Candela Power Draw

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limniscate

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Candela Power Draw
« on: 24 May 2016, 06:31 pm »
How much power does the Candela draw? I don't want to overload my 15 amp circuit.  My monos and subs total to 1540 watts.

richidoo

Re: Candela Power Draw
« Reply #1 on: 24 May 2016, 09:24 pm »
Candela probably <100 watts. Most of it is heat from tube heaters and power transformer.

The 1548W is the sum of your amps' maximum rated output power, not how much power they consume in normal use. Depending on your speakers, and assuming the amps are typical solid state class AB amps, you would rarely exceed 100W power consumption.

The real advantage (in home audio) of high power amplifiers is that they have lower distortion at a given power output than a smaller amplifier at the same power output because in most amps distortion rises as percentage of power output. 10W output from a 20W rated amp is 50% and will have higher distortion than 10W from 1000W amp with is only 1% max power. So even at normal volume levels the bigger amp sounds more at-ease and more confident on dynamic peaks. No cringing when the loud notes play.  :thumb:

Usually the max current draw on the circuit is the first 1 second after you turn on the amplifier. That's when it draws the most current, to charge up the transformer (a magnetic reservoir) and power supply caps (static charge reservoir.) Some amps have large power supply so they must use a temporary current restriction scheme for the first seconds to limit the P.S. charging current to avoid tripping the breaker, but once it's started, it won't ever draw that much current in operation. You may notice the lights dim for a second if your transformer is ~300VA+. But if it turns on without tripping the breaker you're OK. ;)

jea48

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Re: Candela Power Draw
« Reply #2 on: 24 May 2016, 09:51 pm »
How much power does the Candela draw? I don't want to overload my 15 amp circuit.  My monos and subs total to 1540 watts.

1540 watts.


15 amp circuit.

Dedicated circuit?
Mains voltage? 120V?
Total length of the branch circuit wiring? Up down and all around.
What type of music do you listen to? High Dynamic?
How loud?

Would you believe the average 15 amp circuit breaker will pass short quick busts of current all day long well over 50 amps and not trip open?
The VD, Voltage Drop, on the line can dip pretty good at the same time.
Power amps power supply's hate quick fluctuating mains voltage.

 

limniscate

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Re: Candela Power Draw
« Reply #3 on: 24 May 2016, 10:24 pm »
120V

Total length of the run is probably 50 ft..  The wiring is only 14 ga..  I listen to some dynamic music like Daft Punk/Justice at fairly high volumes 85-90db.  I have two Kismet in Stratos in monos, dual Rythmik F12g's and Magnepan 3.7's.

G Georgopoulos

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Re: Candela Power Draw
« Reply #4 on: 24 May 2016, 10:52 pm »
120V

Total length of the run is probably 50 ft..  The wiring is only 14 ga..  I listen to some dynamic music like Daft Punk/Justice at fairly high volumes 85-90db.  I have two Kismet in Stratos in monos, dual Rythmik F12g's and Magnepan 3.7's.

85 - 90 db spl isnt much power demanding (depends also on spk sensitivity),anyway power draw is how much power the amp puts out,class-ab amps vary power levels/power consumption with volume setting

if your amps play at max say 300w ,((300 /120=2,5A) x 2=5A) ,power draw then is 120v x 5A =600w...

jea48

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Re: Candela Power Draw
« Reply #5 on: 25 May 2016, 12:10 am »
120V

Total length of the run is probably 50 ft..  The wiring is only 14 ga..  I listen to some dynamic music like Daft Punk/Justice at fairly high volumes 85-90db.  I have two Kismet in Stratos in monos, dual Rythmik F12g's and Magnepan 3.7's.

Dedicated branch circuit? Or a 15 amp convenience outlet branch circuit shared with other things like lights and such?

Quote from a post of atmashere on Agon:

With power cords its all about voltage drop across the cord. Some of that is at 60Hz, and some of that is much much higher- well above 30KHz-100KHz depending on the power supply in the unit with which it is being used.

