7/26/14 at 10:30am
Posts by jcx
7/22/14 at 1:56pm
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...
7/21/14 at 4:53pm
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...
7/16/14 at 4:56pm
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...
7/15/14 at 8:55pm
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
7/15/14 at 1:46pm
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...
7/15/14 at 12:55pm
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...
7/11/14 at 9:06pm
7/7/14 at 10:10pm
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
7/5/14 at 7:43am
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