@tarnhelm5
You are right, one can use higher quality parts for the parallel notch filter, air coils with even less resistance, MOX or Mundorf MResist resistors or even more expansive capacitors. I would agree replacing the budget ceramic resistor with e.g. a Mundorf MResist classic for a few extra Euros might be more adequate just to be safe. Anyway I am still very happy with the result and a direct A/B comparison doesn’t show any negative side effect of the simple filter. As usual it is a price vs. performance question, maybe the eventually existing extra inductance of the ceramic resistor is not so critical in this use case since high frequency will bypass via the capacitor. Meanwhile also Lowther offers a so called "Phase & Frequency Response Compensation Board" in two quality levels, haven't tried this out so far.
BTW currently I am looking for a Dirac Live enabled affordable amplifier, probably Pioneer or Onkyo (currently hard to get in Germany / EU). I have done some initial tests with the Dirac Live software version 2 weeks free trial and I am very impressed by the results, both measurement and sound (some initial measurements can be found at the bottom of my website). Could be that this will make the parallel notch filter obsolete in my setup. If the hardware implementation of Dirac Live could compete with the software version this could really be a very significant improvement. Might be worse looking at Dirac Live for Lowther and other setups with a not so super flat frequency response in the midrange as well, in case you are not afraid of DSP filtering.
Best regards
Randolf
You are right, one can use higher quality parts for the parallel notch filter, air coils with even less resistance, MOX or Mundorf MResist resistors or even more expansive capacitors. I would agree replacing the budget ceramic resistor with e.g. a Mundorf MResist classic for a few extra Euros might be more adequate just to be safe. Anyway I am still very happy with the result and a direct A/B comparison doesn’t show any negative side effect of the simple filter. As usual it is a price vs. performance question, maybe the eventually existing extra inductance of the ceramic resistor is not so critical in this use case since high frequency will bypass via the capacitor. Meanwhile also Lowther offers a so called "Phase & Frequency Response Compensation Board" in two quality levels, haven't tried this out so far.
BTW currently I am looking for a Dirac Live enabled affordable amplifier, probably Pioneer or Onkyo (currently hard to get in Germany / EU). I have done some initial tests with the Dirac Live software version 2 weeks free trial and I am very impressed by the results, both measurement and sound (some initial measurements can be found at the bottom of my website). Could be that this will make the parallel notch filter obsolete in my setup. If the hardware implementation of Dirac Live could compete with the software version this could really be a very significant improvement. Might be worse looking at Dirac Live for Lowther and other setups with a not so super flat frequency response in the midrange as well, in case you are not afraid of DSP filtering.
Best regards
Randolf