@PENG - So you think the 46 watts registered by the 4700 is also for the internal amp stage? The power draw stays at the 46 watt level no matter where the volume control is moved to. The 4700 still emits heat in "Preamp" mode so maybe some of that is created by the "DC power rail" being on? What exactly is a power rail?
Is it the rail voltage mentioned in this article?
This article explores the purpose and function of the impedance switch found on some A/V receivers. Tradeoffs of following manufacturers recommended settings are also discussed. YouTube video inside.
www.audioholics.com
Thank you!
Yes, he explained it in the first paragraph. Power rail is commonly referred to as the "rail" where the amplifier gets its DC voltage from, and in essence that's the power supply for the amplifier. The power flow is, from the AC outlet to the power supply supply transformer, to the DC rectifier bridge and the output of the rectifier bridge is connected to the so called "power rail".
Below is a power supply block diagram, the simplest one I could find on the net, without having to worry about copy right:
The working of regulated and unregulated power supply is explained in detail with a Block Diagram, and Circuit Diagram
www.circuitstoday.com
In a real practical circuit, you can imagine the output of the bridge rectifier will be connected to what we call the "DC power rail", that powers the amplifier circuitry.
I have read the sms of some models including the X8500H but not the X4700H. The X4400H, X4500H, SR6012,SR6014, SR7012's rail voltages are exactly the same, pretty sure the X4700H and SR7015 will be the same too.
Gene mentioned more than once about in the so called pre-amp mode, the power amp section would still be "powered". It is just the signal input from the pre-amp get "disconnected".
In his video review of the SR8015, he actually emphasized that (not allowing D+M's Phil Jones to overlooked the important point I guess
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He suggested (and I have done exactly that since I had my X4400H over a year ago) that users set the Eco to always "On", to avoid the heat dissipation in the power amp section because it is still "connected to power". Strictly speaking, even for models without preamp mode such as my X4400H, one should set Eco to always on anyway as it won't affect the preamp section. That is, as long as the internal amps are not used.
You can fast forward to 6:17 to hear that part.
