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About opus101

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    Hangzhou, PRC

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  1. I have a collection of el-cheapo DMMs - my most recent impulse buy :
  2. Definitely it would be worth looking at AverLab as the price is well within your budget (last time I checked I recall the starting point was $3k) : https://www.avermetrics.com/products/averlab/ Picoscope makes a high resolution USB scope for $1200 or so : https://www.amazon.com/Pico-PicoScope-16-bit-Oscilloscope-probes/dp/B0153KEQEW
  3. DSC-1 isn't a ladder DAC its an analog FIR filter. Resistor values don't need to be particularly closely matched as the output is a summation of time-delayed single bit DACs.
  4. Given that you do seem to accept that its CM noise which is the issue and isn't going to be much filtered by the mains trafo its just a small step to envisage a particular design of mains cable to act as a distributed common-mode choke.
  5. In normal (aka differential) mode, this is true. But then you'll also have a bank of reservoir caps to help with the filtering. However its not the case for common mode, particularly if the transformer's a toroidal.
  6. I can only see a marketing advantage myself, in that its different for the sake of being different.
  7. Presumably the 'extremely unique feature' here is simply the use of an EF800 valve in this application. AMR beat AN to it it seems as the now-fairly-long-in-the-tooth DP-777 also had a valve to buffer the S/PDIF signal : https://superphonica.com/all-products/components-digital/digital-to-analog-converters-dac/amr-digital-processor-777-se/
  8. If perchance anyone's interested in learning why unbalanced cables may well be audible from a technical perspective, this long article is one of the best I've come across. It is though pretty heavy going for anyone without an EE background : http://www.soundstagenetwork.com/articles/pete01.htm Turns out that the commonly held belief that only the differential-mode lumped parameters of cables (that's R, L, and C to you and me) make any difference to a cable's sonic contribution isn't all there is to consider in this application. There are the common-mode parameters of the system configuration to consider as well. These parameters, often misunderstood or ignored, play as an important, if not more important, a role than the more easily understood differential parameters.
  9. False - I have a basic understanding of wire and connectivity and I know no such thing.
  10. Healthy being less profitable than unhealthy it's a reasonable assumption they're content to stick with the latter.
  11. Going back quite a few months you were going to be doing research into the ringing question. Is there anything of that going to come later perchance?
  12. To me, the pic in post #5 is a very close relative of a wall wart, hence my 'wall wart type supply brick'. Is that called 'SBOOSTER' ? If so then its still a backwards step to exchange an EI for a toroid in that.
  13. Notice the context there - '...in the most powerful audio systems...'. That to me indicates power amps. In a power amp, lack of radiated flux is a big benefit as the trafo's in the same box as the electronics. A power amp is a completely different application from a wall-wart type supply brick.
  14. The best for an audio application would be the one with lowest capacitance between the windings. Which is normally a split-bobbin EI. Both R-core and toroid have more capacitance than split-bobbin EI. Toroid comes in useful when you want very low radiated flux but in a wall-wart that's not a requirement.
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