at no audio frequency can the eha5 generate 700vrms without the amp going into shutdown mode. bob katz and others have tested this.
the nfca modules are limited to about 4 watts of power output, and that is nowhere near enough to drive those transformers.
a pair of edcor transformers and a bias...
1600 volts peak to peak measured stator to stator is 571 volts rms measured stator to stator.
electrostatic headphones are a balanced load and need to be measured as a balanced load.
400 volts rms measured stator to stator is 1120 volts peak to peak measured stator to stator. typical of...
better sinad? not really. a few db due to fully regulated power supplies. the noise of a 60db gain amplifier is due to thermal noise. unless you happen to have an infinite supply of liquid nitrogen.
this was the schematic of the nfca module as used in the eha5. so the 90d may be slightly different as it probably does not have the 18khz filter.
and the volume pot is replaced by a discrete relay attenuator. high res pictures posted elsewhere. too big to fit here.
you take say 3 meters of this stuff and coil it up in a box. what you have is an unterminated transmission line. not an antenna.
being an open transmission line it acts as a notch filter whose frequency depends on the inductance and capacitance of the cable etc.
picking reasonable numbers for...
Its all about size (as in core cross sectional area) and maximum flux before saturation.
its obvious from the graphs above that the core saturation of the eha5 transformer is about 1.4 tesla indicating the cheapest of core materials.
better and much bigger transformers are available from lundahl...
biggest problem with the attenuator above is that the resistance is too low and will effect the gain and frequency response of the amplifier.
the appropriate pair of high voltage 909k resistors is a far more reasonable dc load.
the lower power stax made tube amps will measure orders of...
so after working on a very old stax amp, turns out that plugging a pro bias headphone into the normal bias jack results in at least 8db less volume and significant balance issues. tried with a number of different headphones. that means you have to turn up the volume a bunch which might cause...
class D making 2000 vppss. not any time soon. or ever.
full frequency range electrostatic output transformers are VERY hard. and quite large and stupidly expensive.
the lundhall's are $5k each. you need 2.
when square wave pictures of the topping are published we will know whether they know...