I've seen a 2 1/2 volt drop rob an amplifier of about 30% of its output power. The cord was rated for 10 amps, and the draw was about 6 amps. This measurement was done with a simple 3 1/2 digit Digital Voltmeter.

The more insidious problem is high frequency bandwidth. The power supplies of most amplifiers have a power transformer, a set of rectifiers, and a set of filter capacitors. The rectifiers only conduct when the power transformer output is higher than that of the filter caps. So:

When the caps are fully charged the amp is able to play. As it does so, the caps are discharged until the AC line voltage waveform gets high enough again that the rectifiers in the power supply are able to conduct. Depending on the state of charge of the filter capacitors, this might only be for a few microseconds or it might be a few milliseconds. Either way, the charge is a spike which has very steep sides- and requires some bandwidth to make it happen.

If the power cord has poor high frequency response, it will current limit on these spikes. This can result is subtle modulations in the power supply or even a sagging power supply voltage.

Romex wiring found in many buildings actually works quite well. So it really becomes all about that last few feet and also how well the power cord is terminated- molded cords generally are not terminated very well. If the ends of your power cord get warm after a while, you know you have a problem!

This can be measured, its quantifiable and also audible as many audiophiles know. Anyone who tells you differently probably has not bothered to do any measurements- please refer them to this post.

I can go into more depth but this is it in a nutshell. Incidentally, Shunyata Research is refining an instrument that does a more in-depth analysis of what this is all about. At the link you will see that their tests essentially confirm what I have said here.

http://www.theaudiobeat.com/visits/shunyata_visit_interview.htm
[/I]
https://forum.audiogon.com/discussions/audiphile-power-cords#41

Same holds true for a branch circuit. You don't want the voltage fluctuating, bouncing around, when you are driving the power amps hard listening to dynamic music.

richidoo

Re: Candela Power Draw
« Reply #6 on: 25 May 2016, 12:20 am »
120V

Total length of the run is probably 50 ft..  The wiring is only 14 ga..  I listen to some dynamic music like Daft Punk/Justice at fairly high volumes 85-90db.  I have two Kismet in Stratos in monos, dual Rythmik F12g's and Magnepan 3.7's.

Your speakers' sensitivity is 86db/2.83V/m, so playing 90dB will require ~4W of power. Your musical selections are extremely compressed so you don't need much headroom for dynamic peaks. If you played them at 107dB (both speakers) you would draw about 250W total both Stratos amps. Add 500W for the subs at that level. You'll never play it that loud.

If your concerned with tripping the breaker unnecessarily, the most likely way it would trip is if you have a loose connection on an outlet, switch or wirenut. A good tweak is to shut off the power on that circuit, open the receptacles and tighten all the wire screws on the outlets (and switches) as tight as you can. If the wires are stabbed into the back of the outlet, take the time to move the wires to the side screws. Make sure any wirenuts are clean wire, twisted with pliers and nutted tight as possible. Loose connections in house wiring is common enough to make it worthwhile to check. Loose connections raise the source impedance of the mains which audibly reduces the bass performance and wastes power which could prematurely trip your breaker. To lower the impedance to the max, run a new dedicated 20A / 12ga circuit straight to one all copper outlet for your system, that will eliminate all those impedance raising screw connections, steel outlet conductors, switches and wirenuts.

Sorry if I'm repeating any advice already offered by others here.

Phil A

Re: Candela Power Draw
« Reply #7 on: 25 May 2016, 12:37 am »
How big is your room and how loud do you listen (if I missed this I'm sorry)?  I have a Candela in a secondary system with a Bryston 3BST, Rel sub along with Ohm Microwalsh Talls (which are not super efficient - 85db) and don't have any issue and have other things on the circuit.  The room is not big - just under 11x13 with a 10 ft. ceiling.

Phil A

Re: Candela Power Draw
« Reply #8 on: 25 May 2016, 12:38 am »
This is my room (I've just changed the source components since the below pic):





jea48

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Re: Candela Power Draw
« Reply #9 on: 25 May 2016, 12:39 am »
120V

Total length of the run is probably 50 ft..  The wiring is only 14 ga..  I listen to some dynamic music like Daft Punk/Justice at fairly high volumes 85-90db.  I have two Kismet in Stratos in monos, dual Rythmik F12g's and Magnepan 3.7's.

