Gary,

Here is part of an E-mail I received from Caleb on 04-24-07

Jack,

I’m in no position to scrutinize your measurements. I’ll just take your word for it. The sub should only draw 4 or 5 watts when in the on position vs 2-3 when in stand-by mode. Can’t imagine why it would draw in the off mode. I don’t have the technical expertise to wager any sort of guess.

Best Regards,

Caleb Denison

No one has refuted my findings but I still have no answer to this issue and I think that I have supplied a lot of information.

If my findings were substantiated by Aperion, then there may be other issues involved.

My amp is now running 12 degrees above room temp when OFF.

I would wait until 2 days before expiration of the 30 days and then decide. If we have no explanation by then, well?

Regards,

Jack

Fellow Forum Folks,

Foremost, I want to correct some bad information that I issued earlier regarding the assumed power consumption of the s-10 amp. I indicated that I thought that the amp was supposed to draw something like 4-5 watts in the ‘on’ position and 2-3 in the off position. This was based on someone else’s guesswork and is/was entirely inaccurate. Please accept my apologies for being the original source of this inaccurate information.

Second, I want to thank you for your patience while we gathered useful information regarding the amplifier’s power consumption. Our in house testing was rather pedestrian so we chose to hire an independent engineer to analyze the s-10 amplifier and report his findings.

The following was reported:

The Off / Auto / On switch on the rear of the SP10 Subwoofer refers to the unit’s internal operation – in all modes, the internal power transformer remains connected to the Mains outlet.

Under normal conditions with a 110VAC input, the SP10 Subwoofer will consume just under 10W RMS in the “Off” position, and at 120VAC somewhere between 11W to 13W RMS. In this position the power amplifier and associated circuits are essentially powered off.

As with any transformer (no device is 100% efficient), there are small losses associated with its normal operation, this is the cause of the small current draw which is dissipated as heat that has been observed by some users when the Subwoofer is in the “Off” position – the internal power amplifier is however powered down.

This is normal operation of the design, the Auto music-detect circuit of the SP10 actively power’s down the power amplifier section when no music is detected for a period of time when set to Auto Mode. The amplifier is also powered down in the “Off” position. When the Amplifier is in it’s powered down mode (in Auto or Off) there will be no effect to the lifetime of the product, no matter how long it’s connected to the Mains power outlet. However, as with any Mains powered electronic item it’s recommended to unplug the unit from the Mains outlet when it’s intended to be left unused for longer periods of time (say, a week or longer.. vacations etc.)

Due to the very high output power capability of the SP10 Subwoofer, the mains transformer is much larger than would normally be found in most consumer products, the “idle” losses of any transformer is directly related to the size of its magnetic core (size of the transformer) – this accounts for the SP10’s slightly higher idle current.

As for an explanation for the higher current reads posted on this thread, it’s important remember that AC current measurements are measured in RMS and the input must be a PURE Sine Wave. Quality of multi-meters may vary AND the US mains supply is anything but a pure Sine Wave.

To convert Pk-Pk to RMS:-

RMS=0.707*PP

So 22W Pk-Pk * 0.707 = 15.6W RMS, closer to the Aperion lab measurements of 11W to 13W RMS with a pure Sine Wave @ 120V AC.

Thanks again, folks. Please feel free to email any additional questions to customerservice@aperionaudio.com

Hey Caleb,

My measurements are not Peak to Peak, and I do know the difference.

Yeah well,

I am not using Peak to Peak measurements thank you.

My measurements were taken with three calibrated

Fluke DMM’s all registered True RMS meters.

I used three meters. Fluke 87, Fluke 79III and the Fluke 112, all were within .001 amps at 123 VAC.

The implication that my findings reflect Peak to Peak instead of True RMS (Root Mean Square ), is false.  My findings are RMS dependant.

Your post implicates that I was using Peak to Peak, which I was not.

No one has 110 VAC these days; it’s more like 120 to 125.

Since you have confirmed that my suspicions were correct that the transformer was constantly online drawing power in my post # 4530, how, can you and Ben say that this S-10 is energy conservative?

My S-10 now, when OFF stays 13 degrees F above Room Temp so I guess that it is energy efficient enough for Aperion.

Jack

Jack,

The information that was posted was a verbatim copy of what was sent to us, hence the use of italicized text.

 The Engineer had no knowledge of you, your capabilities as an Engineer or the quality of equipment that you have at your disposal. He was only provided with the basics: "it has been reported by forum thread members that the s-10 subwoofer was measured to draw 22 watts while the switch was in the off position. Please conduct a study and report your findings"

In posting this information, Aperion had no intention of implicating that your findings specifically reflect Peak to Peak as opposed to True RMS or anything else, for that matter. I beleive that our Engineer simply formed conjecture based on the information that he was given in an effort to explain variations in the measurements.

The measurements were made using both 110 VAC and 120 VAC connections in China.

Caleb,

So, the “Aperion Lab” did have power draw rating established for the S-10  which now emerges in this report. I would like to see the entire Aperion Lab report.

The following italicized text of the report reveals this.

To convert Pk-Pk to RMS:-

RMS=0.707*PP

So 22W Pk-Pk * 0.707 = 15.6W RMS, closer to the Aperion lab measurements of 11W to 13W RMS with a pure Sine Wave @ 120V AC.

I do not see actual measurements of current and voltage in the report such as I provided.

I only see a derivative of my findings based on an assumed de-rating factor.

Once you remove the conjecture and speculation of the de-rating formula of .707, we are back to 22 watts and the heat it creates.

Jack

The results of the amplifier testing as posted were provided by an engineer on location at our manufacturing facility. These reports confirm that the power transformer does remain active when the sub's power switch is in the 'off' position. As a result, a small amount of current is dissipated as heat.

This explains the small temperature differential that you observed.  We appreciate your curiosity, and have done our best to remain open and transparent by discussing these questions with you in a public forum and posting the results of tests that we performed in an effort to provide as much information as we could about the normal operation of this amplifier. The power consumption of the amplifier while in the off position is inherent to the design and will not affect the life of the amplifier. It is not a defect. We stand behind our products and as far as we know, we offer the longest sub amplifier warranty in our industry.

We thank everyone for their participation in this discussion.