Originally Posted by Keithpgdrb
new question. I am a bit confused by the different voltages and such of the stax gear.
In short there are two ways to drive a Stax (or other electrostatic headphones).1. Direct driven amplifier.
Like the Stax SRM-007t, SRM-717, SRM-1/MK2, SRM-T1, ... and lots of aftermarket amplifiers like the KGBH, KGSS, GES; Aristaeus, ...
They are complete amplifiers, which take line in level (RCA or XLR). Then output signal to drive the headphone, including bias voltage (to charge the diaphragm).2. Energizer / Transformer.
Like the Stax SRD-7, SRD-7 Pro, SRD-7 MK2, ... and aftermarket energizers like the Illusion ESC-1001.
They are just a transformer box, not a complete amplifier. They accept speaker level input, feed from a regular speaker amplifier. Then output signal to drive the headphone, including bias voltage. The bias voltage can be powered by the mains (most common), or drawn from the input signal (SB unit, which are less common).
Some related info:
* The Stax amplifiers (at least the newer one) are limited to the mains voltage in the country it Were originally sold in. Japan = 100v, US = 110v, Europe = 230v, ...
They also cut away unused cables on the trafos, making it hard to alter the voltage. All this to protect their international distributors.
* The Stax energizers accept any mains voltage, regardless if its 100, 110 or 230v.
Stax headphones operate using two (or actually three) different bias voltages.
- Pro bias (5 pin connector) -> 580 volts. All phones since ~1990 have Pro bias.
- Normal bias (6 pin connector) -> 230 (or 200) volts. Most phones prior to 1990 had Normal bias (230v), while the "really" old ones had 200v.
Pro bias headphones can
run on Normal bias amplifiers/energizers, but not the other way around.
Hope that answered some questions.