Are these the amps?

http://www.6moons.com/audioreviews/odyssey2/1.html

limniscate

  • Jr. Member
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Re: Candela Power Draw
« Reply #10 on: 25 May 2016, 03:48 am »
Are these the amps?

http://www.6moons.com/audioreviews/odyssey2/1.html

No, I wish my cases were that nice.  They're an early version of the Kismet in Stratos case.

limniscate

  • Jr. Member
  • Posts: 82
Re: Candela Power Draw
« Reply #11 on: 25 May 2016, 03:49 am »
How big is your room and how loud do you listen (if I missed this I'm sorry)?  I have a Candela in a secondary system with a Bryston 3BST, Rel sub along with Ohm Microwalsh Talls (which are not super efficient - 85db) and don't have any issue and have other things on the circuit.  The room is not big - just under 11x13 with a 10 ft. ceiling.

25'x15'x10'

The room is actually longer because it's a row house where the living/dining/and kitchen are all on the same floor, but 25' is where the living and dining meet the kitchen.  I use my dining as part of my living room. :)

limniscate

  • Jr. Member
  • Posts: 82
Re: Candela Power Draw
« Reply #12 on: 25 May 2016, 03:50 am »
Dedicated branch circuit? Or a 15 amp convenience outlet branch circuit shared with other things like lights and such?

Quote from a post of atmashere on Agon:

With power cords its all about voltage drop across the cord. Some of that is at 60Hz, and some of that is much much higher- well above 30KHz-100KHz depending on the power supply in the unit with which it is being used.

I've seen a 2 1/2 volt drop rob an amplifier of about 30% of its output power. The cord was rated for 10 amps, and the draw was about 6 amps. This measurement was done with a simple 3 1/2 digit Digital Voltmeter.

The more insidious problem is high frequency bandwidth. The power supplies of most amplifiers have a power transformer, a set of rectifiers, and a set of filter capacitors. The rectifiers only conduct when the power transformer output is higher than that of the filter caps. So:

When the caps are fully charged the amp is able to play. As it does so, the caps are discharged until the AC line voltage waveform gets high enough again that the rectifiers in the power supply are able to conduct. Depending on the state of charge of the filter capacitors, this might only be for a few microseconds or it might be a few milliseconds. Either way, the charge is a spike which has very steep sides- and requires some bandwidth to make it happen.

If the power cord has poor high frequency response, it will current limit on these spikes. This can result is subtle modulations in the power supply or even a sagging power supply voltage.

Romex wiring found in many buildings actually works quite well. So it really becomes all about that last few feet and also how well the power cord is terminated- molded cords generally are not terminated very well. If the ends of your power cord get warm after a while, you know you have a problem!

This can be measured, its quantifiable and also audible as many audiophiles know. Anyone who tells you differently probably has not bothered to do any measurements- please refer them to this post.

I can go into more depth but this is it in a nutshell. Incidentally, Shunyata Research is refining an instrument that does a more in-depth analysis of what this is all about. At the link you will see that their tests essentially confirm what I have said here.

http://www.theaudiobeat.com/visits/shunyata_visit_interview.htm
[/I]
https://forum.audiogon.com/discussions/audiphile-power-cords#41

Same holds true for a branch circuit. You don't want the voltage fluctuating, bouncing around, when you are driving the power amps hard listening to dynamic music.

It's dedicated.  Had I done more extensive research, I would have put three dedicated 10 gauge, 20a circuits in.  I only put one 20a with 14 gauge, which technically should use 15a breaker (so I'm told).

jea48

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Re: Candela Power Draw
« Reply #13 on: 25 May 2016, 03:18 pm »
Quote
limniscate said:
It's dedicated.  Had I done more extensive research, I would have put three dedicated 10 gauge, 20a circuits in.  I only put one 20a with 14 gauge, which technically should use 15a breaker (so I'm told).

Shame you did not go with your first gut instinct. Old saying when in doubt.....

