Does listening fatigue go away???
IMPORTANT FOLLOW-UP to my previous comment about the Minimax DAC: It appears that the original version of the Minimax DAC had extremely high output impedances of 22K and 10K for its tube and solid state outputs, respectively. Those output impedances would be unsuitable for use with a resistive-based passive attenuator, optically controlled or not. Even more so in this particular situation, where the attenuator is driving the low 10K input impedance of your active speakers. And although the original Minimax DAC included a volume control function, chances are that the high output impedance would also create problems if you were to use it directly into the speaker inputs, without the Warpspeed. On the other hand, several references indicate that the Minimax DAC Plus, introduced last year, has tube and solid state output impedances of 3K and 200 ohms, respectively. The 200 ohm output would certainly be fine; the 3K output may not be, depending on how much it and the input impedance of the speakers vary as a function of frequency, and on the characteristics of the Warpspeed. According to John Atkinson's measurements in Stereophile, the Squeezebox Touch has an output impedance of 599 ohms at mid and high frequencies, and 878 ohms at 20 Hz. I suspect that both the magnitude and the frequency variation of those numbers are not affecting sonics in your setup significantly, although it's hard to say for sure without knowing how the input impedance of the speaker varies with frequency. Although of course the Squeezebox's DAC function itself could very conceivably be contributing to the issues, as I previously suggested. Regards, -- Al |
