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  1. DonH56

    RFI of a radio amateur on a Naim Uniti 2 amplifier

    Had to deal with this many times over the years, as a back-then novice ham and as a tech. Most of the time ferrite beads would work, though sometimes I had to add RF bypass caps to an input (typically a phono input). Now and then bad interconnects were found, and occasionally the sneak path was...
  2. DonH56

    RF issue - insane noise from Logitech's Powerplay mat

    This seems like a good time to try a star-quad XLR cable...
  3. DonH56

    Emotiva XMC-2 Review (AV Processor)

    Tonewinner designs much of the Emotiva product line, or did... I don't know about the AVPs. I have a vague memory of Emotiva saying they pulled the designs in-house but I really do not know. My SDP-75 takes a while to boot, too...
  4. DonH56

    Best spec ADC Chip currently.... ??

    Agreed, for most designs the amplifier dominates the noise. I helped design a fs source many years ago and it was basically all about the amplifier. And the housing in that case; extreme vibration resistance was required. And mil-spec temp range, radiation hardness, etc. Not an audio...
  5. DonH56

    Best spec ADC Chip currently.... ??

    OK, got it. In bulk I think we are getting crystals for maybe 10~25 cents, and if a customer implements the circuit properly they save money. For customers without the expertise, or without access to design help (which my company will supply, as will the crystal companies), then the packaged...
  6. DonH56

    Class A vs AB -- Do They Really Sound Different?

    Crossover distortion happens in synch with the signal so will usually show up in normal THD/IMD tests, though it typically is not sinusoidal and has higher-frequency terms that show up in a frequency plot (FFT). It can cause higher distortion at lower signal levels and contribute to the rising...
  7. DonH56

    Best spec ADC Chip currently.... ??

    If you're asking about audio, I tend to think the packaged oscillators sold to improve jitter performance are overkill the vast majority of the time. I have seen $100 DIY modules that are basically rebadged off-the-shelf oscillators up to $10k+ clock boxes with fs jitter performance. A recording...
  8. DonH56

    Best spec ADC Chip currently.... ??

    Crystal oscillators have an optimal load impedance typically set by a couple of shunt capacitors and a feed back resistor across the amplifier. Some require a series resistor at the amplifier's output to limit the power into the crystal. Improper loading will change the oscillation frequency and...
  9. DonH56

    Class A vs AB -- Do They Really Sound Different?

    Not really qualified, as audio amplifier design is not my day job. But @restorer-john provided excellent examples in his post. Here are my thoughts, though hopefully some of our more learned audio designers will chime in to correct my mistakes: The class A designs I have seen have much higher...
  10. DonH56

    Please welcome BDWoody as our new moderator!

    I thought y'all just had to share the camper?
  11. DonH56

    Class A vs AB -- Do They Really Sound Different?

    Most of the class A amplifiers I have measured over the years perform worse than their AB (or D) counterparts. Perhaps our realities and science differ. AC leakage from 50/60 Hz lines and corresponding 100/120 Hz power supply rectifiers is much worse on many "linear" products -- look at the...
  12. DonH56

    Class A vs AB -- Do They Really Sound Different?

    OK. I would call that the DAC interfering with the amp, not the amp interfering with the DAC.
  13. DonH56

    Class D Amplifiers 101

    As said by others, dead time is not a big concern for most class D amps due to fast switching times and the output filter. Duty cycle distortion from varying dead time can increase distortion, but that's what feedback fixes quite handily. A glance at the specs and test results of any competent...
  14. DonH56

    Best spec ADC Chip currently.... ??

    Layout changes around the crystal could muck them up... Load capacitance and coupling could change.
  15. DonH56

    Class A vs AB -- Do They Really Sound Different?

    How does the amp interfere with the DAC? I can see where a DAC with excessive image output (e.g. a non-filtered output from the DAC) might cause problems for any wideband amp, but do not understand how the amp can interfere with the DAC... If anything I would expect it to be the other way around.
  16. DonH56

    Please welcome BDWoody as our new moderator!

    The Brazilian pianist? That would be so cool... I am looking forward to when my wife starts playing again.
  17. DonH56

    Effects of a large screen (85" inch)

    Gee, I got tagged, this is not a thread I would normally read... Ranks'a'rot, @FrantzM ! :) Disclaimer: I am not a speaker designer, nor claim to be an acoustics expert. Take comments FWIWFM. The higher frequencies from conventional speakers are directional and those horns are not going to...
  18. DonH56

    Best spec ADC Chip currently.... ??

    Re. programs, why not Python? More on topic, is there a link to these soon-to-be products? @IVX ?
  19. DonH56

    Emotiva XMC-2 Review (AV Processor)

    That is the problem with any manufacturer's forum -- people think posting to a forum is the same as posting to the support department, and that is very rarely true IME. Especially these days when a forum is likely to be set up and run by a third party with "outside" moderators and such. Chances...
  20. DonH56

    Emotiva XMC-2 Review (AV Processor)

    There's a bunch of outcry on the Emo Lounge but the bug is not yet fixed. There is a thread dedicated to the bass issue.
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