user54
Member
I think you are clear on the preamp mode, that will give you "clean" preamp output at 2 V and a little higher.
So I'll just try to explain the other "configuration(s)" you seem to be referring to.
Scenario/Configuration 1, that is, non preamp mode, and you are not using the amp assign feature, or "trick" in this case, to disconnect the FL and FR internal power amps.
In this case you can still expect SINAD of about 97 dB up to 1.4 V or a little higher. If you consider 97 dB clean (for me even 75 dB SINAD is "clean") then it is clean at 1.4 to 1.45 V. At higher output voltages, such as at 2V, SINAD would deteriorate to about 75 dB and probably down to 60-65 dB at 3 V.
Scenario 2, still in non preamp mode, but you are using the amp assign trick to disconnect the FL and FR internal power amps:
In this case, since the FL and FR power amp inputs are disconnected from the FL and FR preamp outputs, you can expect about 97 dB SINAD at preamp outputs (FL and FR only) of 2 V. Again, the preamp outputs can actually reach much higher than 2 V. If you looked at the curve of the AVR-X6700H, SINAD remained quite "clean", at 92 dB when the preamp output reached 4.4 V. I wouldn't count on the exceptionally high 4.4 V consistently but I would say 3 to 3.5 V should be attainable consistently.
That's for the FL and FR preamp outputs that are disconnected from the internal power amps, the other preamp channel outputs that are still connected to their corresponding power amp inputs will again, have about 97 dB SINAD at voltages up to 1.4 to 1.45 V and will drop to about 75 dB at 2 V.
So the bottom line is, if you don't use preamp mode, you can only disconnect the FL and FR power amps from the FL and FR preamp outputs, so you can only expect the FL and FR preamp output signals to remain "clean" at 2 V, whereas the other preamp output signals will remain "clean at up to 1.4 to 1.45 V and down to about 75 dB at 2 V and beyond.
I hope this is clear, if not, we can try again.
Lastly, keep in mind "clean" is a relative term, we all know Amir seems to set his bar quite high. For me, and I am sure many others as well, 75 dB SINAD is perhaps clean enough. Put it this way, the Marantz AV7705's SINAD was about 75 dB at 2 V (that is 4 V from the XLR outputs) and that is for preamp mode naturally because it is a preamp processor. So clearly many of the AV7705's owners may consider 75 dB is "clean".
if I limit the gain on the njr8080 which stands after the DAC to 1.4 Volts - 0 dB, and not like now 2V - 0dB? will I get the maximum efficiency of the whole device, studying the manuals tells me this