15 amp vs 20 amp

@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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