15 amp vs 20 amp

Best practice is to run two direct lines, one for the power amp without a power conditioner and one for the power conditioner with the rest of the components plugged in to it. I can't think of any reason you would want a power conditioner rated for 20amps. I don't know of any amps that pull that much power. Even if there are, I assume you don't have one. I can't see any benefit... high quality is what you want in a power conditioner... like Shunyata, or IsoTek. 

Assume the 15 amp unit will have #14awg internal wiring. (wire rated for 15 amps)

Assume the 20 amp unit will have #12awg minimum internal wiring. (wire rated for 20 amps, minimum)

Assume all other components in the 20A unit is rated for 20 amps minimum.

Theory, less chance of VD (Voltage Drop) with a 20A rated wiring for a power amp when the music source being fed to the amp’s inputs is high dynamic material passages with the amp being pushed above a moderate to loud level.

FWI, if the 20A unit has a captive power cord, and is UL Lised, it will have a NEMA 5-20P Plug that will only plug into a NEMA 5-20R 20A rated wall outlet. (Power cord #12awg wire, minimum.)

In your case I assume the Furutech duplex receptacle is a NEMA 5-20R, 20A. (I don’t think Furutech makes a NEMA 5-15R, 15A.

If the power conditioner you buy is a 20A unit with a 20A IEC inlet connector, and a power amp will be plugged into the unit, you might want to use an audiophile grade power cord that uses an equivalent wire gauge of 10awg minimum.  

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I installed a dedicated 20 amp circuit in the wall and use a very high end furutech outlet. 

In wall branch circuit wiring 10awg? 10awg wire, best practices, IMO, for an audio equipment dedicated 20A branch circuit. (Circuit breaker in electrical panel, per code, 20A.)

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@ghdprentice, if using powered subwoofers, would you run those through the power condtioner or the same (or different) line as the amp(s)?

Thanks for input.  I took the power cable for my amp out of the conditioner and straight into the wall and sure enough it did make a difference!.  

Hmmm. Good question. Ideally, a separate direct line, or if that is more than you can do, along with the amp. But, I have never experimented with adding a sub to the amp circuit. The sub is an amp… you don’t want to constrict flow. I am sure the former is best. Combining multi-Le amps will not be ideal. 

I think most subs are Class D amps that don't require as much current. 

@jea48 always makes sound technical explanations

On a side note, you would be quite surprised how few amps you really draw if you were to measure your wall outlet to the system running at a high level. In the past, a similar system to my present was drawing less than 5 amps. So, headroom is very important, but 15 amp products are not going to impede your system.

@mlapenta Yep, cables do matter.

@bugredmachine  Thanks for the kind words.

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@bugredmachine  said:

On a side note, you would be quite surprised how few amps you really draw if you were to measure your wall outlet to the system running at a high level. In the past, a similar system to my present was drawing less than 5 amps.

Your ammeter was only reading an average, not very quick draws, gulps, of current peaks... The meter is not capably of reading much higher millisecond pulses of current. 

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Example: 

2x200W amp might take from mains close to 1kW during peaks. The problem is that peak supply current won’t be expected 8A, but rather close to 40A. It is because current is drawn only for very short time (millisecond pulse) at the peak of full wave rectified sinewave. It applies to most of LPS. Power delivered with such short pulses not only creates larger voltage drops in house wiring, but also heat-up amp’s power transformer, that has to be oversized (higher copper losses and higher core losses for eddy currents and hysteresis).
 

https://electronics.stackexchange.com/questions/329443/current-through-the-smoothing-capacitor-in-bridge-rectifier

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jea48 question:

Please explain what happens if the power transformer’s secondary winding voltage is lower feeding the rectifier, due to a quick AC mains VD event, and the electrolytic capacitors voltage is higher. Just going from memory the rectifier will not conduct and the caps do not get recharged for that "(millisecond pulse)" in time.

