Hi James, I have the BDA-1 dac, which i love, I read somewhere that if i use the -3 db feature, i make sure not to overload the digital filter which could cause
distortion. My question is will i loose resolution when selecting the -3 db feature, since i am in the digital domain.
Thanks in advance. 
Hi!
The answer is both yes and no. The variable output is an intrinsic feature of the CS4398 DAC chip used in the BDA-1. This feature was enabled because the chip has a somewhat higher voltage output level, 2.4 V if I remember correctly, so decreasing the output somewhat can bring it closer to a more typical 2.0 V.
Theoretically, any volume manipulation done through bit truncation leads to loss of resolution. That being said, because we are talking only but a few dB, it is seriously unlikely it will cause any loss, either in terms of measurements or subjective. Here’s why:
If one bit equals approximately 6 dB, decreasing the output level by 6 dB would reduce the resolution from the native 24 bit to 23 bit. If you think that’s serious, keep in mind that a vast majority of DACs have a measured dynamic range of less than 120 dB. In other words, 20 bits. So, with 23 bits of available resolution, there is simply no way it can affect the performance in any way. This is, of course, presuming you are using a high-res 24 bit file. If you are using CD-format files of 16 bits, then you can truncate all the bits you want!
Cheers,
Antun
