Thanks, Rick.
Part of the concern I expressed about that issue was the possibility that if the DAC's volume control would have to be set in the lower part of its range, and if the volume control function is implemented digitally (I don't know whether or not that is the case in the Aeris), its sonics might be adversely affected as a result of what is referred to as "bit stripping." Which can occur to a greater or lesser degree, or not at all, depending on the design of the particular DAC as well as on the particular volume setting. And I raised that point in connection with the particularly high gain that most VAC amps provide, which (everything else being equal) would necessitate a lower setting of the DAC's volume control.
I see that your Rowland Corus preamp provides overall gain that is "Independently Programmable 0 to 20 dB on each input." It would be relevant to the discussion to know what you have that set to in your system, or if it is set to some default value, what that default value is. If that gain is set to a high value it would necessitate a correspondingly lower setting of the DACs volume control, to enable the preamp's volume control to be used in a desirable part of its range. Thereby increasing the possibility of adverse sonic effects due to bit stripping, if the DACs volume function is implemented digitally.
Pending knowing how that is set in your system, though, my guess is that the high gain of the VAC amps would not be a problem for Rinpoche. I say that based on your results together with the fact that the 5 db or so higher gain of the VAC amps, relative to the gain of your Rowland amp, closely corresponds to the approximately 6 db lower efficiency of her speakers compared to yours. Which would result in essentially the same overall system gain, aside from preamp differences.
In any event, though, I would suggest to her that if she obtains a high gain amp such as one of the VACs, and also eventually purchases a preamp, that high gain preamps be avoided. Examples of high gain preamps include many Conrad Johnson models, which provide gains in the area of 25 db or so. A preamp providing a gain in single digits, or at most around 12 db or so, would be a much more suitable choice.
Best regards,
-- Al
Part of the concern I expressed about that issue was the possibility that if the DAC's volume control would have to be set in the lower part of its range, and if the volume control function is implemented digitally (I don't know whether or not that is the case in the Aeris), its sonics might be adversely affected as a result of what is referred to as "bit stripping." Which can occur to a greater or lesser degree, or not at all, depending on the design of the particular DAC as well as on the particular volume setting. And I raised that point in connection with the particularly high gain that most VAC amps provide, which (everything else being equal) would necessitate a lower setting of the DAC's volume control.
I see that your Rowland Corus preamp provides overall gain that is "Independently Programmable 0 to 20 dB on each input." It would be relevant to the discussion to know what you have that set to in your system, or if it is set to some default value, what that default value is. If that gain is set to a high value it would necessitate a correspondingly lower setting of the DACs volume control, to enable the preamp's volume control to be used in a desirable part of its range. Thereby increasing the possibility of adverse sonic effects due to bit stripping, if the DACs volume function is implemented digitally.
Pending knowing how that is set in your system, though, my guess is that the high gain of the VAC amps would not be a problem for Rinpoche. I say that based on your results together with the fact that the 5 db or so higher gain of the VAC amps, relative to the gain of your Rowland amp, closely corresponds to the approximately 6 db lower efficiency of her speakers compared to yours. Which would result in essentially the same overall system gain, aside from preamp differences.
In any event, though, I would suggest to her that if she obtains a high gain amp such as one of the VACs, and also eventually purchases a preamp, that high gain preamps be avoided. Examples of high gain preamps include many Conrad Johnson models, which provide gains in the area of 25 db or so. A preamp providing a gain in single digits, or at most around 12 db or so, would be a much more suitable choice.
Best regards,
-- Al