MRC01
Major Contributor
This was a popular card 10-15 years ago. I've had mine about that long. It's unique in that it has a daughter board that you can unplug & flip around to switch between single ended (RCA) & balanced (1/4" TRS) outputs and inputs. It uses the AK4358 for DA and AK5385A for AD. It supports PCM up to 24-bit 192 kHz, both input and output. For outputs, it also two digital: coax and toslink.
Summary: it was a great card for its time, still decent but nowhere near state of the art.
I tested it by playing REW frequency sweeps through a loopback connector. I'll show some unexpected results and ask questions.
Here's distortion & noise, SE, at 48 kHz, sweep at -0.5 dB digital:
Nothing special or surprising above.
Below is the same thing in balanced mode:
This is surprising: higher noise, about the same distortion. If you squint you can see the 2nd harmonic (light orange) is lower than SE, as expected with balanced.
Question 1: why is noise higher in balanced mode? Balanced should have lower noise!
Here's distortion in SE mode, with sweeps at 0, -1 and -3 dB.
Nothing surprising above. Distortion is slightly lower as you reduce the digital signal level below max.
Here's the same thing in balanced mode:
Well that is different: distortion is relatively constant at 0, -1 and -3 dB.
Question 2: why does distortion vs. level react differently in SE vs. balanced mode?
To help with this question, here are direct comparisons of distortion (not noise, couldn't get that to work in REW) between SE & balanced, at different signal levels. In each graph, SE is black and balanced is blue:
Sweep at 0 dB:
Balanced has slightly lower distortion up to about 1 kHz, above which it rises and SE is slightly lower.
Sweep at -1 dB:
Above we see the same pattern, though SE distortion dropped a bit while balanced remained the same.
Sweep at -3 dB:
Here, balanced has lost its advantage and SE has lower distortion across the board.
Sweep at -30 dB:
This is almost identical to the situation at -3 dB, but of course the levels are higher overall due to the lower level signal.
Summary: it was a great card for its time, still decent but nowhere near state of the art.
I tested it by playing REW frequency sweeps through a loopback connector. I'll show some unexpected results and ask questions.
Here's distortion & noise, SE, at 48 kHz, sweep at -0.5 dB digital:
Nothing special or surprising above.
Below is the same thing in balanced mode:
This is surprising: higher noise, about the same distortion. If you squint you can see the 2nd harmonic (light orange) is lower than SE, as expected with balanced.
Question 1: why is noise higher in balanced mode? Balanced should have lower noise!
Here's distortion in SE mode, with sweeps at 0, -1 and -3 dB.
Nothing surprising above. Distortion is slightly lower as you reduce the digital signal level below max.
Here's the same thing in balanced mode:
Well that is different: distortion is relatively constant at 0, -1 and -3 dB.
Question 2: why does distortion vs. level react differently in SE vs. balanced mode?
To help with this question, here are direct comparisons of distortion (not noise, couldn't get that to work in REW) between SE & balanced, at different signal levels. In each graph, SE is black and balanced is blue:
Sweep at 0 dB:
Balanced has slightly lower distortion up to about 1 kHz, above which it rises and SE is slightly lower.
Sweep at -1 dB:
Above we see the same pattern, though SE distortion dropped a bit while balanced remained the same.
Sweep at -3 dB:
Here, balanced has lost its advantage and SE has lower distortion across the board.
Sweep at -30 dB:
This is almost identical to the situation at -3 dB, but of course the levels are higher overall due to the lower level signal.