dave

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About dave

  • Rank
    incurable tinkerer
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  • Location
    cambs
  • Real Name
    dave

Wigwam Info

  • Turn Table
    Pioneer PL L1000
  • Tone Arm & Cartridge
    Shure V15 iii
  • SUT / Phono Stage
    834p tweeked
  • Digital Source 1
    eternal cd player
  • Digital Source 2
    Teknica tv tuner
  • Pre-Amp
    tubed dynaco PAT4
  • Power Amp/s
    diy Fast Class A
  • My Speakers
    Wharfedale Teasdale
  • Trade Status
    I am not in the Hi-Fi trade

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  1. dave

    Does rfi makes a system sound brighter?

    Thanks, I have an hp8591e that I rescued from work, and a digilent analog discovery, very versatile tool for the lower frequencies. I live in a dip, so RF is not to bad, apart from local transmitter on 96MHz, but the pumping station down the road, I am convinced is doing strange flickering on the mains, suspect a VFD beating with the 50Hz.....
  2. dave

    Does rfi makes a system sound brighter?

    This is an entirely reasonable perspective IMO (of wich I am generaly sympathetic) for some one who obviously has skills in electronics, but who does not hear differences in cables. (This is not supposed to be an attack, I am not sure if there is a name for this type of audiophile, maybe Serge's * would suffice?). But then again, there are people who do hear what really are quite subtle effects. There does not seem to be much widely held "belief"? in the effects Mr Chord seems to suggest, this is the first time it has been thrust into my consciousness, enough to give it serious consideration. It is an interesting theory, but it does seem to have some holes in for me, mainly the known effects of demodulation V what seems to be some amorphous "RFI harshness field". And yes, I have spent countless hours with headphones plugged into multi k£ Rhode & Schwartz EMI receivers, debugging all sorts of emissions problems, mostly caused by inadequate screening curiously.... and occasionally immunity. Anyway, I will be now on the lookout for for this possible cause and effect, and curiously again, I have just been given a DA03A, which I have connected to my TV tuner for DATV radio 3 reception. My stereo has been sounding really quite odd at times since, I have turned it off now and some kind of normality has been restored. (maybe, or was it a coincidence) Oh wait, I used TOSlink. *Serge = certified measurist
  3. dave

    Does rfi makes a system sound brighter?

    It would not produce any output if it was not fed some RFI, I mean digital data.
  4. dave

    Does rfi makes a system sound brighter?

    I used to be a bit suspicious of them when I was a yooth. Now I design high speed amplifiers driving peculiar loads down, shock horror, wires, I see the true need and purpose of the zobel network. As the frequency extends towards the low MHz, it's a jungle. At one frequency the load is open, at another a dead short. It is no wonder the poor amplifier gets confused and starts oscillating. The zobel is an attempt to isolate the amplifier from the anarchy and give it a more predictable environment for its feedback to work, without getting its knickers in a twist.
  5. dave

    Does rfi makes a system sound brighter?

    Early ac coupled solid state amps use a solitary transistor at the input.
  6. dave

    Does rfi makes a system sound brighter?

    Maybe you could qualify that, I thought it was only strange people like me trying to escape from that circuit.
  7. dave

    Does rfi makes a system sound brighter?

    One of the hifi mags, can't remember if it was choice or news, did an RF immunity sweep in their testing once iirc, must have been 20 years or so ago, possibly coinciding with the CE mark. Doesn't seem to have caught on though.
  8. dave

    Does rfi makes a system sound brighter?

    I am not convinced of anything till I have proved it to my self in a quasi controlled manner.... I have no axe to grind incidentally, and thanks for your responses, you seem to be making things that make people happy, and that can't be bad. I feel my self being drawn in to the head fi for a number of reasons, I may be some time, I am a slow reader......
  9. dave

    Does rfi makes a system sound brighter?

    er that would be me actually...
  10. dave

    Does rfi makes a system sound brighter?

    I am not convinced that the effect / improvements are necessarily caused by normally occuring "RFI". My problem is what appears to be apparent repeatability of the phenomenon. RFI of any consequence typically comes from a thing, and would often have a characteristic signature. It is rarely an amorphous background hash, and even if it was, it would be stronger in some areas than others, and probably vary during the working day. These things are regulated an policed, with the possible exception of power line ethernet extenders.
  11. dave

    Does rfi makes a system sound brighter?

    no I am not....
  12. dave

    Does rfi makes a system sound brighter?

    If there is no filter on the input, like an IEC filtered inlet (and they don't block everything), it just comes in on the power cable, then it is inside the essentially Faraday cage.
  13. dave

    Does rfi makes a system sound brighter?

    You did indeed, I think the OP was talking about mains cables, where I guess screening of this type could be of some benefit to stop electrostatic 50Hz interference escaping, but personally I do not really associate that with the term RFI, because it is not RF..... This is an interesting point and reminds me of something I read somewhere, it was the first article I read that made any sense of power cables having a sound. Extrapolating a little, what you are also implying /saying is that if the impedance (resistance) of the path through the screen return of the RCA phono wire is the same, for example, as the resistance of the path between the two pieces of equipment through their respective ground connections, half the return signal will travel through the power cable ground wires.... So the power cable is in the signal path..... Unless one uses proper transformer balanced connections and run all the electronics on their own internal battery power supplies. This stuff makes my head hurt sometimes... I am still a little confused about your IMD statements, to help me understand, I understand IMD in principle, but is that the same the demodulation of an RF carrier, like taxi breakthrough in the old days, or a different effect, which, with typical minuscule levels of EMI, I would tend to agree. should not really be audible.
  14. dave

    Does rfi makes a system sound brighter?

    As soon as I clicked the post button, I started wondering about just this, as I deal with differential signals mostly, so I had to do some rummaging. It seems that the ferrite works on the magnetic field (not the electrostatic) and therefore effects the screen and the core in the same way, so differential signals are unaffected because their sum magnetic field cancels out, but common mode see the higher impedance. So if there is an unbalance in the current the ferrite will not be as effective. There are multiple other factors like the screening effectiveness, and (the dreaded) ground loop currents etc, etc. Just for my own satisfaction I put 10 clip-on ferrites onto a piece of coax. This increased the inductance across the length (measured on the screen) from 9uH to 30uH, but I could see no change in attenuation at randomly selected frequency of 170MHz, or anywhere else for that mater, of the spectrum of my wide-band noise source. I ensured that there was no alternative ground path. In defense of the 640, I had recently replaced the transport... In response to the original poster, partial screening is a bit like trying to stop light with mirrors. It is interesting if it made a repeatable change, but whatever you have done, you have not stopped RFI, just changed the environment. If it made an improvement.
  15. dave

    Does rfi makes a system sound brighter?

    Sorry that wasn't supposed to be a dig, can't stop being an inquisitive engineer type person. If anybody actually knows, with some measurements from whichever domain, would be quite interesting to know what was happening. Did read an interesting article on all the things that can go wrong with USB audio, and why wires are important. https://www.audiostream.com/content/usb-audio-gremlins-exposed-beyond-1s-and-0s-ifi-audio