
maximum of 120 volts will not output more than 2400 watts.

That's a standrad part of the game for audio amps.
Since they also rate them indoor.outdoor
and with a/c requirements, So the 2600 watts
is the maximum sound power it will
produce in some sound stage, and the
2400 watts is the max electrical power it will draw
from the line.

The rocker switch is 120vac I guess,
So if you want to operate that with
a 12vdc button, you'll need to replace it with
a 120v relay and jumper wires from the
preamp to to amp.




I realize
 
B

bakin

Jan 1, 1970
0
Thank you again for your help. I didn't locate the exact specs on the
12 volt trigger but I can tell you with certainty that the current is
continuous. With the information provided I am confident I can achieve
my power on by trigger goals. I appreciate your time and knowledge.
Thanks!

bakin said:
O.K. Point made and taken on the importance of posting accurate
information. I apologize for my uppityness. I did read the watt
ratings off the amp speaker outputs but, I now realize, that doesn't
mean the info is technically accurate. Anyway the power amplifier that
I wish to power on via the 12v trigger is a Mackie FR2600 high current
power amplifier. The preamp that has the 12v trigger is a Krell KAV
preamp. I'll double check the exact model number and find the specs on
what current the 12v trigger can provide and post that information.
Again, apologieson my lackof specificness.

No problem. Armed with the preamp name, I was able
to find some (but not enough :-( ) information.

I couldn't find info on the FR 2600, but did find
the FR 2500. Assuming they are similar, the FR 2600
does not have a built in provision for remote turn on.
Please correct my assumption if it's wrong.

Based on the scanty information, 2 possibilities
suggest themselves, and another is speculative.

1) You may be able to directly operate a relay
via the 12 volt trigger signal. That depends on
how much current the 12V trigger can provide, and
whether it is a pulse or a constant 12 volts. I
could not find that in the owner's or developer's
manual. The circuit would be as diagrammed below:

+-----|<----+
------- | |
| +|---+---[Rly]---+
|12V DC | |
|Trigger| |
| -|---------------+
-------

2) If the current available from the 12V trigger
is low (ie less than the 75 mA that the relay coil
needs) or if it is unknown, you can use this circuit,
provided the 12V signal from the Krell is constant
and not a pulse:

+-----|<----+
-------- | |
| +|---+---[Rly]---+
| 12V DC | /c
| Power | +---[1K]---| PN2222
| Supply | | \e
| -|---------------+
------- | |
| |
Trigger + ---+ |
Trigger - ---------------+

The power supply above should be a 12V DC wall wart
rated 200 mA or more. The wall wart can plug in to
the same receptacle as the Krell. The Mackie needs
to be on a dedicated circuit.



For either circuit you need a heavy duty relay:
Mouser part # 677-PCF-112D2M
The relay needs 75 mA at 12 volts to operate,
and its contacts are rated to switch 20 amps
inductive or 25 amps resistive. The contact
wiring is shown below:

|> |
| | -------
AC Mains Hot --Fuse--o o----| | | |---+
| o | |
------- |
| |
AC Mains Ground ------------------+ |
|
AC Mains Neutral -------------------------+

You will need a heavy duty line cord. Install
add a 25 amp fuse from the black (hot) wire to the
relay contact. The fuse, relay and receptacle
are all mounted in a heavy duty plastic project
box.


The last idea is speculative: there may be
a manufactured product that will accept the
12V trigger from the Krell to turn on a
power distribution box (for lack of a better
term) that will provide power to your Mackie.
You could contact Krell to ask:
Krell Industries, Inc.
45 Connair Road
Orange, CT 06477-3650 USA
TEL 203-799-9954
E-MAIL [email protected]


If you can get the details on the 12V signal,
you can choose the approach that fits. If the
trigger is a pulse instead of a constant signal,
it gets more complex.

Ed
 
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