ProSoundWeb Community

Sound Reinforcement - Forums for Live Sound Professionals - Your Displayed Name Must Be Your Real Full Name To Post In The Live Sound Forums => LAB Lounge => Topic started by: Poopedi Kwena on July 31, 2011, 03:35:53 pm

Title: Amping amps
Post by: Poopedi Kwena on July 31, 2011, 03:35:53 pm
Hi guys once more

I wanted to add a power distro to my rack and it had me thinking, how much current (in amperes) will one amp draw. and does it varry if the amp is used for different applications (i.e subs, mids, comps).

i was looking at FURMAN products but i am worried that 16A might not be enough current to push 2 amplifiers, one doing the subs in bridge mode. plus all other equipment.
Title: Re: Amping amps
Post by: g'bye, Dick Rees on July 31, 2011, 03:49:39 pm
Hi guys once more

I wanted to add a power distro to my rack and it had me thinking, how much current (in amperes) will one amp draw. and does it varry if the amp is used for different applications (i.e subs, mids, comps).

Short answer:  The manufacturer generally gives that info on their product.  For example

http://media.qscaudio.com/pdfs/Specifications/PLX2_spec.pdf

Quote


i was looking at FURMAN products but i am worried that 16A might not be enough current to push 2 amplifiers, one doing the subs in bridge mode. plus all other equipment.

It is not generally considered necessary or a good idea to use "power conditioners" in an amp rack.  If you want to use such a piece of gear it should be put on your "other gear" like FOH.

Personally, I use a Furman AR1215 "line regulator" for my mix position rather than a cheap "power conditioner".  Google the Furman site and look up the difference for yourself.
Title: Re: Amping amps
Post by: Jeff Bankston on July 31, 2011, 04:49:17 pm
Hi guys once more

I wanted to add a power distro to my rack and it had me thinking, how much current (in amperes) will one amp draw. and does it varry if the amp is used for different applications (i.e subs, mids, comps).

Short answer:  The manufacturer generally gives that info on their product.  For example

http://media.qscaudio.com/pdfs/Specifications/PLX2_spec.pdf

Quote


i was looking at FURMAN products but i am worried that 16A might not be enough current to push 2 amplifiers, one doing the subs in bridge mode. plus all other equipment.

It is not generally considered necessary or a good idea to use "power conditioners" in an amp rack.  If you want to use such a piece of gear it should be put on your "other gear" like FOH.

Personally, I use a Furman AR1215 "line regulator" for my mix position rather than a cheap "power conditioner".  Google the Furman site and look up the difference for yourself.
   +1
Title: Re: Amping amps
Post by: Conrad Muzoora on August 01, 2011, 08:26:35 am
Agree with looking at the manufacturer specs, but 4ohm bridged = 2ohm stereo loading, which is not commonly given by most manufacturers. Most will give you 8ohm stereo at (1/8th, 1/3 power) and 4 stereo draw (1/8th and 1/3power). Class D amps will generally draw much less power as they are more efficient but as a general rule, sub amps will draw way more power than top amps.
Story short, you need to provide more details like amp models, load (Ohms), program material and an idea about how hard you run your amplifiers for a meaningful advice on how much current you require.

Conrad
Title: Re: Amping amps
Post by: Chris Carpenter on August 02, 2011, 01:11:04 am
Agree with looking at the manufacturer specs, but 4ohm bridged = 2ohm stereo loading, which is not commonly given by most manufacturers. Most will give you 8ohm stereo at (1/8th, 1/3 power) and 4 stereo draw (1/8th and 1/3power). Class D amps will generally draw much less power as they are more efficient but as a general rule, sub amps will draw way more power than top amps.
Story short, you need to provide more details like amp models, load (Ohms), program material and an idea about how hard you run your amplifiers for a meaningful advice on how much current you require.

Conrad
He is talking about power draw, not power output. As dick stated, many products have the maximum power draw printed on the product, typically near the power jack.
Title: Re: Amping amps
Post by: Poopedi Kwena on August 08, 2011, 01:07:01 pm
Story short, you need to provide more details like amp models, load (Ohms), program material and an idea about how hard you run your amplifiers for a meaningful advice on how much current you require.

Conrad

actually i am not intending to give details rather looking for a fool proof formula or rule of thumb
Title: Re: Amping amps
Post by: John Livings on August 08, 2011, 02:10:27 pm
actually i am not intending to give details rather looking for a fool proof formula or rule of thumb

In addition to the other advice, Go to the old Forum and read this link;

http://srforums.prosoundweb.com/index.php/m/560959/23882/#msg_560959

Hope this helps.

Regards,  John

Title: Re: Amping amps
Post by: Bob Leonard on August 08, 2011, 02:14:25 pm
OK, no details here either. Go tothe manufacturers web site and that will tell you how much your amp(s) will draw under full load. Then you add the figures together for the amps you connect to an AC outlet and that will be the current draw.

If that's not good enough go and buy an AC amp meter and measure the load in real time. So, no details, no rules of thumb, just information you could have and should have found out on your own in about 5 minutes time.
Title: Re: Amping amps
Post by: Mark Chrysostom on August 08, 2011, 06:25:35 pm
OK, no details here either. Go tothe manufacturers web site and that will tell you how much your amp(s) will draw under full load. Then you add the figures together for the amps you connect to an AC outlet and that will be the current draw.

If that's not good enough go and buy an AC amp meter and measure the load in real time. So, no details, no rules of thumb, just information you could have and should have found out on your own in about 5 minutes time.

Get 'em.
Title: Re: Amping amps
Post by: Stu McDoniel on August 09, 2011, 08:09:52 am
Hi guys once more

I wanted to add a power distro to my rack and it had me thinking, how much current (in amperes) will one amp draw. and does it varry if the amp is used for different applications (i.e subs, mids, comps).

i was looking at FURMAN products but i am worried that 16A might not be enough current to push 2 amplifiers, one doing the subs in bridge mode. plus all other equipment.

Plug your amps straight into the power or use regulation.  Never plug amps into power conditioners!
As a rule for myself I like to have a 20 amp circuit for every two of my system amplifiers.  Keep in mind
the current spec they give on those amps is max draw.  I prefer high power amps and to stay away
from the bridge mode for many reasons I wont get into.   At peak an amp can instantly want 15 amps
right now!  Imagine having four amps with only 20 amps available...YIKES
Title: Re: Amping amps
Post by: Marty McCann on August 09, 2011, 02:55:39 pm
Quote from: Stu McDoniel
   Keep in mind
the current spec they give on those amps is max draw. 

Stu,

Most amplifier manufacturers do NOT even list maximum current draw.  1/8 and 1/3 power ratings are what most list according to an AES spec.
Title: Re: Amping amps
Post by: Chris Carpenter on August 09, 2011, 05:56:02 pm
Stu,

Most amplifier manufacturers do NOT even list maximum current draw.  1/8 and 1/3 power ratings are what most list according to an AES spec.
That's interesting, I didn't know that. Can you cite the AES spec? Would be an informative read.
Title: Re: Amping amps
Post by: Stu McDoniel on August 09, 2011, 07:28:00 pm
Stu,

Most amplifier manufacturers do NOT even list maximum current draw.  1/8 and 1/3 power ratings are what most list according to an AES spec.
So using 20amps for two power amps is definitely a good practice if this is the case. I have my gain structure and limiters set right on my EAW processor and I know I am pushing my amps pretty hard most of the night so they are sucking current up the ying. 
Title: Re: Amping amps
Post by: Tim McCulloch on August 09, 2011, 07:37:32 pm
That's interesting, I didn't know that. Can you cite the AES spec? Would be an informative read.

www.aes.org