Not really true, at least not entirely true! That 1.4 V reference, assuming you got it from ASR, is just one point on Amir's SINAD (dB) vs Measured load (Vrms) graphs derived from the AP instrument.
Let's be clear that the 1.4V is not the maximum output even when the internet amps are used. I have repeated this point a many times. Unfortunately if Amir (ASR) says something, people would (understandably) repeat it, sometimes taken out of context, and that led to misconceptions on forums.
As experienced Audioholics, I think we should not contribute to spreading the 1.4 V presumed/false limit when it clearly is not. Amir never said it was the limit either, but he was awfully harsh in using the term "clips" on those graphs.
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In general, people should not look at output at a single point on the output vs SINAD, or THD+N graphs, the same applies to both preamp and power amps.
Now let's look at the graphs, that unfortunately I also posted several times to help debunk the notion of the 1.4 V perceived limit:
1) SINAD was about 100 dB (0.001% THD+N)
2) At 1.4 V, 77.5 dB (about 0.013% THD+N) at about 1.7 V
3) 2V it was about 76 dB or 0.016%.(about and 76)
4) If you extend the line to 4V, assuming the same slope, it would be about 65 dB, or 0.056%.
Note: 76 dB SINAD, the AVR-X3700H would be almost 1 full dB better than the AV7705 (two samples measured by Amir), and we all know the AV7705 is a so called separate, without any influence of the internal power amps that are not even there!! Also, there are many very happy owners of the AV7705 that they thought it sounded great to them so I highly doubt 75 to 77 dB SINAD at 2 V is an issue for most (there are always exceptions obviously) people.
did a great job highlighting some of the key points in his review of the X3300W, people just have to read that article to have a better understanding.
I don't know how many times I have to link his article but here I am doing it again.
Denon AVR-X3300W A/V Receiver Measurements and Analysis | Audioholics
Note that the X3300W is a good example because it has the updated volume control chip and DAC chip that are the same as those used in the X3700H and other Denon/Marantz AVRs/AVPs, and it has no preamp mode nor any means to "disconnect" the internal power amps.
On that note, Gene, can you please say something about the term "clips" that is often used in reviews and measurements. For example, what is the basis you use? Would it be the point where SINAD starts to rise exponentially, or a hard number like 60 dB SINAD/i.e. -60 dB THD+N/0.1%, or both are used for your reference when you considered the clipping point? I understand for preamps, in order for them not to become the bottleneck, it may be appropriate to use a higher standard such that if 1% is used for power amps as the clipping point, then it may be good to use 0.1% or 0.05% for preamps, what's your opinion, based on practical real world applications?