As for what you have now. By NEC Code definition the overcurrent device determines the size of the branch circuit. Your problem the minimum size wire that can be used for a 20 amp circuit is #12awg copper. It is rated for 20 amps at 60 degree C. 14awg is only rated at 15 amps at 60 degree C.


National Electrical Code 90.1 Purpose:

 (A) Practical Safeguarding. The purpose of this Code is the practical safeguarding of persons and property from hazards arising from the use of electricity.

 B) Adequacy. This Code contains provisions considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.

 FPN: Hazards often occur because of overloading of wiring systems by methods or usage not in conformity with this Code. This occurs because initial wiring did not provide for increases in the use of electricity. An initial adequate installation and reasonable provisions for system changes provide for increase in the use of electricity.

 (C) Intention. This Code is not intended as a design specification or instruction manual for untrained persons.
[/I]

Note B).

B) Adequacy. This Code contains provisions considered necessary for safety. Compliance therewith and proper maintenance results in an installation that is essentially free from hazard but not necessarily efficient, convenient, or adequate for good service or future expansion of electrical use.






Why did you use a 20 amp breaker instead of the correct 15 amp breaker that would have met Code?  When you bought the 20 amp breaker did you notice it was the same price as the 15 amp breaker? In fact the 15, 20, and 30 amp are the same price.
How can that be? The current carrying parts and contacts are the same in all three breakers. Only the trips sensing units are different. I would suggest you replace the 20 amp breaker with the correct 15 amp breaker for electrical safety for the 14awg branch circuit wire.



Quote from Link below:

The first (and most
common) misconcep-
tion is that a breaker
trips when its nameplate
rating is exceeded. One
fire text has stated (in-
correctly) that a circuit
breaker will trip in sev-
eral minutes with a small
increase in current over
its rating[1]. Actually, a 20
amp breaker must trip at
a sustained current of 27
amperes (135 percent) at
less than one hour, and at
40 amperes (200 percent
of wire rating) in less than
120 seconds—far differ-
ent from what the cited
text implies. These two trip points (135 percent and 200 percent) are
defined in NEMA Standard AB-1, MCCBs and Molded Case Switch-
es[2]. TABLE 1 lists the 200 percent allowable trip times for different
size (amperage) circuit breakers. MCCBs have characteristic ‘curves’ published by their respective manufacturers.
[/I]
http://goodsonengineering.com/wp-content/uploads/2011/08/CircuitBreakerMyths_web.pdf

AlexG

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  • Posts: 223
Re: Candela Power Draw
« Reply #14 on: 25 May 2016, 10:30 pm »
 limniscate,

In general, source components use (draw) very little power - both solid state and tube designs. Also keep in mind that most solid state circuits are lower voltage/high current (amps) and tube circuits are the opposite, higher voltage but much lower current!

To your question, the Candela Preamp as design dissipates (draw) a little under 6.6W. This includes both filament and high voltage sections! Think of it as a night light bulb with a "sonic personality".

Alex

« Last Edit: 26 May 2016, 03:23 am by AlexG »

Big Red Machine

Re: Candela Power Draw
« Reply #15 on: 26 May 2016, 12:25 am »
Get one of these and put all the guessing to bed. My entire system (includes peripherals) running at 85 db only draws 3.5 amps and never spikes up to anything substantially higher (as in over 4 amps). You'll be surprised how little current you really draw unless you are using terribly inefficient speakers and Class A amps (things going in opposite directions).

http://www.globalindustrial.com/p/tools/test-measurement/Metrs-HVAC-R/energy-saver?infoParam.campaignId=T9F&gclid=COvYz6C89swCFYk9gQodI2gKjw

Speedskater

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  • Kevin
Re: Candela Power Draw
« Reply #16 on: 31 May 2016, 01:23 pm »
The above linked 'Kill-a-Watt' meter (and similar meters) are informative to have around the house. My line voltage can be anything from 113V to 126V over long periods of time. Mostly it's not related to time of day or weather conditions. The other day was an exception when the temperature hit 90F for the first time this year. I think that the power company has voltage taps at the sub-station.