Thank you, Peng! I believe it is an important matter to discuss.
The definition of "Rated Output Voltage" is not a standard indeed and can be considered by different ways. For example, some electrical engineers believe that:
Obviously you have now done your research reading so we can discuss (be clear, just discussion) some more. Below are my additional points:
1. "Rated", by itself is just a word, rated speed, temperature, output power, distortions, frequency response would not mean much unless the conditions, e.g. atmospheric pressure (for speed), humidify (for temperature), frequency, load impedance (for amps) etc., under which the equipment, device etc., are measured.
Specifically for pre out voltage, it could be a little more useful if the spec include more details such as:
continuously rated Vrms, Max Vrms (specified max duration), Distortions specs for full bandwidth, input sensitivity, gain, input impedance, output impedance, SNR (A weighted/unweighted)
While other engineers believe that:
That's just what they believe right? I am not going to say the quoted ones were taken out of context as I have not read the whole thing, but I suspect they did not mean what they stated as "definition", because they should know better that one cannot define "rated whatever" without stating all the conditions under which the measurements were taken.
In one of your quote: "
Rated simply means maximum amount of current and maximum amount of voltage which any particular Electrical Equipment can withstand or carry when it is performing at its peak capacity - by Vatsal Talati, works at Electrical Engineering.."
That makes little sense, specifically, "Rated" what?, I gathered that he/she meant rated current, or voltage in this case, and I suspect if you had quoted the whole article it would make some, or total sense. Another example, I am sure you would agree that "can withstand............" means little, without the other conditions such as, but not limited to duration, ambient temperature, without/without forced cooling etc..
What Marantz means is unclear indeed. However we can not approximate the the Yamaha's numbers, may be they mean completely different things?
Agreed, and that's the exact point I tried to make.
Such as Marantz doesn't provide any additional data for the maximum voltage, I believe we shall assume that their numbers correlate with the maximum output voltage due to the following reasons:
1. 1.23Vrms in unbalanced mode means +4dBu Pro Audio Reference Level (ref Rane note 145),anything above it is a "headroom" up to +26 dBu Maximum Output Level in professional Audio. Consumer Reference Level is -10 dBV, and Marantz 8805 is not a professional device. Although it can obviously output higher levels that +4dBu, the measurements have to be performed at this level (or lower)as a rated level with provided level of THD+N.
2. Previously the measurements for Marantz 8802 have been made at 2Vrms output voltage by hometheaterhifi.com with completely different numbers for THD+N comparing to Amir's. They also performed such measurements at 5Vrms to demonstrate the overloading capabilities of the device, and those numbers are pretty similar to Amir's results. It tells us about the actual overloading, and such as the DAC circuit in 8802 and 8805 is similar, we can compare the measurements.
Interesting points, but in the service manuals, it does say: "vol IC NJU72343....non clip max signal level 4.2Vrms...", and that's what I based my previously comments on The AV8805's is actually downloadable (try Googling for it) or you can read the data sheet of the volume IC yourself if you are electrically savvy. Note that hometheaterhifi.com's numbers are what they choose for their measurements, just like Amir's who could have used a lower voltage for his measurements too.
https://www.njr.com/semicon/PDF/NJU72343_E.pdf
The Marantz AV8805, SR6012 and up, Denon AVR-X3400H and up all use the same preamp/vol IC, so their "rated" pre out voltage are most likely the same or very similar.
3. "whopping 4.5Vrms unclipped output"
It is unclear for me why do we need it, if majority of amplifiers "will be happy" with significantly lower input levels.
Bryston 4b sensitivity at 1.4V for 250W at 8 ohm (it has switchable gain 23dB for balanced or for unbalanced 29dB).
Onkyo 5501 sensitivity 1V balanced, 2V unbalanced
Proceed AMP 5 sensitivity 2.24V for full rated output (balanced),1.12V for full rated output (single-ended or unbalanced)
You may not need it, but others may as it depends on how much average and peak power you need. THX standard for peaks is 20 dB above the average 85 dB SPL. Someone like
@Irvrobinson,
@RichB have the Revel Salon 2 that has relatively low sensitivity and impedance specs, so if they listen to media contents that have very say >20 dB dynamic peaks from 4 or even 5 meters in a large room, they may in fact need >4 Vrms or almost 6 V/12 Vp-p peak to avoid any amount of clipping, especially if their power amps have say less than 28 dB of gain. For example, the AT6000 power amp needs 2 Vrms to output 450 W into 4 ohms, or 300 W into 8 ohms. So if they sit 5M from the speakers, even with room gain, they would need more than 4 Vrms to ensure the preamp won't clip during dynamic peaks of 105 dB (yes, that would be rare) or higher from 5 meters assuming their amps such as the AT6000 won't clip during such short duration peak outputs.
