DMC-1 Measurements and Analysis

The frequency response via the analog outputs of the DMC-1 are ruler flat out to about 50kHz with a -3dB point of around 200kHz.

When the analog preamp was driven at 1Vrms (typically ½ signal strength to achieve ½ of max power of most power amps with voltage gain of 29dB) distortion levels were (+.0.18 + 106.062)dBv = 106.242dBv or 100*alog(-106.242/20) = .000487%. This is excellent performance for a preamp.

When the analog preamp was driven at 6Vrms (more gain than you should ever need to drive any power amp to maximum power) distortion levels were (+.15.761 + 76.607)dBv = 92.368 or 100*alog(-92.368/20) = .00241%. Again this is excellent performance and indicates distortion is not an issue with this preamp at any unclipped drive level.

Using the EXT 8CH Input and setting the source to 200mV in, and adjusting the output of the D M C-1 until it produced 1Vrms Output, we measured the following:

-105.703dBra without signal

-19.448dBra with signal

< 10 Hz - 22k Hz bandwidth , no option filter.

SNR: 86.3dBra (unweighted)

This is very good performance. Though a few dB shy of what we consider stellar noise performance for a preamp we never heard any noise issues in real world listening tests. This is a marked improvement over what we observed when we conducted our review of the Sunfire Theater Grand III.

At Max Output

Ch-A SIGNAL to NOISE RATIO

-105.86 dB below 16.46 dBV or 6.6Vrms; Reference Level (at 0.10 % THD+N)

< 10 Hz - 22k Hz bandwidth , no option filter.

-94.122 without signal

-19.531dBrA with signal

< 10 Hz - 22k Hz bandwidth , no option filter.

SNR: 74.6dBrA (unweighted)

As you can see, going through ADC to DAC conversion stages on native analog signals adds about 12dB of noise. We recommend using the digital inputs on the D M C-1 on sources (assuming they have digital outputs) you wish to add DSP processing to for the best possible performance.

Subwoofer output distortion was significantly higher than the rest of the preamp outs, though likely inaudible due to our ears perception of distortion at low frequencies. It was about .15% at all unclipped levels and reached clipping about +7.5Vrms which is more gain than you will likely use in any application.

The processor outputs provided maximum output levels 6.6Vrms unclipped and accepted a maximum unclipped input signal of 5.5Vrms.