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@jea48   You are right - there will be no current thru rectifiers until capacitor voltage will drop below rectifier supplied peak voltage.  Theoretically it is possible to build LPS where capacitors keep average instead of peak voltage, but it requires huge inductor in series (in order of Henries) made with thick wire and AFAIK nobody is doing it.  One problem is lower rail voltage (average instead of peak) while the other is dependency on the load current.

http://www.r-type.org/articles/art-144.htm

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When the amplifier is plugged directly into the wall outlet the only thing that will cause VD at the outlet mains is the size and length of the branch circuit wiring. A 20A circuit breaker will easily pass 40amps of short quick draws of 40 amps of current all day long without tripping. 

How about the power conditioner you are looking at? Will it supply a steady state AC voltage feeding a power amp? 

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FYI: Kil-a-watt will capture peaks. Didn't use a handheld meter. Certainly understand that 15 amps will never be reached even with transients.

FYI: Kil-a-watt will capture peaks. Didn’t use a handheld meter. Certainly understand that 15 amps will never be reached even with transients.

My understanding only a scope will display very quick millisecond pulses, draws of current.

https://electronics.stackexchange.com/questions/329443/current-through-the-smoothing-capacitor-in-bridge-rectifier  

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Certainly understand that 15 amps will never be reached even with transients.

What do you base that on?

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@bugredmachine 

Certainly understand that 15 amps will never be reached even with transients.

As for transients. (Not to be confused with short duration of current draw pulses in a power amplifier’s power supply) 

You can’t measure transient voltages or transient currents with a Kil-a-watt  plug-in device or a regular multimeter. 

Examples of what is needed:

Tools for Measuring Transients

• Oscilloscopes: Oscilloscopes are the go-to instruments for capturing transient waveforms in real-time. They allow engineers to visualize voltage and current changes over time, providing immediate insights into transient behavior.
• Transient recorders: Unlike oscilloscopes, transient recorders focus on logging transient events for subsequent analysis. They are particularly useful for capturing infrequent or random transients that may not be easily observable in real-time.
• Spectrum analyzers: Spectrum analyzers break down the transient signal into its frequency components. By examining these frequencies, engineers can gain insights into the causes and potential impacts of the transient.

https://www.keysight.com/used/us/en/knowledge/glossary/oscilloscopes/what-is-a-transient-in-electronics

I would imagine any of the above would measure the current draw pulses on the AC mains feeding a power amplifier as in the example of the quoted material in my post above.

2x200W amp might take from mains close to 1kW during peaks. The problem is that peak supply current won’t be expected 8A, but rather close to 40A. It is because current is drawn only for very short time (millisecond pulse) at the peak of full wave rectified sinewave. It applies to most of LPS. Power delivered with such short pulses not only creates larger voltage drops in house wiring, but also heat-up amp’s power transformer, that has to be oversized (higher copper losses and higher core losses for eddy currents and hysteresis).  

Food for thought...

@mlapenta said: 

Thanks for input.  I took the power cable for my amp out of the conditioner and straight into the wall and sure enough it did make a difference!.  

I assume the amp sounded better plugged straight into the wall outlet. Maybe the 15A power conditioner was staving the amplifier of power. Limiting the power supply in the power amp.

Would a 20A rated power conditioner have worked better? Maybe. It depends if it was capable of delivering the same power as the wall outlet. Therein, it wouldn’t limit the amplifier full potential, apparently like the 15A rated power conditioner did. 

I’ve read posts where someone posts the average FLA of an average audio system is less than, say, 10A. A 15A branch circuit with 14awg wire is plenty big. Usually no regard to the length of the branch circuit wiring. If questioned someone will chime in VD, Voltage Drop, is not an issue because at a moderate listening level  the audio system is probably hardy drawing any current.

OP said:

I installed a dedicated 20 amp circuit in the wall and use a very high end furutech outlet. 

My response above:

"In wall branch circuit wiring 10awg? 10awg wire, best practices, IMO, for an audio equipment dedicated 20A branch circuit. (Circuit breaker in electrical panel, per code, 20A.)"

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It would be good to know if #10awg, (or #12awg, smaller wire), branch circuit wiring was used. Also approximate length of the branch circuit wiring.

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