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Posts by jcx

AC can be as dangerous or more than DC - even DC danger depends on DC current direction through thoracic cavity, for both AC and DC time and current matter, less current over longer time - by few seconds even ES headphone amp peak output currents could be fatal   once the V either AC or DC exceeds 200 V it becomes more likely to punch through dry skin - even lower V when you are wet, or have poked yourself with the conductor   a output xfmr does block some failure...
SE DHT - do you mean a gapped xfmr with DC current? - makes an already hard job really expensive in material   I don't see anything saying you can't push-pull DHT - but that does largely cancel even order tube distortion     and why would Classic Rock lack enough distortion in the recording? - that's what Marshalls, Fenders on the stage are for       once you have enough V to punch through dry skin's normal insulation it doesn't help all that much that its xfmr...
don't use the mains for direct connection to anything you handle, put on your head - it can be done safely but there are several critical topology and component rating issues to get right for safety   and the shown circuit doesn't have them - yes may have been done in the past, but standards, acceptable risk evolve   use the secondary isolated Vac to drive the doubler and then divide or regulate - and the series R may need to be multiple series devices to add up to...
I believe star quad will have same or superior electrical characteristics for similar wire awg and insulation thickness - the "inter-8" weave page gives no data - the shielding pdf only claims mechanical improvements when you recognize that star quad has the same conductor count when both are used as 2 conductor cable
I've never seen braiding recommended on electrical grounds - may look pretty though   EE's spec twisted pairs, star quad, coax, shielding - for electrical performance, immunity to external field coupling   Litz wiring may be "braided" to move the individual conductors evenly over the radius of the cable - but it is then used as a single electrical conductor - and headphone cable are too a small gage wire to have audible skin effect loss   braiding is likely to cause...
it is mostly time integrated dose that appears to do the damage - though high enough SPL will do irreversible damage in a single cycle   there are really fast dynamics in acoustic music - many sound pressure meter's "fast" response doesn't capture them so you will get fasley low estimates of instantaneous dynamic peaks of live performances   you have to balance the 2 perspectives the Headwize article http://headwize.com/?page_id=266 should be read for both perspectives...
after the O2 there's nothing left to do except electrostat amps
Sony has never put it out in the public domain but people have calculated that they must be using at least 5th order noise shaping - so 6th order analog low pass filtering is the least that starts to actually roll off the DSD shaped noise rather than merely level it off
SACD DSD single bit "DAC" initially speced a 100 kHz analog low pass filter - this needs to be >5th order to get ahead of the noise shaping curve   the shaped noise rises rapidly above 20 kHz and was accused of melting down some "audiophile" power amps - the noise rise can be seen the links in post #30   so the spec was modified to 50 kHz low pass - giving ~ the same BW as 96k PCM
does anyone have an example of any hearing related phenomena 1st being deduced from Physiology?   Psychoacoustics is the more useful field for audio equipment design engineers looking for human hearing description - as far as I know the tracing the Anatomy, Neurophysiology of Psychoacoustic phenomena mainly flows in practice from the Psychoacoustic clues/observations to the Physiology detective work   so the book I look at is Fastl Psychoacoustics...
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